KR100257602B1 - Projection type image display apparatus - Google Patents

Abstract

PURPOSE: An image display device is to reduce optical noise caused by an initial tilt angle by forming an actuator of an AMA(actuated mirror array) module in a structure that a lower electrode, a deforming layer, an upper electrode and a supporting layer are sequentially stacked. CONSTITUTION: Beam is generated in a light source. A projection lens projects an image on a screen. An AMA module(118) has a pixel array comprising a mirror(300) and an actuator(290) formed below the mirror for deforming the mirror. When a maximum signal is applied to the actuator, the mirror reflects an incident beam out of the projection lens. The actuator comprises a lower electrode(260) to which an image signal is applied, a deforming layer(265) deposited on the lower electrode, an upper electrode(270) deposited on the deforming layer to which a bias signal is applied and a supporting layer(275) deposited on the upper electrode. The mirror is mounted on the supporting layer through a post(295). When a signal is applied to the actuator, the mirror arranged on the supporting layer tilts in a direction opposite to a direction in which the supporting layer is formed.

Description

Projection type image display device

The present invention relates to a projection type image display device, and more particularly, to a projection type image display device including an Actuated Mirror Array (AMA) module used to project an image onto a screen. The present invention relates to a projection type image display device capable of reducing optical noise due to an initial tilting angle of the device.

In general, spatial light modulators, which are devices for projecting optical energy onto a screen, can be applied to various fields such as optical communication, image processing, and information display devices. Typically, such devices are classified into a direct-view image display device and a projection-type image display device according to a method of displaying optical energy on a screen.

An example of a direct-view image display device is a CRT (Cathode Ray Tube). The CRT device is called a CRT, which has excellent image quality but increases in weight and volume as the screen is enlarged, leading to an increase in manufacturing cost. There is. Examples of the projection image display apparatus include a liquid crystal display (LCD), a deformable mirror device (DMD), and an actuated mirror array (AMA). Such projection image display devices can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmissive spatial light modulators, while DMD and AMA can be classified as reflective spatial light modulators.

Transmission optical modulators, such as LCDs, have a very simple optical structure, which makes them thinner, lighter in weight, and smaller in volume. However, due to the polarity of the light, the light efficiency is low, there is a problem inherent in the liquid crystal material, for example, there is a disadvantage that the response speed is slow and the inside is easy to overheat. In addition, the maximum light efficiency of existing transmission light modulators is limited to a range of 1-2%, requiring dark room conditions to provide acceptable display quality.

Optical modulators such as DMD and AMA have been developed to solve the problems of the aforementioned LCD type optical modulators. DMD shows a relatively good light efficiency of about 5%, but serious fatigue problems are caused by the hinge structure employed in the DMD. In addition, there is a disadvantage that a very complicated and expensive driving circuit is required.

The AMA reflects the light incident from the light source at each of the mirrors installed therein, and the reflected light is projected on the screen through an aperture such as a slit or a pinhole. It is a device that can adjust the speed of light to form an image. Therefore, its structure and operation principle are simple, and high light efficiency (more than 10% light efficiency) can be obtained compared to LCD or DMD. In addition, the contrast of the image projected on the screen is improved to obtain a brighter and clearer image.

Each actuator of the AMA generates a deformation in accordance with the electric field generated by the applied electric picture signal and the bias signal. As the actuator deforms, each of the mirrors mounted thereon is tilted. Accordingly, the inclined mirrors reflect light incident from the light source at a predetermined angle to form an image on the screen. Piezoelectric materials such as PZT (Pb (Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as actuators for driving the respective mirrors. Further, the actuator may be configured by using a warping material such as PMN (Pb (Mg, Nb) O ₃ ).

These AMAs are largely divided into bulk type and thin film type. Such bulk AMA is disclosed in US Pat. No. 5,085,497 to Gregory Um et al. The bulk AMA is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then processing by a sawing method and installing a mirror thereon. However, bulk AMA requires very high precision in design and manufacture, and has a disadvantage of slow response of the strained layer. Accordingly, recently, a thin film type AMA that can be manufactured using a semiconductor manufacturing process has been developed. For example, such a thin film type AMA is disclosed in Korean Patent Application No. 95-13353 filed by the applicant of the Korean Patent Office.

The thin film type AMA is a reflective type light modulator using a thin film piezoelectric actuator in connection with microscopic mirrors. It has been developed to have. The thin film type AMA is composed of 640x480 pixels representing red (R), green (G), and blue (B), respectively. The pixels are designed as a cantilever structure to maximize the mirror surface area to increase the light efficiency. The container structure includes an active matrix to which an image signal is applied and a mirror operated by the applied signal.

A conventional projection type image display device including a single panel thin film type AMA module is shown in FIG. Referring to FIG. 1, a conventional projection type image display apparatus 10 includes a metal halide lamp 11 of 170 W to 250 W for emitting light, and a reflector for reflecting light from the lamp 11. reflector 15, a source lens 12 for condensing the light rays emitted from the lamp 11, a source stop 13 for determining the amount of light rays forming an image with apertures for passing the light rays ), A source mirror 14 for primarily changing the path of the light ray passing through the source stop 13, and a field for mapping the image of the source stop 13 to the projection stop 20 at 1: 1. Lens 16, an array of mirror pixels, an AMA module 18 for modulating the intensity of the light emitted from the field lens 16, an aperture for passing the light and having an aperture for To concentrate the flux The stop projection (20) to, and includes a projection lens 22 for projecting a light beam passing through the stop projection (20) on a screen (not shown).

The operation principle of the conventional projection type image display apparatus 10 having the above-described structure will be described with reference to FIGS. 1 and 2 as follows.

First, light rays emitted from the halogen metal lamp 11 are collected by the source lens 12, and then irradiated through the opening of the source stop 13 to the source mirror 14 so that the optical path is primarily changed. . The light reflected by the source mirror 14 is irradiated onto the AMA module 18 with parallel light through the field lens 16. Each mirror of the AMA module 18 vibrates, tilts or bends according to a signal applied to an actuator provided thereunder. Accordingly, light rays passing through the field lens 16 are reflected from the mirrors and then passed through the opening of the projection stop 20 to be projected on the screen through the projection lens 22 to form an image.

For example, if a signal is not applied to each actuator of the AMA module 18 (ie, 0V state), the corresponding mirror does not vibrate, tilt or bend. As a result, as shown in FIG. 2A, the light beam is imaged out of the projection stop 20 and thus cannot reach the screen (not shown). Thus, in the initial state, a black image is displayed on the screen.

If a signal smaller than the maximum signal is applied to each actuator of the AMA module 18, the mirror corresponding thereto is inclined to some extent so that some of the incident light beams pass through the opening of the projection stop 20. Thus, as shown in FIG. 2B, some of the light rays reflected by each mirror of the AMA module 18 are reflected by the front surface of the projection stop 20, and the remaining light rays are the openings of the projection stop 20. Display an image on the screen by passing through it.

If the maximum signal is applied to each actuator of the AMA module 18, the mirror corresponding thereto is tilted completely so that all incident rays are directed through the opening of the projection stop 20. As a result, as shown in Fig. 2C, the light rays reflected by each mirror of the AMA module 18 are all projected onto the screen by the projection lens 22 after passing through the opening of the projection stop 20 and are white. (white) Displays an image. At this time, the path of the light beam reflected from each mirror determines the intensity of the light beam passing through the opening of the projection stop 20. That is, the flux of the light rays passing through the opening of the projection stop 20 is controlled by the direction of the mirror of the AMA module 18 with respect to the projection stop 20.

3 is a cross-sectional view of the AMA module 18. Referring to FIG. 2, the AMA module 18 includes an active matrix 30 and an actuator 90 having a container structure formed on the active matrix 30. The active matrix 30 includes a protective layer 40 stacked on the active matrix 30 and the drain pad 35, and an etch stop layer 45 stacked on the protective layer 40.

The actuator 90 has one side in contact with a portion of the etch stop layer 45 in which the drain pad 35 is formed, and the other side has a membrane 55 and a membrane formed horizontally through the air gap 50. Lower electrode 60 stacked on top of 55, strained layer 65 stacked on top of lower electrode 60, upper electrode 70 stacked on top of strained layer 65, and the strained layer. In the via hole 80 formed from the one side of the 65 to the drain pad 35 through the strained layer 65, the lower electrode 60, the membrane 55, the etch stop layer 45, and the protective layer 40. The via electrode 85 includes a lower electrode 60 and a drain pad 35 connected to each other.

In the AMA module 18 having the above-described structure, the first signal (image signal) transmitted from the outside is connected to the lower electrode through the transistor, the drain pad 35 and the via contact 85 embedded in the active matrix 30. Is applied to 60. In addition, a second signal (bias signal) is applied to the upper electrode 70 to deform the strained layer 65 formed between the upper electrode 70 and the lower electrode 60, thereby deforming the strained layer 65. The actuator 90 to be included is bent upwards. Therefore, the upper electrode 70 on the actuator 90 is also bent in the same direction. Light rays incident from the light source are reflected by the upper electrode 70 bent at a predetermined angle, and then are projected onto a screen to form an image.

However, the actuator 90 having the tilter structure as shown in FIG. 3 is convex downward due to the compressive residual stress present in the lower electrode 60, the strained layer 65, and the upper electrode 70 which are sequentially stacked. Since it is bent so much, there is always an initial inclination angle of about 3 ° to 5 ° even when no signal is applied. In general, the unit mirror of the AMA module 18 has an inclination angle of 3 ° when a maximum voltage of 10V is applied. Therefore, the optical system using the AMA module 18 should be configured to handle an inclination angle of about 6 ° to 9 °, such that the 'sum of the initial inclination angle and the drive tilting angle' is larger, the design of the optical system. Becomes difficult and the optical noise becomes severe.

Accordingly, it is an object of the present invention to provide a projection image display apparatus which can reduce optical noise due to the initial tilt angle of the AMA module in the projection image display apparatus using the AMA module.

1 is a schematic diagram showing a conventional projection type image display apparatus.

2A and 2C are schematic views for explaining a light projection method by the apparatus shown in FIG.

3 is a cross-sectional view of the AMA used in the apparatus shown in FIG. 1.

4 is a schematic diagram showing a projection image display device according to the present invention.

FIG. 5 is a sectional view of an actuated mirror array module used in the apparatus shown in FIG. 4. FIG.

6A through 6D are cross-sectional views illustrating a method of manufacturing the actuated mirror array module shown in FIG. 5.

7A to 7C are schematic views for explaining a light projection method by the apparatus shown in FIG.

<Explanation of symbols for main parts of the drawings>

100: AMA optical system 111: lamp

112: source lens 113: source stop

114: source mirror 115: reflector

116: field lens 118: AMA module

120: projection stop 122: projection lens

200: active matrix 215: drain pad

220: protective layer 225: etching prevention layer

255: air gap 260: lower electrode

265 strain layer 270 upper electrode

275 support layer 280 beer hole

285: via contact 300: mirror

In order to achieve the above object, the present invention provides a light source for generating light beams, a projection lens for projecting an image on a screen, and an actuator for deforming the mirror according to a mirror and a signal formed under and applied to the mirror. And an AMA module having an array of pixels, the AMA module reflecting light rays incident on the mirror out of the projection lens when a maximum signal is applied to the actuator.

As described above, according to the present invention, the actuator of the AMA module is formed in a structure in which a lower electrode, a deformation layer, an upper electrode, and a support layer are sequentially stacked, thereby applying a first signal to the lower electrode and a second to the upper electrode. When the signal is applied, the strained layer formed between the upper electrode and the lower electrode causes the strain, thereby causing the actuator including the strained layer to bend downward. In the initial state where no signal is applied to the actuator, due to the initial tilt angle of the actuator itself (i.e., the tilt angle of 3 ° to 5 °), the light reflected by the mirror tilted upwards passes through the projection stop and the white ( white) When the maximum signal is applied to the actuator, the light reflected by the mirror tilted downward at an inclination angle of about -3 ° forms an image beyond the projection stop, and thus a black image is displayed on the screen. Is displayed.

Therefore, the optical system only needs to process an angle of '3 ° to 5 ° initial inclination angle + about -3 ° driving inclination angle = about 0 ° to 2 °', making it easier to design and reduce optical noise as compared with the conventional structure. have.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 4 is a schematic diagram showing a projection type image display apparatus including a single plate type thin film type AMA module according to the present invention, illustrating a single plate type monochrome system.

Referring to FIG. 4, the projection image display apparatus 100 according to the present invention includes a lamp 111 for emitting light rays, a source lens 112, a source stop 113, a reflector 115, and a field lens 116. , AMA module 118, projection stop 120, and projection lens 122.

The lamp 111 for emitting light is preferably a 170W to 250W halogen metal lamp that emits long wavelength infrared (LWIR) to ultraviolet (UV) light in the spectrum. The reflector 115 serves to reflect the light emitted from the lamp 111 in the opposite direction with respect to the source lens 112 so as to be directed back to the source lens 112.

The source lens 112 collects light rays emitted from the lamp 111. The source stop 113 is an optically opaque member and has an opening formed to allow light to pass therethrough. The source stop 113 determines the amount of light that forms the image.

The field lens 116 transmits each ray passing through the source stop 113 without light loss so that the image of the source stop 113 corresponds to the projection stop 120 at 1: 1. 118).

The AMA module 118 has an array of pixels consisting of a mirror for reflecting the irradiated light rays and an actuator for modifying the mirror according to a signal formed under and applied to the mirror. Unlike the conventional method shown in FIG. 3, the AMA module 118 according to the present invention forms an actuator in a structure in which a lower electrode, a deformation layer, an upper electrode, and a support layer are sequentially stacked, thereby providing a first signal to the lower electrode. When the second signal is applied to the upper electrode, the strained layer formed between the upper electrode and the lower electrode causes deformation, and thus the actuator including the strained layer is bent downward.

5 is a cross-sectional view of the AMA module 118. Referring to FIG. 5, the AMA module 118 includes an active matrix 200, an actuator 290, and a mirror 300. The active matrix 200 in which an M × N (M, N is an integer) MOS transistor (not shown) is formed therein and a drain pad 215 extending from the drain of the transistor is formed. ) And a protective layer 220 stacked on the drain pad 215 and an etch stop layer 225 stacked on the protective layer 220.

The actuator 290 may have one side contacting a portion of the etch stop layer 225 in which a drain pad 215 is formed and a lower electrode 260 and a lower electrode formed horizontally through the air gap 255. The strained layer 265 formed on the upper portion of the 260, the upper electrode 270 formed on the strained layer 265, the support layer 275 formed on the upper electrode 270, and one side of the strained layer 265. The lower electrode 260 and the drain in the via hole 280 formed perpendicularly to the drain pad 215 through the strained layer 265, the lower electrode 260, the etch stop layer 225, and the protective layer 220. The pad 215 includes a via contact 285 formed to be connected to each other.

The mirror 300 is supported by a post 295 formed on one side of the support layer 275, and has a rectangular flat plate shape formed on both sides of the mirror 300.

6A to 6D are manufacturing process diagrams of the AMA module. Referring to FIG. 6A, a protective layer 220 is formed by using an silicate glass (PSG) on top of an active matrix 200 having M × N MOS transistors (not shown) and a drain pad 215 formed thereon. Laminated. The protective layer 220 is formed to have a thickness of about 1.0 μm using a chemical vapor deposition (CVD) method. The protective layer 220 protects the active matrix 200 in which the transistor is embedded during a subsequent process.

An etch stop layer 225 made of nitride is stacked on the passivation layer 220. The etch stop layer 225 is formed to have a thickness of about 1000 to 2000 kPa using a low pressure chemical vapor deposition (LPCVD) method. The etch stop layer 225 prevents the protective layer 220, the active matrix 200, and the like from being etched during the subsequent etching process. The first sacrificial layer 230 is stacked on the etch stop layer 225. The first sacrificial layer 230 is formed of phosphorous silicate glass (PSG) having a high concentration of phosphorus (PG) to have a thickness of about 1.0 to 3.0 μm by using an atmospheric chemical vapor deposition (APCVD) method. . In this case, since the first sacrificial layer 230 covers the upper portion of the active matrix 200 in which the transistor is embedded, the flatness of the surface is very poor. Accordingly, the surface of the first sacrificial layer 230 is planarized by using spin on glass (SOG) or chemical mechanical polishing (CMP). Subsequently, an anchor, which is a support part of the actuator 290, may be formed by etching a portion of the first sacrificial layer 230 in which the drain pad 215 is formed below to expose a portion of the etch stop layer 225. Make a location.

Referring to FIG. 6B, a metal such as platinum (Pt), tantalum (Ta), or platinum-tantalum (Pt-Ta) is disposed on the exposed etch stop layer 225 and on the first sacrificial layer 230. The configured lower electrode 260 is stacked. The lower electrode 260 is formed to have a thickness of about 0.01 to 1.0 µm using a sputtering method. The first electrode (image signal) is applied to the lower electrode 260 through a transistor built in the active matrix 200 from the outside.

A strained layer 265 made of a piezoelectric material such as PZT or PLZT is stacked on the lower electrode 260. The strained layer 265 is formed to have a thickness of about 0.1-1 .0 μm, preferably about 0.4 μm by using a sol-gel method, followed by heat-treatment using a rapid heat treatment (RTA) method to phase change. . In the strained layer 265, a second signal (bias signal) is applied to the upper electrode 270, and a first signal is applied to the lower electrode 260 according to a potential difference between the upper electrode 270 and the lower electrode 260. It is deformed by the generated electric field.

The upper electrode 270 is stacked on the strained layer 265. The upper electrode 270 is formed of a metal having excellent electrical conductivity such as aluminum or platinum so as to have a thickness of about 0.01 to 1.0 탆 using a sputtering method. The second signal is applied to the upper electrode 270 through a common electrode line (not shown) from the outside.

On the upper electrode 270, a support layer 275 is stacked to a thickness of about 0.01 to 1.0 mu m. The support layer 275 is formed using low pressure chemical vapor deposition (LPCVD). At this time, the support layer 275 is formed while changing the ratio of the reaction gas in the low pressure reaction vessel to adjust the stress in the support layer 275.

Referring to FIG. 6C, the support layer 275, the upper electrode 270, the strain layer 265, and the lower electrode 260 are each patterned to have a predetermined pixel shape, and then, from one side of the strain layer 265. The strained layer 265, the lower electrode 260, the etch stop layer 225, and the protective layer 220 are sequentially etched up to the drain pad 215 so as to be perpendicular from the strained layer 265 to the drain pad 215. The via hole 280 is formed. Subsequently, a via contact 285 is formed in the via hole 280 to electrically connect the drain pad 215 and the lower electrode 260 by sputtering a metal such as tungsten, platinum, or titanium. Thus, the via contact 285 is formed vertically from the lower electrode 260 to the drain pad 215 in the via hole 280. Therefore, the first signal is applied from the outside to the lower electrode 260 through the MOS transistor, the drain pad 215, and the via contact 285 embedded in the active matrix 200.

Subsequently, platinum-tantalum (Pt-Ta) is deposited on the bottom of the active matrix 200 using a sputtering method to form a backside metal layer (not shown). Subsequently, the first sacrificial layer 230 is etched with hydrogen fluoride (HF) vapor to form an air gap 255 at the position of the first sacrificial layer 230 to complete the actuator 290.

Referring to FIG. 6D, after forming the air gap 255 as described above, the second sacrificial layer 292 is formed on the entire surface of the resultant. The second sacrificial layer 292 is formed using a spin coating method such as a polymer having good fluidity, and is formed to completely cover the actuator 290 while completely filling the air gap 255. Subsequently, the second sacrificial layer 292 is patterned using a photolithography process to form a post 295 in which the mirror 300 is to be formed on one side of the support layer 275. Subsequently, aluminum (Al) or silver (Ag) having good reflectivity is formed on the second sacrificial layer 292 and the exposed support layer 275 by a sputtering method to a thickness of about 0.01 to 1.0 µm. Deposition to form a mirror 300. After the mirror 300 is formed as described above, the second sacrificial layer 292 is removed using an oxygen plasma (O ₂ plasma), and rinsing and drying are performed to complete the AMA module as shown in FIG. 5. do.

In the above-described AMA module, when the first signal is applied to the lower electrode 260 and the second signal is applied to the upper electrode 270, an electric field according to a potential difference between the upper electrode 270 and the lower electrode 260 is applied. Will occur. Due to the electric field, the strained layer 265 formed between the upper electrode 270 and the lower electrode 260 causes deformation, and the strained layer 265 shrinks in a direction perpendicular to the electric field. Accordingly, the actuator 290 including the deformation layer 265 is bent downward in the direction opposite to the direction in which the support layer 275 is formed, that is, in the figure. The mirror 300 mounted on the upper portion of the support layer 275 reflects light incident from the light source by being tilted downward by moving its axis by the bent support layer 275. Light rays incident from the light source are reflected by the tilted mirror 300 at a predetermined angle and then projected onto a screen to form an image.

Referring again to FIG. 4, the projection stop 120 is an optically opaque member and has an optically reflective surface and an opening formed to pass a light beam. Preferably, the opening is a pinhole or slit. The flux of light rays passing through the opening of the projection stop 120 controls the intensity of the light rays reflected by each mirror of the AMA module 118. The projection lens 122 projects a ray passing through the opening of the projection stop 120 on a screen (not shown) to display a corresponding image.

The operation principle of the projection image display apparatus 100 according to the present invention having the above-described structure will be described with reference to FIGS. 4 and 7 as follows.

First, light rays emitted from the halogen metal lamp 111 are collected by the source lens 112, and then irradiated through the opening of the source stop 113 to the source mirror 114 so that the optical path is primarily changed. . The light reflected by the source mirror 114 is irradiated onto the AMA module 118 through parallel light through the field lens 116.

If a signal is not applied to each actuator of the AMA module 118 (ie, 0V state), the corresponding mirror does not vibrate, tilt or bend. However, since each of the actuators has an initial inclination angle of 3 ° to 5 °, each mirror of the AMA module 118 is tilted upward with the initial inclination angle described above even in the initial state where no signal is applied. As a result, as shown in FIG. 7A, the light rays reflected from each mirror of the AMA module 118 are projected onto the screen by the projection lens 122 after all of the light passes through the opening of the projection stop 120. , A white image is displayed.

If a signal less than the maximum signal is applied to each actuator of the AMA module 118, only a part of the light rays incident by the mirror corresponding thereto is tilted downward with a predetermined inclination angle passes through the opening of the projection stop 120. do. Thus, as shown in FIG. 7B, some of the light rays reflected by each mirror of the AMA module 118 are reflected by the front surface of the projection stop 120, and the remaining light rays are the openings of the projection stop 120. Display an image on the screen by passing through it.

If the maximum signal is applied to each actuator of the AMA module 118, the mirror corresponding thereto is fully tilted downward with an inclination angle of -3 °. As a result, as shown in FIG. 7C, the light rays reflected by each mirror of the AMA module 118 are imaged out of the projection stop 120 and thus cannot reach the screen (not shown). Therefore, since a black image is displayed on the screen when the maximum signal is applied, the projection type image display device of the present invention can be driven using the signal inverted by the existing driving circuit.

Here, each mirror of the AMA module 118 is deformed to a deformation size corresponding to the intensity of the corresponding one pixel among the plurality of pixels displayed on the screen, and the path of the light rays reflected from each mirror is projected. The intensity of the light rays passing through the opening of the stop 120 is determined. That is, the flux of the light rays passing through the opening of the projection stop 120 is controlled by the direction of the mirror of the AMA module 118 relative to the projection stop 120.

Here, FIG. 4 illustrates a monochromatic system using a single-plate AMA, but in accordance with another preferred embodiment of the present invention, a series of color segments of a red transmission filter, a green transmission filter and a blue transmission filter The invention can be applied to a single-plate color system capable of displaying red, green and blue images by sequentially illuminating red, green and blue light to a single panel AMA using a color wheel. have.

In addition, according to another preferred embodiment of the present invention, the present invention can be applied to a multi-panel color system using a three panel AMA.

As described above, according to the present invention, the actuator of the AMA module is formed in a structure in which a lower electrode, a deformation layer, an upper electrode, and a support layer are sequentially stacked, thereby applying a first signal to the lower electrode and a second to the upper electrode. When the signal is applied, the strained layer formed between the upper electrode and the lower electrode causes the strain, thereby causing the actuator including the strained layer to bend downward. In the initial state when no signal is applied to the actuator, the light reflected by the mirror tilted upward due to the initial tilt angle of the actuator itself (i.e., the tilt angle of 3 ° to 5 °) passes through the projection stop and the white image is displayed on the screen. In the state where the maximum signal is applied to the actuator, the light reflected by the mirror tilted downward at an inclination angle of about -3 ° is imaged beyond the projection stop, and a black image is displayed on the screen.

Therefore, the optical system can handle an angle of "initial inclination angle of 3 degrees to 5 degrees + driving inclination angle of about -3 degrees = about 0 degrees to 2 degrees", so that the design is easier and the optical noise can be reduced as compared with the conventional structure. have.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (3)

A light source 111 for generating light rays; A projection lens 122 for projecting an image onto the screen; And It has an array of pixels consisting of a mirror 300 and an actuator 290 for deforming the mirror 300 according to the signal formed and applied to the lower portion of the mirror 300, the maximum signal to the actuator 290 And an actuated mirror array (AMA) module (118) that, when applied, reflects an incident ray of the mirror out of the projection lens (122). 2. The actuator 290 of claim 1, wherein the actuator 290 is stacked on the lower electrode 260 to which an image signal is applied, the strained layer 265 stacked on the lower electrode 260, and the strained layer 265. And an upper electrode 270 to which a bias signal is applied, and a support layer 275 stacked on the upper electrode 270, and the mirror 300 has a post 295 on the support layer 275. Projection type image display device characterized in that mounted via. The method of claim 2, wherein when a signal is applied to the actuator 290, the mirror 300 mounted on the support layer 275 is tilted in a direction opposite to the direction in which the support layer 275 is formed. Projection type image display device.

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