Source: http://www.google.com/patents/US5550680?dq=6,064,942
Timestamp: 2016-09-26 09:48:00
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Patent US5550680 - Thin film actuated mirror array having an improved optical efficiency - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn array of M�N thin film actuated mirrors for use in an optical projection system, comprises an active matrix, an array of M�N actuating structures, an array of M�N mirror layers and an array of M�N supporting members. Each of the actuating structures includes a first and a second identically structured...http://www.google.com/patents/US5550680?utm_source=gb-gplus-sharePatent US5550680 - Thin film actuated mirror array having an improved optical efficiencyAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS5550680 APublication typeGrantApplication numberUS 08/346,958Publication dateAug 27, 1996Filing dateNov 30, 1994Priority dateNov 30, 1993Fee statusLapsedAlso published asCN1050674C, CN1115856APublication number08346958, 346958, US 5550680 A, US 5550680A, US-A-5550680, US5550680 A, US5550680AInventorsDong-Seon YoonOriginal AssigneeDaewoo Electronics Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (15), Referenced by (9), Classifications (11), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetThin film actuated mirror array having an improved optical efficiency
An array of M�N thin film actuated mirrors for use in an optical projection system, comprises an active matrix, an array of M�N actuating structures, an array of M�N mirror layers and an array of M�N supporting members. Each of the actuating structures includes a first and a second identically structured actuating parts, each of the first and second actuating parts having at least a thin film layer of a motion-inducing material, a first and a second electrodes. The first electrodes from each of the first and second actuating parts are physically joined, thereby serving as the common bias electrode, and the second electrodes function as the signal electrode. Furthermore, each of the mirror layers is divided into a first and a second reflectors. Each of the reflectors is provided with a first surface, a second opposing surface and a central tab portion therebetween. The central tab portion of each reflector is directly secured on top of each actuating part such that when the central tab portion in each of the reflectors deforms in response to an electrical signal, the first and second opposing surfaces in each of the reflectors tilt while remaining planar, thereby allowing all of the first and second opposing surfaces to reflect light beams, resulting in an increased optical efficiency.
1. An array of M�N thin film actuated mirrors, wherein M and N are integers, for use in an optical projection system, comprising:a substrate; an array of M�N thin film actuating structures, each of the actuating structures including a first and a second actuating parts, the first and second actuating parts being identically structured, each of the first and second actuating parts being provided with a top, a bottom and a side surfaces, and a proximal and a distal ends, each of the first and second actuating parts having at least a thin film layer of a motion-inducing material including a top and a bottom surfaces, each of the first and second actuating parts further being provided with a first and a second electrodes with the first electrode being placed on the top surface of the motion-inducing thin film layer, and the second electrode, on the bottom surface of the motion inducing layer, the side surface from each of the actuating parts in each of the actuating structures being in physical contact with each other, the first electrode from each of the first and second actuating parts in each of the actuating structures being common to the first and second actuating parts, thereby functioning as a common bias electrode, the second electrode from each of the first and second actuating parts in each of the actuating structures functioning as a signal electrode in the corresponding actuating part, wherein an electrical signal applied across the motion-inducing thin film layer between the first and second electrodes in each actuating part causes a deformation of the motion-inducing thin film layer, and hence said each actuating part; an array of M�N supporting members, each of the supporting members being placed on top of the substrate wherein the proximal end of the actuating parts of each of the actuating structures is secured to the corresponding supporting member; and an array of M�N mirror layers, each of the mirror layers including a mirror for reflecting light beams and a supporting layer, each of the mirror layers being divided into a first and a second reflectors, the first and second reflectors being symmetric to each other, each of the reflectors being provided with a first surface, a second opposing surface and a central tab portion therebetween, the first surface and central tab portion, and the second opposing surface and central tab portion being separated by a dividing slot therebetween, wherein the central tab portion of each reflector is directly attached on top of each actuating part in each of the actuating structures such that when the central tab portion in each of the reflectors deforms in response to the electrical signal, the first and second opposing surfaces in each of the reflectors tilt while remaining planar, thereby allowing all of the first and second opposing surfaces to reflect light beams, resulting in an increased optical efficiency. 2. The thin film actuated mirror array of claim 1, wherein each of the supporting members is made of a ceramic.
The present invention relates to an optical projection system; and, more particularly, to an array of M�N thin film actuated mirrors for use in the system having an improved optical efficiency.
In FIG. 1, there is shown a cross sectional view of an array 10 of M�N thin film actuated mirrors 5 for use in an optical projection system, disclosed in a copending commonly owned application, U.S. Ser. No. 08/331,399, entitled "THIN FILM ACTUATED MIRROR ARRAY AND METHOD FOR THE MANUFACTURE THEREOF", comprising: an active matrix 11 including a substrate 12, an array of M�N transistors (not shown) and an array 13 of M�N connecting terminals 14; an array 15 of M�N thin film actuating structures 16, each of the actuating structures 16 having at least a thin film layer 17 of a motion-inducing material, a first electrode 18 and a second electrode 19, the first and second electrodes being placed on top and bottom of the thin film motion-inducing layer 17, respectively; an array 20 of M�N supporting members 21, each of the supporting members 21 being used for holding each of the actuating structures 16 in place by cantilevering each of the actuating structures 16 and also for electrically connecting each of the actuating structures 16 and the active matrix 11; and an array 22 of M�N mirrors 23 for reflecting light beams, each of the mirrors being placed on top of each of the actuating structures 16. In the thin film actuated mirror array 10, an electrical signal is applied across the thin film layer 17 of the motion-inducing material located between the pair of electrodes 18, 19 in each of the actuating structures 16, causing a deformation thereof, which will in turn deform the mirror 23 placed on top thereof, thereby changing the optical path of the incident light beam.
It is, therefore, a primary object of the present invention to provide an array of M�N actuated mirrors having an improved optical efficiency.
In accordance with one aspect of the present invention, there is provided an array of M�N thin film actuated mirrors for use in an optical projection system, the array comprising: an active matrix including a substrate, an array of M�N transistors and an array of M�N connecting terminals; an array of M�N thin film actuating structures, each of the actuating structures including a first and a second actuating parts, the first and second actuating parts being identically structured, each of the first and second actuating parts being provided with a top, a bottom and a side surfaces, and a proximal and a distal ends, each of the first and second actuating parts having at least a thin film layer of a motion-inducing material including a top and a bottom surfaces, each of the first and second actuating parts further being provided with a first and a second electrodes with the first electrode being placed on the top surface of the motion-inducing thin film layer, and the second electrode, on the bottom surface of the motion inducing layer, the side surface from each of the actuating parts in each of the actuating structures being in physical contact with each other, the first electrode from each of the first and second actuating parts in each of the actuating structures being common to the first and second actuating parts, thereby functioning as a common bias electrode, the second electrodes from each of the first and second actuating parts in each of the actuating structures functioning as a signal electrode in the corresponding actuating part, wherein an electrical signal applied across the motion-inducing thin film layer between the first and second electrodes in each actuating part causes a deformation of the motion-inducing thin film layer, and hence said each actuating part; an array of M�N supporting members, wherein the proximal end of the actuating parts of each of the actuating structures is secured to the corresponding supporting member; and an array of M�N mirror layers, each of the mirror layers including a mirror for reflecting light beams and a supporting layer, each of the mirror layers being divided into a first and a second reflectors, the first and second reflectors being symmetric to each other, each of the reflectors being provided with a first surface, a second opposing surface and a central tab portion therebetween, the first surface and central tab portion, and the second opposing surface and central tab portion being separated by a dividing slot therebetween, wherein the central tab portion of each reflector is directly attached on top of each actuating part in each of the actuating structures such that when the central tab portion in each of the reflectors deforms in response to the electrical signal, the first and second opposing surfaces in each of the reflectors tilt while remaining planar, thereby allowing all of the first and second opposing surfaces to reflect light beams, resulting in an increased optical efficiency.
FIG. 2 represents a cross sectional view of an array of M�N thin film actuated mirrors in accordance with a preferred embodiment of the present invention;
Referring now to FIGS. 2 to 4, there are provided two schematic cross sectional and a top views of the inventive array of M�N thin film actuated mirrors for use in an optical projection system, wherein M and N are integers, in accordance with preferred embodiments of the present invention. It should be noted that like parts appearing in FIGS. 2 to 4 are represented by like reference numerals.
In FIG. 2, there is illustrated a cross sectional view of an array 50 of M�N thin film actuated mirrors 51, comprising an active matrix 52, an array 53 of M�N thin film actuating structures 54, an array 55 of M�N supporting members 56, and an array 57 of M�N mirror layers 58.
FIG. 3 represents a detailed cross sectional view of the thin film actuated mirror array 50 shown in FIG. 2. The active matrix 52 includes a substrate 59, an array of M�N transistors (not shown) and an array 60 of M�N connecting terminals 61. Each of the thin film actuating structures 54 includes a first and a second identically structured actuating parts 62, 63, wherein each of the first and second actuating parts 62, 63 is provided with a top, a bottom and a side surfaces 64, 65, 66, and a distal and a proximal ends 67, 68. Each of the first and second actuating parts 62, 63 is further provided with a thin film layer 69 of a motion-inducing material including a top and a bottom surfaces 70, 71, e.g., a piezoelectric material or an electrostrictive material, a first and a second electrodes of a specific thickness 72, 73 with the first electrode 72 being disposed on the top surface 70 of the motion-inducing thin film layer 69, and the second electrode 73, on the bottom surface 71 thereof. If the motion-inducing thin film layers 69 are made of a piezoelectric material, e.g., lead zirconium titanate(PZT), they must be poled in the same direction. The first and second electrodes 72, 73 are made of an electrically conducting metal, e.g., silver(Ag) or gold(Au). In the thin film actuating structure 54, the side surfaces 66 from each of the-first and second actuating parts 62, 63 are in physical contact with each other. Furthermore, the first electrodes 72 from each of the first and second actuating parts 62, 63 are physically in contact with each other, thereby functioning as a common bias electrode, and the second electrodes 73 function as a signal electrode in the respective actuating parts 62, 63. An electrical signal applied across the motion-inducing thin film layer 69 between the first and second electrodes 72, 73 in each of the actuating parts 62, 63 causes a deformation of the motion-inducing thin film layer 69, and hence the actuating parts 62, 63.
Each of the M�N supporting members 56, provided with a top and a bottom surface 74, 75, is used for holding each of the actuating parts 62, 63 in place and also for electrically connecting each of the actuating structures 54 with the corresponding connecting terminal 61 on the active matrix 52.
In this inventive array 50 of M�N thin film actuated mirrors 51, each of the first and second actuating parts 62, 63 in each of the actuating structures 54 is cantilevered from each of the supporting members 56 by being mounted on the top surface 74 of each of the supporting members 56 at bottom of each of the first and second actuating parts 62, 63 at the proximal end 68 thereof, and the bottom surface 75 of each of the supporting members 56 is placed on top of the active matrix 52. The second electrodes 73 from each of the first and second actuating parts 62, 63 are connected to the corresponding connecting terminal 61. The supporting members are made of a ceramic.