JP2001318324A - Optical switching unit, method for manufacturing the same and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure spacings of extremely good accuracy with light guides of an optical switching unit of an active type to move macrooptical elements and further to assure reliability and high-speediness. SOLUTION: This optical switching unit is provided with walls 30 so as to enclose spaces 15 where the optical switching elements 10 line up, by which the dimensions between the light guides 1 and a substrate 20 are assured and the sealing of the spaces 15 with the substrate 20 and the walls 30 is made possible. Resistance is eliminated and the driving of the optical switching elements at high speed is made possible by reducing the pressure in the spaces 15 and further, the problem, such as deterioration by adsorption and oxidation may be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching unit used for an image projection device such as a data projector and a video projector or an image display device suitable for an image display device, and an image display device using the same. .

[0002]

2. Description of the Related Art As a light valve of an image display apparatus such as a projector, an image display device using liquid crystal is known as an image display device capable of controlling light on / off. However, an image display device using this liquid crystal has a poor high-speed response characteristic and operates only at a response speed of at most several milliseconds. Therefore, a device that displays a high-resolution image that requires a high-speed response, an optical recording device such as an optical communication device, an optical operation device, and a hologram memory, and an optical printer are realized by a switching device using a liquid crystal. Difficult.

Therefore, there is a need for a switching device or an image display device capable of operating at a high speed capable of coping with the above-mentioned applications, and a switching device having a microstructure on the order of microns or a smaller submicron order. Development is under way.

[0004]

One of the problems is that the extraction surface of the optical element is applied to the total reflection surface of the light guide (light guide) capable of totally reflecting and transmitting light, which is filed by the present applicant. It is an optical switching device capable of extracting evanescent light by making contact with it, and controlling the modulation of light at high speed by a small movement of about one wavelength or less of the optical element.

FIG. 1 shows an image display device (optical switching device) that performs switching by evanescent light.
The outline of a projector 80 is shown as an example of an image display device using the. The projector 80 includes a white light source 81 and a rotary color filter 82 that separates light from the white light source 81 into three primary colors and causes the light to enter the light guide plate (light guide) 1 of the image display unit (light switching unit) 55.
Display unit 55 that modulates and emits light of each color
And a projection lens 86 for projecting the emitted light 85. Then, the modulated light 85 for each color is projected on a screen 89 and mixed with time to output a multi-tone multi-color image. The projector 80 further controls the image display unit 55 and the rotary color filter 82 to display a color image.
4 is provided. The image display unit 55 includes the light guide 1
And an image display device (optical switching device) 50 described in detail below.
The data φ and the like for displaying a color image from 4 are supplied to the image display device 50.

The image display unit 55 is a trapezoidal prism-shaped light guide 1 having a surface 1b for receiving or entering light.
The projector 80 shown in FIG. 1 includes a light source 81 for supplying light for projection to the incident surface 1 b of the light guide 1, a lens 86 for projecting light emitted from the light guide 1, and the like. Means for inputting and outputting light provided
An image display device 50 for modulating the projection light supplied to the light guide 1 on the total reflection surface 1a is provided. And
The image display device 50 controls the evanescent light leaking from the light guide 1 to display an image.

FIG. 2 shows an outline of an image display device (evanescent light switching device) 50 for modulating light using an evanescent wave (evanescent light). The image display device 50 is a switching device in which a plurality of active optical switching elements (optical switching mechanisms) 10 are two-dimensionally arranged. Each of the optical switching elements 10 can transmit the incident light 2 by total reflection. Optical element (switching unit) 3 capable of modulating light by approaching and moving away from a light guide plate (light guide) 1;
And an actuator 6 for driving the actuator. And
The layer of the optical element 3 and the layer of the actuator 6 are stacked on a semiconductor substrate 20 on which a drive circuit for driving the actuator 6 and a digital storage circuit (storage unit) are built, and are integrated as one image display device. I have.

Referring to FIG. 2, the image display device 50 of the present embodiment using evanescent light will be described in more detail. When the individual optical switching elements 10 are described as a base, the optical switching elements 10 shown on the left side of FIG.
a is an ON state, and the optical switching element 10b shown on the right side is an OFF state. The optical element 3 has a surface (contact surface or extraction surface) 3a that is in close contact with the total reflection surface 1a of the light guide 1.
A V-shaped reflecting prism (microprism) 4 for extracting evanescent waves leaked when the surface 3a is in close contact with the total reflection surface 1a and internally reflecting the evanescent wave in a direction substantially perpendicular to the light guide plate 1; And a support structure 5 for supporting the V-shaped prism 4.

The actuator 6 shown in FIG. 2 is of a type for driving the optical element 3 electrostatically. For this purpose, the actuator 6 is mechanically connected to the support structure 5 of the optical element 3.
And a lower electrode 8 fixed to the semiconductor substrate 20 at a position facing the upper electrode 7.
Further, the upper electrode 7 is supported by columns 11 extending upward from the anchor plate 9, and the upper electrode 7 is mechanically attached to the uppermost surface 20 a of the semiconductor substrate 20 via the anchor plate 9. Therefore, when different voltages are supplied to the upper electrode 7 and the lower electrode 8, the upper electrode 7 moves downward,
In conjunction with this, the optical element 3 separates from the light guide 1 (second position). On the other hand, the upper electrode 7 partially has a function as an elastic member. When the voltage supplied to the upper electrode 7 and the lower electrode 8 is removed, the upper electrode 7 separates and the upper electrode 7 separates.
Causes the optical element 3 to adhere to the total reflection surface 1a of the light guide 1 (first position).

As shown in FIG. 1, the light guide 1 has a trapezoidal shape, and transmits the illumination light (incident light) 2 perpendicularly incident on the incident surface 1b at an angle at which it is totally reflected by the total reflection surface 1a. Is done. Therefore, all interfaces inside the light guide 1,
That is, light is repeatedly totally reflected on the side 1a facing the optical element 3 and on the upper surface (emission surface), and the inside of the light guide plate 1 is filled with light rays. In this state, the illumination light 2 is macroscopically confined inside the light guide plate 1 and propagates therein without any loss. On the other hand, microscopically, near the total reflection surface 1a of the light guide plate 1, the incident light 2 leaks from the light guide plate 1 only for a very small distance of about the wavelength of light, and changes its course. The phenomenon of returning to the inside of the light guide plate 1 again occurs. The light leaked from the surface 1a in this manner is generally called an evanescent wave. The evanescent wave can be extracted by bringing the optical element close to the total reflection surface 1a at a distance of about the wavelength of light or less. The optical switching element 10 of the present embodiment is designed to modulate light transmitted through the light guide plate 1 at high speed, that is, to switch (on / off) using this phenomenon.

In the optical switching element 10a shown in FIG. 2, the optical element 3 is pressed against the total reflection surface 1a of the light guide plate 1, and the extraction surface 3a comes close to or in close contact with the total reflection surface 1a. Evanescent waves can be extracted. For this reason, the micro prism 4 of the optical element 3
Is changed in angle to become emitted light 2a, which is used as light 85 for projection of the projector 80 shown in FIG.

On the other hand, in the optical switching element 10b, an electrostatic force acts on the electrodes 7 and 8, so that the optical element 3 is moved to the second position away from the total reflection surface 1a. Therefore, the evanescent wave is not extracted by the optical element 3,
The light 2 is reflected by the total reflection surface 1a and does not exit from inside the light guide 1.

An optical switching element using an evanescent wave functions as a device capable of switching light by itself, but as shown in FIG.
It is configured so that it can be arranged in a three-dimensional direction, or even three-dimensionally. In particular, an image display device 50 capable of displaying a two-dimensional image like a liquid crystal or a DMD by arranging two-dimensionally in a matrix or an array, and an image display unit 55 integrated with a light guide are provided. be able to. In the image display unit 55 using the evanescent light, the moving distance of the optical element 3 as a switching unit is on the order of submicron, so that it can be used as an optical modulator having a response speed one digit or more faster than that of liquid crystal. It is possible to provide a projector 80 or a direct-view type image display device capable of high-speed operation using a camera. Further, the optical switching element 10 using the evanescent light can turn on and off the light almost 100% with a movement on the order of submicron, and can express an image with a very high contrast. For this reason, it is easy to increase the temporal resolution, and a high-contrast image display device can be provided.

Further, the optical switching unit 55
Is a one-chip image display device 50 having a configuration in which actuators 6 and optical elements 3 arranged in an array are stacked on a semiconductor integrated substrate 20 in which a drive circuit and the like are built.
And the light guide 1. That is, the actuator 6 is placed on the semiconductor substrate 20.
The image display unit 55 can be supplied by assembling the light guide 1 with the image display device 50, which is a micromachine or an integrated device in which a microstructure such as the optical element 3 is constructed, and by incorporating this, the operation speed is high and the resolution is high. A projector capable of displaying a high-contrast image with an image can be provided.

The actuator 6 for forming the switching device and the optical switching unit using the evanescent light is not limited to the one having the pair of upper and lower electrodes shown in FIG. 2, but the upper electrode 7 shown in FIG. An intermediate electrode (movable electrode) 5 that moves between the
1 can be provided so that the optical element 3 is driven in conjunction with the intermediate electrode 51. The image display device 50 has a merit that the configuration of the actuator 6 is complicated but can be driven at a low voltage. Furthermore, instead of electrostatic actuators using electrode pairs,
It is also possible to configure the actuator using a mechanism capable of supplying a driving force by another electric signal such as a piezo element, and some actuators are considered. Therefore, in the following description, the description will be made based on an actuator of an electrostatic drive type with upper and lower electrodes for simplicity, but the configuration of the actuator is not limited to this.

As described above, the optical switching unit using the evanescent light performs optical switching by moving to a position in contact with the total reflection surface on the lower surface of the light introducing prism (light guide) and a position separated by a submicron. , Or an assembly thereof, and can be driven at high speed. Furthermore, since the microactuator and the micro-optical element are arranged in an array on the semiconductor substrate, it can be provided as a very compact image display unit with high resolution and high contrast.

On the other hand, micron-order or submicron-order switching in which the upper surface of the micro-optical element contacts the lower surface of the light introducing prism and moves a sub-micron distance to a position spaced apart by a sub-micron therefrom. Because it is a unit, it is necessary to examine various performances such as assembly accuracy, reliability, and durability. That is, it is necessary to accurately secure the moving distance of the micro optical element. In order to increase the switching speed, air may impede the operation of the optical element and the actuator under normal pressure. Furthermore, when trying to move at high speed, adsorption occurs between the resin constituting the optical element and the glass constituting the light guide due to the interposition of moisture, etc., and the switching speed is reduced or the power at the time of switching is reduced. There is a possibility that the switching operation may be required or the switching operation may not be possible due to sticking. When an insulating layer is provided to prevent contact between the electrodes, a small amount of electric charge is accumulated, and the electric charge causes electrostatic attraction. Therefore, it is desirable to eliminate such a load and to minimize the attraction force due to mechanical factors such as moisture. When a metal film is used for the reflection surface of the prism, the reflectance may be reduced by oxidation. Further, the interaction with light deteriorates the resin constituting the optical element.

Accordingly, it is an object of the present invention to provide an optical switching unit having high performance, reliability and durability. It is still another object of the present invention to provide a highly reliable optical switching unit having a very simple structure and an image display device using the same.

[0019]

For this purpose, an optical switching unit according to the present invention comprises a substrate, at least one driving actuator disposed on the substrate, an optical element driven by the actuator, and A light guide having a total reflection surface for transmitting incident light, and a light driven by the actuator to a position where the optical element extracts evanescent light and a position where the evanescent light is not extracted with respect to the total reflection surface of the light guide. The switching unit further includes a wall disposed so as to surround the actuator and the optical element, and the wall, the substrate, and the light guide can seal the actuator and the optical element. That is, it has a substrate, at least one driving actuator disposed on the substrate, an optical element driven by the actuator, and a light guide having a total reflection surface for transmitting incident light, In a method of manufacturing an optical switching unit in which an optical element is driven by an actuator to a position at which evanescent light is extracted and a position at which evanescent light is not extracted with respect to a total reflection surface of the light guide, a wall disposed so as to surround the actuator and the optical element. Thus, a step of sealing the actuator and the optical element together with the substrate and the light guide is provided.

In the optical switching unit of the present invention, the distance between the total reflection surface and the substrate can be accurately maintained by the wall. At the same time, the space inside, that is, the space in which the actuator and the optical element move can be sealed, so that the space can be depressurized. Therefore, the switching speed can be increased by eliminating or reducing the air resistance. In addition, since the partial pressure of water is reduced by reducing the pressure, the water can be prevented from intervening between the optical element and the light guide. Therefore, the problem of adsorption due to this can be prevented beforehand. Furthermore, since the oxygen partial pressure is reduced by reducing the pressure, even when a metal film is used for the reflection surface of the prism, oxidation can be prevented, and a reduction in reflectance due to the oxidation can be prevented. In addition, it is possible to prevent the resin constituting the optical element from deteriorating due to interaction with light due to the presence of oxygen. Therefore, by reducing the pressure, it is possible to improve performance, reliability and durability.

In a region where the wall is in contact with the total reflection surface, the incident light is not totally reflected. Therefore, it is desirable to form a reflective film on the surface where the wall contacts the light guide. In addition, a step having an appropriate size can be easily and accurately provided between the region in contact with the wall of the light guide and the total reflection surface by molding. For this reason, the distance between the substrate and the total reflection surface can be further accurately controlled. It is desirable that at least one protrusion is provided in a space sealed by the wall, that is, a space in which the optical element and the actuator are arranged, and the protrusion is in contact with both the light guide and the substrate. In addition to providing accuracy with walls forming the outside of the space, it becomes easier to accurately maintain the dimensions inside the space.

In order to decompress the area surrounded by the wall, the substrate and the light guide, there is a method of assembling them all in a decompressed atmosphere. However, in order to perform these assembling operations in a reduced-pressure atmosphere, facilities for constructing such an environment are expensive, and it is difficult for workers to access them. On the other hand, most of the assembly is performed by closing the communication portion after penetrating the wall and communicating with the space sealed by the wall and communicating with the outside in advance through the communication portion. Can be performed under normal conditions. Therefore, manufacturing costs can be reduced.

The light guide generally has a polyhedral shape such as a trapezoid or a parallelogram in order to provide a surface on which light for forming an image is incident, and a thick prism is required. Therefore, if it is attempted to seal the space by using such a light guide as it is, handling of the light guide is difficult and the assembled size is large. For this reason, there is a problem that the occupation rate of the decompression space such as the vacuum chamber is increased and the production efficiency is deteriorated. Therefore, in the present invention, the light guide used as the sealing portion is a flat cover member separated from the main body having the light incident portion, thereby reducing the size of the unit during the decompression process. are doing. For example, if the cover member is greatly deformed when the space is substantially evacuated (the pressure difference is 1 atm), the degree of adhesion between the optical element and the total reflection surface is reduced, and the evanescent light extraction efficiency is reduced. When the distortion of the total reflection surface is about 30 nm or less, the extraction efficiency of evanescent light becomes 80% or more. In order to maintain this degree of deformation or a degree of deformation lower than that, when quartz glass having a size of about 5 mm to 10 mm on one side is used as the cover member, its thickness is preferably about 3 mm or more.

In order to increase the degree of sealing of the space surrounded by the wall, the substrate and the light guide, it is desirable to mold the outside of the wall with a resin. Further, the wall can be made of a resin mold. At this time, in order to ensure the distance between the substrate and the light guide (total reflection surface) with high accuracy, it is desirable to provide a temporary fixing portion, adjust the distance, and then form the wall in full scale.

If the viscosity of the molding resin is too low, the resin may penetrate into the internal space and hinder the operation of the actuator and the like. On the other hand, if the viscosity is too high, workability is poor. Therefore, the viscosity of the molding resin before curing is desirably adjusted to 20,000 to 150,000 cP. Further, it is preferable that the outgas after curing is small, and it is desirable that moisture permeability and oxygen permeability are also small. Then, in order to adjust the amount of intrusion into the wall or the inside of the wall during curing, a UV-curable resin, for example, an acrylic resin or a UV-curable epoxy resin is desirable. Further, it is also effective to put a gap agent (spacer) for maintaining a predetermined size in the molding resin.

There are several methods for forming a wall and a communicating portion with a mold resin and closing the wall after reducing the pressure. When a thermosetting resin is used, it can be cured by being applied while being heated to about 100 ° C. to close the communicating portion. If a UV-curable resin is used, the communication part can be closed from the outside at an appropriate timing by using a UV-transmissive chamber. Further, it is also possible to vacuum-deposit a material that closes the communicating part after the pressure is reduced, and the pressure reduction and sealing can be realized in a continuous process in the vacuum chamber. Therefore, it is possible to provide an optical switching unit in which the vacuum is easily maintained and the space in which the optical element and the actuator move is in a high vacuum.

It is desirable that the molding resin is formed so that its outer surface is tapered. If the shape is semicircular or semi-elliptical, the area in contact with the substrate and the light guide becomes small, so that it is difficult to secure the hermeticity, and it is difficult to expect a significant improvement in reliability and durability. In the following, it becomes difficult to deposit a gas barrier film.

After sealing with a resin mold, it is desirable to prevent oxygen or moisture from penetrating into the space through this mold resin. Therefore, in the present invention, a gas barrier film made of a metal oxide is further formed outside the mold resin so as to prevent gas such as moisture and oxygen from entering as much as possible. As a method of forming the gas barrier film, a vacuum evaporation method, an ion-assisted evaporation method, an ion plating evaporation method, an oxidation reaction evaporation method, or the like can be used. Furthermore, as a material, silicon oxide,
There are metal oxides such as aluminum oxide, metal nitrides such as silicon nitride, and metal films such as aluminum. Of these, metal gas aria films are conductive, so care must be taken to avoid contact with wiring and the like.
The thickness is preferably about 50 to 5000 angstroms.

As described above, the operation speed of the optical switching unit according to the present invention is higher, the reliability is higher, and the durability is better. Therefore, by using the optical switching unit according to the present invention, in particular, an optical switching unit in which actuators and optical elements are arranged in an array, and a unit for inputting and outputting display light to and from the optical switching unit, High-speed, high-contrast, high-resolution images can be displayed, taking advantage of the advantages of switching by evanescent light.
An image display device with high reliability and durability can be provided.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment The present invention will be further described below with reference to the drawings. FIG. 4 shows an optical switching unit 55 according to the present invention.
A device 50 in which the optical switching elements 10 using evanescent light described with reference to FIG. 3 are arranged in an array and the light guide 1 are combined. Also,
FIG. 5 is a diagram showing a cross section of the optical switching unit 55 in FIG. Note that the number of optical switching elements is simplified for explanation, and is not limited to the illustrated number.

The optical switching unit 55 shown in FIGS. 4 and 5 is an active optical element device in which the optical switching elements 10 are arranged in an array of 3.times.3. The elements are arranged with an interval 12 therebetween. Further, a wall 30 surrounding the optical switching elements 10 arranged in an array is provided. As described above, the optical switching element 10 of the present example has the lower electrode 8 and the intermediate electrode 51 as the actuator 6, and generates an attractive force by applying a potential difference to the lower electrode 8 and the intermediate electrode 51, and the intermediate electrode 51 also functions as a spring. It moves downward while bending it. Similarly, the upper electrode 7 and
An attractive force is generated by applying a potential difference to the intermediate electrode 51,
The intermediate electrode moves upward. One end of the intermediate electrode 51 is connected to the micro optical element 3 via a support 52. Therefore, at the same time when the intermediate electrode moves upward or downward by the electrostatic force, the micro-optical element 3 connected to the support 52 also moves upward or downward. The micro optical element 3 has a V-shaped reflection mirror 4a, the upper part of the V-shaped reflection mirror 4a is a prism 4 made of a transparent member, and the upper surface thereof is a flat extraction surface 3a.

These array-shaped optical switching elements 1
0, a wall 30 is provided.
A light introducing prism (light guide) 1 is fixed on the reference numeral 0. The light beam 2 obliquely incident on the lower surface of the light guide 1 and on the total reflection surface 1a is transmitted to the lower surface 1a of the micro optical element 3 and the lower surface 1a of the light introducing prism 1 when the micro optical element 3 is moved downward by the actuator 6. Are totally reflected in the direction 2b on the lower surface 1a of the light introducing prism 1. On the other hand, the micro optical element 3 is moved upward by the actuator 6, and the upper surface 3 of the micro optical element 3 is moved.
a is in contact with the lower surface 1 a of the light introducing prism 1, the light beam 2 obliquely incident on the lower surface of the light introducing prism 1 passes through the upper surface 3 a of the micro optical element 3, and V The light is reflected by the reflection mirror 4a of the mold and becomes an outgoing light beam 2a, and is emitted upward. According to this principle, the light beam is moved up and down by the micro-optical element 3 for two times.
Light can be switched in the directions a and 2b.

In order to efficiently turn on and off the evanescent light leaked from the total reflection surface 1a in this manner, it is necessary to move the micro optical element 3 by the actuator 6 at high speed and with high accuracy. To this end, it is important, for one thing, that the dimension between the substrate 20 and the total reflection surface 1a of the light guide 1 is accurately maintained. In the optical switching unit 55 of the present example, the wall 30 surrounds the outer periphery of the optical switching elements 10 arranged in an array, whereby
The distance between the total reflection surface 1a and the upper surface 20a of the substrate 20 can be accurately maintained, and the distance can be prevented from changing due to a shock at the time of installation or assembly. That is, the lower surface 1a of the light introducing prism 1 is
The micro optical element 3 does not contact the lower surface 1a of the light guide or the distance (0.5 μm
Above) can be secured.

Further, the wall 30 has a structure surrounding the optical switching elements 10 arranged in an array. The space 15 in which the optical switching elements 10 are arranged in an array is
, The substrate 20 and the light guide 1. Therefore, it is possible to fill the space 15 with an inert gas or to maintain the inside of the space 15 at a pressurized or reduced pressure with respect to the external pressure. By filling with an inert gas, a phenomenon that the adhesion is increased by moisture or a phenomenon that the durability is deteriorated by oxygen can be avoided, and the optical switching element can be protected. Therefore, reliability and durability are dramatically improved.

On the other hand, in order to improve the switching speed, it is desirable to reduce the pressure inside the space 15. FIG.
FIG. 2 shows the result of simulation performed by the inventors of the present application. This simulation is performed for an optical switching element of the type shown in FIG. 2 that moves with the upper and lower electrodes. The response time is reduced by reducing the pressure from atmospheric pressure (760 torr) to 1/100 atmospheric pressure (7.6 torr). 1
The response speed is improved from / 4 to about 1/6, and the response speed is increased from 4 times to 6 times. Further, by reducing the pressure, moisture and oxygen inside the space 15 can also be removed. Therefore, it is possible to solve the problem of adsorption, the problem of corrosion or deterioration caused by these. For this reason, by providing the wall 30 to cover the outside of the optical switching element and decompress the inside, the optical switching device 50 and the optical switching unit 55 having higher response speed, higher reliability and durability are provided. be able to. In addition, by configuring the image display device 80 as shown in FIG. 1 using the optical switching unit 55, it is possible to provide an image display device with higher resolution, higher reliability and higher durability.

FIG. 7 shows an optical switching device 50 in which the optical switching elements 10 are arranged in an array.
An example of a manufacturing process for forming the wall 30 together with the optical switching element 10 is shown. Since the optical switching element 10 is required to have an accuracy on the order of microns or less, in this example, the actuator 6 and the microcircuit are formed using a photolithography technique and a technique for forming a fine structure by die transfer developed by the present inventors. The optical element 3 is manufactured. Further, the distance between the total reflection surface 1a of the light guide 1 and the extraction surface 3a of the optical element 3 needs to be accurately assembled by the wall 30. For this reason, in the present example, the mold is formed so as to form a step 16 having a predetermined size between the height of the wall 30 and the extraction surface 3a of the optical element 3, and the wall 30 is formed.
The desired accuracy can be maintained simply by placing the light guide 1 on the light guide.

First, as shown in FIG. 7A, an actuator structure 6 for moving the micro optical element 3 is formed by using a photolithography process. By the photolithography process, the lower electrode 8, the resilient intermediate electrode 51, the upper electrode 7, and the support 52 for connection with the micro optical element 3 are formed.
The gap is filled with the sacrifice layer 109. Further, a lower half 30a of the wall 30 is formed on the outside. Then, before etching the sacrificial layer, a prototype of the micro optical element is formed by resin molding as described below. On top of that, a V-shaped reflecting mirror 4a of the optical element 3
Is formed of a resin, and a metal serving as the reflection mirror 4a, for example, aluminum is adhered by a method such as sputtering to form a film. On top of these, the transparent resin 18 is further filled in a V-shaped groove, and the shape of the optical element 3 is molded by a mold 100 having a step 101 between itself and the wall 30. Thereby, the upper surface of the transparent resin filled in the V-shaped groove is flattened, and
And the step 101 can be accurately formed.

Thereafter, as shown in FIG. 7B, a resist film 102 is applied and an opening 10 for partially removing the resist film 102 is formed.
3 is patterned. Thereafter, the portion 103 where the resist film has been removed by patterning is vertically etched.

When the resist film 102 is removed, FIG.
The shape shown in FIG. That is, the V-shaped structure 5 supporting the transparent resin layer 4 is separated for each element, and the micro optical element 3 having the extraction surface 3a on the upper surface is formed. Also, the upper half 30b of the wall 30 is formed at the same time, and the lower half 30a and the upper half 30b overlap to form the wall 30 having a predetermined height. On the other hand, the sacrifice layer 109 is not etched by the resin etching, so that only the surface 108 of the sacrifice layer is exposed in the actuator 6.

Thereafter, when the sacrifice layer 109 is removed by a method such as plasma etching of the sacrifice layer 109, as shown in FIG. 7D, the actuator 6 can be moved by electrostatic force, and the optical element 3 moves together. Available space 15
Is generated. Then, the upper surface 3a of the optical element 3 and the wall 3
If a very accurate step 101 is formed on the mold 100 by etching or the like, the step is formed between the zero and the upper surface 31 and the accuracy is extremely increased. Further, since the upper surface 3a of the micro optical element 3 and the mold 100 forming the upper surface 31 of the wall 30 are the same, the step 101 is accurately transferred. Therefore, the optical switching device 50 in which the accurate submicron step 16 is formed between the wall 30 and the switching element 10 can be manufactured by the manufacturing method of this example. By assembling the optical guide 1 on the optical switching device 50, it is possible to provide the optical switching unit 55 having high dimensional accuracy and further covered with the wall 30.

The optical switching unit 55 shown in FIG.
Is obtained by superposing the light guide 1 on the optical switching device 50 manufactured by the above manufacturing method. Further, in this example, a reflective film 32 is deposited on the upper surface 31 of the wall 30. Accordingly, the light beam 2 propagating in the light guide 1 is reflected by the reflective film 32 provided on the upper surface 31 of the wall 30 in the same direction 2b as the total reflection. Therefore, even if the lower surface 1 a of the light guide 1 is in close contact with the upper surface 31 of the wall 30, the light beam 2 does not pass through the upper end of the wall 30 to generate scattered light and the like, and the light beam 2 passes through the inside of the light guide 1. Is transmitted. For this reason, the S / N ratio of the optical switching becomes extremely high, and the optical switching unit 55 in which active optical elements with high reliability are arranged in an array can be provided.

The optical switching unit 55 shown in FIG.
Is an example in which a distance between the optical element 3 and the total reflection surface 1a can be accurately set without providing a step in the molding die 100 shown in FIG. The optical switching device 50 after the sacrificial layer has been etched so that no step is formed in the mold 100, as shown in FIG.
And the upper surface 31 of the wall 30 are in the same level. Therefore, the light guide 1 having a predetermined step 16 is connected to the upper surface 31 of the wall 30 between the region 1b in contact with the upper surface 31 and the region (total reflection surface) 1a in contact with the optical element 3. According to this method as well, a predetermined distance can be accurately secured between the micro optical element 3 and the total reflection surface 1a. That is, the micro optical element 3
Does not come into contact with the lower surface 1a of the light introducing prism 1 or the distance (0.5 μm
Above) can be secured.

The step 16 of the light guide 1 can be accurately formed by etching or the like. For this reason, the method of forming a step on the side of the light guide 1 makes it possible to make the molding die 100 for molding the optical element 3 a flat surface, and a manufacturing method having a large permissible error in the positioning and the like during molding can be adopted. Further, a precise submicron gap 17 can be easily formed between the upper surface 3a of the micro optical element 3 and the lower surface 1a of the light guide 1.

Also in this embodiment, it is desirable that a portion where the wall 30 contacts the light guide 1 be formed with a reflective film in the same manner as described above. Furthermore, the step 16 of the light guide 1 does not become a total reflection surface, and the incident light 2 is transmitted. Therefore, it is desirable to form a reflective film or to prevent irregular reflection as a step having the same angle as the incident light 2.

Further, in these examples, a precise submicron gap 17 can be easily formed between the upper surface 3a of the micro optical element 3 and the lower surface 1a of the light guide 1. Therefore, it is not necessary to provide a stopper between the intermediate electrode 51 and the upper electrode 7. That is, the intermediate electrode 5
An attractive force is generated by giving a potential difference between 1 and the upper electrode 7, the intermediate electrode moves upward, and the micro optical element 3 moves upward. At this time, the intermediate electrode 51 and the upper electrode 7
When they come into contact with each other, they become conductive. For this reason, the intermediate electrode 5
It is necessary to provide a stopper or to cover one of the electrodes with an insulator so that the upper electrode 7 does not contact the upper electrode 1. However, in the optical switching unit of the present example, the distance between the optical element 3 and the light guide 1 is determined very accurately, so that the intermediate electrode 51 and the upper electrode 7 are positioned at the position where the optical element 3 hits the light guide 1. It is possible to maintain a small space between them, and such a design can be realized or implemented with very high accuracy and high reliability. Therefore, it is possible to omit the stopper or the insulator layer, and it is possible to reduce the manufacturing cost. Further, by eliminating the insulating layer, it is possible to realize an active type optical switching unit having an optical switching element having good repetitive durability without charging in the insulating layer.

Second Embodiment FIGS. 10 and 11 show different examples of the optical switching unit according to the present invention. FIG. 10 is a plan view of the optical switching unit 55 of the present example as seen through the light guide 1 from above, and FIG. 11 is a cross-sectional view. The optical switching unit 55 of this example is also an active optical device in which the 3 × 3 optical switching elements 10 are arranged in an array, and the individual optical switching elements 10 are arranged at intervals 12 with the adjacent switching elements. Have been. A wall 30 serving as a step is provided so as to surround these optical switching elements 10. Further, the optical switching element 1
The projections 19 having the upper surface having the same height as the upper surface 31 of the surrounding wall 30 are arranged in the interval 12 between 0.

The optical switching unit 55 of this embodiment is also an active type optical switching unit in which the optical element 3 is driven by the electrostatic actuator 6. The configuration of each optical switching element 10 is the same as that described above. Also, in the optical switching unit 55 of this example, the wall 30 surrounds the array-like optical switching elements 10, and the space 15 of the array-like optical switching elements together with the substrate 20 and the light guide 1 forms the wall 30.
And the space 15 can be filled with an inert gas or decompressed. Therefore, also in the optical switching unit 55 of the present example, an operation speed can be increased by reducing the pressure, and furthermore, an optical switching unit having significantly improved reliability and durability by protecting the optical switching element is provided. be able to.

Further, the protrusions 19 provided in or between the optical switching elements 10 arranged in an array form
Similarly to the wall 30, the lower surface 1a and the upper surface 19a of the light guide 1 are in contact with each other and serve to fix the light guide 1. Therefore, even when the surface accuracy of the lower surface of the light guide 1 is somewhat poor, or when the space 15 surrounding the switching element 10 is depressurized and the lower surface 1a of the light guide 1 is bent due to a pressure difference from the surroundings, the micro-optics can be used. More precisely, the interval at which the upper surface 3a of the element 3 contacts the lower surface (total reflection surface) 1a of the light guide 1 or moves to a distance where the totally reflected light does not enter the micro optical element (0.5 μm or more). You can do it.

Also in this example, at the portion 19a where the protrusion or the post 19 contacts the total reflection surface 1a of the light guide, light may be irregularly reflected or light may pass through the post 19. Therefore, it is desirable to form a reflection film on the upper surface 19a of the support, so that the light 2 can be totally reflected and transmitted like the other surfaces.

Third Embodiment FIGS. 12 and 13 show still another example of the optical switching unit according to the present invention. FIG. 12 is a plan view of the optical switching unit 55 of the present example as seen through the light guide 1 from above, and FIG. 13 is a cross-sectional view. The optical switching unit 55 of this example is also an active optical device in which the 3 × 3 optical switching elements 10 are arranged in an array, and the individual optical switching elements 10 are arranged at intervals 12 with the adjacent switching elements. Have been. A wall 30 serving as a step is provided so as to surround these optical switching elements 10.

The wall 30 of the present embodiment has a structure surrounding the optical switching elements 10 arranged in an array, and has recesses 33a and 33b in a part thereof. Hollow 33
Since a and 33b are similar depressions, the depression 33
Only b will be described. FIG. 13 is a cross-sectional view of a plane crossing the depression 33b. As shown in the drawing, the lower surface 1a of the light guide 1 is fixedly adhered to the upper surface 31 of the wall 30, and the space 15 surrounding the optical switching element 10 is sealed by the wall 30, the light guide 1 and the substrate 20. ing. Furthermore, a hole penetrating the wall 30 is formed in the wall 30 of the present example by the depression 33b. Therefore, after the light guide 1 is fixed to the stepped wall 30 through the hole by the recess 33b, it is possible to control the atmosphere in the space 15 where the optical switching elements 10 arranged in an array exist. By activating gas, deterioration of durability due to adsorption prevention treatment or oxidation can be prevented. In addition, by reducing the pressure in the space 15, in addition to these effects, it is possible to provide an optical switching unit that can lower the air resistance to increase the switching speed and reduce the driving power to reduce the power consumption.

In the optical switching unit having the above-described wall, when the space 15 is decompressed, the substrate 2 on which the wall 30 is formed is placed in a vacuum atmosphere such as a vacuum chamber.
It was necessary to perform an operation of fixing the light guide 1 as the light introducing prism on the light guide 0. On the other hand, in the optical switching unit 55 of this example, as shown in FIG.
Since the through hole 33 is provided in the wall 30, after the light guide 1 is fixed in advance, the light guide 1 can be placed in a container such as a vacuum chamber capable of creating a vacuum atmosphere. Therefore, it is easy to reduce the pressure in the space 15.

Then, as shown in FIG. 15, after the air in the space 15 is exhausted, the depressions or holes 33a and 33b can be closed by applying an adhesive 34. According to this method, the space 15 can be sealed in a state where the gas filling the space 15 in which the optical switching elements 10 arranged in an array exists is decompressed. Further, by replacing the space 15 with an inert gas before the pressure is reduced, the influence of the remaining air, moisture, or moisture can be further prevented. In this manner, by maintaining the space 15 in which the array-like optical switching elements 10 are present in a state where the inert gas is depressurized, the reliability of the switching unit 55 is increased, and at the same time, the air damping effect is reduced and the speed is increased. An optical switching unit 55 capable of performing optical switching can be provided.

FIGS. 16 and 17 show different examples of holes penetrating the wall 30 and means for closing the holes. In this example, a recess 33c of the wall 30 surrounding the space 15 in which the arrayed optical switching elements 10 exist is provided so that a part of the upper surface 31 of the wall 30 is recessed. When the light guide 1 is fixed, a hole penetrating the wall 30 is formed. In this state, a water-repellent treatment, gas filling, pressurization or decompression can be performed. Then the wall 30
A film is formed on the upper surface 31 so as to cover the depression 33c, and the depression 33c is sealed by patterning. Thus, the through holes 33c are closed by the film 34, so that the space 15 in which the optical switching elements 10 exist in an array can be sealed. If such a method is used, before the adhesive for closing the hole hardens, it penetrates between the upper surface of the wall and the lower surface of the light guide to contaminate the total reflection surface 1a or cause the optical element 3 to be totally reflected. It is possible to eliminate the possibility that a problem such as sticking to the surface 1a occurs. Further, since there is no deformation or the like at the time of curing of the adhesive, the distance between the light guide 1 and the optical element 3 can be set more accurately, and strong sealing can be easily realized.

Fourth Embodiment FIGS. 18 to 21 show still another example of the optical switching unit according to the present invention. FIG. 18 is a plan view of the optical switching unit 54 of the present example as seen through the light guide 1 from above, and FIGS. 19 to 21 are sectional views. The optical switching unit 54 of this example is also 3 × 3
Is an active optical device in which the optical switching elements 10 are arranged in an array.
0 is arranged at an interval 12 from the adjacent switching element. A wall 30 serving as a step is provided so as to surround these optical switching elements 10. Further, holes 33a and 33b are provided in the wall 30 so as to penetrate or communicate with each other.
After the space 15 is decompressed through the hole b, the holes 33a and 33b are sealed by a film 34 made of a suitable resin.
Further, the wall 30 and the sealing film 34 are coded by a metal oxide film or a metal thin film 35 so that gas does not pass therethrough.

The optical switching unit 54 of this embodiment
In FIG. 19, as shown in FIGS. 19 to 21, the space 15 in which the optical switching elements 10 are arranged in an array is
It is surrounded by the wall 30, the substrate 20, and the flat cover 60, and the flat cover 60 is in close contact with the prism body 61 for introducing light, and functions as the light guide 1. . That is, the flat cover (hereinafter referred to as a sealing plate or a sealing prism) 60 is provided with the light introducing prism 6.
1 is formed of a transparent member having the same refractive index as that of FIG. 1, the lower surface of which functions as a total reflection surface 1a.
The light is totally reflected at a. Then, light is switched when the optical element 3 of the optical switching element 10 comes into contact with or separates from the lower surface 1a of the sealing prism 60.

The light guide 1 is divided into such a plate-shaped sealing prism 60 and a light introducing prism 61, and the unit 54 is temporarily mounted with only the sealing prism 60 attached.
When the space 15 is sealed, it is not necessary to assemble the large light introducing prism 61 on the substrate 20. Therefore, the size of the device during the decompression process is reduced, and handling becomes very easy. Further, as shown in FIG. 18, on the surface 20a of the substrate 20,
Electrodes 70 for supplying a drive signal to the optical switching element 10 are arranged. However, when the light introducing prism 61 is attached, it is difficult to perform a bonding operation on the electrode 70. On the other hand, when the sealing prism 60 is attached. In this case, there is an advantage that a sufficient space is secured, so that the bonding operation can be easily performed.

The sealing prism (sealing plate, cover glass) 60 is desirably thinner in terms of reducing the thickness of the entire device. However, when the pressure is reduced, that is, when the pressure difference from the outside air becomes 1 atm, the sealing prism 6 is caused by the stress caused by the pressure difference.
0 is distorted inside. If the distortion is large, the optical element 3 of the switching element 10 is less likely to adhere to the lower surface 1a of the sealing prism 60, and the evanescent light extraction efficiency is reduced.
For this reason, it is desirable that the sealing prism 60 has such a thickness that the deformation due to the pressure difference falls within a certain range. For example, the quartz glass used as a sealing prism 60, more than about 30nm the deformation to 5mm, i.e., 10 ^{- 5} to 10 ^- to fit the ⁶ degree of deformation degree, one side of the size of about 10mm from 5mm quartz The thickness of the sealing prism 60 made of glass is desirably about 3 mm or more.

Further, the optical switching unit 5 of this embodiment
In 4, the wall 30 is formed by a resin mold 39. Therefore, after appropriately setting the distance between the substrate 20 and the sealing prism 60, the wall 30 is formed by a method of injecting or applying resin along the periphery thereof. At this time, in order to accurately set the interval between the substrate 20 and the sealing prism 60, after temporarily fixing with an adhesive or the like, a molding resin is injected or a spacer having an appropriate height is sandwiched. The substrate 20 and the sealing prism 60
It is desirable to inject a molding resin after setting the height.

Further, as described in the previous embodiment, it is also possible to form the rigid wall 30 by molding or the like and apply the molding resin 39 to the outside of the rigid wall 30 to seal the space 15. Further, it is also possible to assemble the sealing prism 60 after applying in a state where a spacer or a filler for maintaining the distance is mixed in the resin.

As the adhesive for temporary fixing or the resin 39 for molding, it is desirable to use a UV-curable resin which has a high viscosity and a small amount of outgas after curing.
In order to cure the resin in a state in which it is properly inserted between the substrate 20 and the sealing prism 60, an acrylic resin or an epoxy resin-based UV-curable resin is easy to handle. If the viscosity of the resin is low, the resin may penetrate into the space 15 and hinder the operation of the switching element 10. On the other hand, when the viscosity is high, workability deteriorates. For this reason, the viscosity is suitably about 20,000 to 150,000 cP. Further, the inside of the space is sealed under reduced pressure by the mold resin. If outgas is generated from the resin after sealing, the effect of reducing the pressure is weakened. For this reason, it is desirable that outgassing be as small as possible.
For example, it is desirable to select a resin that loses weight when heated at 120 ° C. for 2 hours after curing, that is, a gasification rate of about 0.5% or less. Further, a resin having a transmittance as low as possible for gas, for example, air and water vapor, is desirable. There are several resins that satisfy such conditions. For example, World Rock No. manufactured by Kyoritsu Chemical Industry Co., Ltd. 8723.

In this example, as shown in FIG. 19, when the wall 30 is formed by the resin mold 39,
The outer peripheral surface 36 of the wall 30 is tapered so as to gradually spread from the sealing prism 60 toward the substrate 20. There are several ways to apply the mold resin, but if the resin is molded in a hemispherical shape or the like, the contact area between the mold resin and the sealing prism 60 or the substrate 20 tends to be small, and the outside air tends to enter. Further, in the following, a gas barrier is manufactured by covering the surface of the mold resin 39 with the metal thin film 35.
When the metal thin film 35 is formed by vapor deposition, sputtering, or the like, it is easy to form a uniform film if the surface is uniformly spread in one direction. On the other hand, if the surface has irregularities such as a hemisphere, a portion where a film cannot be formed occurs, and a sufficient effect cannot be obtained even if a gas barrier film is formed.

FIG. 20 shows a state in which the gas barrier film 35 is formed outside the wall 30 by the mold resin. As described above, in the optical switching unit 54 of the present example, the wall 30 is formed by the mold resin 39 between the sealing prism 60 and the substrate 20, and at this time, the communication holes 33 for communicating the space 15 with the outside are formed. Is an open wall 30. Then, the internal space 15 is put in a vacuum chamber or the like to reduce the pressure. After that, the sealing film 34 is formed so that the space 15 is depressurized. In these steps, for example, if a vacuum chamber that transmits UV light is used, the film 34 that seals the walls and the communication holes 33 can be cured in a state where the pressure is reduced to a vacuum. Thereby, the space 15 can be made high vacuum. Further, as a post-processing, the gas barrier film 35 is formed outside the wall 30 and the sealing film 34 by the mold resin, thereby improving the adhesion and preventing the gas from passing through the wall 30 and entering the space 15. are doing.

As the gas barrier film, it is desirable to use a metal oxide such as silicon oxide and aluminum oxide, a metal nitride such as silicon nitride, and a metal such as aluminum, which can form a dense thin film. By these, 50
To 5000 angstroms, or 5 to 50
By forming a gas barrier film having a thickness of 0 nm, gas permeability can be significantly improved.

Further, when forming a film, a vacuum evaporation method can be used. However, by adopting an evaporation method such as an ion-assisted evaporation method, an ion plating evaporation method, or an oxidation reaction evaporation method in accordance with the material, a dense film is formed. Thus, a thin film having a high gas barrier effect can be formed. In the case of forming a metal or other conductive gas barrier film, it is required to perform vapor deposition so as to avoid interference with surrounding electrodes.

In this manner, the optical switching unit 54 which performs the decompression processing on the space 15 in which the switching elements are arranged
As shown in FIG. 21, as shown in FIG. 21, the optical switching unit 55 capable of switching the introduced light can be assembled by attaching the light guiding prism 61 serving as the main body of the light guide 1.

In the optical switching unit shown in these embodiments, the space 15 in which the optical switching elements are arranged is sealed from the outside, and the inside can be decompressed. Therefore, the air resistance can be reduced, and the operation speed can be increased to four times or more in the simulation. Furthermore, since the effect of adsorption by moisture is also eliminated, the rate of actually contributing to speeding up is considered to be higher.

Then, the resistance due to gas when driving the optical element of the optical switching element is reduced, and power for coping with switching due to moisture or the like becomes unnecessary. Further, if an insulating layer is provided to prevent contact between the electrodes, a small amount of electric charge accumulates, and the electric charge causes electrostatic attraction. However, as described above, the gap is precisely controlled to stop the light guide. The insulating layer can be omitted. Therefore, in the optical switching unit of the present invention, it is possible to reduce the power required to drive the actuator due to these factors, and to provide an optical switching unit that consumes less power and operates at high speed.

By reducing the pressure in the space 15,
When a metal film is used for the reflection surface 4a of the prism, oxidation can be prevented by reducing the pressure, and the reflectance can be prevented from lowering. Further, it is possible to prevent the resin constituting the optical element from deteriorating due to the interaction with light through oxygen. For this reason, in the optical switching unit of the present invention, the optical characteristics can be kept good, and the durability and reliability can be greatly improved.

In the above description, the present invention has been described based on an optical switching element and an optical switching unit having an intermediate electrode 51 in addition to the upper and lower electrodes 7 and 8 as the actuator 6, but the actuator is constituted by the upper and lower electrodes. It is needless to say that the optical switching element and the optical switching unit may be used. further,
Instead of an electrostatic actuator, the present invention can be provided to an apparatus using another type of actuator such as a piezo element. In some of the above embodiments, it is not described that the upper surface 31 of the wall 30 is reflective. However, as described above, by forming a reflective film on the upper surface, light can be effectively emitted. It can be used, and the contrast can be increased when forming an image.

Each of these optical switching units 55 according to the present invention is applicable as a light valve to the image display device 80 shown in FIG.
The light emitted from the light source 81 is condensed on a color filter 82 by a lens or the like, becomes more parallel light through a collimator lens or the like, and enters the light guide 1 having a function as a light introducing prism. The light incident on the light guide 1 is incident on the above-mentioned active optical switching device 50 attached to the total reflection surface 1a, and the optical switching device 10 or the optical element 3 arranged in the array forms a pixel display. Is selectively switched and emitted. Light 85 having image information is projected on a screen 89 by a projection lens 86 to display a moving image or the like. As described above, since an active optical element having a simple structure and a small number of steps and the optical switching unit 55 including the active element can be realized, an image with very high reliability and durability required for an image display device is obtained. A display device can be provided. In addition, because the introduction prism, projection lens, etc. can be made smaller,
A power-saving image display device can be realized.

Further, the optical switching unit according to the present invention is capable of turning light on and off digitally at high speed, and is being developed not only for image display devices but also for optical computers and optical printers. The present invention can be applied to a device using light whose conversion is desired as a medium.

[0073]

As described above, according to the present invention, an interval of 1 micron or less, at which the optical element of the optical switching element moves, can be realized with very high accuracy, and a step or a gap for ensuring an accurate interval. Walls can be easily made. Therefore, variation in the drive voltage of the actuator that drives the optical element can be suppressed, and the interval can be narrowed, so that driving at a low voltage is also possible, and a power-saving active optical switching unit can be provided.

Such a highly accurate wall can be formed at the same time as the step of manufacturing the micro optical element by the resin transfer technique. Therefore, a very inexpensive and energy-saving manufacturing process was realized.

By using the wall, the space where the optical switching elements are arranged can be accurately maintained between the light guide and the substrate, and this space can be sealed by the wall. Therefore, in the present invention, the reliability of the optical switching element including the optical element and the actuator can be improved, and at the same time, the optical switching speed can be increased by keeping the space under reduced pressure.

Further, by sealing the area where the optical switching elements are arranged and reducing the pressure, it is possible to prevent stinking due to moisture, deterioration of the metal film forming the reflection surface of the prism, and deterioration of the material of the optical elements due to oxidation. can do.

Therefore, with the optical switching unit of the present invention, it is possible to provide a digital light modulator capable of high-speed, high-contrast, high-reliability and durability, and capable of high-gradation display. For this reason, by using the optical switching unit of the present invention as a light valve, an image display device with extremely high reliability and durability can be realized, and a light-weight and power-saving image display device can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a projector using an image display device using evanescent light.

FIG. 2 is a diagram illustrating an outline of an image display device (optical switching device) using evanescent light.

FIG. 3 is a diagram illustrating another example of an optical switching device using evanescent light.

FIG. 4 is a diagram showing an outline of an optical switching unit according to the first embodiment of the present invention.

FIG. 5 is a sectional view of the optical switching unit shown in FIG.

FIG. 6 is a graph showing a result of simulating a relationship between a response speed and an air pressure.

FIG. 7 is a diagram illustrating an example of a method of manufacturing the optical switching unit illustrated in FIG.

FIG. 8 is a diagram showing an example of an optical switching unit different from the above.

FIG. 9 is a diagram illustrating an example of an optical switching unit that is further different from the above.

FIG. 10 is a diagram schematically illustrating an optical switching unit according to a second embodiment of the present invention.

11 is a sectional view of the optical switching unit shown in FIG.

FIG. 12 is a diagram schematically illustrating an optical switching unit according to a third embodiment of the present invention.

FIG. 13 is a sectional view of the optical switching unit shown in FIG.

FIG. 14 is a diagram showing a state where the pressure is reduced by the optical switching unit shown in FIG. 12;

FIG. 15 is a diagram illustrating a state in which a communication hole is sealed by the optical switching unit illustrated in FIG. 12;

FIG. 16 is a diagram illustrating a configuration of a sealing film different from the above.

FIG. 17 is a sectional view of FIG. 16;

FIG. 18 is a diagram schematically illustrating an optical switching unit according to a fourth embodiment of the present invention.

FIG. 19 is a cross-sectional view of the optical switching unit shown in FIG. 18, showing a state where a wall is formed by a mold resin.

20 is a cross-sectional view of the optical switching unit shown in FIG. 18, showing a state where a gas barrier film is formed.

FIG. 21 is a cross-sectional view showing a state where light introducing prisms are superimposed.

[Explanation of symbols]

Reference Signs List 1 light guide plate (light guide) 1a total reflection surface 2 illumination (incident) light 2a emission light 3 optical element 3a extraction surface 4 microprism 5 V-type support structure 6 actuator 7 upper electrode and spring structure 8 lower electrode 9 anchor 10 light Switching element 11 Post (post) 15 Space in which optical switching elements are arranged 17 Gap between total reflection surface and extraction surface 20 Semiconductor substrate 30 Wall 31 Upper surface of wall 32 Reflection film 33 Through hole (dent or communication hole) in wall 34 Sealing Stop film 35 Gas barrier 36 Outer surface of mold resin 39 Mold resin 50 Optical switching device (image display device) 51 Intermediate electrode 54 Optical switching unit employing sealing prism 55 Optical switching unit (image display unit) 60 Flat cover glass ( (Sealing prism, sealing plate) 61 Of the light introducing prism (trapezoidal prism) 70 bonding pad (electrode for connection) 80 projector

Claims (24)

[Claims] 1. A substrate, at least one driving actuator disposed on the substrate, an optical element driven by the actuator, and a light guide having a total reflection surface for transmitting incident light. An optical switching unit driven by the actuator to a position where evanescent light is extracted and a position where evanescent light is not extracted with respect to the total reflection surface of the light guide, wherein the actuator surrounds the actuator and the optical element. An optical switching unit further comprising a wall disposed on the actuator, wherein the wall, the substrate, and the light guide seal the actuator and the optical element. 2. The optical switching unit according to claim 1, wherein a reflection film is formed on a surface where the wall contacts the light guide. 3. The optical switching unit according to claim 1, wherein a step is formed between a region of the light guide contacting the wall and the total reflection surface. 4. The optical switching unit according to claim 1, further comprising at least one projection in a space sealed by the wall, wherein the projection is in contact with both the light guide and the substrate. 5. The method of claim 1, wherein
An optical switching unit that has a communication part that communicates the outside with the space sealed by the wall, and the communication part is closed. 6. The optical switching unit according to claim 1, wherein the light guide is a flat plate-shaped cover member separated from a main body having a portion through which light is incident. 7. The optical switching unit according to claim 6, wherein the cover member has a thickness of 3 mm or more. 8. The optical switching unit according to claim 1, wherein the outside of the wall is resin-molded. 9. The optical switching unit according to claim 1, wherein the wall is a resin mold. 10. The optical switching unit according to claim 9, wherein the resin mold forming the wall is formed in two stages: a temporary fixing portion and a portion forming the wall. 11. The optical switching unit according to claim 8, wherein an outer surface of the resin mold is tapered. 12. The optical switching unit according to claim 8, wherein a metal oxide film, a metal nitride film, or a metal film is formed on an outer surface of the resin mold. 13. The optical switching unit according to claim 1, wherein a space sealed by the wall, the substrate, and the light guide is reduced in pressure. 14. The optical switching unit according to claim 13, wherein a reduced pressure inert gas or air is present in the sealed space. 15. The optical switching unit according to claim 1, wherein the actuator and the optical elements are arranged in an array. 16. An image display device comprising: the optical switching unit according to claim 15; and means for inputting and outputting display light to and from the optical switching unit. 17. A substrate, at least one driving actuator disposed on the substrate, an optical element driven by the actuator, and a light guide having a total reflection surface for transmitting incident light. A method of manufacturing an optical switching unit, wherein the optical element is driven by the actuator to a position where evanescent light is extracted and a position where evanescent light is not extracted with respect to the total reflection surface of the light guide, wherein the actuator and the optical element A method for manufacturing an optical switching unit, comprising a step of sealing the actuator and the optical element together with the substrate and the light guide by a wall arranged so as to surround the optical switching unit. 18. The method according to claim 17, wherein, in the step of sealing, a step of penetrating the wall and providing a communicating portion communicating the space sealed by the wall with the outside is provided; A method for manufacturing an optical switching unit, comprising: a step of reducing the pressure of a space sealed by a guide; and a step of closing the communication part. 19. The method for manufacturing an optical switching unit according to claim 17, wherein the light guide is a flat plate-shaped cover member separated from a main body having a portion through which light is incident. 20. The method according to claim 17, further comprising a step of resin-molding the outside of the wall. 21. The method according to claim 17, wherein the wall is formed by a resin mold. 22. The method for manufacturing an optical switching unit according to claim 21, wherein the resin mold forming the wall is formed in two stages: a temporary fixing portion and a portion forming the wall. 23. The method according to claim 21, wherein an outer surface of the resin mold is tapered. 24. The method of manufacturing an optical switching unit according to claim 21, further comprising a step of forming a metal oxide film, a metal nitride film, or a metal film on an outer surface of the resin mold.