JP2018004990A - Mems display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance display mounted with an electromechanical optical modulator and a backlight which are efficient and inexpensive.SOLUTION: An MEMS (Micro Electro Mechanical System) display comprises: a first and a second actuators; and a shutter which has a first and a second edge sections. The shutter is supported above a surface by a plurality of support sections fixed to the first and the second edge sections. The support sections fixed to the first and the second edge sections are inclined with respect to each other and to the surface.SELECTED DRAWING: Figure 15A

Description

  The relevant US patent documents are: US patent application Ser. No. 12 / 58,465 filed on Sep. 3, 2009 and became US Pat. No. 7,995,261; US patent application Ser. No. 14 / 589,699 filed Jan. 5, 2015, Jan. 2015 U.S. Patent Application No. 14/589634 filed on May 5, U.S. Patent Application No. 14/589434 filed on Jan. 5, 2015, U.S. Patent Application No. 14/58 filed on Jan. 5, 2015. 589551, US patent application Ser. No. 14 / 589,715, filed Jan. 5, 2015, which is incorporated herein by reference.

  The present invention relates generally to displays. More specifically, the present invention relates to a display that includes an electromechanical imaging element.

  Currently, liquid crystal displays are dominant in the flat panel display market.

  Displays based on electromechanical light modulators have been proposed as a viable alternative to LCDs. The present invention discloses electromechanical light modulators and displays that can compete with LCDs in terms of image performance, light efficiency and cost.

  The following is a general description of an exemplary embodiment of the present invention. This is not intended to limit the scope of the claims appended hereto in any way so that those skilled in the art can more fully understand the present invention. It is provided as an introduction to facilitate a quicker understanding of the detailed design discussion described.

  This specification discloses several electromechanical light modulators. According to an exemplary embodiment of the present invention, the modulator comprises a surface of the substrate by one or two electrostatic actuators and a plurality of supports attached to the shutter at the first and second ends of the shutter. An optical shutter supported above. In operation, the actuator applies a force to the shutter. The shutter support limits the movement of the shutter in the direction of the force and allows the shutter to move substantially transverse to the force. The shutter moves laterally between the first position and the second position without physically contacting the stationary part or the surface. Each electrostatic actuator includes two electrodes that are substantially parallel and located at a distance close to each other. In some embodiments, the shutter is electrically conductive and acts as one of the actuator electrodes. In other designs, the shutter includes a flange that extends vertically from the edge of the shutter to form an electrostatic actuator with a fixed electrode. The fixed electrode can be placed substantially in close proximity to the flange to form an efficient electrostatic actuator.

  The shutter support is arranged between the shutter and the surface, so in the display, the shutters are arranged substantially close to each other, only allowing space for the shutter movement between them. sell. In some modulators, the shutter is supported on the surface by a cantilever beam. The present invention discloses a method of manufacturing a cantilever and a shutter supported by the cantilever. The present invention also provides a light absorption layer having a light transmission region, a backlight including a back reflector for reflecting light toward the light absorption layer, and a shutter disposed between the backlight and the light absorption layer. A display comprising a plurality of modulators, each comprising a light transmissive region and a light reflective surface for reusing light emitted from the backlight facing the backlight. The light incident on the light transmission region of the shutter from the backlight is transmitted through the light transmission region of the light absorption layer when the shutter is in the first position and is absorbed when the shutter is in the second position. Absorbed into the layer.

  The present invention also discloses another display including a plurality of modulators each including a shutter having a light transmissive region and a substrate having a surface and a plurality of embedded reflectors, wherein the light is transmitted to the substrate. Escapes from the surface to the outside of the substrate and is focused on each light transmission region of the shutter.

  The foregoing and other objects of the invention are shown in the accompanying drawings and described in the following specification.

FIG. 3 is a perspective view of a shutter assembly, according to an exemplary embodiment herein. 1B is a front view of the shutter assembly shown in FIG. 1A. FIG. FIG. 1B is a top view of an exemplary mold for manufacturing the shutter assembly shown in FIG. 1A. It is sectional drawing along the straight line 2B of FIG. 2A. 1 is a perspective view of a light modulator, according to an illustrative embodiment of the invention. FIG. 3B is a front view of the optical modulator shown in FIG. 3A. FIG. FIG. 3B is a front view of the light modulator shown in FIG. 3A showing the shutter in a first position. FIG. 3B is a front view of the light modulator shown in FIG. 3A showing the shutter in a second position. 1 is a perspective view of a light modulator according to an exemplary embodiment of the present invention. FIG. FIG. 4B is a front view of the optical modulator shown in FIG. 4A. 1 is a perspective view of a light modulator according to an exemplary embodiment of the present invention. FIG. FIG. 5B is a front view of the optical modulator shown in FIG. 5A. 1 is a perspective view of a light modulator according to an exemplary embodiment of the present invention. FIG. FIG. 6B is a side view of the optical modulator shown in FIG. 6A. FIG. 6B is a perspective view showing a shutter support portion of the optical modulator shown in FIG. 6A. FIG. 6B is a top view of the optical modulator shown in FIG. 6A. FIG. 6B is a top view of the light modulator shown in FIG. 6A showing the shutter located in the first position. FIG. 6B is a top view of the light modulator shown in FIG. 6A showing the shutter located in the second position. 1 is a top view of an optical modulator according to an exemplary embodiment of the present invention. FIG. FIG. 7B is a side view of the optical modulator shown in FIG. 7A. It is a top view which shows the shutter support part of the optical modulator shown by FIG. 7A. FIG. 7B is a top view of the light modulator shown in FIG. 7A showing the shutter located in the first position. FIG. 6 is a perspective view of a shutter support according to an exemplary embodiment of the present invention. It is a perspective view of the mold for manufacturing the shutter support part shown by FIG. 8A. FIG. 8B is a cross-sectional view taken along line CC of FIG. 8B showing the steps for manufacturing the shutter support shown in FIG. 8A. It is a top view which shows the step for manufacturing the shutter support part shown by FIG. 8A. FIG. 8B is a front view showing the steps for manufacturing the shutter support shown in FIG. 8A. FIG. 8B is a front view showing the steps for manufacturing the shutter support shown in FIG. 8A. It is a top view which shows the step for manufacturing the shutter support part shown by FIG. 8A. FIG. 8B is a side view showing the steps for manufacturing the shutter support shown in FIG. 8A. FIG. 3 is a perspective view of a shutter according to an exemplary embodiment of the present invention. FIG. 9B is a perspective view of a mold for manufacturing the shutter shown in FIG. 9A. FIG. 9B is a cross-sectional view taken along line CC of FIG. 9B, showing a stage of manufacturing the shutter shown in FIG. 9A. It is a perspective view which shows the step which manufactures the shutter shown by FIG. 9A. FIG. 9B is a cross-sectional view taken along line EE of FIG. 9D, showing a stage of manufacturing the shutter shown in FIG. 9A. FIG. 9B is a cross-sectional view taken along line FF of FIG. 9D, showing a stage of manufacturing the shutter shown in FIG. 9A. 1 is a perspective view of a display backlight according to an exemplary embodiment of the present invention. FIG. 10B is a side view of the display backlight shown in FIG. 10A. FIG. 10B is an enlarged view of a region indicated by 10C in FIG. 10B. FIG. 6 is a cross-sectional view illustrating steps for manufacturing an optical layer having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing an optical layer having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing an optical layer having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing an optical layer having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing a substrate having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing a substrate having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating steps for manufacturing a substrate having an embedded light reflector, in accordance with an exemplary embodiment of the present invention. FIG. 3 is a plan view of a display cover assembly according to an exemplary embodiment of the present invention. It is sectional drawing along the straight line 13B in FIG. 13A. FIG. 3 is a cross-sectional view of a display according to an exemplary embodiment of the present invention showing a shutter located in a first position. FIG. 14B is a cross-sectional view of the display shown in FIG. 14A showing a shutter located in a second position. FIG. 3 is a cross-sectional view of a display according to an exemplary embodiment of the present invention showing a shutter located in a first position. FIG. 15B is a cross-sectional view of the display shown in FIG. 15A showing the shutter located in a second position.

  FIG. 1A is a perspective view and FIG. 1B is a front view of a shutter assembly 100 according to an exemplary embodiment of the present invention. The shutter assembly 100 includes an optical shutter 101 supported above the surface 103 of the transparent substrate 102 by support portions 104 and 105. The support portion 104 is attached to the first end portion 106 of the shutter 101, and the support portion 105 is attached to the second end portion 107 of the shutter 101. The supports 104 and 105 are substantially straight and are inclined with respect to each other and with respect to the surface 103 and form an angle 113 with respect to the surface 103 of 70 ° to 85 °. The support portions 104 and 105 are attached to the surface 103 of the substrate 102 by a pad 109 at a distance 114 larger than the distance 115 between the attachment points of the support portions 104 and 105 of the shutter 101. The shutter assembly 100 may be constructed with supports 104 and 105 inclined relative to each other and may be attached to the surface 103 at a distance 114 that is less than the distance 115. Supports 104 and 105 and pad 109 are formed from a thin film conductive material and provide electrical connection from surface 103 to shutter 101. The shutter 101 is also formed from a multilayer film including a thin film conductive material or a conductive layer. The shutter 101 includes a light transmission area 108 and a light blocking area or light blocking area 110. The light blocking area 110 is larger (wider and longer) than the light transmitting area 108. The light transmission region 108 transmits 90% or more of the light incident on the light transmission region 108, and the light blocking region 110 blocks at least 99% of the light.

  The outer edge or all edges of the shutter 101 are inclined so that the shutter 101 does not bend. The shutter assembly 100 can be fabricated on a mold from a metal such as aluminum or a silicon alloy. In one implementation, all surfaces of the shutter 101 can have a light absorbing finish. In other implementations, the shutter 101 can have a light-reflective first surface 120 and a light-absorbing second surface 121. The light reflective surface 120 reflects 80% or more of the light, and the light absorbing surface 121 absorbs 80% or more of the light.

  By forming an aluminum layer on the smooth surface of the mold, a shutter 101 having a mirror-like first surface 120 is provided, and a black oxide layer is formed on the second surface 121 by anodic oxidation. Can be formed. The black oxide layer may be formed after the light transmission region 108 is etched. Therefore, the inner edge of the light transmission region 108 is covered with the black oxide layer.

  Chromium oxide or niobium oxide may be deposited, or a black organic resin may be applied to the surface of the shutter 101 to form a light absorbing surface.

  Without limitation, a portion of the shutter assembly 100 may have the following dimensions. The shutter 101 may have a width 115 of 50 to 1000 micrometers and a thickness of 0.5 to 5 micrometers. The light transmissive region 108 may have a width 122 of 2 to 50 micrometers. Supports 104 and 105 may have a width of 2 to 20 micrometers and a thickness of 0.5 to 5 micrometers. The support portions 104 and 105 may have a length 112 that is 1.5 to 3 times larger than the width 122 of the light transmission region 108.

  2A and 2B show a mold 200 for manufacturing the shutter assembly 100. 2A is a top view of the mold 200, and FIG. 2B is a cross-sectional view taken along the line 2B in FIG. 2A.

  The mold 200 is formed on the surface 103 of the substrate 102 using gray scale mask photolithography or multiple mask photolithography. A layer of sacrificial material 201 is deposited on the surface 103. The groove 203 and the recessed area 206 are formed on the surface 205 of the layer 201. The shutter assembly 100 is formed by depositing and selectively etching a thin layer of a conductive thin film on the surface of the mold 200. The support portions 104 and 105 are formed on the side wall 204 of the groove 203. The side wall 204 has the same inclination angle 113 as the support portions 104 and 105 with respect to the surface 103. The recessed area 206 is provided to form the shutter 101 having an inclined edge. The beveled edge helps to prevent the shutter 101 from bending or bending. A combination of directional film formation and shape following film formation of the conductive material can be used to control the relative thicknesses of the support portions 104 and 105 and the shutter 101.

  3A through 3D illustrate an optical modulator 300 according to an exemplary embodiment of the present invention.

  Referring to FIGS. 3A and 3B, the modulator 300 includes the shutter assembly 100 and the cover assembly 303 of FIG. 1A. Cover assembly 303 includes a transparent substrate 304 supported above surface 103 of substrate 102 by spacers 306 and 307. Two electrodes 308 and 309 are formed on the inner surface 305 of the substrate 304.

  The electrode 308 and the conductive shutter 101 form a first electrostatic actuator 311 and an electrode 309, and the conductive shutter 101 forms a second electrostatic actuator 312. In operation, the voltage potential applied between the electrode 308 and the shutter 101 pulls the support 104 attached to the first end 106 of the shutter 101 closer to a position that is closer to the surface 103, An electrostatic force (FIG. 3C) that moves the shutter 101 laterally (FIG. 3C) to the first position is generated, or the voltage potential applied between the electrode 309 and the shutter 101 is the second potential of the shutter 101. The electrostatic force (FIG. 3D) for pulling the support portion 105 attached to the end portion 107 to a position nearer to the surface 103 and moving the shutter 101 laterally (FIG. 3D) to the second position. generate.

  The mechanical force accumulated in the supports 104 and 105 pulls the shutter 101 back from the first position or the second position to the mechanical stable position or the neutral position, as shown in FIG. 3B.

  In the modulator 300, the first actuator 311 and the second actuator 312 respectively apply force to the shutter 101 in substantially the same direction, and move the shutter 101 in the lateral direction in the opposite direction.

  In FIG. 3C, an arrow 314 indicates the direction of the force applied to the shutter 101 by the first actuator 311, and an arrow 315 indicates the direction of the lateral movement of the shutter 101 from the mechanically stable position to the first position. Indicates. The shutter 101 moves from the mechanically stable position to the first position in the lateral direction at least five times that in the direction of the force applied to the shutter 101 by the first actuator 311.

  In FIG. 3D, an arrow 316 indicates the direction of the force applied to the shutter 101 by the second actuator 312, and an arrow 317 indicates the direction of the lateral movement of the shutter 101 to the second position.

  When a gradually increasing voltage is applied to the actuator 311 and a gradually decreasing voltage is applied to the actuator 312, the shutter gradually moves between the first position and the second position, and a fixed voltage is applied to the actuator 311. Even when the variable voltage is applied to the actuator 312, the shutter gradually moves between the first position and the second position.

  In the display, the electrodes 308 and 309 may be shared by multiple shutter assemblies that are formed wider and located in consecutive rows or columns.

  4A and 4B illustrate an optical modulator 400 according to an exemplary embodiment of the present invention. The modulator 400 includes a shutter assembly 401 and a cover assembly 418. The shutter assembly 401 includes a shutter 410 supported above the surface 403 of the transparent substrate 402 by support portions 406 and 407. The support portion 407 is attached to the first end portion 408 of the shutter 410, and the support portion 406 is attached to the second end portion 409 of the shutter 410. The shutter 410 is made of an electrical insulator or dielectric material, and includes a light transmission region 411 and a light blocking region 412. The shutter 410 further includes a first electrode 405 and a second electrode 404. Support 407 provides an electrical connection from surface 403 to electrode 405, and support 406 provides an electrical connection from surface 403 to electrode 404.

  Cover assembly 418 includes a transparent substrate 413 supported above surface 403 by spacers 416 and 417. The cover assembly 418 further includes a transparent conductive layer 415 formed on the inner surface 414 of the substrate 413 from a material such as indium tin oxide.

  In the modulator 400, the first electrode 405 having the conductive layer 415 forms the first electrostatic actuator 418, and the second electrode 404 having the conductive layer 415 forms the second electrostatic actuator 419. .

  In operation, the first actuator pulls the support 407 to a position near perpendicular to the surface 403 to move the shutter 410 laterally to the first position, and the second actuator moves the support 406 Pulling to a position near the surface 403 perpendicular to the surface 403, the shutter 410 is moved laterally to the second position. The mechanical force accumulated in the supports 406 and 407 pulls the shutter 410 back from the first position or the second position to the mechanical stable position or the neutral position, as shown in FIG. 4B.

  5A and 5B show an optical modulator 500 according to an exemplary embodiment of the present invention. Modulator 500 includes spacers 508 and 509 and a shutter assembly 503 formed from a polymer on surface 502 of substrate 501. The shutter assembly 503 includes a shutter 507 and shutter supports 505 and 506 formed from a conductive material and attached to spacers 508 and 509 with conductive pads 512 and 513.

  The modulator 500 further includes two electrodes 510 and 511 formed on the surface 502 of the substrate 501. The electrode 510 and the conductive shutter 507 form a first electrostatic actuator 514, and the electrode 511 and the conductive shutter 507 form a second electrostatic actuator 515.

  The shutter assembly 503 may be formed similarly to the shutter assembly 401, and the two electrodes 510 and 511 can be replaced with a transparent conductive layer.

  6A through 6F show an optical modulator 600 according to an exemplary embodiment of the present invention. 6A to 6C, the modulator 600 includes an optical shutter 601 formed of a conductive material, and includes a light transmission region 602 and a light blocking region 603.

  The shutter 601 is supported on the surface 605 of the substrate 604 by four cantilevers 606 and 607 formed between the shutter 601 and the surface 605 and substantially within the boundary of the shutter 601. (FIG. 6C). The first end of each cantilever 606 and 607 is attached to the surface 605 with a post 609 and a conductive pad 610 and the second end is attached to the shutter 601 with a post 608. Cantilever 606 is attached at first end 618 of shutter 601 and cantilever 607 is attached at second end 617 of shutter 601. Beams 606 and 607 are disposed substantially parallel to surface 605 and are spaced from surface 605 by first gap 619. The beams 606 and 607 are also disposed substantially parallel to the shutter 601 and are spaced from the shutter 601 by a second gap 620. The cantilevers 606 and 607 may be formed thin and long so that they can be bent and deformed without requiring a large force. The beams 606 and 607 may also be formed to have a sufficient height oriented perpendicular to the surface 605 to support the weight of the shutter 601.

  The shutter 601 further includes a first flange 613 extending from the first end or edge 618 of the shutter 601 toward the surface 605 within 5 ° from the normal to the surface 605. The shutter 601 also includes a second flange 615 extending from the second edge 617 toward the surface 605 and within 5 ° of the normal to the surface 605.

  Beams 606 and 607 are tilted with respect to surface 629 of flange 613 to form an angle 628 between 70 and 89 ° (FIG. 6D).

  Modulator 600 further includes two electrodes 614 and 616 extending from surface 605 in a direction near normal. Electrode 614 is attached to surface 605 with conductive pad 611, and electrode 616 is attached to surface 605 with conductive pad 612. The electrode 614 and the flange 613 form a first electrostatic actuator 622, and the electrode 616 and the flange 615 form a second electrostatic actuator 621.

  In operation, the actuator 622 applies a first force 625 to the shutter 601, pulls the beam 606 attached to the first end 618 of the shutter 601, and causes the shutter 601 to be substantially against the first force 625. Thus, the actuator 621 applies a second force 627 to the shutter 601 and moves to the first position in the lateral direction 626 (FIG. 6E), and the beam 607 attached to the second end 617 of the shutter 601. To move the shutter 601 to a second position, substantially laterally 628 to the second force 627 (FIG. 6F). The shutter 601 moves in the lateral direction 626 at least five times greater than that in the direction of the first force 625.

  The mechanical force accumulated in beams 606 and 607 pulls shutter 601 back from the first or second position to the mechanically stable or neutral position, as shown in FIG. 6D. The shutter 601 moves between a first position and a second position in a plane substantially parallel to the surface 605.

  When the shutter 601 moves from the mechanical stable position (FIG. 6D) to the first position (FIG. 6E), the linear distance between the posts 608 and 609 attached to the end of the beam 607 increases. As such, the beam 607 is formed in a slightly curvilinear shape to compensate for the increase in linear distance between the posts 608 and 609.

  7A-7D illustrate an optical modulator 700 according to an exemplary embodiment of the present invention. The modulator 700 includes an optical shutter 701 formed from a conductive material, and includes a light transmission region 702 and a light blocking region 703. The shutter 701 further includes a first flange 708 attached to the shutter 701 at a first end 706. The shutter 701 is supported on the surface 704 of the substrate 705 by four cantilevers 712 and 714 (FIG. 7C).

  The first end of each cantilever 712 and 714 is attached to the surface 704 with a post 716 and a conductive pad 717, and the second end is attached to the shutter 701 with a post 715. Cantilever 714 is attached at first end 706 of shutter 701 and cantilever 712 is attached at second end 707 of shutter 701. Cantilever beams 712 and 714 are substantially straight. The cantilever 714 is tilted with respect to the flange 708 and forms an angle 730 between 70 ° and 89 °, and the cantilever 712 forms an angle 731 close to 90 ° with respect to the flange 708.

  The modulator 700 further includes an electrode 709 extending vertically from the surface 704 and attached to the surface 704 with a conductive pad 710. The electrode 709 and the flange 708 of the shutter 701 form an electrostatic actuator 711.

  In operation, the actuator 711 pulls the beam 714 attached at the first end 706 of the shutter 701 in the direction 720 and moves the shutter 701 substantially transversely 721 to the direction 720 to the first position. Move (FIG. 7D). The mechanical force accumulated in the beams 712 and 714 pulls the shutter 701 back from the first position to the mechanically stable or neutral position (FIG. 7A). The shutter 701 moves between a plurality of positions in a plane substantially parallel to the surface 704.

  The modulator 700 further includes a second flange 722 attached to the shutter 701 at the second end 707 and a second flange extending vertically from the plane 704 and attached to the surface 704 with a conductive pad 724. A second electrostatic actuator 725 formed by the electrode 723 may be included. In the modulator 700, the support 712 restricts the shutter 701 and the second flange 722 from moving closer to the second electrode 723, so that the second electrode 723 is efficient. It may be placed at a close distance from the second flange 722 to form an actuator.

  In the display, a pixel addressing voltage can be applied to the second actuator 725 to selectively hold the shutter 701 in a mechanical neutral position.

  FIGS. 8A through 8F illustrate a manufacturing stage for a shutter support 800 according to an exemplary embodiment of the present invention, similar to the support in modulators 600 and 700. FIG. FIG. 8A shows a shutter support 800 that includes a cantilever 803. The first end of the beam 803 is attached to a first post 804 that connects the beam 803 to the surface 801 of the substrate 802 with a pad 805, and the second end of the beam 803 is connected to the shutter later on to the shutter. 2 post 806. The first post 804 and the second post 806 each have three sides and a top.

  The support unit 800 is formed on the mold 807. The first manufacturing step is a step of forming a mold 807 from a sacrificial material on the surface 801 of the substrate 802 (FIG. 8B). The mold 807 is formed to have a rectangular parallelepiped shape, and has four side walls 808, 809, 810, and 811 and a top portion 812. The sidewalls are oriented perpendicular to the surface 801 within a range of +/− 5 ° with respect to the normal. The next step is to form a shape following layer of the conductive material 814 on the surface of the mold 807 and the surface 801 by magnetron sputtering, and to form a positive photoresist 815 on the conductive layer 814 by electrophoretic film formation or spraying. This is the step of applying the shape following layer (FIG. 8C).

  The next step is to place a first photomask 816 over the mold 807 (FIG. 8D) and place the photoresist layer 815 at 45 ° from the direction of the sidewalls 808 and 809 relative to the surface 801 with a deviation of less than 2 degrees. Illuminating with a UV light source having a collimated and tilted light beam with a tilt angle 817 between 1 and 75 ° (FIGS. 8E and 8F). The mold 807 and the first photomask 816 emit UV light from regions on the photoresist layer 815 that define the geometric shapes of the cantilever 803, the first post 804, the second post 806, and the pad 805. Cut off. A further step is a step of placing a second photomask 818 above the mold 807 (FIG. 8G) and irradiating the photoresist layer 815 from the direction of the side wall 811 (FIG. 8J). This irradiates the photoresist layer 815 applied to the lower part of the side wall 811. The steps shown in FIGS. 8G and 8J are omitted if the second post 806 is formed with only two sides formed on the sidewalls 808 and 809 of the mold 807 and on top. Can be done.

  After irradiation from all three directions, the photoresist layer 815 is developed and the unprotected areas of the conductive layer 814 are removed by etching. The cantilever 803 formed on the mold 807 has a width equal to the thickness of the conductive layer 814.

  If the conductive layer 814 is formed from a material such as aluminum that can reflect UV light, a light absorbing layer is applied over the conductive layer 814 prior to applying the photoresist layer 815, or It may be formed. This will reduce the reflection of UV light from the horizontal and vertical surfaces. To reduce reflection from the surface of the photoresist layer 815, the mold and mask can be immersed in a liquid having a refractive index similar to that of the photoresist layer 815.

  FIGS. 9A through 9F illustrate the manufacturing stages of shutter 900 and electrode 905 according to an exemplary embodiment of the present invention similar to modulators 600 and 700.

  FIG. 9A shows a shutter 900 including a light transmission region 901 and a flange 902. The shutter 900 is connected to the post 806 of the support unit 800 described above. FIG. 9A further shows an electrode 905 attached to the surface 801 of the substrate 802 with a pad 904.

  The first manufacturing stage is a stage in which a mold 910 including two rectangular parallelepipeds 911 and 912 is formed from a sacrificial material on the surface 801 of the substrate 802 (FIG. 9B). The rectangular parallelepiped 911 includes four side walls 914, 915, 916, 917 and a top 918. The rectangular parallelepiped 912 includes four side walls 920, 921, 923, 924 and a top 925. The sidewalls are oriented perpendicular to the surface 801 within a range of +/− 5 ° from the normal. A via hole 926 for connecting the shutter 900 to the post 806 of the support unit 800 is formed on the top 918 of the rectangular parallelepiped 911.

  The next step is to form a shape following layer of the conductive material 930 on the surface of the mold 910 and the surface 801 and to form a shape following layer of the negative photoresist 931 on the conductive layer 930. Yes (FIG. 9C).

  The subsequent step is to place a photomask 932 over the mold 910 (FIG. 9D) and irradiate the photoresist layer 931 from the direction of the side walls 916 and 924 with a UV light source having collimated and tilted light rays. (FIGS. 9E and 9F).

  The mask 932 blocks UV light irradiation of the photoresist layer 931 applied to the surface of the side walls 915, 916, 917, 920 and 923 where the light transmission region 901 of the shutter 900 is formed and the region of the top surface 918. The mold blocks the lower portion of the surface of the sidewalls 914 and 921 where the flange 902 and the electrode 905 are formed and the portion of the surface 801 between the sidewalls 914 and 921.

  After irradiating from both directions, the photoresist layer 931 is developed and the unprotected areas of the conductive layer 930 are etched.

  The next step is to remove the sacrificial layer and release the shutter 900 and the support portion 800.

  The shutter 900 may be formed to include a flange, such as a flange 902, on all four edges of the shutter 900. These flanges can effectively block stray light exiting the display, thereby improving contrast.

  10A, 10B, and 10C illustrate a display backlight 1000 according to an exemplary embodiment of the present invention. 10A is a perspective view of the backlight 1000, FIG. 10B is a side view of the backlight 1000, and FIG. 10C is an enlarged view of a region indicated as 10C in FIG. 10B.

  The backlight 1000 generally includes a flat light guide 1001 formed from acrylic or other transparent material having a refractive index n1 between 1.45 and 1.6. The light guide 1001 includes a top surface 1002, a bottom surface 1003, opposing side surfaces 1004 and 1005, and a light input end 1006.

  The bottom surface 1003 is inclined with respect to the top surface 1002 and forms an angle 1009 having a value between about 0.1 and 2.0 degrees (FIG. 10B). The bottom plane 1003 converges the top surface 1002 in a direction away from the light input end 1006.

  The backlight 1000 further includes a light absorbing film 1010 disposed in the vicinity of the plurality of light sources 1011 disposed in the vicinity of the bottom surface 1003 of the light guide 1001 and the light input end 1006.

  The backlight 1000 also includes a first optical layer 1015 formed from a substantially transparent material having a refractive index n2 that is a value of about 1.45 to 1.6. The first optical layer 1015 includes a light escape surface 1016, a light input surface 1017, and a plurality of embedded light reflectors 1018 disposed between the light input surface 1017 and the light escape surface 1016. The light reflector 1018 is formed from a thin light reflective material such as aluminum or silver. The light reflector 1018 may have a substantially flat surface or a curved surface with a cross section having a radius of curvature of about 20 to 80 microns. The light reflector 1018 is inclined with respect to the top surface 1002 of the light guide 1001 and forms an angle 1026 having a value of about 20 to 40 degrees.

  The backlight 1000 also includes a second optical layer 1020 formed between the light input surface 1017 of the first optical layer 1015 and the top surface 1002 of the light guide 1001. The second optical layer 1020 is formed from a fluorinated polymer or other substantially transparent material having a refractive index n3 that is between about 1.3 and 1.4.

  In operation, light beam 1023 entering from light input end 1006 of light guide 1001 reflects from top surface 1002 and bottom surface 1003 and changes its angle in a direction perpendicular to top surface 1002. If the angle of incidence with respect to the top surface 1002 is smaller than the critical angle 1024 (FIG. 10C) defined by the refractive index n1 of the light guide 1001 and the refractive index n3 of the second optical layer 1020, the light beam 1023 is reflected by the light guide 1001. Exit. The light beam 1023 that has passed through the second optical layer 1020 enters the first optical layer 1015 from the light input surface 1017 and changes the angle defined by the refractive index n2 of the first optical layer 1015. Most of the light rays 1023 entering the first optical layer 1015 are reflected inward from the light escape surface 1016. Light rays exit the first optical layer 1015 from the light escape surface 1016 by being reflected from the embedded light reflector 1018. Light rays reflected from the bent light reflector 1018 exit the first optical layer 1015 from the light escape surface 1016 and converge at a distance 1025 from the light escape surface 1016.

  The backlight 1000 may also include a transparent substrate such as a glass substrate and a dichroic filter layer interposed between the first optical layer 1015 and the second optical layer 1020.

  The stages of fabrication of the optical layer 1108 having an embedded light reflector or light reflecting facet 1106 are shown in FIGS. 11A-11D. In step (A), microprisms 1101 are formed on substrate 1103 using photolithography from a transparent UV curable liquid polymer. In step (B), the substrate 1103 is tilted by an angle 1105 (FIG. 11B), and the extension 1104 of the microprism 1101 is formed from the same liquid polymer. The microprism 1101 having the extension 1104 may also be formed by a mold. In step (C), a reflector film is deposited on each facet of the extension 1104 to form a light reflecting facet 1106. In step (D), the groove 1107 is filled with the same UV curable liquid polymer. FIG. 11D shows the completed formation of the optical layer 1108 with embedded light reflecting facets 1106.

  The optical layer 1108 may be combined with the shutter assembly 100 or 401 of the modulators 300 and 400 described above. The optical layer 1108 may be formed on a substrate disposed between the shutter supports prior to forming the shutter assembly 100 or 401. For modulators 500, 600 or 700 having shutters located at close distances from the substrate surface, the embedded light modulator may be formed in the substrate.

  12A, 12B, and 12C illustrate the steps of manufacturing a glass substrate 1200 having an embedded light reflector 1205 in accordance with an exemplary embodiment of the present invention. The first step is a step of etching the groove 1203 in the glass substrate 1200. The next three stages are similar to stages B, C and D described above. The second step is to tilt the substrate 1200 to form extensions 1204 from the UV curable liquid polymer inside each groove. The third stage is a stage in which a reflecting mirror film is formed on the extension 1204 to form a light reflecting facet 1205. The fourth stage is to fill the groove with the same UV curable liquid polymer. FIG. 12C shows a glass substrate 1200 formed with an embedded light reflector 1205. The cured polymer preferably has substantially the same refractive index as the glass substrate 1200. In the backlight 1000, the first optical layer 1015 may be replaced with a glass substrate 1200, and the modulator 500, 600, or 700 may be formed on the glass substrate 1200.

  13A and 13B show a display cover assembly 1400 according to an exemplary embodiment of the present invention. Cover assembly 1400 includes a transparent substrate 1401 having a first surface 1402 and a second surface 1403. Cover assembly 1400 also includes a light diffusing layer 1404 formed on first surface 1402 and a light absorbing layer 1405 formed on light diffusing layer 1404. For thin substrates having a thickness of 200 micrometers or less, the diffusion layer 1404 may be formed on the second or outer surface 1403 and the light absorbing layer 1405 is formed on the inner surface 1402 of the substrate 1401. May be. The light absorption layer 1405 includes a light transmission region 1407 and an opaque light absorption region 1406. Cover assembly 1400 further includes electrodes 300 and 309 of modulator 300 formed on opaque light-absorbing region 1406 of light-absorbing layer 1405 having a light-reflective mirror or a transparent conductive layer such as electrode 415 of modulator 400. An electrode may be further included.

  The light absorption layer 1405 may be formed of a conductive material. The conductive light absorbing layer 1405 may serve as an electrode for an actuator such as an EMI or electrostatic shield of the display or an actuator of the modulator 400.

  The light absorption layer 1405 may absorb 80% or more of light incident on the opaque light absorption region 1406 and transmit less than 1% of light.

  A display based on an electromechanical light modulator may include a number of modulators arranged in rows and columns. Each image element or pixel in the display may include one or more modulators. For illustrative purposes, the following figures show a display with only one modulator.

  14A and 14B show a cross-sectional view of a display 1500 according to an exemplary embodiment of the present invention. Display 1500 includes a cover assembly 1501, a modulator 1502, and a backlight 1503 that includes a back reflector 1504. The cover assembly 1501 includes a transparent substrate 1505, a light diffusion layer 1506 formed on the first surface 1507 of the substrate 1505, and a light absorption layer 1508 formed on the light diffusion layer 1506. The light absorption layer 1508 includes a light transmission region 1509 and an opaque light absorption region 1510. The modulator 1502 includes a shutter 1511 having a light transmission region 1514 and a light blocking region 1515. The surface of the shutter 1511 facing the backlight 1503 is a light reflecting surface, and the surface facing the light absorbing layer 1508 is a light absorbing surface. The light transmission region 1509 of the light absorption layer 1508 is larger than the light transmission region 1514 of the shutter 1511 and smaller than the light blocking region 1515 of the shutter 1511. In FIG. 14A, the shutter 1511 is in the first position or the ON position, and in FIG. 14B, the shutter 1511 is in the second position or the OFF position. The light 1520 from the backlight 1503 incident on the light transmission region 1514 of the shutter 1511 passes through the light transmission region 1509 of the light absorption layer 1508 when the shutter 1511 is in the first position (FIG. 14A). When it is at position 2 (FIG. 14B), it is absorbed by the light absorption layer 1508. Light incident on the light blocking area 1515 of the shutter 1511 is reflected back toward the backlight 1503 and recirculated by being reflected from the back reflector 1504. The modulator 1502 may be any of the modulators described above, or a shutter having a light reflective surface facing the backlight 1503 to recirculate the light emitted from the backlight 1503. It may be a modulator including.

  It is important to design the modulator so that the shutter support does not occupy a substantially larger display surface than is required by the shutter, so that the shutter will have some movement between them and some degree between them. They can be arranged substantially close to each other to allow only space for the conductors.

  The shutter assembly described above meets this requirement. In the shutter assembly disclosed above, as compared to some prior art shutter assemblies where the shutter support is located on the side of the shutter and occupies more than 50% of the display surface, the shutter support is a shutter; It is disposed between the surface on which the shutter is supported and is substantially disposed within a shutter boundary that substantially includes movement of the shutter between the first position and the second position.

  This improves the light efficiency by increasing the total light transmission area relative to the display surface and reduces the gap between the rows and columns of the display.

  In the display 1500, the light absorption layer 1508 may be formed of a conductive material and can replace the electrode 415 in the modulator 400 described above.

  The electrodes 308 and 309 of the modulator 300 may be formed on a light absorbing layer 1508 having a light reflective surface facing the backlight 1503, and the shutter 101 may be supported on the surface 1522 of the substrate 1521. Good. The shutter 601 of the modulator 600 and the shutter 701 of the modulator 700 may also be supported on the surface 1522 of the substrate 1521. The spacers 508 and 509 of the modulator 500 may be formed on the light absorption layer 1508, and the shutter 503 may be suspended from the spacers 508 and 509.

  In the display 1500, the backlight 1503 emits surface light and may be edge illumination or direct illumination backlight known for LCD displays.

  15A and 15B show a cross-sectional view of a display 1700 according to an exemplary embodiment of the present invention. Display 1700 includes a cover assembly 1701, a modulator 1702, and a backlight 1703. The cover assembly 1701 includes a transparent substrate 1705, a light diffusion layer 1706 formed on the first surface 1707 of the substrate 1705, and a light absorption layer 1708 formed on the light diffusion layer 1706. The light absorption layer 1708 includes a light transmission region 1709 and a light absorption region 1710. The modulator 1702 includes a shutter 1711 having a light transmission region 1714 and a light blocking region 1715. The surface of the shutter 1711 facing the backlight 1703 may be a light reflecting surface or a light absorbing surface, and the surface facing the light absorbing layer 1708 is a light absorbing surface. The light transmission region 1709 of the light absorption layer 1708 is larger than the light transmission region 1714 of the shutter 1711 and smaller than the light blocking region 1715 of the shutter 1711. The modulator 1702 further includes a substrate 1716 having a light escape surface 1721 and a buried light reflecting facet 1717. The facet 1717 is bent, and the light 1720 from the backlight 1703 escapes from the substrate 1716 and is focused by the light transmission region 1714 of the shutter 1711. The shutter 1711 is supported on the surface 1721 of the substrate 1716. The backlight 1703 includes a light guide 1719 and an optical layer 1718 located between the light guide 1719 and the substrate 1716. The backlight 1703 is similar to the backlight 1000 of FIGS. 10A-10C. The backlight 1703 further includes a light absorbing layer 1704 disposed behind the light guide 1719 to absorb stray light or light reflected from the shutter 1711.

  In FIG. 15A, the shutter 1711 is in the first position or the on position, and in FIG. 15B, the shutter 1711 is in the second position or the off position. Light 1720 emitted from the substrate 1716 passes through the light transmission region 1714 of the shutter 1711 and the light transmission region 1709 of the light absorption layer 1708 when the shutter 1711 is in the first position (FIG. 15A). When it is at position 2 (FIG. 15B), it is blocked by the light blocking area 1715 of the shutter 1711. The light reflected and returned from the light blocking area 1715 of the shutter 1711 is absorbed by the light absorption layer 1704.

  In the display 1700, the bent reflector 1717 increases the viewing angle of the display and reduces the required travel distance of the shutter 1711 between the on position and the off position compared to a flat reflector.

  The above-described display further includes spacers for maintaining an accurate distance between the substrates, row and column conductors formed on one or both substrates, and 1 for addressing the display pixels. It may include one or more thin film transistors and storage capacitors, a ground or power plane, a common interconnect for resetting display pixels, a dichroic or color filter, and an anti-reflective coating.

  The above-described display may be shown as an electromechanical display, a micromechanical display, a microelectromechanical display, or a microelectromechanical system (MEMS) display. The display described above may be a black and white display, a color display or a color sequential display.

  Having described the invention in detail as required by patent law, one of ordinary skill in the art may make changes or improvements in the individual parts or their associated assembly or manufacturing methods to meet specific requirements or conditions. There will be no difficulty. Such changes and modifications can be made without departing from the scope and spirit of the invention as set forth in the following claims.

DESCRIPTION OF SYMBOLS 100 Shutter assembly 101 Optical shutter 102 Board | substrate 103 Surface 104 Support part 105 Support part 106 1st edge part 107 2nd edge part 108 Light transmission area 109 Pad 110 Light blocking area 120 Light reflective surface 121 Light-absorbing surface 200 Mold 201 Sacrificial material 203 Groove 204 Side wall 206 Recessed area 300 Optical modulator 303 Cover assembly 304 Transparent substrate 306, 307 Spacer 308, 309 Electrode 311 First electrostatic actuator 312 Second electrostatic actuator 400 Optical modulator 401 Shutter assembly 402 Transparent substrate 403 Surface 404, 405 Electrode 406, 407 Support portion 408 First end portion 409 Second end portion 410 Shutter 411 Light transmission region 412 Light blocking region 413 Substrate 414 Inner surface 415 Transparent conductive layer 416, 417 Spacer 418 Cover assembly 500 Optical modulator 501 Substrate 502 Surface 503 Shutter assembly 505, 506 Shutter support 507 Shutter 508, 509 Spacer 510, 511 Electrode 514 First electrostatic actuator 515 Second electrostatic Actuator 600 Modulator 601 Optical shutter 602 Light transmission region 603 Light blocking region 605 Surface 606, 607 Cantilever 608, 609 Post 610, 611 Conductive pad 614 Electrode 615 Flange 616 Electrode 619 First gap 621 Second electrostatic Actuator 622 First electrostatic actuator 700 Optical modulator 701 Optical shutter 702 Light transmission area 703 Light blocking area 705 Substrate 708 Flange 709 Electrode 710 Conductive pattern 711 Electrostatic actuator 712, 714 Cantilever 715, 716 Post 717 Conductive pad 722 Second flange 723 Second electrode 724 Conductive pad 800 Shutter support 802 Substrate 803 Cantilever 804 First post 806 First Post 2 807 Mold 814 Conductive layer 815 Photoresist layer 816 First photomask 900 Shutter 901 Light transmission region 1000 Back light 1001 Light guide 1002 Top surface 1003 Bottom surface 1004, 1005 Side surface 1006 Light input end 1010 Light absorbing film 1011 Light source 1015 First optical layer 1016 Light escape surface 1017 Light input surface 1018 Light reflector 1020 Second optical layer 1023 Light beam 1024 Critical angle 1101 Microprism 1103 Base 1104 Extension 1106 Light reflection facet 1107 Groove 1108 Optical layer 1200 Glass substrate 1203 Groove 1204 Extension 1205 Embedded light reflector 1400 Cover assembly 1401 Transparent substrate 1402 First surface 1403 Second surface 1404 Light diffusion layer 1405 Light absorption layer 1406 Light absorption area 1407 Light transmission area 1500 Display 1501 Cover assembly 1502 Modulator 1503 Backlight 1504 Back reflector 1505 Transparent substrate 1506 Light diffusion layer 1507 First surface 1508 Light absorption layer 1509 Light transmission area 1510 Light absorption area 1511 Shutter 1514 Light Transmission area 1515 Light blocking area 1520 Light 1700 Display 1701 Cover assembly 1702 Modulator 1703 Backlight 1705 Transparent substrate 1706 Light diffusion layer 1707 First surface 1708 Light absorption layer 1709 Light transmission region 1710 Light absorption region 1711 Shutter 1714 Light transmission region 1715 Light blocking region 1716 Substrate 1717 Embedded light reflection facet 1718 Optical layer 1719 Light guide 1721 Light escape surface

Claims (15)

A plurality of modulators each including a shutter having a light transmission region;
A substrate having a surface and a plurality of embedded light reflectors,
A display in which light escapes the substrate from the surface of the substrate and converges in each light transmission region of the shutter by the embedded light reflector. A light absorption layer having a plurality of light transmission regions;
The display according to claim 1, wherein light transmitted through the light transmission region of the shutter is transmitted through each light transmission region of the light absorption layer. The substrate further comprises a light input surface;
The light input surface is optically coupled to a light guide via an optical layer;
The display according to claim 1, wherein the optical layer has a refractive index smaller than that of the light guide.   The display of claim 1, wherein the embedded light reflector has a curved surface having a cross-section with a radius of curvature of 20 to 80 micrometers.   The shutter has first and second ends, and is supported above the surface by a plurality of support portions attached to the first and second ends, and is disposed on the first and second ends. The display according to claim 1, wherein the attached support portions are inclined with respect to each other and with respect to the surface.   The shutter is supported above the surface by a plurality of cantilevers disposed between the shutter and the surface, and the cantilever is spaced from the shutter by a first gap. The display of claim 1, spaced from the surface by a second gap.   The shutter has first and second ends, is supported above the surface by a plurality of supports attached at the first and second ends, and is attached to the first end The display according to claim 1, wherein the support portion is substantially linear and the support portion attached to the second end is bent.   The shutter includes a flange extending from an edge of the shutter, and the shutter is disposed substantially parallel to the surface and has a plurality of support portions inclined with respect to the surface of the flange. The display of claim 1, supported above.   Each of the modulators further applies a first force to the shutter, the shutter being substantially transverse to the first force and substantially parallel to the surface of the substrate. The display of claim 1, comprising an actuator that moves in a plane.   A light absorption layer having a light transmission region; and the shutter includes a light blocking region; the light transmission region of the light absorption layer is larger than the light transmission region of the shutter; and the light blocking region of the shutter. The display of claim 1, wherein the display is smaller.   The display according to claim 1, wherein the modulator further includes first and second electrodes, respectively, and the first and second electrodes are formed on the shutter.   The display according to claim 1, further comprising a light diffusion layer and a light absorption layer formed on the light diffusion layer, wherein the light absorption layer has a light transmission region and a light blocking region.   The display according to claim 1, further comprising a backlight including a back light absorber for absorbing light reflected from the shutter.   The display of claim 1, further comprising a light absorbing layer formed from a conductive material.   A light absorbing layer formed of a conductive material; wherein the shutter includes first and second electrodes; and the first and second electrodes form an electrostatic actuator together with the conductive light absorbing layer. The display according to claim 1.

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