JP2002221678A - Optical switching device, manufacturing method thereof, and image display device - Google Patents

Abstract

(57) [Problem] To provide an optical switching device of an optical interference type, which is easy to manufacture and can improve optical performance. SOLUTION: A distance d between a semi-transmissive body 22 and a high reflector 42.
In the interference-type optical switching device 4 for controlling the light transmission, a thin-film semi-transmissive body 22 is formed on the glass substrate 21 side, an actuator 33 is provided on another substrate 31, and a reflector 42 which is vertically driven by the actuator 33. And are formed. Since the substrates 21 and 31 can be manufactured separately, the yield can be improved. In addition, it is possible to provide an optical switching device in which the processing of the reflection surface 41 is ready and which can display a bright image with high reflection efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching device used for a direct-view image display device or a projector device.

[0002]

2. Description of the Related Art In a projector or the like, an optical switching device such as a DMD capable of turning on and off light at high speed is known as an image display device for forming a desired image. Furthermore, instead of turning on and off light by changing the angle of a reflective mirror like a DMD, an interference type device that uses a reflective mirror and a semi-transmissive mirror and changes the distance between them to control the light. Is being considered. FIG.
The interference-type display elements shown in FIGS.
IEE Japan, Vol, 119-E, No 12, '99, pp631-635). This interference type device 100
Highly reflective mirror (bottom mirror) on silicon substrate 101
A half mirror 103 is provided on the bottom mirror 102 at an appropriate interval D. The half mirror 103 also serves as the transparent electrode 104, and a member such as SiO 2 for providing a gap is disposed between the half mirror 103 and the silicon substrate 101.

As shown in FIG. 12B, when an appropriate voltage is applied, the interference type element 100 causes an electrostatic attraction between the bottom mirror 102 on the substrate 101 and the upper half mirror 103. Works. Therefore, the half mirror 103
Is controlled in the up and down direction, interference occurs as the optical path difference between the half mirror 103 and the bottom mirror 102 shifts by half a wavelength (λ / 2), and the contrast of light and dark changes. For example, when monochromatic light having a wavelength λ is used, the half mirror 103 moves up and down, and the distance D from the bottom mirror 102 becomes λ.
A change of / 4 causes a change in brightness. Therefore, if the position of the half mirror 103 that moves up and down is controlled with high accuracy using white light, color display using interference colors becomes possible. Therefore, when a large number of the interference devices 100 are integrated, a reflection type display can be configured. Compared to the conventional color display method using a color filter that time-divides white light into each of the three primary colors, the degree of integration of pixels is expected to be improved by about three times. By not using it, by making it a mirror that is a machine element,
It is expected that it can be formed on the order of several tens of μg, can respond at high speed, and can reduce power consumption by using electrostatic driving.

[0004]

As described above, the device using the light interference type element has many advantages such as easy downsizing, higher speed response and lower power consumption than the conventional liquid crystal device. Have. However, the above-mentioned interference type device 100 has many problems for practical use. For example, the transparent electrode 104
Also serves as the half mirror 103, that is, the drive (actuator) structure and the optical structure are formed of the same component. For this reason, it is very difficult to optimize in consideration of the respective roles in terms of structure, material, and the like. For example, it is almost impossible at a mass production level to obtain an appropriate reflectivity by depositing aluminum or the like on a transparent electrode. Furthermore, since the half mirror that also serves as the transparent electrode is bent by the electrostatic force, color bleeding or the like appears, and it is difficult to obtain a high-resolution image.

On the other hand, M. W. Miler (SID 00
DIGEST / pp32-35) has proposed a modulator as shown in FIG. In this device 110, the thin film 11
3 is provided on a glass substrate 111, and a thin film 112 made of aluminum is provided below the glass substrate 111 so as to face the glass substrate. And
Switching is performed by moving the aluminum thin film 112 with electrostatic force. As shown on the left side of FIG. 13, when the aluminum thin film 112 is separated, the white light 7
1 emits a light 72 of a particular color, while
It has been reported that when the aluminum thin film 112 shown in the right side of FIG.

In the device 110 shown in FIG. 13, since the film 112 movable as an actuator is made of aluminum, it is not necessary to appropriately change the transmittance of the transparent electrode as described above. Are more suitable for mass production than the above coherent elements. However, if the film 112 that moves as an actuator bends, the optical performance deteriorates, which causes bleeding and the like, and the structure is not suitable for an image display device. further,
Considering the electrostatic characteristics and the arrangement of the members that support the electrodes, the material and size (area) of the thin film 112 are limited, and the selectable range is not wide.

Further, the substrate 111 supporting the thin films 113 and 112 is common, and the material is limited to glass and the like having higher transparency. Therefore, if a circuit for controlling a pixel is to be formed in an image device, a complicated manufacturing process using a transparent electrode or the like is required as in the case of a liquid crystal substrate, and manufacturing at low cost is not possible.

As described above, although some light interference type devices have been proposed, there is no device capable of displaying a pixel of a desired color without bleeding, and the device is bright enough to be actually used as an image display device. , And good mass productivity,
Further, there is no disclosure of a device which can be manufactured at low cost and with good yield.

Therefore, the present invention is a light interference type device which can display pixels without color bleeding, has high mass productivity, and can incorporate a control circuit for a switching element at low cost. It is intended to provide an optical switching device. It is another object of the present invention to provide an image display device capable of performing high-resolution color display at low cost using the optical interference type device of the present invention.

[0010]

For this reason, in the present invention, a transflector of an interference type optical switching device for controlling the distance between the transflector and the reflector and the reflector are mounted on one substrate. Instead of placing it on a different board,
The interference type device is constituted by combining these substrates. The reflector is formed on the actuator that controls the distance (position) between the transflector and the reflector, so that the functions of the transflector and the reflector are separated from the function of the actuator, and each is optimized. I can do it.

That is, in the optical switching device of the present invention having a plurality of optical switching elements whose ON / OFF and / or color can be controlled by changing the distance between the transmitting member and the reflecting member, a semi-transmitting member is formed. It has a first substrate and a second substrate in which the reflector is formed on an actuator capable of driving the reflector. In this optical switching device, a first step of forming a semi-transparent body on a first substrate and a second step of forming a reflector on a second substrate by overlapping the reflector with an actuator capable of driving the reflector And a step of combining the first and second substrates such that the transflector and the reflector face each other.

In the optical switching device of the present invention, the transflector can be provided on the first substrate and does not need to be moved. Further, switching is performed by driving a reflector supported on another substrate. Therefore, it is not necessary to process the transparent electrode to be semi-transparent, and it can be manufactured by forming a semi-permeable thin film of an appropriate material on a transparent substrate such as glass. Further, the on / off of the switching element forming each pixel is performed by a reflector, and the reflector is disposed on another substrate. Therefore, there is no need to support the reflector, and it is not necessary to separate the transflector for each optical switching element or each pixel. For this reason, the first substrate may be a transparent substrate such as a glass plate, and a semi-transmissive layer serving as a semi-transmissive body may be continuously formed on one surface of the transparent substrate over the optical switching elements constituting each pixel. It is possible. Therefore, in the case of the optical switching device of the present invention, a known thin-film technology such as a semi-transparent body as a first substrate using a transparent substrate such as a glass plate, and spin coating or depositing a dielectric or metal in multiple layers thereon. Thereby, it can be easily and accurately formed. Therefore, it is possible to easily provide a semi-transmissive body having uniform properties such as film thickness, high accuracy, and small variations.

Further, since the reflector is provided on the second substrate different from the first substrate, it is not necessary to drive the reflector with respect to the first substrate. Therefore, the reflector itself is used as an actuator. If not, an actuator for moving the reflector with respect to the second substrate can be provided, and the reflector can be driven by the actuator. Therefore, it is not necessary for the reflector to also function as an actuator, and it is possible to provide an optical switching device capable of forming a pixel or image of a clear color without the reflector being bent and the color blurring.

Since the reflector only needs to have a function as an optical element, the clearance between the reflector and an adjacent reflector may be small. Therefore, it is possible to reduce the pixel separation interval, and it is possible to provide an interference type optical switching device capable of displaying a bright image with high resolution.

Furthermore, since the optical element driven by the actuator with respect to the second substrate is of a reflection type,
The substrate need not be transparent. Therefore, it is easy to form a semiconductor circuit such as a silicon substrate as the second substrate, and a substrate with a proven track record can be used. For this reason,
A control circuit for driving each optical switching element can be easily incorporated in the second substrate, and an optical interference type optical switching device with a drive circuit can be provided at low cost.

Further, since the reflector does not need to double as an actuator, the actuator is not limited to the electrostatic type, and other means such as piezo can be used. However, an electrostatic actuator in which electrodes are stacked can be manufactured using a photolithography technique, and there are advantages such as low power consumption.

As described above, the optical switching device of the interference type according to the present invention, by forming the transmitting body on the first substrate and forming the reflecting body on the second substrate, is optically free from color blur. It is an excellent, bright reflective optical switching device with a large switching area. And
Since the transmitting body and the reflecting body are manufactured on different substrates, the yield of manufacturing each layer is dispersed or independent, and the yield is overlapped as in the case where these are manufactured on one substrate, and the yield of the optical switching device is reduced. It can be prevented from lowering. Therefore, an optical switching device with good performance at low cost can be provided. And since the optical switching device of the present invention is a reflection type,
This can be used to provide a direct-view image display device similar to a reflective liquid crystal panel. Further, it is possible to provide an image display device which is faster than a liquid crystal panel, has higher resolution, and consumes less power, and can be used as a display panel of a mobile phone or the like.

Also, by providing the optical switching device of the present invention, a light source capable of entering light into the optical switching device, and a lens system for projecting the light modulated by the optical switching device onto the screen, It is also possible to provide a projector-type image display device that projects an image. These image display devices will be described in detail later. However, since the interference type optical switching device itself has wavelength selectivity, a color filter can be omitted. Therefore, in addition to being fast and high resolution, by omitting filters,
A compact and low-cost image display device capable of displaying a high-quality image can be provided.

In the present invention, as described above, since the actuator and the semi-transparent body can be formed to be supported on separate substrates, there are the following advantages. For example, in the case where an optical switching device using such coherence is used as a reflection type, since desired light is output from the first substrate side, the opposing second substrate is
It does not need to be transparent. Therefore, on the second substrate,
It is possible to use a silicon substrate or the like.
The semiconductor circuit can be easily provided on the side of the substrate.

Also in the optical interference type optical switching device of the present invention, the distance between the transflector and the reflector needs to be controlled to a predetermined distance in order to output light of a desired wavelength λ. Therefore, with respect to the wavelength λ of the light emitted from each of the optical switching elements that constitute the pixels, the reflector is at least positioned at a position where the distance d from the semi-transmissive member has the value of the following formula (1). Need to work with actuator. Here, n is an integer of 1 or more.

D = nλ / 2 (1) Further, if the optical path difference 2d from the semi-transmissive body to the reflector is shifted by a half wavelength (λ / 2), light of wavelength λ is not emitted. Therefore, in order to turn on / off or modulate light, the reflector (reflection surface) is set to λ / 4 with respect to the semi-transmission member (half mirror surface).
The light can be turned on and off by moving it one by one.

As described above, the optical interference type optical switching device of the present invention has wavelength selectivity depending on the distance d between the reflector and the semi-reflector. Therefore, in order to realize color display by applying the optical switching device of the present invention, different wavelengths λ of different light, which need to be emitted for performing color display, have different distances d corresponding thereto. It is possible to arrange at least three types of optical switching elements. Thus, white light can be modulated by using at least three pixels as a unit to perform color display.

Furthermore, by driving the reflector to at least three different distances d corresponding to different wavelengths λ, only light of a color corresponding to the distance d can be output. For this reason, it is possible to time-divide incident white light and display in color. For example,
When the actuator is of an electrostatic drive type, an optical switching device capable of color display can be easily provided by providing at least three types of electrode pairs having different distances x for driving the reflector. It is also possible to perform time division by another method such as changing the drive voltage.

Further, it is desirable to provide a minute projection on at least one of the semi-transmitter and the reflector so that the distance between the semi-transmitter and the reflector does not become less than a predetermined value. Thus, even when the semi-transmissive body and the reflector are separated from the position where they are in close contact with each other, adsorption can be prevented, and smoother and faster switching can be realized.

Further, since the distance d between the semi-transmissive member and the reflector can be strictly controlled by the minute protrusion, the distance d0 between the semi-transparent member and the reflector limited by the minute protrusion is determined by the on / off position of the optical switching element. It is desirable that For that purpose, it is desirable to satisfy the value of the following equation (2). Here, n is an integer of 1 or more.

D0 = nλ / 4 (2) For example, to turn off the position at the distance d0, the wavelength λ
In this case, when the reflector moves by λ / 4, the optical path difference becomes λ / 2 and the reflector is turned on. Therefore, it is sufficient that the distance d0 limited by the minute projections satisfies the value of the following expression (3).

D0 = (2n−1) λ / 4 (3) Further, in order to turn on the position at the distance d0, the wavelength λ /
In this case, when the reflector moves by λ / 4, the optical path difference becomes λ3 / 4 and the reflector is turned off. Therefore, it is sufficient that the distance d0 limited by the minute projections satisfies the value of the following equation (4).

D0 = nλ / 2 (4) As described above, one position is strictly controlled by the minute projection, thereby simplifying position control of the reflector. Further, a minute projection serving as a stopper is provided also in a region movable by the actuator, so that the moving distance of the reflector can be limited to simplify the on / off control. For example, in the case of an actuator of an electrostatic drive type, λ / 4 is applied from a position stopped by a minute projection provided between a semi-transmissive body and a reflector.
If a stopper is provided between the electrodes so that the movement of the reflector stops at the moved position, the on / off position can be defined by the stopper, and control becomes very easy.

Such an optical switching device of the present invention can be manufactured by separately manufacturing and combining the first and second substrates. Since the second substrate can use a non-transparent silicon substrate or the like, in the second step of forming the second substrate, an actuator layer in which a plurality of actuators are arranged is provided on a substrate provided with a semiconductor circuit. It is possible to laminate a reflective layer in which a plurality of reflectors corresponding to each actuator are arranged,
An optical switching device incorporating a drive circuit can be easily manufactured.

Further, in the second step, an actuator layer on which a plurality of actuators are arranged is formed on a substrate provided with a semiconductor circuit, and an optical element layer serving as a reflection layer is formed on a third substrate. And a step of superposing the optical element layer on the actuator layer formed on the second substrate, and then separating the third substrate from the optical element layer. According to this manufacturing method, the optical element layer serving as the reflector can be further formed on another substrate.
The yield can be made independent, and the yield can be further improved.

Further, since the reflector can be manufactured on the second substrate different from the semi-transmissive body, the surface processing of the reflector can be performed, and an optical switching device having good reflection performance can be provided. That is, since the surface serving as the reflection surface of the optical element layer is formed facing the surface on the second substrate, it is possible to provide a step of flattening by a method such as spin coating or CMP. A uniform reflecting surface can be formed. Further, by increasing the surface accuracy, the distance d between each reflecting surface and the translucent body can be maintained uniform, and an optical switching device capable of performing more accurate switching can be provided.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a projector device 1 including an optical switching device 4 of the present invention. The projector device 1 includes a light source unit 2 that outputs white light 71 such as a xenon lamp, and a beam splitter 3 that can reflect a white light beam 71 emitted from the light source unit 2 at right angles. The light beam 71 incident through the splitter 3 is turned on and off by the switching device 4 of the present embodiment to form an image. Light 7 for forming an image turned on and off by the optical switching device 4
2 reaches a lens system 6 through a beam splitter 3 and is projected on a screen 7 to display a color image.

The optical switching device 4 of the present embodiment is an interference type switching device 4 in which optical switching elements each having a transflector and a reflector are two-dimensionally arranged, and includes a driving circuit. Therefore, the drive circuit switches the optical switching elements for displaying the individual pixels according to the image data φ supplied from the control mechanism 5, and the display light 72 modulated by the switching device 4 as the image display device is output.

FIG. 2 shows the optical switching device 4 of this embodiment.
Is schematically shown. The optical switching device 4 of the present example includes a semiconductor substrate 31 serving as a second substrate,
A substantially transparent glass substrate 21 serving as a first substrate superposed on the semiconductor substrate 31; and a silicon-based thin-film semi-transmissive layer 22 on a lower surface 21a of the glass substrate 21.
Are formed.

On the other hand, the semiconductor substrate 31 is
1a, an actuator layer 32 in which electrostatic actuators 33 are two-dimensionally arranged;
The optical element layers 40 in which reflectors (optical elements) 42 driven in the vertical direction are two-dimensionally arranged are stacked in this order from the bottom. Each of the reflectors 42 includes a support 43
Are connected to the individual actuators 33 by
It is individually moved up and down by the actuator 33. Also,
The reflector 42 is a reflecting surface 4 facing the upper semi-transmissive body 22.
1, in this example, the reflection surface 41 is made of aluminum, and can reflect light with high reflectance.

The actuator 33 is of an electrostatic drive type, and has an upper electrode 34 to which a support 43 of a reflector 42 is mechanically connected, and a lower electrode 35 facing the upper electrode 34. The upper electrode 34 has a function as an elastic member, and when the electrostatic force (electrostatic attraction force) does not act between the electrodes 34 and 35, the upper electrode 34 presses the reflector 42 upward by the elastic force. A drive circuit (control circuit) 3 for driving these actuators 33 is provided on the semiconductor substrate 31.
8. Further, a memory and the like are built as required.

The semiconductor substrate 31 on which the reflector 42 is formed on the upper layer and the glass substrate 2 on which the transflective layer 22 is formed on the lower layer
1 is combined so that the reflection surface 41 of the reflector 42 and the lower surface (semi-transmission surface) 22a of the semi-transmission layer 22 face each other, and their distance is formed continuously or intermittently around the substrate 31. And is supported by a wall 39. Further, a small projection 50 protruding downward is formed intermittently on the semi-transmissive surface 22a of the semi-transmissive layer 22, so that the semi-transmissive body 22 and the reflector 42 are not attracted.

As described above, the optical switching device 4 according to the present embodiment includes the actuator layer 32 on the semiconductor substrate 31,
The optical element layer 40, the semi-transmissive layer 22, and the transparent substrate 21 are laminated, and the driving circuit 38, the actuator 33, the reflector 42, and the semi-transmissive layer 22 facing the same form one. One optical switching element 10 is formed. Therefore, the plurality of optical switching elements 10 are arranged or integrated in a two-dimensional array in the entire optical switching device 4, and each optical switching element corresponds to a pixel which is a unit for forming an image. By controlling this, a two-dimensional image can be expressed.

In the optical switching device 4 of this embodiment, the optical switching element 10a shown on the left side of FIG. 2 is in the off state, and the optical switching element 10b shown on the right side of FIG.
Is on. In the optical switching element 10 of the present example, the electrodes 34 and 35 constituting the actuator 33
When an appropriate drive voltage is applied during this time, an electrostatic force acts between the lower electrode 35 and the upper electrode 34 of the actuator 33,
The reflector 42 is driven downward. Therefore, the reflector 4
The distance d between the second high-reflection surface 41 and the semi-transmissive surface 22a on the facing glass substrate 21 increases. On the other hand, when the driving voltage disappears, the reflector 42 is driven upward by the elasticity of the upper electrode 34. For this reason, the distance d decreases.
Therefore, by controlling the driving voltage supplied to the actuator 33, the position is moved from the position L0 of the reflector 42 of the left optical switching element 10a to the position L1 of the reflector 42 shown in the right optical switching element 10b in FIG. And vice versa.

In the light interference type switching element of this embodiment,
As shown in FIG. 3, light having an appropriate wavelength λ can be turned on and off depending on the value of the distance d between the semi-transmissive surface 22a and the highly reflective surface 41. That is, assuming that the wavelength of light desired to be emitted from the optical switching element 10 is λ, the semi-transmissive surface 22
When the distance d between the semi-transmissive surface 22a and the highly reflective surface 41 becomes an integral multiple of a half wavelength (λ / 2), the optical path difference 2 between the semi-transmissive surface 22a and the highly reflective surface 41 becomes larger.
Since d becomes an integral multiple of the wavelength λ, the light 72 having the desired wavelength λ can be output. Therefore, in order to output light having a desired wavelength λ, it is necessary to control the distance d between the semi-transmissive surface 22a and the high-reflection surface 41 to a position represented by the following equation (1).
Here, n is an integer of 1 or more, and the same applies to the following formulas.

D = nλ / 2 (1) On the other hand, the distance d between the semi-transmissive surface 22a and the highly reflective surface 41 is 1
When the wavelength becomes an odd multiple of 波長 wavelength (λ / 4), the semi-transmissive surface 22 a
Since the optical path difference 2d between the light and the high reflection surface 41 is an integral multiple of the half wavelength λ / 2, the light 72 having the desired wavelength λ is not output. For this reason, in order to turn on and off the light having the desired wavelength λ with high contrast, it is necessary to control the reflector 42 at the position of the following equation (1) ′.

D = (2n−1) λ / 4 (1) ′ As described above, in the optical switching device 4 of the present example, the desired wavelength λ is obtained by moving the reflector 42 by １ ／ wavelength. Can be turned on and off. In the optical switching device 4 of this example, the off position L shown on the left side of FIG.
The distance d0 of 0 is a position satisfying the expression (1) ′, and the distance d1 of the ON position L1 shown on the right is a position satisfying the expression (1). It is easy to reverse the relationship between the off position and the on position, and any of them can be adopted. In addition, if the white light having a spread of about visible light is the incident light 71, by appropriately setting the distance d, light having a desired wavelength can be selected and output from the white light. Therefore, it can be said that the optical switching device 4 of this example is an image device suitable for color display. Furthermore, in the optical switching device 4 of the present example, light can be turned on and off only by moving the distance d of about the wavelength λ, so that there is a merit that the response is faster, the response is higher, and the size can be reduced by eliminating the color filter. . Further, an electrostatic drive type actuator is suitable for a power saving type image display device because it consumes less power.

Further, the optical switching device 4 of this embodiment
Then, the semi-transparent body 22 is replaced with the glass substrate 21 as the first substrate.
And the reflector 42 is provided on the semiconductor substrate 31 as the second substrate.
It is provided in. As described above, the transflector 22 and the reflector 42
As described above, there are many advantages such as not only simplification of the manufacturing process but also improvement in optical characteristics as described above. That is, since the currently proposed optical interference type device as described above has a switching element formed on a single substrate, a structure that serves both as an electrode and a reflector or a transflector is required. I have. Accordingly, there are disadvantages that the manufacturing process becomes complicated, optical characteristics are hardly improved, and a driving circuit cannot be easily incorporated.

On the other hand, in the optical switching device 4 of the present embodiment, first, since the semi-transmissive body 22 and the reflector 42 can be manufactured on different substrates, the yield is not synergistically deteriorated. Easy to manufacture. Since the reflector 42 is supported by the semiconductor substrate 31 which is a separate substrate, the actuator 33 can be stacked on the semiconductor substrate 31. The actuator 33 is not limited to the electrostatic type, and may be a type such as a piezo. Can also be adopted. Since the reflector 42 and the semi-transmissive body 22 do not need to double as electrodes, neither of these ends is fixed to the substrate or to the support. Therefore,
The possibility of bending or distortion during switching is very low, and the distance d between the reflector 42 and the transflector 22 can be controlled uniformly. For this reason, the optical switching device 4 of the present example can turn on and off light of a desired wavelength λ with extremely high accuracy, and has high contrast and good color separation performance.

Since the second substrate 31 is located on the opposite side of the reflector 42, it does not need to be a transparent substrate, and a drive circuit is formed as a semiconductor substrate by a conventional process for manufacturing a semiconductor substrate. Can be included. Moreover,
In the manufacturing process, since the reflector 42 can be manufactured by element isolation in addition to the improvement of the yield, the interval between the adjacent reflectors can be reduced to the processing limit by etching or the like, and the optical switching device having a large reflection area can be manufactured. Can be provided. Further, the optical switching device 4 of the present example has a configuration suitable for being an optical switching device having high reflection performance, for example, since the reflection surface 41 faces the outer surface of the second substrate 31 for easy processing. As described above, while the optical switching device of the present example is of the optical interference type, the configuration of each of the optical interference type optical switching elements is achieved by forming the transflector 22 and the reflector 42 on separate substrates. Optimization is possible, and a high-performance optical switching device can be provided at low cost. Of course, the substrate (first substrate) 31 is not limited to the above-described semiconductor substrate, and the effects of the present invention can be obtained as long as the substrate can support the actuator 33.

An example of a process for manufacturing the optical switching device 4 will be described. FIGS. 4A to 4D show an outline of a process of stacking an actuator and a reflector. First, as shown in FIG. 4A, a layer 3 of an actuator 33 is formed on a surface 31a of a semiconductor substrate (second substrate) 31 on which CMOS such as a driving circuit is formed.
2 is manufactured. This process can be manufactured using a photolithographic technique using a sacrificial layer of an appropriate material, not shown. For example, first, an electrode layer (A) is formed on the surface 31a of the substrate.
1), and patterning is performed thereon to form an anchor portion 36 having a structure of the lower electrode 35 and the upper electrode 34 which also serves as a spring. Then, a layer (Al film) serving as the upper electrode 34 is deposited. Then, the Al layer is patterned to form an upper electrode 34 and a post 36 for supporting the upper electrode 34 on the substrate 31. Although the removal of the sacrificial layer can be performed at any time, in this example, since machining such as CMP is performed as described below, it is desirable to remove the sacrificial layer at the final stage of element isolation.

Next, as shown in FIG. 4B, an optical element layer 40 serving as a reflector 42 driven by the actuator 33 is manufactured. In this process, the optical element layer 40 can be formed by photolithography using a sacrificial layer in the same manner as described above so as to be stacked on the actuator layer 32, or by using a technique such as mold transfer or spin coating. It is also possible to form the optical element layer 40. Then, the reflective surface 41 is formed by coating the surface of the optical element layer 40 with a highly reflective material such as aluminum, and is flattened by a fine polishing technique such as a CMP method. Thereby, a flat reflection surface 41 having a high reflection coefficient can be obtained. After that, for each optical switching element 10 as a unit of each pixel, element isolation is performed by a technique such as dry etching. At this time, it can be removed including the sacrificial layer for forming the actuator layer 32. When each reflector 42 is formed by element isolation technology such as dry etching, the distance between adjacent reflectors 42 can be reduced to a gap that can be formed by etching. Therefore, an optical switching device having a large reflection area per pixel (one switching element) and high reflection efficiency can be manufactured.

Although not shown, simultaneously with the process of manufacturing the actuator layer 32 and the optical element layer 40, the wall 39 or the support 36 is manufactured on the semiconductor substrate 31.

On the other hand, before or after the step of manufacturing a structure on the semiconductor substrate 31 as the second substrate shown in FIGS. 4A and 4B, or at the same time, as shown in FIG.
The process of forming the semi-transmissive layer 22 on the glass substrate 21 as the first substrate can also proceed. In this process, silicon oxide or the like is applied to the surface 21a of the glass substrate 21 by a method such as spin coating in which the film thickness can be easily controlled, thereby forming a thin translucent layer 22. Further, the minute projections 5 interrupted on the upper surface (semi-transmissive surface) 22a of the translucent layer 22
0 is provided.

Then, as shown in FIG. 4D, the substrate 21 on which the semi-transmissive layer 22 is formed and the semiconductor substrate 31 on which the actuator 32 and the reflector 42 are formed are combined with the semi-transmissive surface 22a and the reflective surface 41. And face-to-face. The distance between the substrates 21 and 31 is held by columns 39 formed around the optical switching element 10, and the small projections 50 are caused by the elasticity of the upper electrode 34 so that the high reflector 4
It is desirable that the gap between the substrates is managed to such an extent that the substrate 2 is slightly pressed.

As described above, in the optical switching device 4 of this embodiment, since the semi-transmissive body 22 and the actuator 33 can be manufactured on the individual substrates 21 and 31, respectively, the manufacturing process is simplified and the yield is synergistic. The defective rate does not increase. That is, in the case of a stacked structure, if a failure occurs in any of the stacked layers, the structure of the lower layer and the manufacturing process are all wasted. In particular, when a structure is stacked on a semiconductor integrated circuit, an expensive semiconductor substrate is wasted just because a defect occurs in the uppermost layer. On the other hand, in the optical switching device 4 of the present embodiment, the semi-transmissive layer 22 is formed on a different substrate 21 and then combined with the semiconductor substrate 31, so that even if a defect occurs in the semi-transmissive layer 22, The substrate 31 is not wasted.

In the above-mentioned conventional optical interference type device, there is no timing at which the transflective surface and the reflective surface can be individually flattened. Therefore, the surface accuracy depends on the manufacturing process by the photolithography technology or the like, and cannot be made so high. On the other hand, in the optical switching device 4 of this example, since the semi-transmissive layer 22 and the reflector 42 are formed on different substrates, respectively, the respective surfaces 22a and 41 can be processed, and the surface accuracy can be improved. Improvement can be achieved.

In the process of manufacturing the actuator layer 32 and the optical element layer 40 on the semiconductor substrate 31, the actuator layer 32 and the optical element layer 4 are further divided into a plurality of substrates.
By manufacturing 0, the yield can be improved. FIGS. 5A to 5C show an example thereof. First, as shown in FIG. 5A, a layer 32 of an actuator 33 having a pair of a lower electrode 35 and an upper electrode 34 also serving as a spring is manufactured on a semiconductor substrate (second substrate) 31. . This process can be manufactured by photolithography using an appropriate sacrificial layer as in FIG. The sacrificial layer can be removed at this stage, but if there is a possibility of machining as described above,
It is desirable to remove at the final stage.

As shown in FIG. 5B, before or after the process shown in FIG. 5A, or at the same time, as shown in FIG. An optical element layer 40 to be the body 42 is formed. First, a release layer 62 of silicon oxide or the like is provided on the substrate 61, and the optical element layer 40 including the high reflector 42 and the support portion 43 is manufactured thereon. At this stage, it is possible to perform element isolation by a method such as dry etching. However, as described above, if there is a possibility that machining will be performed in a later process, it is desirable to perform element isolation thereafter.

Next, as shown in FIG. 5C, a layer 32 of the actuator 33 formed on the semiconductor substrate 31 is formed.
, A third substrate 61 is laminated so that the optical element layer 40 overlaps the upper electrode 34 of the actuator 33 and the support portion 4.
3 is bonded or joined. Thereafter, the third substrate is removed by removing the release layer 62 with an appropriate etchant. At this stage, the actuator layer 32 and the optical element layer 40 are manufactured on the semiconductor substrate 31 shown in FIG. 4B, and the surface 41 serving as the surface of the high reflector 42, that is, the separated surface It can be planarized by performing CMP or the like. The reflective film of aluminum or the like is
1 can be formed when the optical element layer 40 is formed, or can be deposited or coated by an appropriate method before and after flattening.

As in the process shown in FIG. 5, the optical element layer 40 is changed to the actuator layer 32 by using the third substrate 61.
By forming the optical switching device 4 on a different substrate, the yield can be further dispersed, and the optical switching device 4 with low cost and high performance can be provided.

As described above, the optical switching device 4 of this embodiment is easy to manufacture, and furthermore, the reflection surface 4
1, the surface precision is high, and the distance d between the semi-transmissive surface 22a and the reflective surface 41 can be accurately controlled. Therefore,
It is suitable as an image display device that displays pixels in a plurality of colors and synthesizes or displays a color image. When displaying a color image, it is necessary to display at least three primary colors (red R, green G, and blue B) separated spatially or temporally. For this reason, it is necessary for the optical switching device 4 to be able to control at least three colors of light. In this regard, as described above, the light interference type switching device of the present example has the semi-transmitter 22 and the high reflector 4.
The wavelength to be emitted can be selected by controlling the distance d between them.

FIG. 6 is a graph showing how the wavelength of each color is selected. As shown in the figure, light of three different wavelengths λR, λG, and λB needs to be output by the optical switching device 4, but for that purpose, different distances dr corresponding to half wavelengths of each light are required. , Dg and db may be moved. On the other hand, in order to turn off the light of each wavelength λR, λG and λB, it is desirable to move to a position corresponding to １ ／ λ of each light. However, as shown in FIG. 6, the reflectance of light of each wavelength becomes sufficiently small at the center wavelength, for example, at a position of １ ／ wavelength of the wavelength λG, so that there will be no practical problem. Furthermore, since the wavelength λG of the green light is close to the center wavelength of the visible light, it is possible to substantially turn off the white light by disposing the reflector 42 at a position １ ／ of this wavelength. Therefore, when white light is used as incident light and light of each color is selected by each optical switching element to perform color display, it is desirable to set the off position to １ ／ λG or an odd multiple thereof.

For example, when selecting a red light flux 72R having a peak near about 650 nm, the distance dr is about 3
When outputting the green light flux 72G, the distance dg is about 275 nm, and when outputting the blue emission light 72B, the distance db is about 220 nm. And
If the off position distance d0 is about 140 nm, 100
By driving the reflector 42 at a distance of about nm, light of a desired color can be selected and output.

FIGS. 7 and 8 show red R, green G and blue B, respectively.
3 shows an example of the optical switching device 4 of the present example capable of emitting light of each color and displaying in color. The optical switching device 4 of the present example is also substantially the same as the configuration described with reference to FIG. 2. A reflector 42 is formed.
The optical switching elements have a common configuration, and light can be switched by changing the distance d between the semi-transmissive body 22 and the high-reflective body 42.

In the optical switching device 4 of this embodiment, 3
Types of optical switching elements 10R, 10G and 10B
Are two-dimensionally arranged at an appropriate pitch, and one pixel in a color image is displayed by these three types of optical switching elements 10R, 10G, and 10B. These three types of optical switching elements 10R, 10G, and 10B have the same configuration, but differ in the distance (moving distance) x by which the high reflector 42 of each switching element is driven by the actuator 33. That is, the actuators 33 of the optical switching elements 10R, 10G, and 10B are configured such that the reflector 42 can be moved by the moving distances xr, xg, and xb from the off position shown in FIG. 7 to the on position shown in FIG. ing.

In this example, the optical switching elements 10R, 1R,
Lower electrode 35 of actuator 33 of 0G and 10B
By changing the thickness a of r, 35g and 35b,
The moving distance x is adjusted. That is, the thickness a of the lower electrode 35B of the optical switching element 10B that outputs the blue light 72B is the largest, the lower electrode 35g of the optical switching element 10G that outputs the green light 72G, and the optical switching that outputs the red light 72R. The thickness a of the lower electrode 35r of the element 10R decreases in order. The lower surface of the upper electrode 34 is coated with a suitable non-conductive material so that even if it contacts the lower electrode 35, there is no short-circuit, and the lower electrode 35 is in close contact with the lower electrode 35 so as not to be separated.

Therefore, as shown in FIG. 8, when an appropriate voltage is applied to the actuator 33, the optical switching device 4 of the present example is lower by the distance xr (the semiconductor substrate 31) in the optical switching element 10R shown on the left side. Side)
And the distance between the transflector 22 and the high reflector 42 becomes the distance dr. Therefore, only the red light 72R of the incident white light 71 passes through the glass substrate 21 and is output outside. Similarly, the optical switching element 10G shown at the center
Then, when the actuator 33 is driven, it moves downward by the distance xg, and the distance between the semi-transmissive body 22 and the high-reflector 42 becomes the distance dg, so that only the green light 72G of the incident white light 71 is output. . In the optical switching element 10B shown on the left side, since it moves downward by the distance xb, the distance between the semi-transmissive body 22 and the high reflector 42 becomes the distance db, and the blue light 71B is output.

Therefore, in the optical switching device 4 of this embodiment, the incident white light 71 is converted into the light 7 of each color by the respective optical switching elements 10R, 10G and 10B.
2R, 72G, and 72B can be selectively output, and a color image can be output. That is, the optical switching device 4 of the present example performs color display by dividing the area of the white light 71 by the switching elements 10 of each color and outputting the divided light.

In this example, the distance defined by the minute projection 50 shown in FIG. 7 is set to the off distance d0.
The distance defined by the minute projection 50 is the above-mentioned distance dr,
By using dg and db, light of each color can be selected and output by each of the switching elements 10R, 10G and 10B. In this case, the actuator 33
As a result, the reflector 42 of each switching element is further
You need to move about four. Also, the actuator 33
There are several methods for setting the moving distance of the reflector 42 by changing the thickness of the electrodes as described above, and there is a method of limiting the moving distance of the electrodes by providing a stopper between the electrodes, as described above. This will be further described later.

FIG. 9 shows an outline of the optical switching device 4 for color-displaying white light in a time-division manner. This optical switching device 4 also has the same basic configuration as the device shown in FIG. 2, a semi-transparent body 22 is formed on a glass substrate 21, an actuator 33 is mounted on a semiconductor substrate 31, and the actuator 33 is driven vertically by the actuator 33. Reflector 42
Are formed. Then, the transflector 22 and the high reflector 4
Switching (color modulation) can be performed by changing the distance d in FIG.

In the optical switching device 4 of this embodiment, the actuator 33 of the optical switching element 10 is further provided.
Are provided with three types of lower electrodes 35r, 35g and 35b having different heights a. The lower electrode 35r is an electrode for outputting red R light, has the smallest thickness a, and is located at the center. Therefore, the upper electrode 34 can be driven to drive the reflection surface 41 to the position of the distance dr. The lower electrode 35g is an electrode for outputting green B light, has a thickness a slightly larger than the lower electrode 35r, and is located on both sides of the lower electrode 35r. Therefore, the upper electrode 34 can be driven to drive the reflection surface 41 to the position of the distance dg.
Further, the lower electrode 35b is an electrode for outputting blue B light, and has the largest thickness a and is located on the outermost sides. By driving the upper electrode 34, the reflection surface 41 can be driven to the position of the distance db.

In the optical switching device 4 of this embodiment, the driving circuit 38 drives the driving sections 38r, 3g, and 3b so as to drive these lower electrodes 35r, 35g, and 35b, respectively.
8g and 38b, and each electrode 35
The drive voltage can be supplied by switching between r, 35g and 35b. Therefore, the range in which the actuator 33 can move can be switched stepwise by the drive circuit 38, and the light 72R, 72G, and 72B of each color can be separately output by one optical switching element 10.

FIGS. 10A to 10C show how the light of each color is emitted by the optical switching device 4 of this embodiment. First, as shown in FIG. 10A, when a driving voltage is applied to the outermost lower electrode 35b, the lower electrode 35b
An electrostatic force acts between the upper electrode 34 and the upper electrode 34, and the high reflector 42 moves downward (toward the semiconductor substrate 31) by the distance xr. Therefore, the distance between the semi-transmissive body 22 and the high-reflector 42 is from the off distance d0 to the distance db, and only the incident white light 71 to blue light 72B are output via the glass substrate 21.

As shown in FIG. 10B, when a drive voltage is supplied to the outermost lower electrode 35b and the inner lower electrode 35g, these lower electrodes 35b and 35g
An electrostatic force acts between the upper electrode 34 and the upper reflector 34, the high reflector 42 moves downward by a distance xg, and the distance between the semi-transmissive body 22 and the high reflector 42 is changed from the off distance d0 to the on distance dg. . Therefore, only the green light 72G is output from the incident white light 71. Similarly, as shown in FIG.
When a drive voltage is supplied to the center lower electrode 35r in addition to the outermost lower electrode 35b and the inner lower electrode 35g, all the lower electrodes 35r, 35g and 35b and the upper electrode 34 The electrostatic force acts, and the high reflector 42 moves x
Move by r. Therefore, the distance between the semi-transmissive surface 22a and the reflective surface 41 becomes the distance dr from the off distance d0, and only the incident white light 71 to red light 72R is output. Further, not only from the off position shown in FIG.
10 from any of the states shown in FIGS.
It is possible to shift to the states shown in (a) to (c), and the timing can be freely controlled by the drive circuit 38.

As described above, in the optical switching device 4 of the present embodiment, the white light 71 is time-divisionally divided by the single optical switching element 10 into the light 72R, 72G and 72R of each color.
Can be output, and a color display can be performed using light of each color. In the case of the optical switching device 4 of this example, the semi-transmissive body 2 is placed on a different substrate.
2, the reflector 42 and the actuator 33 can be formed, so that the functions of the reflector and the actuator can be separated, and an actuator including the lower electrodes 35 having different heights as described above can be configured. Further, the driving circuit 38 for driving the driving circuit can be easily designed and manufactured. The actuator capable of driving the reflector 42 to a plurality of positions having wavelength selectivity other than ON / OFF is not limited to this example. By the distance d
Can be controlled. In addition, in the case of an actuator using a piezoelectric body such as a piezo element, the position of the reflector can be accurately controlled by changing the drive voltage.

FIG. 11 shows a further different optical switching device 4. The optical switching device 4 of the present example has substantially the same configuration as that shown in FIG. 2, in which a semi-transmissive body 22 is formed on a glass substrate 21 and a semiconductor substrate 31 is formed.
, An actuator 33 and a high reflector 42 driven by the actuator 33 in the vertical direction are formed. Therefore, the optical switching device can switch light having a desired wavelength by changing the distance d between the semi-transmissive body 22 and the high reflector 42.

The optical switching device 4 of this embodiment has a semi-transparent body 22 and a reflector 42 in the same manner as the above-described device.
Are provided on the surface 22a of the semi-transmissive body 22 so that the distance d does not become less than a certain value. Therefore, the semi-transmissive body 22 and the high reflector 42 do not adhere to each other, and the switching can be performed by moving the reflector 42 smoothly and at a high speed by preventing adsorption. The minute projections 50 formed on the surface 22a of the semi-transparent body 22
It is also possible to provide it on the reflection surface 41 of the high reflector 42.
However, as described above, if a flattening process such as CMP is performed to increase the surface accuracy and increase the reflection efficiency, it is difficult to manufacture minute projections. Therefore, it is desirable to provide the fine projections 50 on a flat continuous surface as in this example. For example, a material constituting the semi-permeable film 22 such as silicon oxide may be provided with a spherical member for securing a gap having a predetermined diameter. By mixing and applying, the reflection surface 41 and the semi-transmission surface 22a
Distance can be properly managed.

Further, in order to properly manage the position when the reflecting surface 41 is separated, the actuator 33 is also provided with
It is possible to provide the minute projection 52. In the case of an electrostatic actuator, as shown in FIG.
Alternatively, by providing the minute projection 52 facing the side of the electrode facing a part of the lower electrode 35, the function as a stopper for preventing a certain or more movement can be achieved.
Further, it is possible to prevent the upper electrode 34 and the lower electrode 35 from coming into contact with each other even when they come closest to each other by these stoppers 52, so that the electrodes 34 or 35 do not need to be covered with a suitable non-conductive member. , Short circuit and adsorption can be prevented. Therefore, a highly reliable optical switching device can be provided.

As described above, the position restricted by these minute projections 50 and 52 can be set to the on or off position, and one means for controlling the wavelength of emitted light with high accuracy. It is. Since the on or off position is at λ / 4 pitch, the distance d0 limited by the minute projection 50 that defines the distance between the semi-transmissive surface 22a and the reflecting surface 41, that is, the height h of the minute projection is given by the following equation. (2)
Is required to be satisfied.

D0 = nλ / 4 (2) Then, the distance d0 limited by the minute projection 50 is λ / n.
If an odd multiple of 4, that is, the value of the following equation (3) is satisfied, the position defined by the minute protrusion 50 becomes the off position.

D0 = (2n + 1) λ / 4 (3) With this optical switching device, it is possible to select and output an appropriate wavelength according to the distance moved by the actuator 33, and output one light It is suitable for an optical switching device that selects and outputs light of a plurality of wavelengths by the switching element 10.

On the other hand, if the distance d0 limited by the minute projections 50 is an integral multiple of λ / 2, that is, the value of the following equation (4) is satisfied, the position defined by the minute projections 50 becomes the ON position. become.

D0 = nλ / 2 (4) With this optical switching device, the position shifted by λ / 4 by the actuator 33 becomes the off position.
Therefore, by setting the stopper 52 on the actuator side so as to move by a distance corresponding to the off position, the on position and the off position can be set to the minute protrusion 50 and the stopper 5.
2 can be specified. Of course, even when the distance d0 defined by the minute projection 50 is the off position, the on position can be set by the stopper 52 on the actuator side.

As described above, the optical switching device 40 of the present embodiment is an optical interference type optical switching device, and can emit light of a desired color from each optical switching element 10 without using a color filter. . Therefore, the projector can be used as a light valve of the projector 1 shown in FIG. 1 and a color filter can be omitted, so that a more compact and low-cost projector can be provided. Then, as described above, the optical switching device 4 of the present example can improve the reflection efficiency and increase the reflection area, so that a bright image can be emitted. In addition, since the response speed is higher and the response is higher than that of a liquid crystal display, a high-resolution image can be displayed and power consumption can be reduced.

The optical switching device 4 of the present embodiment can be used not only for the projector but also for other image display devices. Since it is a reflection type and has high reflection efficiency and can display a bright image, it is suitable for a direct-view image display device. In particular, since it is an energy-saving type, it is suitable for a display panel of a portable information terminal such as a mobile phone. I have.

Further, in the above description, the present invention has been described by taking as an example an optical switching device in which incident light is perpendicularly incident on the semi-transmissive surface and the reflective surface. Modulation can be performed by the optical switching device of the present invention even when the optical switching device of the present invention is inclined at an angle to the reflecting surface. In this case, it is only necessary to set the distance d between the semi-transmissive surface and the reflective surface in consideration of the angles of the incident light and the emitted light, and such an optical switching device and an image display device using the same are also provided by the present invention. Included in the range.

[0083]

As described above, the present invention relates to an interference type optical switching device for controlling the distance between a transflector and a reflector, wherein the transflector and the reflector are provided on different substrates. In this case, it is possible to prevent the increase in product defects due to the synergistic yield, and to obtain a manufacturing advantage. At the same time, by supporting the reflector on a separate substrate, a semiconductor substrate,
The function of the reflector and the function of the actuator can be separated, the distortion of the reflector can be prevented, the optical performance can be improved, and further, the drive circuit can be incorporated into the semiconductor substrate. The disclosed various effects can be obtained. Therefore, according to the present invention, light of a desired wavelength can be turned on and off with extremely high accuracy, and a high-contrast optical switching device with good color separation performance can be provided at low cost.
It is possible to provide a bright and compact image display device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a projector device using an optical switching device according to the present invention.

FIG. 2 is a diagram showing an outline of the optical switching device shown in FIG.

FIG. 3 is a diagram showing a wavelength characteristic of incident light supplied to the optical switching device shown in FIG. 2, and showing a relationship between a distance and switching (on / off).

FIG. 4 is a view schematically showing a process in a method for manufacturing the optical switching device shown in FIG. 2;

FIG. 5 is a view schematically showing a process different from the method for manufacturing the optical switching device shown in FIG. 4;

FIG. 6 is a graph showing wavelength characteristics of incident light of each color, showing a relationship between a distance and switching (on / off) of each color light.

FIG. 7 is a diagram showing an outline of a different optical switching device that divides white light into areas and outputs luminous flux of each color.

FIG. 8 is a diagram schematically showing a state in which the area-divided optical switching device shown in FIG. 7 outputs each color light.

FIG. 9 is a diagram showing an outline of still another optical switching device that displays white light in a time-division manner and performs color display.

10 is a diagram illustrating a state in which the optical switching device illustrated in FIG. 9 is controlled to output a luminous flux of each color.

FIG. 11 is a diagram showing an outline of still another optical switching device having a stopper on the actuator side.

FIG. 12 is a schematic view showing an example of a conventional interference type optical switching device.

FIG. 13 is a schematic diagram showing another example of a conventional interference type optical switching device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 projector 2 light source 3 beam splitter 4 optical switching device 5 control mechanism 6 zoom lens 7 screen 10 optical switching element 21 glass substrate (first substrate) 22 semi-transmissive body (semi-transmissive layer) 22a surface of semi-transmissive body 31 semiconductor substrate (Second substrate) 32 Actuator layer 33 Actuator 34 Upper electrode 35 Lower electrode 38 Drive circuit 39 Wall (post) 40 Optical element layer 41 Surface of high reflection layer (High reflection surface) 42 High reflection layer (Reflector) 43 Support Units 50, 52 Microprojections 61 Third substrate 71 Light flux of white light (incident light) 72 Display light to be output

Claims (23)

[Claims] 1. An optical switching device having a plurality of optical switching elements capable of controlling on / off and / or color by changing a distance between a semi-transmissive body and a reflector, wherein the semi-transmissive body is formed with a plurality of optical switching elements. An optical switching device comprising: a first substrate; and a second substrate in which the reflector is formed so as to overlap an actuator capable of driving the reflector. 2. The light emitting device according to claim 1, wherein the reflector has a wavelength λ of light emitted from the optical switching element.
An optical switching device operable at least at a position where a distance d from the semi-transmissive member has a value of the following expression. d = nλ / 2 where n is an integer of 1 or more. 3. The method according to claim 1, wherein the second substrate comprises:
An optical switching device including a semiconductor circuit. 4. The optical switching device according to claim 1, wherein the first substrate is a transparent substrate, and a semi-transmissive layer serving as the semi-transmissive body is formed on one surface of the first substrate over the plurality of optical switching elements. . 5. The optical switching device according to claim 1, wherein the actuator is an electrostatic actuator. 6. The light according to claim 1, wherein minute projections are formed on at least one of the semi-transmissive body and the reflector to prevent the distance between the semi-transmissive body and the reflector from becoming less than a predetermined value. Switching device. 7. The distance d0 between the semi-transmissive body and the reflector limited by the minute projection with respect to a wavelength λ of light emitted from the optical switching element.
Is an optical switching device having the following formula: d0 = nλ / 4 where n is an integer of 1 or more. 8. The optical switching device according to claim 7, wherein the distance d0 has a value represented by the following expression. d0 = (2n-1) λ / 4 where n is an integer of 1 or more. 9. The optical switching device according to claim 7, wherein the distance d0 has a value represented by the following expression. d0 = nλ / 2 where n is an integer of 1 or more. 10. The optical switching device according to claim 6, further comprising a stopper for preventing a distance between the transflector and the reflector from being equal to or greater than a predetermined value. 11. The optical system according to claim 10, wherein a distance y from the position restricted by the minute projection to the position restricted by the stopper is a value of the following formula with respect to a wavelength λ of light emitted from the optical switching element. Optical switching device. y = nλ / 4 where n is an integer of 1 or more. 12. The method according to claim 2, wherein the different wavelengths λ
An optical switching device in which at least three types of the switching elements having different distances d are arranged. 13. The optical switching device according to claim 2, wherein the actuator can drive the reflector at at least three different distances d corresponding to the different wavelengths λ. 14. The optical switching device according to claim 13, wherein the actuator is of an electrostatic drive type and includes at least three types of electrode pairs having different distances x capable of driving the reflector. 15. A method of manufacturing an optical switching device having a plurality of optical switching elements capable of controlling on / off and / or color by changing a distance between a transflector and a reflector, wherein the first substrate has A first step of forming a semi-transparent body; a second step of forming the reflector on a second substrate so as to overlap an actuator capable of driving the reflector; and the first and second substrates. And combining the semi-transparent body and the reflector so that they face each other. 16. The method according to claim 15, wherein, in the second step, an actuator layer in which a plurality of the actuators are arranged on the second substrate provided with a semiconductor circuit;
A method for manufacturing an optical switching device in which a plurality of the reflectors corresponding to the respective actuators are stacked with a reflective layer. 17. The method according to claim 15, wherein the actuator is an electrostatic actuator. 18. The method according to claim 15, wherein, in the first step, a semi-transmissive layer serving as the semi-transmissive body is formed on one surface of the transparent substrate as the first substrate over the plurality of optical switching elements. A method for manufacturing an optical switching device. 19. The semi-transparent body according to claim 15, wherein in the first step and / or the second step, the minute projection for preventing the distance between the semi-transmissive body and the reflector from being less than a predetermined value. And a method for manufacturing an optical switching device formed on at least one of the reflectors. 20. The method according to claim 16, wherein in the second step, the actuator layer is formed on the second substrate provided with the semiconductor circuit, and the reflection layer is formed on a third substrate. A method for manufacturing an optical switching device, comprising: a step of forming an optical element layer; and a step of, after laminating the optical element layer on the actuator layer, removing the third substrate from the optical element layer. 21. The optical element according to claim 16, wherein in the second step, the actuator layer and an optical element layer serving as the reflection layer are formed on a substrate having the semiconductor circuit. Flattening a surface to be a reflection surface of the layer. 22. A direct-view image display device having the optical switching device according to claim 1. 23. The optical switching device according to claim 1, a light source capable of entering light into the optical switching device, and a lens system for projecting light modulated by the optical switching device onto a screen. An image display device comprising: