KR100230004B1 - Thin film actuated mirror arrays having large deformable actuators and a method thereof - Google Patents

Abstract

A thin film type optical path adjusting device capable of increasing the driving angle of an actuator and a manufacturing method thereof are disclosed. The apparatus includes a lower electrode, a deformed portion, and an upper electrode on an active matrix with a built-in transistor, and has a plurality of bent portions formed by being rotated by 90 degrees in a clockwise direction. The device has a vertical bending at regular intervals even within a narrow area, so that the driving angle of the mirror on the upper part of the actuator can be increased to 3 to 4 times or more as compared with the conventional optical path adjusting device. Thus, the light efficiency of the light flux incident from the light source can be increased, and the contrast can be improved, so that a clear image can be formed.

Description

Thin film type optical path adjusting device having a large driving angle and manufacturing method thereof

The present invention relates to AMA (Actuated Mirror Arrays) as a thin film optical path adjusting device and a manufacturing method thereof, and more particularly, to a thin film optical path adjusting device capable of increasing a driving angle of a mirror within a narrow area and a manufacturing method thereof.

An optical path adjusting device or optical modulator capable of adjusting the light flux can be applied to various applications such as optical communication, image processing, and information display devices. Generally, such devices are roughly classified into two types according to their optical characteristics. One type is a direct-view type image display device, such as a CRT (Cathode Ray Tube), and the other type is a liquid crystal display (LCD), a DMD (Deformable Mirror Device) And so on. The CRT device is excellent in image quality, but its weight and volume increase with an increase in screen size, which increases manufacturing cost. On the other hand, a liquid crystal display (LCD) has a simple optical structure and can be made thin so that the weight can be lightened and the volume can be reduced. However, the liquid crystal display device is inefficient to have a light efficiency of 1 to 2% due to the polarization of light, has a slow response speed of the liquid crystal material, and is easily overheated.

Therefore, an image display device such as AMA or DMD has been developed to solve the above problems. At present, AMA has a light efficiency of 10% or more, compared to DMD having a light efficiency of about 5%. Each of the mirrors installed in the AMA reflects the light incident from the light source at a predetermined angle and the reflected light can control the light flux to pass through the slit and form an image on the screen . Therefore, the structure and operation principle are simple, and a higher optical efficiency can be obtained compared to a liquid crystal display device or a DMD. In addition, it is possible to obtain a bright and clear image by improving the contrast, and it is not affected by the polarity of the incident light beam and does not affect the polarity of the reflected light beam. The mirrors incorporated in the AMA are arranged so as to correspond to the slits, and the mirror is inclined by an electric field generated inside the actuator. Accordingly, the light flux incident from the light source is adjusted to a predetermined angle so that an image can be formed on the screen. Generally, each of the actuators is deformed in accordance with an electric image signal to be applied and an electric field generated by a bias voltage. When the actuator causes deformation, each of the mirrors mounted on the upper portion 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 ) and PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as constituent materials of the deformed parts for driving the respective mirrors. Further, an electrostriction substance such as PMN (Pb (Mg, Nb) O ₃ ) can be used as a constituent material of the deformed portion.

AMA, which is an optical path control device, is divided into a bulk type device and a thin film type device. The bulk optical path control device is disclosed, for example, in US Pat. No. 5,085,497 issued to Gregory Um, et al., Issued to Gregory Um, issued to Gregory Um, et al. . In the bulk optical path adjusting device, a ceramic wafer having a multilayer ceramic thinly cut and having metal electrodes formed therein is mounted on an active matrix with a built-in transistor, and then processed by a sawing method. And a mirror is installed. However, since the bulk optical path adjusting device is required to separate the actuators by the sawing method, high precision is required in design and manufacture, and the response speed of the deformed part is slow. Therefore, a thin film type optical path adjusting device capable of being manufactured using a semiconductor manufacturing process has been developed. Such a thin-film type optical path adjusting device is disclosed in Patent Application No. 95-13353 (a method of manufacturing an optical path adjusting device) in which the present applicant has applied for a patent to the Korean Intellectual Property Office.

FIG. 1 is a plan view of the thin-film type optical path adjusting device described in the above-mentioned prior application, FIG. 2 is a cross-sectional view of the device shown in FIG. 1 taken along line AA ' 1 shows a manufacturing process of a device.

As shown in Figs. 1 and 2, the thin film type optical path adjusting apparatus is composed of an active matrix 1 and an actuator 3 provided on the active matrix 1.

The active matrix 1 is made of a semiconductor such as silicon (Si), and M × N (M, N is an integer) MOS transistors (not shown) are built therein. The active matrix 1 may be formed of an insulating material such as glass or alumina (Al ₂ O ₃ ). A pad 5 is formed on one side of the active matrix 1. The pad 5 is electrically connected to a transistor incorporated in the active matrix 1.

The actuator 3 is composed of a membrane 7, a plug 9, a lower electrode 11, a deformed portion 15 and an upper electrode 17.

As shown in FIG. 1, the membrane 7 has a quadrangular concave portion formed at one side of the central portion of the actuator 3, and a rectangular protrusion corresponding to the concave portion is formed at the other side . The protrusion of the membrane of the actuator adjacent to the concave portion of the membrane 7 is fitted and the protrusion of the membrane 7 is fitted to the concave portion of the adjacent actuator. 2, a part of the membrane 7 is in contact with the upper part of the active matrix 1 on which the pad 5 is formed, and the other side is in contact with the active matrix 1 via an air gap 8, And is formed parallel to the matrix 1.

The plug 9 is formed perpendicular to the portion of the membrane 7 where the pad 5 is formed. The plug (9) is electrically connected to the pad (5). The lower electrode 11 is formed on the upper portion of the membrane 7 and the deformed portion 15 is formed on the lower electrode 11. [ An upper electrode (17) is formed on the upper portion of the deformed portion (15). The upper electrode 17 functions not only as an electrode but also as a mirror for reflecting an incident light beam.

Hereinafter, a method of manufacturing the thin film type optical path adjusting apparatus will be described with reference to the drawings.

3A, a sacrificial layer 2 made of phosphoric-silicate glass (PSG) is stacked on an active matrix 1 having pads 5 formed on one side thereof. The sacrificial layer 2 is formed to have a thickness of about 1.0 to 2.0 탆 by a spin coating method. Then, a part of the sacrificial layer 2 is etched to expose a portion of the active matrix 1 on which the pad 5 is formed.

Referring to FIG. 3B, a membrane 7 having a thickness of about 0.1 to 1.0 μm is laminated on the exposed portion of the active matrix 1 and the sacrificial layer 2. The membrane 7 is formed of silicon nitride (Si ₃ N ₄ ) by sputtering or chemical vapor deposition (CVD). Then, a portion of the membrane 7 formed on the exposed portion of the active matrix 1 is etched by a conventional photolithography method to form an opening 6.

A plug 9 made of a metal having good electrical conductivity such as tungsten (W) or titanium (Ti) is formed through the opening 6. The plug 9 is formed using a lift-off method and is electrically connected to the pad 5.

The lower electrode 11 is stacked on top of the membrane 7 on which the opening 6 is formed. The lower electrode 11 is formed to have a thickness of about 500 to 2000 Å by vacuum deposition or sputtering using platinum (Pt) or platinum-titanium (Pt-Ti). The lower electrode 11 is electrically connected to the plug 9 so that the pad 5, the plug 9 and the lower electrode 11 are electrically connected to each other.

Referring to FIG. 3C, the deformation part 15 is laminated on the lower electrode 11. The deformed portion 15 is formed to have a thickness of about 0.1 to 1.0 mu m by using a piezoelectric material such as PZT or PLZT or an electrostriction material such as PMN. The deformed portion 15 is formed by a sol-gel method or a chemical vapor deposition method (CVD).

An upper electrode 17 is laminated on the upper portion of the deformed portion 15. The upper electrode 17 is formed to have a thickness of about 500 to 1000 angstroms by sputtering or vacuum deposition. Subsequently, the upper electrode 17, the deformed portion 15, the lower electrode 11, and the membrane 7 are sequentially etched and patterned by using a photolithography method. At this time, the upper electrode 17, the deformed portion 15, and the lower electrode 11 are etched so as to separate from the upper electrode, the deformed portion, and the lower electrode of the adjacent actuator. At the same time, the membrane 7 is etched to be connected to the membrane of the adjacent actuator. A protective film 18 is formed by coating photoresist on the upper surface of the upper electrode 17 and the side surface formed when the actuators are separated.

Referring to FIG. 3D, the sacrificial layer 2 is etched with hydrogen fluoride (HF) vapor to form an air gap 8. Then, the protective film 18 is removed by a wet etching method, and the remaining etching solution is rinsed with deionized water. Then, a photoresist is coated on the upper electrode 17 to form a mask 19.

Referring to FIG. 3E, the portion of the membrane 7 connected to the membrane of the adjacent actuator is etched by a reactive ion etching (RIE) method using the mask 19 as an etching mask. Then, the mask 19 is removed by an oxygen plasma method to complete the AMA device.

An image signal generated from the MOS transistor incorporated in the active matrix 1 is applied to the lower electrode 11 through the pad 5 and the plug 9. In the thin film type optical path adjusting apparatus having the above structure, At the same time, a bias voltage is applied to the upper electrode 17, so that an electric field is generated between the upper electrode 17 and the lower electrode 11. The deformed portion 15 contracts in the direction perpendicular to the electric field due to this electric field. The actuator 3 is bent in the direction opposite to the direction in which the membrane 7 is formed and the upper electrode 17 on the actuator 3 reflects the light beam incident from the light source. The light flux reflected by the upper electrode 17 is projected on the screen through the slit to form an image.

However, in the above-mentioned thin film type optical path adjusting apparatus, there is a drawback that only a part of the upper electrode is driven to reflect the light flux, the driving angle of the upper electrode is reduced and the light efficiency is lowered. Further, since the displacement of the actuator due to the deformation of the deformed portion is small, the driving angle of the upper electrode used as the mirror is small, so that the contrast is lowered, and there is also a problem in the design of the system such as narrowing the space between the light source and the screen.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thin film type optical path adjusting apparatus and a method of manufacturing the same, which can increase a driving angle of a mirror by forming an actuator so as to have a maximum length even in a small area.

1 is a plan view of the thin-film type optical path adjusting apparatus described in the prior application of the present applicant.

FIG. 2 is a cross-sectional view of the device shown in FIG. 1 taken along line AA '.

Figs. 3A to 3E are a manufacturing process diagram of the apparatus shown in Fig. 2. Fig.

4 is a cross-sectional view of a thin film type optical path adjusting apparatus according to the present invention.

FIGS. 5A to 5E are a manufacturing process diagram of the thin film type optical path adjusting apparatus shown in FIG.

Description of the Related Art

21: active matrix 23: protective layer

25: etching prevention layer 27: first air gap

29: first sacrificial layer 31: second sacrificial layer

33: lower electrode 35:

37: upper electrode 39: actuator

41: second air gap 43: mirror

According to an aspect of the present invention,

An active matrix in which M x N (M, N is an integer) transistors are built in, and pads are formed on one side of the active matrix; And

I) a lower electrode having one side thereof being in contact with an upper portion of the active matrix on which the pad is formed and having the other side being bent in a plurality of clockwise directions through the first air gap by 90 °, and ii) Iii) an upper electrode stacked on top of the deformed portion, wherein the lower electrode has a plurality of bent portions of a shape that is rotated by 90 ° clockwise according to the shape of the lower electrode A thin film type optical path adjusting device including an actuator is provided.

The active matrix further includes a protective layer stacked on the active matrix and the pad, an etch stop layer stacked on the protective layer, and a plug vertically formed from the etch stop layer to the pad through the passivation layer . The upper electrode may further include a mirror having a central portion contacting an upper portion of one side of the upper electrode and a second electrode formed parallel to the upper electrode through a second air gap. The mirror has a central portion protruding downward and has the shape of a flat plate contacting one upper side of the upper electrode.

According to another aspect of the present invention,

Forming a pad on one side of an active matrix having M x N (M, N is an integer) transistors; And

The method comprising the steps of: i) forming a lower electrode of the active matrix having the pad formed therein, ii) forming a deformation portion on the upper electrode, and iii) forming an upper electrode on the deformation portion, And a step of forming an actuator having a curved shape in which a "? &Quot;

The forming of the pad may include forming a protective layer on the active matrix and the pad, forming an etch stop layer on the protective layer, and etching a part of the passivation layer and the etch stop layer, Forming a plug vertically from the etch stop layer to the pad.

Preferably, the lower electrode is formed by laminating a first sacrificial layer on the etch stop layer and the plug, etching and patterning the exposed portion of the plug to expose the plug-formed portion, and forming a second sacrificial layer on the first sacrificial layer, Layer is stacked and then etched and patterned to expose the plug. The second sacrificial layer is formed by patterning using a negative resist.

Preferably, the second sacrificial layer is formed so as to have a curvature of a shape in which a plurality of magnetizations are rotated by 90 ° in the clockwise direction.

The step of forming the upper electrode of the actuator may further include the step of forming a mirror parallel to the upper electrode through the second air gap on the other side in contact with the upper part of one side of the upper electrode. The mirror is formed of a metal such as silver (Ag) or aluminum (Al) by a sputtering method.

The step of forming the actuator may further include the step of sequentially patterning the upper electrode, the deformed part, and the lower electrode from above to form pixels of a predetermined shape, and cleaning and drying.

In the thin film type optical path adjusting apparatus according to the present invention, an image signal generated from the transistor incorporated in the active matrix is applied to the lower electrode through the pad and the plug. At the same time, a bias voltage is applied to the upper electrode to generate an electric field between the upper electrode and the lower electrode. The deformation between the upper electrode and the lower electrode causes deformation due to this electric field. The deformed portion is contracted in a direction perpendicular to the electric field, so that the actuator is bent in the direction opposite to the direction in which the lower electrode is formed. Therefore, the mirror formed on the upper electrode is inclined in the same direction with a predetermined angle in accordance with the deformation of the deformed portion. In this case, since the actuator is formed to have a curved shape in which the actuator is rotated by 90 degrees in a plurality of clockwise directions, the actuating part has a maximum length so that the driving angle of the mirror can be increased even in a narrow area have.

Therefore, in the thin film optical path adjusting apparatus according to the present invention, the actuator has a plurality of curvatures so that the mirror can be driven at a maximum driving angle even within a narrow area. Thereby, the light efficiency of the light flux incident from the light source can be increased, and the contrast of the image formed by the reflected light flux can be improved and a clear image can be formed. In addition, the design of the system can be facilitated by increasing the distance between the light source and the screen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thin film optical path adjusting apparatus and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a cross-sectional view of a thin film type optical path adjusting apparatus according to the present invention, and FIGS. 5A to 5E are process diagrams of the apparatus shown in FIG.

Referring to FIG. 4, the thin film type optical path adjusting apparatus according to the present invention includes an active matrix 21 and an actuator 39 formed on the active matrix 21.

4, the active matrix 21 includes a pad 22 formed on one side of the active matrix 21, a protective layer 23 stacked on the active matrix 21 and the pad 22, An etch stopper layer 25 stacked on top of the protective layer 23 and a plug 24 formed vertically from the etch stopper layer 25 to the pad 22.

One side of the actuator 39 is in contact with a portion of the etching preventing layer 25 where the plug 24 is formed and the other side is rotated by 90 ° in a plurality of clockwise directions through the first air gap 27, A lower electrode 33 laminated on the etch stop layer 25 having a self-coupled shape and a deformation part 35 stacked on the lower electrode 33, And includes a stacked upper electrode 37.

A mirror 43 is formed at an upper portion of one side of the upper electrode 37 of the actuator 39 such that the middle portion is in contact with the upper portion of the upper electrode 37 and the both sides of the actuator 39 are parallel to the upper electrode 37 via the second air gap 41 have. The mirror 43 is formed in a flat plate shape having a central portion projecting downward and in contact with an upper portion of one side of the upper electrode 37, one side covering the upper electrode 37 and the other side covering an adjacent actuator.

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

FIGS. 5A to 5E are a manufacturing process diagram of the thin film type optical path adjusting apparatus shown in FIG. 5A to 5E, the same reference numerals are used for the same members as those in Fig.

5A, a pad 22 is formed on an active matrix 21 in which M × N (M, N is an integer) MOS transistors (not shown) are embedded. The pad 22 is made of tungsten or the like and is electrically connected to a transistor incorporated in the active matrix 21. [ A protective layer 23 is laminated on the pad 22 and the active matrix 21 using phosphorous silicate glass (PSG). The protective layer 23 is formed to have a thickness of about 1.0 to 2.0 탆 by using a chemical vapor deposition (CVD) method. The protective layer 23 prevents the active matrix 21 from being damaged during subsequent processing.

The etch stop layer 25 is formed by depositing nitride on the protective layer 23 to a thickness of about 1000 to 2000 ANGSTROM using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 25 prevents the active matrix 21 and the passivation layer 23 from being etched and damaged when the first sacrifice layer 29 is etched. Subsequently, a portion of the etching preventing layer 25 and the protective layer 23 where the pad 22 is formed is etched, and then a plug 24 made of tungsten, titanium or the like is formed. The plug 24 is formed vertically from the etch stop layer 25 to the pad 22 by a lift-off method. Thus, the plug 24 is electrically connected to the pad 22 and transfers the image signal generated from the transistor incorporated in the active matrix to the lower electrode 33. [

A phosphorus silicate glass (PSG) or the like is formed on the etching preventing layer 25 and the plug 24 by an atmospheric pressure CVD (APCVD) method to have a thickness of about 1.0 to 2.0 μm The first sacrificial layer 29 is laminated. In this case, since the first sacrificial layer 29 made of the silicate glass covers the surface of the active matrix 21 in which the transistor is embedded, the flatness of the surface is very poor. Therefore, the surface of the first sacrificial layer 29 is planarized by a method using spin on glass (SOG) or a chemical mechanical polishing (CMP) method. Then, a portion of the first sacrificial layer 29 is etched to expose a portion of the etch stopper layer 25 where the plug 24 is formed.

A second sacrificial layer 31 is deposited on the first sacrificial layer 29 to a thickness of 1.0 to 2.0 탆 by using atmospheric pressure chemical vapor deposition (PSG) do. Then, the surface of the second sacrificial layer 31 is planarized by using a spin-on-glass (SOG) method or a CMP method. Then, the second sacrificial layer 31 is patterned using a negative resist so that the second sacrificial layer has a curved shape in which 'convex' is repeated at regular intervals.

Referring to FIG. 5B, the lower electrode 33 is stacked on the exposed portion of the etch stop layer 25 and on the first sacrificial layer 29 and the second sacrificial layer 31. The lower electrode 33 is formed of a metal such as platinum or tantalum using a sputtering method to have a thickness of about 500 to 2000 angstroms. The lower electrode 33, the plug 24, and the pad 22 are electrically connected to each other. Accordingly, the lower electrode 33 is deposited on the first sacrificial layer 29 and the second sacrificial layer 31 to have a plurality of 'convex' shapes repeated along the horizontal plane. The image signal is applied to the lower electrode 33 and the lower electrode 33 also acts as a membrane when the deformed portion 35 is deformed. Therefore, in the thin film type optical path adjusting device described in the prior application, . Therefore, a process for manufacturing a membrane is not required, and the manufacturing process is simplified. Subsequently, the lower electrode 33 is etched and patterned to separate each pixel.

Referring to FIG. 5C, a deformed portion 35 composed of ZnO is stacked on the upper portion of the patterned lower electrode 33. The deformed portion 35 is formed to have a thickness of about 0.1 to 1.0 탆, preferably about 0.4 탆 at a temperature of 300 to 400 캜 by a sputtering method or a chemical vapor deposition (CVD) method. . Therefore, the deformed portion 35 has a curved shape in which a plurality of clockwise '90' -rotated shapes are coupled with each other according to the shape of the lower electrode 33. When the deformed portion 35 is formed using ZnO as described above, PZT or PLZT, which is a constituent material of a general deformed portion, is heat-treated at a temperature of 650 ° C or more to form a phase, thereby forming a deformed portion at a lower temperature than PZT or PLZT can do. Therefore, it is possible to minimize the damage of the active matrix 21 due to the high-temperature process.

The deformations 35 are then etched by dry etching to separate them into individual pixels. The upper electrode 37 is laminated on the upper portion of the deforming portion 35 using a metal such as platinum or tantalum (Ta), which is the same material as the lower electrode 33. The upper electrode 37 is formed to have a thickness of about 500 to 1000 ANGSTROM by a sputtering method. A bias voltage is applied to the upper electrode 37. Subsequently, the upper electrode 37, the deformed portion 35, and the lower electrode 33 are patterned in a pixel shape sequentially from the upper portion of the upper electrode 37.

Referring to FIG. 5D, a mirror 43 is formed on one side of the upper electrode 37 to complete the actuator 39. The mirror 43 is formed to have a thickness of 500 to 1000 angstroms by using a conventional photolithography method and a sputtering method. The mirror 43 has a central portion protruding downward to be in contact with an upper portion of one side of the upper electrode 37 and a flat plate shape formed on both sides of the mirror 43 to be parallel to the upper electrode 37 via a second air gap 41. [ Respectively.

Referring to FIG. 5E, the first sacrificial layer 29 and the second sacrificial layer 31 are etched using hydrogen fluoride (HF) vapor, followed by washing and drying to complete the AMA device. At this time, the first sacrificial layer 29 and the second sacrificial layer 31 under the lower electrode 33 are etched to form a shape in which the lower electrode 33 is rotated by 90 ° in the clockwise direction .

The image signal generated from the transistor incorporated in the active matrix 21 is applied to the lower electrode 33 which is the signal electrode through the pad 22 and the plug 24 . At the same time, a bias voltage is applied to the upper electrode 37, which is a common electrode, to generate an electric field between the upper electrode 37 and the lower electrode 33. The deformation portion 35 between the upper electrode 37 and the lower electrode 33 is deformed by this electric field. The deformed portion 35 contracts in a direction perpendicular to the electric field so that the actuator 39 is bent in a direction opposite to the direction in which the lower electrode 33 is formed. At this time, as the length of the actuator 39 becomes longer, the driving angle of the mirror 43 on the upper part of the actuator 39 becomes larger. Therefore, as shown in Fig. 4, if the horizontal portion of the etching stop layer a lower electrode 33 is close to 25 d each of t _1, t _2, t ₃ from the close to the plug 24, from t ₁ deformable portion 35 of the to the other end of the field and are perpendicular to the shrinkage direction, so that t the actuator (39) at _1, causing the deformation has a driving angle θ size of the lower electrode 33 is formed in the direction Bend. the deformation portion 35 at t ₂ also contracts in a direction perpendicular to the electric field, so that the actuator 39 at t ₂ also deforms in the same direction with a driving angle of theta magnitude. Therefore, the sum of the driving angles of the actuator 39 at t ₁ and t ₂ is 2 ?. Further, the deformed portion 35 at t ₃ also contracts in a direction perpendicular to the electric field, so that the actuator 39 at t ₃ also deforms with a driving angle of theta size. At this time, the driving angle and the driving direction of the actuator 39 at t ₁ , t ₂ , and t ₃ are equal to each other. Therefore, the sum of the driving angles of the actuator 39 at t ₁ , t ₂ , and t ₃ becomes 3?. Since the mirror 43 that reflects the light beam incident from the light source is formed on the upper portion of the actuator 39, the mirror 43 is driven with a driving angle of 3?

By thus forming the actuator 39 having a plurality of bends in the form of a combination of a plurality of clockwise rotation of the actuator 39, the length of the actuator 39 can be increased even if the size of the AMA module is small, even within a small area . As the number of bends of the actuator 39 increases by 3 to 4 or more, the driving angle also increases by 3 to 4 times or more.

In the embodiment of the present invention, a thin film type optical path adjusting device having a driving angle of 3 [theta] is formed by forming an actuator having three deflections. However, by forming an actuator having four deflections, A thin film type optical path adjusting device having a larger driving angle can be manufactured by forming more bends by the above-described method.

Therefore, the thin film type optical path adjusting apparatus according to the present invention can form an actuator having a plurality of bends even in a narrow area, so that the driving angle of the mirror can be increased to three times or more as compared with the conventional optical path adjusting apparatus. Therefore, the light efficiency of the light flux incident from the light source can be increased, and the contrast of the image formed by the light flux reflected by the light path adjustment device can be improved, so that a bright and clear image can be formed. Also, in the design of the system, the interval between the light source and the screen can be widened to facilitate the design of the system.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited thereto and those skilled in the art may change or modify it within the ordinary skill of the art.

Claims (12)

An active matrix 21 in which M × N (M, N is an integer) transistors are embedded and a pad 22 is formed on one side of the active matrix 21; And (I) one side of the active matrix 21 on which the pad 22 is formed is in contact with one side, and the other side is bent in a plurality of clockwise directions through the first air gap 27, A deformed portion 35 stacked on the lower electrode 33 and an upper electrode 37 stacked on the deformed portion 35, And an actuator (39) having a curved shape formed by a plurality of clockwise '90' rotations according to the shape of the lower electrode (33). The method according to claim 1, wherein the active matrix (21) comprises a protective layer (23) laminated on the active matrix (21) and the pad (22), an etch stop layer 25), and a plug (24) formed vertically from the etch stop layer (25) to the pad (22) through the protective layer (23). The upper electrode (37) according to claim 1 or 2, wherein the upper electrode (37) is a mirror formed in parallel with the upper electrode (37) via a second air gap (41) (43). ≪ / RTI > The apparatus of claim 3, wherein the mirror (43) is a flat plate having a central portion protruding downward and in contact with an upper portion of one side of the upper electrode (37). Forming a pad on one side of an active matrix having M x N (M, N is an integer) transistors; And The method comprising the steps of: i) forming a lower electrode of the active matrix having the pad formed therein, ii) forming a deformation portion on the upper electrode, and iii) forming an upper electrode on the deformation portion, And forming an actuator having a curved shape in which a "? &Quot; 6. The method of claim 5, wherein forming the pad comprises: forming a passivation layer over the active matrix and the pad; forming an etch stop layer over the passivation layer; Further comprising forming a plug vertically from the etch stop layer to the pad by etching a part of the etch stop layer. 7. The method of claim 6, wherein the lower electrode is formed by stacking a first sacrificial layer on the etch stop layer and the plug, etching and patterning the exposed portion to expose the plug, Wherein the second sacrificial layer is formed by stacking two sacrificial layers, and then etching and patterning the plug so as to expose the plug. The method according to claim 7, wherein the second sacrificial layer is formed by patterning using a negative resist. [8] The method of claim 7, wherein the second sacrificial layer is formed to have a plurality of curved shapes that are rotated by 90 ° in a clockwise direction. [6] The method of claim 5, wherein the upper electrode of the actuator further comprises forming a mirror parallel to the upper electrode via the second air gap, Wherein the thin film-type optical path adjusting device comprises: The method according to claim 10, wherein the mirror is formed of a metal such as silver (Ag) or aluminum (Al) using a sputtering method. 6. The method of claim 5, wherein the step of forming the actuator further comprises: sequentially patterning the upper electrode, the deformed portion, and the lower electrode from above to form pixels having a predetermined shape, and cleaning and drying Wherein the thin film-type optical path adjustment device comprises: