KR100530645B1 - Method for transferring - Google Patents

Abstract

An object of the present invention is to provide a transfer method for transferring a mirror element formed on a heat-resistant substrate having light transparency to another substrate.

A transfer method for transferring a mirror element formed on a heat resistant substrate having a light transmitting property to another substrate, comprising: forming a light absorption layer on the heat resistant substrate, forming a mirror element on the light absorption layer, and the mirror element And a step of pressing the other substrate, and irradiating light to the light absorbing layer to cause peeling of the light absorbing layer.

Description

Transfer Method {METHOD FOR TRANSFERRING}

The present invention relates to a transfer method for transferring a mirror element formed on a heat resistant substrate having light transmittance to another substrate.

Conventionally, an optical modulation device for performing optical modulation by a reflecting mirror has been manufactured by joining a reflection mirror and a driving substrate together. For example, U. S. Patent No. 4,441, 791 discloses a method of manufacturing a reflective mirror film and a structure of an optical modulation device using the reflective mirror film. According to this document, a reflecting mirror film was first formed by flowing a nitrocellulose film on the surface of the water, and then pulling it onto a screen on a mesh to deposit a metal film. However, in this technique, since no reflective mirror film is formed on a rigid substrate, it is considered difficult to attach a thin reflective mirror film without physical deformation to an appropriate position on the drive element substrate. When the reflective mirror film is attached to the driving device substrate in a loose state, the light reflected in an unnecessary direction increases when modulating the illumination light, the contrast of the modulated light and the non-modulated light decreases, and the light utilization efficiency decreases. Raises the problem.

In Japanese Patent Laid-Open No. 6-301066, a mirror array is provided on a glass substrate, and a resin layer is formed. Then, the resin layer is peeled off together with the mirror array from the substrate to effect the actuator. An technique for bonding an actuator to a substrate is disclosed. However, the technique disclosed in this document is a technique for bonding a light reflecting film to an actuator gear array. In order to drive the actuator array, a process of joining the drive element substrate to the actuator array is further required. Therefore, there is a problem that the method of manufacturing the optical modulation device is complicated.

In order to avoid such a problem, it is thought that after forming a reflection mirror on the board | substrate, such as a silicon, it is preferable to manufacture an optical modulation device by removing the deformation | transformation part of a reflection mirror by etching etc. in a window shape. That is, it is possible to provide a light modulation device having a simple structure in which the reflection mirror is not formed in a loose shape. According to the optical modulation device manufactured in this way, the illumination light required for display is incident through the window provided on the silicon substrate, is reflected by the reflection mirror, and is again emitted through the window.

However, even when such an optical modulation device is devised, a problem arises in that light is diffusely reflected to cause a decrease in brightness and contrast of a projected image. In the configuration in which the window is provided on the substrate, since the incidence and injection of light are performed through the window provided on the substrate, part of the reflected light is blocked or diffused by sidewalls of the window. Since the substrate requires a constant film thickness (about 100 µm) for easy and safe handling in the manufacturing process, the height of the sidewalls cannot be made clear, that is, the substrate cannot be made thin. Since the minimum board | substrate needs a thickness of about 100 micrometers, for example, in the optical modulation device whose width | variety of a window is 50 micrometers, the side wall of a window turns into height twice the width. This causes a significant portion of the light reflected at the peripheral portion of the reflecting mirror to be blocked or reflected at the sidewalls, thus becoming a so-called diffuse reflection state. When the image is displayed based on the diffusely reflected light, the brightness of the projected image is insufficient because the amount of light is insufficient, and the contrast is reduced because light from other pixels is mixed.

A first object of the present invention is to provide a method of manufacturing an optical modulation device capable of light modulation with high efficiency of light by providing a reflection mirror so that it is easy to deform without being diffused and loose. will be.

The 2nd subject of this invention is providing the projector by which the projection mirror which is excellent in a clear contrast is obtained by providing the reflecting mirror which is easy to deform without a diffuse reflection and is not loose.

Moreover, this invention provides the transfer method which transfers the mirror element formed in the heat resistant substrate which has light transmittance to another board | substrate.

The invention to solve the first problem,

a) the peeling layer formation process of forming the peeling layer which generate | occur | produces peeling by irradiation of irradiation light to the heat resistant substrate which has heat resistance,

b) a reflection mirror layer forming step of forming a reflection mirror layer configured to reflect light by a piezoelectric body (for example, a ferroelectric or usually dielectric piezoelectric ceramic) on the release layer formed by the release layer forming step;

c) An active element (a thin film transistor, etc.) electrically connects the driving substrate provided corresponding to the pixel region and the reflective mirror layer laminated on the heat resistant substrate in pixel region units (eg, the output of the active element is the second electrode thin film). Connecting process),

d) A method of manufacturing an optical modulation device having an irradiation separation step of irradiating light from the heat-resistant substrate side to generate a peeling on the release layer and separating the heat-resistant substrate.

In the reflective mirror layer, layers other than the piezoelectric layer may be formed. The piezoelectric layer may have a plurality of laminated structures.

For example, the reflective mirror layer forming step may include forming a first electrode thin film on the release layer, forming a piezoelectric thin film on the first electrode thin film, and forming a second electrode thin film on the piezoelectric thin film. It is composed. Here, it is preferable to form the first electrode thin film with a material having light reflectivity. Further, at least one of the first electrode thin film and the second electrode thin film may be formed of a light reflective material.

In the forming of the reflective mirror layer, after the step of forming the second electrode thin film, the second electrode thin film and the piezoelectric thin film are electrically patterned in units of pixel areas to form a pattern (a quadrangle, And forming a polygon or a circle). Specifically, in the step of patterning the second electrode thin film and the piezoelectric thin film, the second electrode thin film and the piezoelectric thin film are patterned into polygons. Further, the second electrode thin film and the piezoelectric thin film may be patterned in a circle.

In addition, the connecting step includes a step of providing a connecting electrode (for example, a pattern formed by forming a dyke shape by patterning gold) on either the driving substrate or the reflective mirror layer, and on the connecting electrode. Thereby, the process of electrically connecting a drive substrate and a reflecting mirror layer is provided. Specifically, in the connection step, the connection electrode is formed of gold.

The projector which solves the said 2nd subject is a projector provided with the optical modulation device manufactured by the manufacturing method of this invention,

a) an illumination optical system for illuminating parallelized illumination light from a direction substantially perpendicular to the optical modulation device;

b) a light shielding optical system for shielding either reflected light from a pixel region driven by an active element or an undriven pixel region in an optical modulation device;

and c) a display optical system for forming a display image by forming an image of light passing through the light shielding optical system.

In addition, the present invention is a transfer method for transferring a mirror element formed on a heat-resistant substrate having light transmittance to another substrate,

a) forming a light absorption layer on the heat resistant substrate,

b) forming a mirror element on the light absorbing layer;

c) pressing the mirror element with the other substrate, and

and d) irradiating light to the light absorbing layer to cause peeling on the light absorbing layer.

In addition, in the transfer method, the heat resistant substrate is characterized in that it comprises quartz glass.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, the preferred embodiment of this invention is described with reference to drawings.

(First embodiment)

A first embodiment of the present invention relates to a method of manufacturing an optical modulation device for use in a project of projecting an image onto a screen.

1 and 2 show a structural diagram of a substrate for each step of the manufacturing method of the first embodiment. These structural diagrams are sectional views of the manufacturing process in which some of the plurality of pixels formed on one substrate are displayed extensively.

Peeling layer forming process (Fig. 1 (a)):

First, a release layer (light absorption layer) 11 is formed on the substrate 10. It is assumed that the substrate 10 can transmit the irradiation light 12 (to be described later), which will be described later. It is preferable that the transmittance | permeability of irradiation light is 10% or more. This is because the lower the transmittance, the larger the attenuation of the irradiation light. In addition, the substrate 10 needs to be a material having heat resistance and high reliability for strength. In this embodiment, since the whole substrate needs to be placed in a high temperature environment in the thermal annealing step (Fig. 1 (c)), it is necessary to make no modification to this temperature. For this reason, quartz glass is used in a present Example. The thickness of the board | substrate 10 is about 0.1 mm-about 5 mm, Preferably it is about 0.5 mm-about 1.5 mm. This is because if the substrate is too thick, the attenuation of the irradiation light increases, and if too thin, the strength of the substrate decreases.

The release layer 11 absorbs the irradiation light 12 and causes peeling in the layer or the interface. That is, the peeling layer 11 is comprised of the material which loses or reduces the bonding force between atoms or molecules of a component by irradiation light, produces ablation etc., and causes peeling. As the composition of the release layer 11, amorphous silicon (a-Si) or polycrystalline silicon can be used. This is because amorphous silicon withstands heat of about 900 ° C. in the heat annealing step of the present embodiment and exhibits high absorption for constant irradiated light, and therefore is preferable as a material for the release layer. In addition, oxides, metals, and the like that can withstand the heat when thermally annealing the piezoelectric film and can be peeled off by the energy concentration of illumination light can be used as the material of the peeling layer. For example, when titanium oxide has a sufficiently high refractive index by a substrate made of quartz, it is considered that light is trapped by the film thickness and energy can be concentrated. Therefore, when forming a peeling layer with the thickness which can trap light in accordance with the wavelength of irradiation light, it is thought that titanium oxide can be used as a material of a peeling layer.

As thickness of the peeling layer 11, it is preferable that it is about 10 nm-20 micrometers, and it is more preferable that it is about 40 nm-2 micrometers. If the thickness of the exfoliation layer is too thin, the uniformity of the formed film thickness is lost and exfoliation becomes uneven. If the exfoliation layer is too thick, it is necessary to increase the power (light quantity) of the irradiation light required for exfoliation. This is because time is required to remove the residue of the peeling layer remaining after the peeling.

The formation method of the peeling layer 11 should just be a method which can form a peeling layer with uniform thickness, and can be suitably selected according to all conditions, such as composition and thickness of a peeling layer. When the composition of the release layer is amorphous silicon, it is preferable to form a film by the CVD method. For films of other compositions, general thin film formation methods such as sputtering and vapor deposition can be used.

1 and 2, an intermediate layer may be formed on the release layer 11. The intermediate layer functions as a barrier layer that prevents migration of components as a protective layer that insulates the transfer layer in production or use, for example. The composition of this intermediate layer is suitably selected according to the objective. For example, in the case of an intermediate layer formed between the release layer consisting of amorphous silicon and the transfer source layer, there may be mentioned silicon oxide, such as SiO _2. Examples of the composition of the other intermediate layer include metals such as Au, W, Ta, Mo, Cr, Ti, or alloys containing these as main components. The thickness of an intermediate | middle layer is suitably determined according to the purpose of formation. Usually, it is preferable that it is about 10 nm-about 5 micrometers, and it is more preferable that it is about 40 nm-about 1 micrometer. As the formation method of an intermediate | middle layer, the various methods demonstrated by the said peeling layer are applicable. The intermediate layer can be formed in two or more layers using a plurality of materials having the same or different composition, in addition to being formed in one layer. In Fig. 3, a transparent dielectric film 309 made of silicon dioxide is formed as an intermediate layer.

Piezoelectric layer formation (FIG. 1B):

On the release layer 11, a piezoelectric layer (reflective mirror layer) 3 in which the common electrode film 300 and the piezoelectric film 301 are laminated is formed. In the piezoelectric layer 3, however, the mirror electrode film 302 is formed after the thermal annealing process in order to prevent deterioration of characteristics due to thermal annealing. It is preferable that the composition of the common electrode film 300 is conductive and hardly changes in characteristics over time, and has a high resistance to heat in the manufacturing process, for example, a metal such as Pt.

As the piezoelectric film 301, a material whose shape is expanded and contracted by applying voltage is used. Ferroelectric voltage-sensitive ceramics are preferred, and lead zirconate titanate (Pb (Zr, Ti) O ₃ : PZT), lanthanum titanate ((Pb, La) TiO ₃ ), zirconate lanthanum ((Pb, La) ZrO ₃ : PLZT) or magnesium zirconate titanate (Pb (Mg, Nb) (Zr, Ti) O ₃ : PMN-PZT)). The piezoelectric film formation method is based on the sputtering method and the sol-gel method. Although the thickness of the piezoelectric film can be variously changed depending on the size of the required volume change, a piezoelectric film having a thickness of about 0.8 탆 can be formed.

After the common electrode film 300 is formed, the common electrode may be patterned using a known pattern forming technique.

Thermal Annealing Process ((c) of FIG. 1):

Next, heat annealing is performed to form a crystal structure that functions as a piezoelectric body. The piezoelectric layer 3 formed on the board | substrate 10 is put into a furnace, and the whole board | substrate is heated.

Pattern formation (Fig. 1 (d)):

After the thermal annealing treatment, the mirror electrode film 302 is formed on the piezoelectric film 301. It is preferable that the composition of the mirror electrode film 302 is hard to change in characteristics over time in conductivity, and has high resistance to heat in the manufacturing process. For example, metal thin films such as Pt, Ti, Al, and Ag are used.

The mirror electrode film 302 is patterned by applying a known pattern forming technique, for example, a photolithography method. That is, a resist coating, a mask, exposure, development and etching are performed to form a desired electrode pattern. In this pattern formation, the electrode portion remaining in each pixel is a mirror element 307 which is a reflection mirror. The mirror element 307 is formed as a shape and an area which can reflect illumination light sufficiently as a reflection mirror. The electrode area of the mirror element 307 on the mirror electrode film 302 side is patterned to be smaller than the electrode area on the common electrode film 300 side. After the pattern formation of the mirror electrode film 302, a voltage is applied to the piezoelectric film 301 and polarization is performed in a direction perpendicular to the film.

The deformation direction of the mirror element 307 will be described. When a driving voltage is applied to the piezoelectric film subjected to the polarization treatment as described above, the piezoelectric film shrinks to the inner surface in the polarization direction and the direction of the applied electric field. At this time, the common electrode film 300 is physically constrained in the bump 308, and the mirror electrode film 302 is not constrained except for a part thereof. For this reason, the mirror element 307 including the piezoelectric film is deformed so as to be convex upward in FIG. 2G.

After the pattern formation on the mirror electrode film 302, the bump 308 which is an electrode connection part which makes electrical connection with the mirror electrode connection thick film 207 formed later in the drain electrode of the thin film transistor 205 is formed. . Bump 308 is formed in part of the mirror element 307. Since the bump 308 is connected to the drain of the thin film transistor in an extremely small area, it is preferable that the bump 308 is formed of a material, for example, gold (Au), which has a small contact resistance and is hard to oxidize. In addition, in order to improve the adhesion between the bump 308 and the mirror electrode film 302, a metal bump may be further formed on the mirror electrode film to form gold bumps. The distance between the piezoelectric layer 3 and the thin film transistor substrate 2 needs to be such that the heat generated by the irradiation of the irradiation light 12 is hardly transmitted to the thin film transistor 205. Therefore, the height of the bump 308 from the mirror electrode film 302 is set so that the sum of the height and the height of the mirror electrode connection thick film 207 satisfies these conditions.

Connection process (Fig. 2 (e)):

Next, the thin film transistor substrate 2 and the piezoelectric layer 3 formed on the substrate 10 are electrically connected. The thin film transistor (TFT) substrate 2 has an array structure of thin film transistors which are frequently used in a conventional liquid crystal display device. This manufacturing method also follows a conventional method. That is, the thin film transistor substrate 2 includes a thin film transistor 205, a signal driver 201, a scan driver circuit 203, and wirings 202 and 204 for each pixel region on the substrate 200 such as glass or quartz. Is formed. Further, a mirror electrode connection thick film 207 electrically connected to the drain electrode 206 of the thin film transistor 205 among the blocks (transistor elements) 208 of each thin film transistor is electrically connected to the bump 308 of the piezoelectric layer 3. This is formed to a thickness of about 20 μm by the plating method or the like.

The thin film transistor substrate 2 and the piezoelectric layer 3 laminated on the substrate 10 are compressed and connected to each other. In order to reliably perform compression, thermocompression is performed under a heated environment. By this crimping, since the junction part of the bump 308 and the mirror electrode connection thick film 207 is alloyed, connection resistance can be made small and connection strength can be raised.

Irradiation process (FIG. 2 (f)):

After the thin film transistor substrate 2 and the piezoelectric layer 3 are connected, light 12 is irradiated from the inner side of the substrate 10 toward the release layer 11. Light 12 penetrates the substrate 10 and is irradiated to the release layer 11 as a spot 13. For this reason, in the interface of the board | substrate 10 and the peeling layer 11, or in the layer of the peeling layer 11, the bond force between atoms or between molecules decreases or disappears. In the irradiation of the light 12, ablation occurs in the composition of the release layer 11, and the release of gas inside the release layer 11, melting of the light 12, melting, etc. It is assumed that a change occurs.

As light 12, what is necessary is just to generate | generate effective interlayer peeling or interfacial peeling to the peeling layer 11. In particular, laser light is preferable in that it is easy to generate ablation. For example, excimer laser light having a wavelength of 248 nm or 308 nm is used. The type and wavelength of the laser light are determined in consideration of whether or not there is a wavelength dependence or whether to separate and generate a phase change such as gas release, vaporization, sublimation, or the like in generating the ablation in the exfoliation layer 11.

The energy density of the irradiated laser light is about 10 to 5000 mJ / cm 2 and the irradiation time is about 1 to 1000 nsec, preferably about 10 to 100 nsec in the case of excimer laser light. If the energy density is too low or the irradiation time is too short, sufficient ablation cannot occur. On the other hand, if the energy density is too high or the irradiation time is too long, the thin film transistor 205 may be destroyed in addition to adversely affecting the release layer 11 and the piezoelectric layer 3. In addition, if the irradiation light 12 is irradiated with uniform intensity, the incident angle at the time of irradiation does not need to be perpendicular. In addition, in order to irradiate the whole area | region of the peeling layer 11, you may irradiate irradiation light by dividing into several times and may irradiate twice or more to the same location. Furthermore, the type, wavelength, and the like of the laser light may be changed according to the area to be irradiated.

Separation process (Fig. 2 (g)):

After irradiating light, a force is applied to detach the substrate 10 from the piezoelectric layer 3, and the substrate 10 is separated from the release layer 11. Since the residue of the peeling layer 11 adheres to the common electrode layer 300 side of the piezoelectric layer 3, it is removed by methods such as cleaning, etching, ashing, and polishing. In addition, since the separated substrate 1 uses an expensive material such as quartz, it is reused for the manufacture of a new optical modulation device.

3 is a perspective view illustrating the structure of an optical modulation device manufactured by the above-described manufacturing method. In order to facilitate understanding of the structure, the piezoelectric layer 3 and the thin film transistor (TFT) substrate 2 are separately shown for convenience of explanation. As shown in Fig. 3, the optical modulation device in this embodiment is a thin film transistor in which a piezoelectric layer 3 on which mirror elements 307 are arranged and a thin film transistor element 208 for driving each mirror element are arranged. The board | substrate 2 is an electrically connected structure. The piezoelectric layer 3 is comprised of the common electrode film 300, the piezoelectric film 301, and the mirror electrode film 302 formed by the manufacturing method of this embodiment. In addition, FIG. 3 shows the case where the transparent dielectric film 309 is formed as the intermediate layer in the peeling step, which also serves to protect the piezoelectric layer 3.

In the thin film transistor 2, a signal driver 201 and a scan driver circuit 203 are formed. The signal driver circuit 201 is configured to be capable of supplying a switching signal to a source of each thin film transistor 205 via a wiring 202 in accordance with on / off information in the horizontal direction (X-axis direction) of the image. It is. The scanning driver circuit 203 transmits a switching signal to the gates of the thin film transistors 205 in accordance with the on / off information in the vertical direction (Y-axis direction) of the image supplied from the display device. It is configured to be supplied through. The driving voltage generated at the drain electrode 206 of the thin film transistor 205 is supplied to the mirror electrode film 302 of each mirror element 307 through the mirror electrode connection thick film 207.

In the configuration of the optical modulation device, when a driving voltage is supplied from the thin film transistor 205, a potential difference occurs between the mirror electrode film 302 and the common electrode film 300 of the mirror element 307 corresponding thereto. The piezoelectric film 301 shrinks in the in-plane direction, and the mirror element deforms upward in FIG. 3. In other words, in the mirror element 307 to which the driving voltage is supplied, the reflecting surface becomes a mirror with a convex surface, and the focus becomes the inner surface of the mirror element 307. For this reason, the incident illumination light 305 becomes the reflected light 306 which has the light extended by the reflection by the convex mirror. On the other hand, as the mirror element 307 to which the driving voltage is not supplied, the reflecting light 306 is reflected in parallel because the reflecting surface is a flat mirror. However, the deformation of the mirror element into the convex shape or the concave shape depends on the polarization direction of the piezoelectric film and the direction of the applied electric field. Therefore, the projector using the optical modulation device needs to be configured in accordance with the aspect of deformation of the optical modulation device.

Fig. 4 is a cross-sectional view showing the construction of a projector using an optical modulation device (when deformed into a convex shape) manufactured by the manufacturing method of the present embodiment. As shown in FIG. 4, light from a metal halide lamp, which is the light source 41, is reflected by a parabolic face reflector 42 and converted into a substantially parallel light beam, It is deflected by the half mirror 43 and enters into the optical modulation device 44 according to the present embodiment. In the mirror element 441 to which the driving voltage of the optical modulation device 44 is not supplied, since the reflected light 306 is parallel, it is condensed by the lens 45 through the half mirror 43, and the micromirror ( 46). Since the reflecting surface has a constant angle with respect to the optical axis, the micromirror 46 reflects all the incident light and does not reach the screen 49.

On the other hand, in the mirror 442 that is supplied and deformed by the driving voltage, the reflected light 306 becomes light that is emitted so that light is emitted from the focus 48 of the convex mirror. Thus, this light passes through the lens 45, passes around the micromirror 46, and forms an image on the screen 49 through the projection lens 47. That is, the irradiation light 305 is modulated in accordance with the image signal supplied to the light modulation device 44, and the display according to the image signal is performed on the screen 49. At this time, since a partition or a substrate does not exist on the surface where the illumination light 305 is incident, the reflected light 306 is not scattered, and the projected image becomes dark or is projected to a position of another pixel. It doesn't happen.

As described above, according to the first embodiment, since the piezoelectric layer was formed on the substrate through the release layer, light such as a partition wall was applied to the incident surface of the light on the mirror element after the substrate was peeled off in the release layer. There is no obstacle blocking. Therefore, since it is not scattered by the obstacle, the projected image can be brightened. Moreover, since there is no scattering by an obstacle, contrast does not fall. In addition, since the thermal annealing treatment for the piezoelectric layer is performed before connecting to the thin film transistor substrate, the piezoelectric layer does not adversely affect the thin film transistor or the like.

Second Embodiment

The second embodiment of the present invention provides a pattern formation method and a connection method different from the first embodiment.

Fig. 5 shows a part of the manufacturing method of the optical modulation device in the second embodiment. In this embodiment, from the peeling layer forming step (Fig. 1 (a)) to the thermal annealing step (Fig. 1 (c)), and the irradiation step (Fig. 2 (f)) to the separation step (Fig. 2 ( g)) is the same as that of the first embodiment, and description thereof is omitted.

Pattern forming process (Fig. 5 (d)):

The pattern formation for the mirror electrode film 302 is the same as in the first embodiment. After the pattern formation on the mirror electrode film 302, due to the electrical connection with the drain electrode of the thin film transistor 205, instead of the bump 308 of the first embodiment, the drain electrode connection thick film is part of the mirror element 307. 310 is formed. The drain electrode thick film 310 is formed by a publicly known technique such as a plating method. As the metal for plating, a material having a small contact resistance and hardly oxidizing the surface, such as gold (Au), is preferable. The height of the drain electrode connecting thick film 310 is equalized to the distance (above) required between the piezoelectric layer 3 and the thin film transistor substrate 2.

Connection process (Fig. 5 (e)):

The drain electrode 206 of the transistor element in the thin film transistor substrate 2 and the drain electrode connecting thick film 310 formed on the mirror electrode 302 are electrically connected. The thin film transistor (TFT) substrate 2 used in this embodiment is not provided with the mirror electrode connecting thick film 207 in the first embodiment. The connection between the thin film transistor substrate 2 and the piezoelectric layer 3 laminated on the substrate 10 is performed in the same manner as in the first embodiment.

According to the second embodiment, even when the thick film is formed on the piezoelectric layer 3, the optical modulation device by the manufacturing method with the effect of the present invention can be provided.

(Third Embodiment)

The third embodiment of the present invention differs from the second embodiment in that a thick film is formed only on the thin film transistor substrate side.

6 shows a part of the manufacturing method of the optical modulation device in the third embodiment. In the present embodiment, the separation step (Fig. 2 (f)) from the release layer forming step (Fig. 1 (a)) to the thermal annealing step (Fig. 1 (c)) and the irradiation step (Fig. 2 (f)). g)) is the same as that of the first embodiment, and description thereof is omitted.

Pattern forming process (Fig. 6 (d)):

The pattern formation for the mirror electrode film 302 is the same as in the first embodiment. However, the bump 308 is not provided in the mirror electrode 302 of the mirror element 307.

Connection process (Fig. 6 (e)):

In this embodiment, the mirror electrode connection thick film 210 is formed on the drain electrode 206 of the transistor element 205 of the thin film transistor substrate 2 for electrical connection with the mirror element 307. The mirror electrode connection thick film 210 is higher in height than the mirror electrode connection thick film 207 of the first embodiment. This height is equalized by the distance (described above) required between the piezoelectric layer 3 and the thin film transistor substrate 2. The formation method of a thick film is the same as that of the first embodiment.

According to the third embodiment, even if the thick film is formed only on the thin film transistor substrate, the optical modulation device according to the manufacturing method with the effects of the present invention can be provided.

(Example 4)

Instead of the display device using the convex light modulating device shown in the first embodiment, the present invention relates to a configuration of the projector using the concave light modulating device.

7 is a cross-sectional view illustrating the structure of the projector. This figure shows the cross section which cut | disconnected the optical component along the optical axis of irradiation light. As shown in FIG. 7, the display device of the present embodiment includes a light modulation device 60, a light source 61, a reflector 62, a converging lens lens 63, a micromirror 64, and collimating. lens 65 and projection lens 66 are provided. The optical modulation device 60 may apply the optical modulation device manufactured in the first to third embodiments. However, when viewed from the incidence side of the light, the mirror element needs to have a structure that deforms into a concave shape. The light modulation device 60 deforms the reflective surface into a concave shape by the application of a voltage. Thus, the reflected light reflected by the mirror element 602 being deformed has a focus 603 on the collimating lens side when viewed from the light modulation device 60.

Next, the operation of light modulation in the display device of this embodiment will be described. The illumination light 18 emitted from the light source 61 is reflected by the reflector 62 and condensed at the position of the micromirror 64 by the converging lens 63. Since the micromirror 64 is disposed at an angle of 45 ° with respect to the optical axis, the illumination light 18 is incident on the collimating lens 65 while diverging. The collimating lens 65 converts the illumination light 18 into parallel light and makes it enter the light modulation device 60 perpendicularly.

Since the mirror 601 which is not deformed among the mirror elements constituting the optical modulation device 60 has a flat reflecting surface, the reflected light 191 returns to the collimating lens 65 while being parallel light. The light is collected and reflected by the micromirror 64, and the projection lens 66 cannot be reached. Therefore, the pixel is not displayed on the screen 67. The size of the reflecting surface of the micromirror 64 is the minimum size that can shield all the reflected light 191 from the light modulation device 60 when all the mirror elements act as a flat mirror which is not deformed. .

On the other hand, since the deformed mirror 602 acts as a concave mirror, the reflected light 192 enters the collimating lens 65 through the focal point 603. The reflected light 192 is converted into almost parallel light by the collimating lens 65, and part of it is shielded by the micromirror 64, but light passing through the micromirror 64 is projected to the projection lens 66. The screen 67 is imaged.

With the above configuration, when all the mirror elements constituting the optical modulation device 60 do not deform, since all the reflected light 191 is reflected by the micromirror 64 and does not reach the screen 67, the screen 67 ) Mark is black. On the other hand, since the reflected light 192 from the mirror element 602 selected according to the image to be displayed is projected on the screen 67, the image is displayed on the screen 67 in white on a black background.

Further, in order to perform color display, a structure in which a rotating disc filter, which is divided into three colors of red, green, and blue, is divided between the reflector 62 and the converging lens 63, or a light modulation is known, as is conventionally known. A configuration of forming a color filter layer of red, green, and blue on the surface of the mirror element constituting the device 60 may be applied.

By the function of the projection lens 66, various display devices, such as a projection display, a view-finder of a video camera, or a head mounted display, can be comprised.

As described above, according to the fourth embodiment, since there is no diffuse reflection and the light modulation device of the present invention having excellent light utilization efficiency, and there is no element that attenuates light like a half mirror, it is clear and contrast. An excellent projection image is obtained.

(Other modifications)

This invention is not limited to each embodiment of the above-mentioned invention, It is applicable to various deformation | transformation. For example, the structure, composition, and film thickness of the piezoelectric film are not limited to the above embodiments, but may be formed in other structures. Whether or not to form a transparent dielectric film having an intermediate layer at the time of protecting and peeling the piezoelectric layer can be arbitrarily determined according to the properties of the piezoelectric body. The transparent protective film on the surface of the common electrode film may be formed again after the step of peeling off the substrate is completed.

In addition, the shape of the mirror element 307 can be considered to be various shapes, such as a polygon, a circle, an ellipse, etc. other than a square as shown in FIG. In other words, it is possible to change the electrode shape by masking it into an arbitrary electrode shape and patterning the electrode.

In addition to the two-dimensional arrangement shown in Fig. 3, the arrangement of the mirror elements 307 may be a one-dimensional arrangement in which the mirror elements are arranged in a line.

In addition, the optical configuration of the projector device is not limited to FIGS. 4 and 7, and is applicable to the present invention as long as the configuration allows the projection of pixels using reflected light whose light conditions are different depending on whether the pixels are valid or invalid. This is possible.

According to the manufacturing method of the optical modulation device of the present invention, since the substrate serving as the base for forming the reflective mirror layer is peeled off, and only the reflective mirror layer remains, there is no blocking or diffuse reflection of reflected light generated when the substrate is provided. An optical modulation device can be manufactured. In addition, since the reflection mirror is formed on the substrate, the reflection mirror can be formed so that no looseness occurs on the mirror surface at the time of normality. In addition, since the substrate is peeled off to prevent deformation of the reflection mirror, an optical modulation device having a high pixel density can be manufactured. The light modulation device manufactured by the manufacturing method is excellent in light utilization efficiency, and the projector using the light modulation device can provide a clear and excellent projection image.

Further, according to the method of manufacturing the optical modulation device of the present invention, a peeling layer and a reflecting mirror layer are formed on a heat resistant substrate having heat resistance, a pattern is formed on the reflecting mirror layer, and a driving substrate and a reflecting mirror layer are connected. Subsequently, peeling occurs in the release layer by the irradiation separation step to separate the heat resistant substrate. Therefore, by this process, an optical modulation device can be provided which does not adversely affect heat when the reflective mirror layer is formed on the driving substrate.

According to the projector of the present invention, by providing a reflection mirror that is free of diffuse reflection and has no looseness, it is easy to deform, thereby obtaining a clear and excellent projection image.

According to the transfer method of the present invention, the same effects as described above are obtained.

1 is a view showing one of the optical modulation device manufacturing method according to the first embodiment of the present invention;

FIG. 2 is a view showing another one of the optical modulation device manufacturing methods in the first embodiment of the present invention; FIG.

3 is a perspective view of an optical modulation device manufactured by the manufacturing method of the first embodiment;

4 is a structural diagram of an optical system of a projector using the light modulation device of the first embodiment;

Fig. 5 is a view showing a part of the optical modulation device manufacturing method according to the second embodiment of the present invention;

Fig. 6 is a view showing a part of the optical modulation device manufacturing method according to the third embodiment of the present invention; And

7 is a structural diagram of an optical system of the projector of the fourth embodiment.

Claims (7)

As a transfer method for transferring a mirror element formed on a heat resistant substrate having light transmittance to another substrate, Forming a light absorption layer on the heat resistant substrate; Forming a mirror element on the light absorption layer; Pressing the mirror element with the other substrate; And And a step of irradiating light to the light absorbing layer to cause peeling on the light absorbing layer. The method of claim 1, wherein the forming of the mirror element comprises: forming a first electrode thin film on the light absorption layer, forming a piezoelectric thin film on the first electrode thin film, and a second electrode on the piezoelectric thin film. The transfer method characterized by the process of forming a thin film. The transfer method according to claim 2, wherein at least one of the first electrode thin film and the second electrode thin film is formed of a light reflective material. 3. The method of claim 2, wherein the forming of the mirror element further comprises: forming the second electrode thin film and the piezoelectric thin film electrically in a pixel area unit after the step of forming the second electrode thin film. Transfer method, characterized in that. The method of claim 4, wherein the patterning of the second electrode thin film and the piezoelectric thin film comprises patterning the second electrode thin film into a polygon.       5. The transfer method according to claim 4, wherein the step of patterning the second electrode thin film and the piezoelectric thin film comprises patterning the second electrode thin film in a circular shape. The method of claim 1, wherein the heat resistant substrate comprises quartz glass.