KR100208688B1 - Actuated mirror arrays having enhanced light efficiency - Google Patents

Abstract

Disclosed is a thin film type optical path adjusting device capable of improving the flatness of a mirror to make the reflection angle of the mirror constant. The apparatus includes an active matrix having a drain, a protective layer, and an etch stop layer thereon, and an actuator formed on the active matrix. The actuator includes a plurality of actuators having a lower electrode, a strained layer, an upper electrode having a mirror, and a membrane and driving in opposite directions. The flatness of the mirror can be improved by forming one side of the mirror in contact with the upper electrode of each of the actuators formed on both sides of the active matrix to provide two support parts. Therefore, the reflection angle of the mirror is kept constant so that the light efficiency of the light beam incident from the light source can be improved to form an image having higher brightness and higher image quality.

Description

Thin film type optical path control device to improve light efficiency

The present invention relates to AMA (Actuated Mirror Arrays), which is a thin film type optical path control device, and more particularly, to a thin film type optical path control device which can improve light efficiency by improving the flatness of a mirror to make the reflection angle of the mirror constant.

An optical path adjusting device or an optical modulator capable of adjusting the light flux may be variously applied to optical communication, image processing, and information display apparatus. In general, such devices are classified into two types according to their optical properties. One type is a direct view type image display device, such as a CRT (Cathode Ray Tube), and the other type is a projection type image display device, a liquid crystal display (LCD), a deformable mirror device (DMD), or an AMA. And the like. Although the CRT apparatus has excellent image quality, the weight and volume of the CRT apparatus increases, leading to an increase in manufacturing cost. On the other hand, the liquid crystal display (LCD) has a simple optical structure and can be formed thin so that the weight can be reduced and the volume can be reduced. However, the liquid crystal display device is inferior in efficiency to have a light efficiency of 1 to 2% due to polarization of light, has a disadvantage in that the response speed of the liquid crystal material is slow and the inside thereof is easily overheated.

Thus, in order to solve the above problems, an image display device such as AMA or DMD has been developed. Currently, AMA can achieve a light efficiency of 10% or more, compared to a DMD having a light efficiency of about 5%. The AMA is a device that can adjust the luminous flux so that each of the mirrors installed therein reflects the light flowing from the light source at a predetermined angle, and the reflected light passes through a slit to form an image on the screen. . Therefore, the structure and operation principle thereof are simple, and high light efficiency can be obtained compared to a liquid crystal display device or a DMD. In addition, the contrast can be improved to obtain a bright and clear image. The image is not affected by the polarity of the incident light beam and does not affect the polarity of the reflected light beam. The mirrors embedded in the AMA are arranged to correspond to the slits, and the mirrors are inclined by an electric field generated inside the actuator. Therefore, the luminous flux incident from the light source is adjusted at a predetermined angle to form an image on the screen. In general, each actuator causes deformation in accordance with the electric field generated by the applied electric image signal and the bias voltage. When the actuator causes deformation, each of the mirrors mounted on top of the actuator is inclined. Accordingly, the inclined mirrors can reflect light incident from the light source at a predetermined angle. Piezoelectric materials such as PZT (Pb (Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as a constituent material of the deformable portion for driving the respective mirrors. In addition, a warping material such as PMN (Pb (Mg, Nb) O ₃ ) can be used as a constituent material of the deformation portion.

AMA, which is an optical path control device, is classified into a bulk device and a thin film device. The bulk optical path control device is disclosed, for example, in US Pat. Nos. 5,085,497 (issued to Gregory Um, et al.), 5,159,225 (issued to Gregory Um), 5,175,465 (issued to Gregory Um, et al.). It is. The bulk optical path adjusting device is to cut a thin layer of multilayer ceramic, mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then process it by sawing and then It is constructed by installing a mirror. However, since the bulk light path control device must separate the actuators by a sawing method, high precision is required in design and manufacturing, and the response speed of the deformation part is slow. Therefore, a thin film type optical path control apparatus that can be manufactured using a semiconductor manufacturing process has been developed.

The thin film type AMA device is disclosed in Patent Application No. 96-33605 (name of the invention: thin film type light path control device having a large driving angle), filed by the applicant on August 13, 1996.

1 is a plan view of a thin film type optical path adjusting device described in the preceding application, FIG. 2 is a cross-sectional view taken along line AA ′ of the device shown in FIG. 1, and FIG. 3 is a device of FIG. FIG. 4 is a cross-sectional view taken along the line BB ', and FIG. 4 is a cross-sectional view taken along the line CC' of the apparatus shown in FIG.

Referring to FIG. 1, the thin film type optical path adjusting device includes an active matrix 1, two first actuating parts 25 and 26 formed on both sides of the active matrix 1, and a center of the active matrix 1. The third actuating part 31 formed integrally with the two first actuating parts 25 and 26, the first actuating parts 25 and 26 and the third actuating part ( 31, between the two first actuating parts 25, 26 and the second actuating part 31, and two second actuating parts 29, 30 formed integrally with each other. . The first actuating parts 25 and 26, the second actuating parts 29 and 30, and the third actuating part 31 are 'U', 'T', and on the same plane. 'U' has a shape that is combined in sequence.

1 and 2, the active matrix 1 may include a pad 2 formed on one side of the active matrix 1, an active matrix 1, and a protective layer 3 stacked on the pad 2. And an anti-etching layer 5 stacked on top of the protective layer 3, and a plug 4 vertically formed from the surface of the anti-etching layer 5 to the pad 2 through the protective layer 3. It includes.

The two first actuating parts 25 and 26 are respectively in contact with the etch stop layer 5, and the other side thereof is laminated in parallel with the etch stop layer 5 via the first air gap 6. The lower electrode 11, the first lower membrane 9 formed at the lower end of the lower electrode 11, the deformable portion 13 formed on the lower electrode 11, and the upper portion of the deformed portion 13. It consists of an upper electrode 15 formed in.

The protective layer 3 is laminated to a thickness of about 1.0 to about 2.0 μm using a chemical vapor deposition (CVD) method. The protective layer 3 prevents the active matrix 1 from being damaged from subsequent processes.

The etch stop layer 5 is deposited on the upper portion of the protective layer 3 with a thickness of about 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 5 prevents the active matrix 1 from being etched and damaged when etching the sacrificial layer formed later.

After etching the portion of the anti-etching layer 5 and the protective layer 3 in which the pad 2 is formed below, the plug 4 is removed by using a lift-off method to lift a metal such as tungsten or titanium. ) Is formed. The plug 4 is electrically connected to the pad 2 to transfer the image signal generated from the transistor embedded in the active matrix 1 to the lower electrode 11.

Phosphate silicate glass (PSG) on the etch stop layer (5) and the plug (4) by using the atmospheric pressure chemical vapor deposition (Atmospheric Pressure CVD: APCVD) method 1.0 to 2. A sacrificial layer (not shown) is laminated to a thickness of about 0 μm. In this case, the sacrificial layer made of in-silicate glass (PSG) covers the upper part of the active matrix 1 in which the MOS transistor is embedded, so that the surface flatness is very poor. Therefore, the surface of the sacrificial layer is planarized by using a spin on glass (SOG) method or a chemical mechanical polishing (CMP) method. Subsequently, a portion of the sacrificial layer is etched to expose a portion where the plug 4 is formed in the etch stop layer 5.

The first lower membrane 9 made of nitride is stacked on one side of the sacrificial layer. The first lower membrane 9 is formed on the sacrificial layer except for the portion where the etch stop layer 5 is exposed to a thickness of about 0.01 to 1.0 μm using a low pressure chemical vapor deposition (LPCVD) method. . Subsequently, the lower electrode 11 is stacked such that one side is in contact with the exposed portion of the etch stop layer 5 and the other side is in contact with the top of the first lower membrane 9. The lower electrode 11 is formed of platinum (Pt), titanium (Ti), or the like to have a thickness of about 500 to 2000 kW using a sputtering method. Accordingly, the lower electrode 11 is electrically connected to the transistor embedded in the active matrix 1 through the pad 2 and the plug 4.

Deformation portions 13 are stacked on the lower electrode 11. The deformable portion 13 uses a sol-gel (Sol-Gel) method or a chemical vapor deposition (CVD) method for piezoelectric materials such as PZT or PLZT. It is formed to a thickness of about 4㎛. Next, the deformation | transformation part 13 is phase-shifted using the Rapid Thermal Annealing (RTA) method. The upper electrode 15 is stacked on one side of the deformable portion 13. The upper electrode 15 is formed of aluminum, platinum, or the like with a thickness of about 500 to 2000 mW using a sputtering method. The sacrificial layer is etched by an etching method using hydrogen fluoride (HF) vapor to form a first air gap 6 to complete the first actuating parts 25 and 26.

In the process of manufacturing the second actuating parts 29 and 30, except for the process of forming the first upper membrane 27, the lower electrode 11, the deformable part 13, and the upper electrode ( The process of laminating 15 is the same as the process of manufacturing the first actuating parts 25 and 26.

1 and 3, the second actuating parts 29 and 30 may include a lower electrode 11, a deformable part 13, and an upper part of the first actuating parts 25 and 26. The lower electrode 11, the deformation part 13, and the upper electrode 15, which are members integrally formed with the electrode 15, are included. The first upper membrane 27 is stacked on the upper center of the upper electrode 15. The first upper membrane 27 is formed by using a low pressure chemical vapor deposition (LPCVD) method to form nitride, which is the same material as the first lower membrane 9 of the first actuating portions 25 and 26. One. It is formed to a thickness of about 0㎛.

Referring to FIGS. 1 and 4, the third actuator 31 may include a lower electrode of the first actuating parts 25 and 26 and the second actuating parts 29 and 30. 11), the deformable portion 13, and the lower electrode 11, the deformable portion 13, and the upper electrode 15 formed integrally with the upper electrode 15, respectively. As shown in FIG. 4, the third actuating part 31 has the first actuating parts 25 and 26, a configuration thereof, and a manufacturing method thereof, except that a mirror 23 is formed at an upper portion thereof. Is the same.

At the lower end of the lower electrode 13 of the third actuating part 31, a second lower membrane 35 is formed which is the same as the first lower membrane 9 of the first actuating parts 25 and 26. have.

A central portion is in contact with an upper portion of the upper electrode 15 of the third actuating portion 31, and one side of the third actuating portion 31 is disposed in parallel with the upper electrode 15 via the second air gap 32. Formed. The mirror 23 is formed in a flat plate shape having a groove having a 'U' shape at a central portion thereof and covers the upper electrode 15 and a part of the adjacent actuator.

In the above-described thin film type optical path adjusting device, an image signal generated from a MOS transistor (not shown) embedded in the active matrix 1 is applied to the lower electrode 11, and a bias voltage is applied to the upper electrode 15. . Therefore, an electric field is generated between the upper electrode 15 and the lower electrode 11. The deformed portion 13 between the upper electrode 15 and the lower electrode 11 causes deformation by this electric field. Therefore, the deformable portion 13 of the first actuating portions 25 and 26 is contracted in a direction perpendicular to the electric field, so that the first actuating portions 25 and 26 have a driving angle of θ size. To cause deformation. The first actuating parts 25 and 26 are bent in the opposite direction to the direction in which the first lower membrane 9 is formed. At the same time, the deformation part 13 of the second actuating parts 29 and 30 also causes contraction in the direction perpendicular to the electric field. Accordingly, the second actuating parts 29 and 30 also cause deformation with a driving angle of θ. The second actuating parts 29 and 30 are bent in the opposite direction to the direction in which the first upper membrane 27 is formed. In addition, the deformation portion 13 of the third actuating portion 31 also causes deformation. Accordingly, the third actuating part 31 also causes deformation with a driving angle of θ. The third actuating part 31 is bent in the opposite direction to the direction in which the second lower membrane 35 is formed. The magnitude and driving direction of the driving angles of the first actuating parts 25 and 26 and the third actuating part 31 are the same. On the other hand, the second actuating parts 29 and 30 have the same driving angle but the driving direction is the same as the driving direction of the first actuating parts 25 and 26 and the third actuating part 31. In the opposite direction. Accordingly, the sum of the driving angles of the first actuating parts 25 and 26, the second actuating parts 29 and 30, and the third actuating part 31 is 3θ. Since the mirror 23 reflecting the light beam incident from the light source is formed on the third actuator 31, the mirror 23 is driven with a driving angle of 3θ. The light beam reflected by the mirror 23 is projected onto the screen through the slit to form an image.

However, in the above-described thin film type optical path adjusting device described above, the mirror is formed in contact with the upper electrode of the actuating part, and thus the mirror is stressed at a part where the center part and both sides of the mirror are connected when the mirror is manufactured. This occurs, and the reflection angle of the mirror reflecting the light beam incident from the light source is inclined because both sides of the mirror are inclined downward due to such stress, so that there is a problem that the light efficiency is lowered.

Accordingly, an object of the present invention is to improve the flatness of the mirror by maintaining the reflection angle of the mirror by improving the flatness of the mirror by having two support parts such that both sides of the mirror are in contact with the actuating parts formed on both sides of the active matrix. The present invention provides a thin film type optical path control device.

1 is a plan view of a thin film type optical path adjusting device described in the applicant's prior application.

FIG. 2 is a cross-sectional view taken along line A′A ′ of the apparatus shown in FIG. 1.

FIG. 3 is a cross-sectional view of the device shown in FIG. 1 taken along line B′B ′.

4 is a cross-sectional view taken along line C′C ′ of the apparatus shown in FIG. 1.

5 is a plan view of a thin film type optical path control apparatus according to the present invention.

FIG. 6 is a cross-sectional view taken along line D′ D ′ of the apparatus shown in FIG. 5.

FIG. 7 is a cross-sectional view of the device shown in FIG. 5 taken along line E′E ′.

FIG. 8 is a cross-sectional view taken along line F ′ F ′ of the apparatus shown in FIG. 5.

9A to 9C are manufacturing process diagrams of the apparatus shown in FIG. 6.

<Explanation of symbols for main parts of drawing>

51: Active matrix 53: Drain

55: protective layer 57: etching prevention layer

59: sacrificial layer 61: first lower membrane

63: lower electrode 65: strained layer

67: upper electrode 69: empty hole

71 ： Beer contact 73 ： First air gap

75: first actuator 77: mirror

79: first upper membrane 81, 83: second actuating part

85: second lower membrane 87, 89: third actuating part

91: second air gap

In order to achieve the above object, the present invention,

An active matrix in which MxN (M and N are integer) transistors are formed and a drain is formed on one side; And

Iii) a lower electrode in which one side is in contact with an upper portion of the active matrix and the other side is stacked in parallel with the active matrix via a first air gap; ii) a strained layer which is stacked on an upper portion of the lower electrode to cause deformation according to an electric field. And a mirror including a plurality of upper electrodes formed on the deformable layer, the plurality of actuators driving in opposite directions, and a support formed on at least two of the plurality of actuators. Provided is a thin film type optical path control device including an actuator having.

In the above-described thin film type optical path control device according to the present invention, an image signal is applied to a lower electrode as a signal electrode from a MOS transistor embedded in an active matrix, and a bias voltage is applied to an upper electrode as a common electrode. Therefore, an electric field is generated between the upper electrode and the lower electrode. By this electric field, the strained layer between the upper electrode and the lower electrode causes deformation. The deformation layer of the first actuating part contracts in a direction perpendicular to the electric field, thereby causing the first actuating part to deform with a driving angle having a size of θ. The first actuating portion is bent in a direction opposite to the direction in which the first lower membrane is formed. At the same time, the strained layer of the second actuating parts also causes contraction in a direction perpendicular to the electric field. Accordingly, the second actuating parts also cause deformation with a driving angle of θ. The second actuating parts are bent in the opposite direction in which the first upper membrane is formed. In addition, the deformation layer of the third actuating parts also causes deformation. Therefore, the third actuating parts also cause deformation with a driving angle of θ. The third actuating parts are bent in the opposite direction to the direction in which the second lower membrane is formed. The magnitude and the driving direction of the driving angles of the first and third actuators are the same. In contrast, the second actuators have the same driving angle, but the driving direction is opposite to the driving directions of the first and third actuators. Therefore, the sum of the driving angles of the first actuating part, the second actuating parts, and the third actuating parts becomes 3θ. Since the mirror reflecting the light beam incident from the light source is horizontally supported by the upper portion of the third actuating parts, the mirror is driven with a driving angle of 3θ. The light beam reflected by the mirror is projected onto the screen through the slit to form an image.

Therefore, in the above-described thin film type optical path adjusting device, one side of the mirror is in contact with the upper electrode of each of the third actuating parts formed on both sides of the active matrix through two support parts, and the other side is horizontal to the upper electrode. Even if there is a stress formed in the portion where the support and the mirror surface is in contact with each other, it can be relaxed to form a flat mirror without the initial tilt. That is, since the support portion of the mirror is formed in contact with the upper electrodes of the third actuating portions formed on both sides of the active matrix, the mirror does not bend even when stress remains on the mirror surface when the mirror is deposited. Is formed. Therefore, the flatness of the mirror can be improved to maintain a constant reflection angle of the mirror, thereby improving the light efficiency to form an image having high brightness and high image quality.

Hereinafter, a thin film type optical path adjusting apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

5 is a plan view showing a thin film type optical path control apparatus according to an embodiment of the present invention, FIG. 6 is a cross-sectional view taken along line DD ′ of the apparatus shown in FIG. 5, and FIG. 7 is shown in FIG. 5. FIG. 8 is a cross-sectional view of one device taken along line EE ', and FIG. 8 is a cross-sectional view of the device shown in FIG. 5 taken along line FF'. 6, 7 and 8, the same reference numerals are used for the same members as in FIG.

Referring to FIG. 5, the thin film type optical path adjusting device includes an active matrix 51, two third actuating parts 87 and 89 formed on both sides of the active matrix 51, and a center of the active matrix 51. The first actuating part 75, the third actuating parts 87, 89, and the first actuating part formed integrally with the two third actuating parts 87 and 89 at an upper portion thereof. Between the second third actuating portions 87 and 89 and two second actuating portions 81 and 83 integrally formed with the first actuating portion 75. . The third actuating parts 87 and 89, the second actuating parts 81 and 83, and the first actuating part 75 are 'U', 'T', and on the same plane. 'U' has a shape that is combined in sequence.

5 and 6, the active matrix 51 includes a drain 53 formed on one side of the active matrix 51, a protective layer 55 stacked on the active matrix 51 and the drain 53. And an etch stop layer 57 stacked on the protective layer 55.

Each of the first actuating parts 75 may have one side in contact with the etch stop layer 57 and the other side of the lower electrode 63 stacked in parallel with the etch stop layer 57 via the first air gap 73. A first lower membrane 61 formed at one lower end of the lower electrode 63, a strained layer 65 formed on the lower electrode 63, and an upper electrode formed on an upper side of the strained layer 65; 67, a via hole 69 formed from the other side of the strained layer 65 to the drain 53 through the lower electrode 63, the etch stop layer 57, and the protective layer 55, and the via And a via contact 71 formed in the hole 69.

5 and 7, the second actuating parts 81 and 83 are formed on the lower electrode 63, the strained layer 65, and the upper electrode 67 of the first actuating part 75, respectively. ) And a lower electrode 63, a strained layer 65, an upper electrode 67, and a first upper membrane 79 formed on the upper electrode 67.

5 and 8, the third actuating parts 87 and 89 may be the lower electrodes of the first actuating part 75 and the second actuating parts 81 and 83, respectively. 63, a lower electrode 63 integrally formed with the strained layer 65 and the upper electrode 67, and a second lower portion formed at the bottom of the lower electrode 63 with the strained layer 65 and the upper electrode 67. And a mirror 77 formed on the membrane 85 and the upper electrode 67.

Hereinafter, a method of manufacturing a thin film type optical path control apparatus according to an embodiment of the present invention will be described with reference to the drawings.

9A to 9C are manufacturing process diagrams of the apparatus shown in FIG. 6.

Referring to FIG. 9A, a protective layer 55 is stacked on top of an active matrix 51 having M × N MOS transistors (not shown) and having a drain 53 formed on one surface thereof. . The protective layer 55 is formed of a silicate glass (PSG) to have a thickness of about 1.0 to about 2.0 μm using a chemical vapor deposition (CVD) method. The protective layer 55 prevents the transistor embedded in the active matrix 51 from being damaged during subsequent processing.

An etch stop layer 57 is stacked on the passivation layer 55. The etch stop layer 57 is formed to have a thickness of about 1000 to 2000 GPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 57 blocks photocurrent due to the luminous flux incident from the light source and simultaneously prevents the active matrix 51 and the protective layer 55 from being etched due to the subsequent etching process.

The sacrificial layer 59 is stacked on the etch stop layer 57. The sacrificial layer 59 is formed of phosphorus silicate (PSG) to have a thickness of about 1.0 to about 2.0 μm by the atmospheric pressure chemical vapor deposition (APCVD) method. Subsequently, a portion of the sacrificial layer 59 in which the drain 53 is formed is etched to expose a portion of the etch stop layer 57.

Referring to FIG. 9B, a first lower membrane 61 is stacked on one side of the sacrificial layer 59. The first lower membrane 61 is formed on the upper portion of the sacrificial layer 59 except for the portion where the etch stop layer 57 is exposed by using low pressure chemical vapor deposition (LPCVD). It is formed to have a thickness of and then patterned. Subsequently, the lower electrode 63 is stacked such that one side contacts the exposed portion of the etch stop layer 57 and the other side contacts the upper portion of the first lower membrane 61. The lower electrode 63 is formed of platinum (Pt), titanium (Ti), or the like to have a thickness of about 500 to 2000 kW using a sputtering method. An image signal generated from a transistor embedded in the active matrix 51 is applied to the lower electrode 63 through the drain 53.

Subsequently, a strained layer 65 is stacked on the lower electrode 63. The strained layer 65 is laminated using a piezoelectric material such as ZnO, PZT or PLZT so as to have a thickness of 0.1 to 1.0 mu m, preferably about 0.4 mu m. The strained layer 65 is formed by using a sol-gel method or chemical vapor deposition (CVD) method, and then thermally transformed using a rapid thermal annealing (RTA) method to phase change. . The upper electrode 67 is stacked on top of the strained layer 65. The upper electrode 67 is formed of a metal having excellent electrical conductivity, such as aluminum or silver, to have a thickness of about 500 to 2000 kPa using a sputtering method. Subsequently, the upper electrode 67, the strained layer 65, the lower electrode 63, and the first lower membrane 61 are sequentially patterned to form a predetermined pixel shape.

Referring to FIG. 9C, the strained layer 65, the lower electrode 63, the etch stop layer 57, and the protective layer 55 are sequentially turned from the other side of the strained layer 65 using a conventional photolithography method. Etching is performed to form the via hole 69. Therefore, the via hole 69 is vertically formed from the other side of the strained layer 65 to the drain 53. Subsequently, a via contact 71 is formed by sputtering a metal such as tungsten (W) or titanium (Ti). The via contact 71 is electrically connected to the drain 53 and the lower electrode 63. Therefore, the image signal generated from the transistor embedded in the active matrix 51 is applied to the lower electrode 63 which is a signal electrode through the drain 53 and the via contact 71. The sacrificial layer 59 is etched using hydrogen fluoride (HF) to complete the above-described first actuating part 75.

In the process of manufacturing the second actuating parts 81 and 83, except for forming the first lower membrane 61, the lower electrode 63, the strained layer 65, and the upper electrode ( The process of stacking 67) is the same as the process of manufacturing the first actuating part 75. The second actuating parts 81 and 83 further include a first upper membrane 79 stacked on the upper electrode 67. The first upper membrane 79 is formed of a nitride material of the same material as that of the first lower membrane 61 of the first actuating part 75 using low pressure chemical vapor deposition (LPCVD). It is formed to a thickness of about 0㎛. The lower electrode 63, the deformable layer 65, and the upper electrode 67 of the second actuating parts 81 and 83 may be formed of the lower electrode 63 and the deformable layer of the first actuating part 75. When the 65 and the upper electrode 67 are patterned in a predetermined pixel shape, they are patterned together. In addition, the sacrificial layer 59 under the second actuating parts 81 and 83 is also removed when the sacrificial layer 59 under the first actuating part 75 is etched to remove the second actuating parts. (81) (83) is completed.

In the process of manufacturing the third actuating parts 87 and 89, the process of laminating the second lower membrane 85, the lower electrode 63, the strained layer 65, and the upper electrode 67 is performed. It is the same as the process of manufacturing the 1st actuating part 75. FIG. The second lower membrane 85 of the third actuating portions 87 and 89 is patterned together when patterning the first lower membrane 61 of the first actuating portion 75. The third actuating parts 87 and 89 further include a mirror 77 formed on the upper electrode 67. In order to form the mirror 77, first, a photoresist (not shown) is applied on the upper electrode 67, and then the photoresist is patterned to mirror the upper surface of one side of the upper electrode 67. To create a place where the support will be formed. Next, a metal, such as aluminum or platinum, is stacked to have a thickness of about 500 to 1000 mm by sputtering to form a mirror 77, and then the photoresist is etched to form a second air gap 91. This completes the manufacture of the mirror 77. In this case, one side of the mirror 77 forms two support portions in contact with the upper electrodes 67 of the third actuating portions 87 and 89 formed on both sides of the active matrix 51. Even if there is a stress formed in the part where the mirror surface abuts, it can be alleviated to form a flat mirror without initial tilt. Accordingly, the supporting part of one lower end of the mirror 77 is in contact with one upper part of the upper electrode 67 of each of the third actuating parts 87 and 89, and the other side is interposed between the second air gap 91. Thus, it is formed in a flat plate shape parallel to the upper electrode 67. The lower electrode 63, the deformable layer 65, and the upper electrode 67 of the third actuating parts 87 and 89 may include the lower electrode 63 and the deformable layer () of the first actuating part 75. When the 65 and the upper electrode 67 are patterned in a predetermined pixel shape, they are patterned together. In addition, the sacrificial layer 59 under the third actuating parts 87 and 89 is also removed when the sacrificial layer 59 under the first actuating part 75 is etched to remove the third actuating parts. (87) (89) is completed.

In addition, the thin film type optical path control device is completed by cleaning and drying the elements on which the first actuating part 75, the second actuating parts 81, 83, and the third actuating parts 87, 89 are formed. do.

In the above-described thin film type optical path adjusting device, an image signal is applied to the lower electrode 63, which is a signal electrode, from a MOS transistor built in the active matrix 51, and a bias is applied to the upper electrode 67, which is a common electrode. Voltage is applied. Therefore, an electric field is generated between the upper electrode 67 and the lower electrode 63. The strained layer 65 between the upper electrode 67 and the lower electrode 63 causes deformation by this electric field. The deformation layer 65 of the first actuating part 75 contracts in a direction perpendicular to the electric field, and thus the first actuating part 75 causes deformation with a driving angle having a size of θ. The first actuating part 75 is bent in a direction opposite to the direction in which the first lower membrane 61 is formed. At the same time, the strained layer 65 of the second actuating parts 81 and 83 also causes contraction in a direction perpendicular to the electric field. Accordingly, the second actuating parts 81 and 83 also cause deformation with a driving angle of θ. The second actuating parts 81 and 83 are bent in the opposite direction to the direction in which the first upper membrane 79 is formed. In addition, the deformation layer 65 of the third actuating parts 87 and 89 also causes deformation. Accordingly, the third actuating parts 87 and 89 also cause deformation with a driving angle of θ magnitude. The third actuating parts 87 and 89 are bent in the opposite direction to the direction in which the second lower membrane 85 is formed. The magnitude and the driving direction of the driving angles of the first actuating part 75 and the third actuating parts 87 and 89 are the same. In contrast, the second actuating parts 81 and 83 have the same driving angle but the driving direction is the same as that of the first actuating part 75 and the third actuating parts 87 and 89. In the opposite direction. Therefore, the sum of the driving angles of the first actuating part 75, the second actuating parts 81 and 83, and the third actuating parts 87 and 89 is 3θ. Since the mirror 77 reflecting the light beam incident from the light source is supported and horizontally formed on the third actuating parts 87 and 89, the mirror 77 is driven at a driving angle of 3θ. The light beam reflected by the mirror 77 is projected onto the screen through the slit to form an image.

Therefore, in the above-described thin film type optical path adjusting device, one side of the mirror is in contact with the upper electrode of each of the actuating portions formed on both sides of the active matrix through two support portions, and the other side is formed horizontally on the upper electrode. Therefore, even if there is a stress formed in the portion where the support and the mirror surface abut it can be reduced to form a flat mirror without the initial tilt. By improving the flatness of the mirror, the reflection angle of the mirror can be made constant. That is, since the support portion of the mirror is formed in contact with the upper electrodes of the third actuating portions formed on both sides of the active matrix, the mirror does not bend even when stress remains on the mirror surface when the mirror is deposited. Is formed. Therefore, the flatness of the mirror can be improved to maintain a constant reflection angle of the mirror, thereby improving the light efficiency of the light beam incident from the light source, thereby forming an image having higher brightness and higher image quality.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (10)

An active matrix 51 having M × N (M and N are integer) transistors and a drain 53 formed on one side thereof; And (B) a lower electrode 63 in which one side is in contact with an upper portion of the active matrix 51 and the other side is stacked in parallel with the active matrix 51 via a first air gap 73, ii) the lower electrode ( A plurality of layers each including a strained layer 65 stacked on top of the upper portion 63 and deforming according to an electric field, and iii) an upper electrode 67 formed on the upper portion of the strained layer 65, and driving in opposite directions. A plurality of actuators 75, 81, 83, 87, 89, and a plurality of actuators 75, 81, 83, 87, 89, and formed on at least two of the plurality of actuators 75, 81, 83, 87, 89 Thin film type optical path control device comprising an actuator having a mirror (77) comprising a support. The protective layer 55 of claim 1, wherein the active matrix 51 is stacked on the active matrix 51 on which the drain 53 is formed to protect the active matrix 51. And a etch stop layer (57) which is stacked on top of the layer (55) to prevent the active matrix (51) and the protective layer (55) from being etched. The first actuator of claim 1, wherein the actuator has a first lower membrane 61 stacked in parallel with the etch stop layer 57 via a first air gap 73 at a lower end of the lower electrode 63. Thin film type optical path control device, characterized in that it further comprises an actuating unit (75). The method of claim 3, wherein the first actuating part 75 is formed through the strained layer 65, the lower electrode 63, the etch stop layer 57, and the protective layer 55 from the other side of the strained layer 65. Thin film type optical path control device further comprises a via contact (71) formed perpendicular to the drain (53). 4. The actuator of claim 3, wherein the actuator further comprises two second actuating portions (81, 83) each having a first upper membrane (79) stacked in an upper center of the upper electrode (67). Thin film type optical path control device characterized in that. 6. The actuator of claim 5, wherein the actuator has two second lower membranes 85 stacked in parallel with the etch stop layer 57 via a first air gap 73 at a lower end of the lower electrode 63. Thin film type optical path control device further comprises a third actuating portion (87) (89). The upper surface of the two upper electrodes 67 of the two third actuating parts 87 and 89 has one side contacting the two upper electrodes 67 through the plurality of supporting parts. And the other side is formed with the mirror (77) in parallel with the upper electrode (76) via a second air gap (91). The method of claim 6, wherein the third actuating parts 87 and 89 are formed on both sides of the active matrix 51, and the first actuating part 75 is formed on the active matrix 51. It is formed integrally with the third actuating parts (87, 89) in the upper center, and the second actuating parts (81, 83) and the third actuating parts (87, 89) Thin film type optical path control device, characterized in that formed between the first actuating portion (75) and the third actuating portion (87) (89) and the first actuating portion (75) integrally. 7. The actuator of claim 6 wherein the third actuating portions 87, 89, the second actuating portions 81, 83, and the first actuating portion 75 are coplanar 'together. The thin film type optical path control device, characterized in that the U ',' T ', and' U 'is combined in sequence. The driving mechanism of claim 6, wherein the first actuating part 75, the third actuating parts 87, 89, and the second actuating parts 81, 83 are driven in opposite directions. Thin film type optical path control device, characterized in that.