JP2000075224A - Microactuator, active type micro-optical element and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reliable optical element which may be exceedingly improved in space utilization efficiency and is free from attraction by providing the element with a structure in which an intermediate electrode is supported by spring, providing the intermediate electrode with a junctures to a micro- optical element and coupling the micro-optical element by the >=1 junctures. SOLUTION: A lower electrode 101 exists on the lowermost surface of an actuator disposed on a drive circuit. The spring 104 is supported by a strut 105 supporting the spring. Another end is connected to the intermediate electrode 102. The intermediate electrode 102 has the juncture 103 with the micro-optical element in part of its front surface. An upper electrode 106 supported by the strut 107 exists on the intermediate electrode 102. The space utilization efficiency is exceedingly improved by adopting such structure. Even more, the spring may be made longer and the areas of the upper and lower electrodes may be made larger. Then, the active type micro-optical element which is securely connected to the actuator by driving of 5 V, is free from the attraction and is reliable may be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an active optical element which performs optical switching by moving a micro optical element by a micro machine, and an image display device.

[0002]

2. Description of the Related Art Conventionally, in this type of microactuator, a voltage is applied between an intermediate electrode and an upper or lower electrode to move the intermediate electrode up and down. In addition, an insulating film is provided on the upper and lower electrodes on the side of the intermediate electrode, and the insulating layer prevents the intermediate electrode from moving and coming into contact with the upper or lower electrode. The insulating layer also served as an upper or lower stopper when the intermediate electrode moved.

[0003] The spring connected to the intermediate electrode usually has two springs.
Mainly four or four books were used, and each spring was fixed at one end by a support member.

[0004]

In the case of a printer head in which micro-optical elements are arranged in a line or an array, or in the case of an image display element or the like, the size of the elements arranged in a line or an array. In order to save power and reduce costs, it is desirable that the size be small. In order to make the elements smaller, it is necessary to make each micro-optical element smaller. Accordingly, the constituent members of the actuator section also need to be reduced, but a certain size is required to satisfy the required displacement amount.

Therefore, there arises a problem that the effective length of the spring is shortened and the driving voltage is increased. Further, when there are two or more support portions for the spring, there is a problem that the area of the electrode cannot be obtained due to the area of the spring and the spring support portion, the electrode area is reduced, and the drive voltage is increased.

Further, the intermediate electrode is prevented from contacting the upper or lower electrode with an insulating layer, and serves as an upper or lower stopper when the intermediate electrode moves. The surface was in contact with the insulating layer and stopped. When the electrode voltage is switched to separate from the insulating layer, the contact is stopped at the surface, so that problems such as adsorption, air damping and the like cause the actuator to stop moving or the speed of movement to be slow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and realizes a smaller active micro-optical element array which can be driven up and down with a very simple structure, does not cause adsorption, and has high reliability. A main object is to provide a microactuator, an active micro optical element, and an image display element.

[0008]

Means for solving the above problems are as follows: 1) An active optical element having a micro-optical element and a micro-actuator, comprising electrodes above and below an intermediate electrode, and a spring of the micro-actuator. With one support,
It has a structure in which the intermediate electrode is supported by one spring, the intermediate electrode has a coupling portion with the micro optical element, and the intermediate electrode is coupled to the micro optical element by one or more coupling portions.

2) An electrostatic drive microactuator having an array of microactuators and drive circuits, having an intermediate electrode between the lower and upper electrodes, and applying an applied voltage between the intermediate electrode and the lower electrode or the upper electrode. Has an actuator structure for moving the intermediate electrode, the intermediate electrode is supported via a spring structure, the lower electrode, the intermediate electrode,
When the potential of the upper electrode is equal, the interval between the intermediate electrode and the lower electrode,
It is characterized in that the interval between the intermediate electrode and the upper electrode is not equal.

3) In an electrostatically driven microactuator having a microactuator and a drive circuit in an array, the potential of the intermediate electrode is made equal to the potential of the intermediate electrode of at least one adjacent microactuator. When a potential difference is generated between the electrodes and the movable electrode stops moving downward, a part of the intermediate electrode comes into contact with a part of a column supporting a spring connected to an adjacent intermediate electrode.

4) A micro-optical element is coupled to a micro-actuator, and in an active micro-optical element in which the micro-optical element moves by an electrostatically driven micro-actuator having a driving circuit for each micro-actuator, the potential of the intermediate electrode is at least set. Equalizing the potential of the intermediate electrode of one or more adjacent microactuators, a potential difference occurs between the intermediate electrode and the lower electrode, and when moving downward, the bottom surface of the connection between the intermediate electrode and the micro-optical element, or The part or the bottom surface of the intermediate electrode comes into contact with a part of a column supporting a spring connected to an adjacent intermediate electrode and stops.

5) An active micro-optical element in which the micro-optical element moves by means of a micro-optical element, a micro-actuator, and an electrostatically driven micro-actuator having a drive circuit for each micro-actuator. The intermediate electrode has a coupling portion with the micro-optical element, and the coupling portion couples with the micro-optical element. The coupling portion is formed of a conductor or an insulator, and the bottom surface of the micro-optical element is formed of an insulator. When a potential difference is generated between the intermediate electrode and the lower electrode, and when the micro-optical element moves downward, a part or all of the upper surface of the upper electrode and the lower surface of the micro-optical element come into contact with each other and the micro optical element stops. .

6) An active micro-optical element having a micro-actuator, a driving circuit, an intermediate electrode between the lower and upper electrodes, and a micro-optical element connected to the intermediate electrode moving and performing an optical switching operation. When the optical element moves upward, a stopper for defining the position of the micro optical element is provided above the micro optical element. When the micro optical element comes into contact with the stopper and stops, the upper surface of the intermediate electrode (the surface on the upper electrode side) ) And the lower surface (surface on the intermediate electrode side) of the upper electrode are not in contact with at least the entire surface.

7) By forming an array of the active micro optical elements described in 1), 3), 4), 5) and 6), an optical switching element in an array is formed, and an image is displayed on the optical switching element array. It is characterized by doing.

[0015]

(Embodiment 1) FIG. 1 is a schematic view showing an actuator section according to Embodiment 1 of the present invention. FIG. 2 is a sectional view taken along lines 108 to 109 in FIG. 1
Reference numeral 01 denotes a lower electrode located on the lowermost surface of the actuator provided on the drive circuit. The spring 104 is supported by a post 105 that supports the spring, and has the other end connected to the intermediate electrode 102. A part of the upper surface of the intermediate electrode has a connection part 103 with the optical element 203. Above the intermediate electrode is an upper electrode 106 supported by columns 107.
By adopting such a structure, the space utilization efficiency is remarkably improved, and the length of the spring is increased and the area of the upper and lower electrodes is increased. Accordingly, an active micro-optical element driven by 5 V and firmly connected to the actuator was realized.

(Embodiment 2) An electrostatic actuator according to Embodiment 2 will be described with reference to FIG. 1 and FIG. 2 showing a sectional view taken along lines 108 to 109 of FIG. An attractive force is generated by applying a potential difference between the lower electrode 101 and the intermediate electrode 102, and the intermediate electrode 102 moves downward. Similarly, the upper electrode 106
Then, an attractive force is generated by applying a potential difference to the intermediate electrode 102, and the intermediate electrode 102 moves upward. Intermediate electrode 1
02 is connected to a spring 104 and the other end is fixed to a support. Therefore, the same spring constant is obtained when the intermediate electrode moves upward and downward due to electrostatic force. In the case of an electrostatic actuator, the drive voltage decreases in inverse proportion to the area of the electrode, and increases in proportion to the square of the drive distance. In the case of the actuator according to the second embodiment, since the connection portion 103 for connecting to the micro optical element 203 is required, the area of the upper electrode 106 is smaller than that of the lower electrode 101. In such a state, if the interval between the intermediate electrode and the upper and lower electrodes is made equal, the pull-in voltage will be reached unless the potential difference applied to the upper electrode and the intermediate electrode is larger than the potential difference applied to the lower electrode and the intermediate electrode. Absent. Therefore, by making the interval 201 between the intermediate electrode and the upper electrode smaller than the interval 202 between the intermediate electrode and the lower electrode, pull-in can be performed similarly even if the applied voltage of the upper and lower electrodes is the same.

By adopting such a structure, the present embodiment 2
In this case, the upper and lower pull-in voltages could be set to 5 V, and the drive voltage of both upper and lower electrodes could be 5 V or less.

(Embodiment 3) FIG. 3 is a schematic view showing an actuator section according to Embodiment 3 of the present invention. FIG. 4 is a sectional view taken along lines 302 to 303 in FIG. Spring 10
The four support columns 105 and the intermediate electrode 102 connected to the spring are made of a conductive material, and the spring columns 105 of the actuators arranged in an array are electrically connected to each other in a lower drive circuit. . Part 3 of the spring support 105
01 overlaps the intermediate electrode 102 in a plane. The lower electrode is insulated and protected on the intermediate electrode side by the insulating layer 401. A potential difference occurs between the lower electrode 101 and the intermediate electrode 104,
When moved downward, a part of the spring 104
Touch like 02. In this way, when a part of the spring comes into contact with the adjacent spring support, the intermediate electrode 104 and the insulating layer 40 of the lower electrode
There is a gap 403 between the first and the second.

The charge accumulated in the intermediate electrode can escape from the support every time it comes into contact with the spring support, and has an antistatic effect. Also, the intermediate electrode 104 and the insulating layer 401 of the lower electrode
Since contact with water is avoided, adverse effects such as adsorption can also be prevented.

(Embodiment 4) FIG. 5 is a schematic view showing an actuator section according to Embodiment 4 of the present invention. FIG. 6 is a sectional view taken along lines 502 to 503 in FIG. Spring 10
4 and the intermediate electrode 102 connected to the spring are made of a conductive material.
The coupling portion 103 connecting the one intermediate electrode 102 is also conductive. The spring columns 105 of the actuators in the array are electrically connected to each other in the drive circuit below.
A part 501 of the spring support 105 overlaps the connecting part 103 in a plane. The lower electrode is insulated and protected on the intermediate electrode side by the insulating layer 401. Lower electrode 101 and intermediate electrode 1
When a potential difference occurs at 04 and moves downward, a part of the coupling portion 103 comes into contact with the adjacent spring support like 603. When the adjacent spring support and a part of the connecting portion 103 come into contact with each other, a gap 60 is provided between the intermediate electrode 104 and the insulating layer 401 of the lower electrode.
There are two.

Each time the electric charge accumulated in the intermediate electrode comes into contact with the spring support, it can escape from the support through the conductive coupling member, and has an antistatic effect. Also, the intermediate electrode 10
Since contact between the lower electrode 4 and the insulating layer 401 of the lower electrode is avoided, adverse effects such as adsorption can also be prevented. In the fourth embodiment, the coupling portion is made of a conductive material. However, even if it is an insulator, contact between the intermediate electrode 104 and the insulating layer 401 of the lower electrode can be avoided. It can be prevented as in the case.

(Embodiment 5) In Embodiment 5, the intermediate electrode 104 is used.
This is another means for avoiding contact between the lower electrode and the insulating layer 401 of the lower electrode. FIG. 7 is a sectional view taken along lines 502 to 503 in FIG. The entire upper electrode is insulated and protected by the insulating layer 401. When a potential difference is generated between the lower electrode 101 and the intermediate electrode 104 and the optical element 701 moves downward, the lower surface of the optical element 701 comes into contact with the insulating layer 401 that insulates and protects the upper electrode 106 at a point 703. At this time, a gap 702 exists between the intermediate electrode 104 and the insulating layer 401 of the lower electrode.

As described above, since the contact between the intermediate electrode 104 and the insulating layer 401 of the lower electrode is avoided, it is possible to prevent adverse effects such as adsorption. In the fifth embodiment, the lower surface of the optical element is made of an insulator. However, even if it is a conductor, the contact between the intermediate electrode 104 and the insulating layer 401 of the lower electrode can be avoided. Can be prevented as well.

(Embodiment 6) FIG. 8 is a sectional view of an active micro device array according to Embodiment 6. Reference numeral 101 denotes a lower electrode provided on the drive circuit and located on the lowermost surface of the actuator. The spring 104 is supported by a post 105 that supports the spring, and the other end is connected to the intermediate electrode. On a part of the upper surface of the intermediate electrode, there is provided a connection portion 103 for connecting to a micro optical element. Above the intermediate electrode is an upper electrode 106 supported by columns. The micro optical element 901 according to the sixth embodiment has a reflection part having a V-groove structure on the upper part. Lower electrode 10
When a potential difference occurs between 1 and the intermediate electrode, it opposes the spring,
The light guide 802 and the micro optical element 80 move downward.
A gap of about 0.5 μm is generated between 1. In this state, the light ray 808 in the light guide part is totally reflected at the bottom of the light guide part and the light ray 808
It is reflected in the direction of 07. On the other hand, when a potential difference is generated between the upper electrode 106 and the intermediate electrode, the upper electrode 106 moves upward against the spring, and the bottom surface of the light guide 802 and the upper surface of the micro optical element 801 are in close contact. It can enter the optical element. Since the micro optical element has a reflecting surface having a v-structure, the incident light is reflected on the inclined surface, and is emitted as a light ray 806 perpendicular to the bottom surface of the light guide 802. In this way, by moving the micro optical element up and down by the micro actuator provided below, the angle of light can be changed by about 70 degrees, and an optical switching operation can be obtained using this. When the bottom surface of the light guide 802 and the top surface of the micro optical element 801 are in close contact with each other, the contact between the insulating layer 401 on the upper electrode 106 and the intermediate electrode is avoided, and
To leave a gap.

As a result, even if a potential difference is generated between the upper electrode and the intermediate electrode, the light guide 802 functions as a stopper even if the electrode moves upward, thereby avoiding contact between the insulator of the upper electrode and the intermediate electrode. it can. Therefore, adverse effects such as adsorption can be prevented as in the case of the lower electrode.

(Embodiment 7) FIG. 9 is a schematic view showing an image display apparatus according to Embodiment 7 of the present invention. Light emitted from the light source 901 is condensed on a color filter 903 by a lens 902, converted into parallel light by a collimating lens 904, and incident on a light introducing prism 906. Light introducing prism 90
6 enters the active micro-optical element array 905 described in the first to sixth embodiments, and is selectively emitted to 907 as a pixel display. Light 907 having image information is projected onto a screen by a projection lens 908 to display a moving image or the like. As described above, since a very small micro-optical element array was realized, a small and bright image display device having a very small number of components was realized.

[0027]

As described above, according to the present invention, 1) By using one spring and a spring supporting mechanism at one place, even in an actuator having upper and lower electrodes, the upper and lower electrode areas can be reduced. At the same time, the joint area with the micro-optical element could be increased. As a result, space utilization efficiency has been dramatically improved, and the conflicting issues of reducing the size of the micro-optical element and reducing the energy input to the micro-actuator that drives the micro-optical element have been simultaneously solved. The micro optical element was made very small, and the electric energy to be applied to the actuator was reduced.

2) According to the microactuator of the present invention, the difference in the size of the upper and lower electrode areas was absorbed, and the upper and lower electrodes could be driven at the same voltage of 5V. Therefore, since the area of the drive circuit provided under the microactuator can be reduced, an effective means for a large-scale microactuator array is obtained.

3) According to the active micro-optical element of the present invention, the intermediate electrode does not come into contact with the insulating layer protecting the upper and lower electrodes, and the intermediate electrode is driven every time the micro-optical element is driven up and down once. Since the charge accumulated in the electrode can be released,
It can be used for devices such as printers and image display devices that have a very large number of times of optical switching.

4) By using the active type micro-optical element array for the image display device, a more power-saving image display device can be realized, and since one image display device can be made smaller, a high pixel like HDTV can be obtained. Even if the number of image display devices is 0.9 inches or less, the number of image display devices that can be obtained from one silicon wafer is dramatically improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an actuator unit according to a first embodiment.

FIG. 2 is a schematic diagram showing a cross-sectional view of FIG.

FIG. 3 is a schematic diagram illustrating an actuator unit according to a third embodiment.

FIG. 4 is a schematic view showing a sectional view of FIG. 3;

FIG. 5 is a schematic diagram illustrating an actuator unit according to a fourth embodiment.

FIG. 6 is a schematic diagram showing a sectional view of FIG. 5;

FIG. 7 is a schematic view showing a sectional view of FIG. 5 in a fifth embodiment.

FIG. 8 is a sectional view of an active micro element array according to a sixth embodiment.

FIG. 9 is a schematic diagram illustrating an image display device according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Lower electrode 102 ... Intermediate electrode 106 ... Upper electrode 201 ... Distance between upper electrode and intermediate electrode 202 ... Distance between lower electrode and intermediate electrode 203 ... Optical element 802 ... Light introduction part 805 ... Incident light beam

Claims (7)

[Claims] 1. An active optical element having a micro-optical element and a micro-actuator, wherein electrodes are provided above and below the intermediate electrode, the micro-actuator has one spring supporting portion, and the intermediate electrode is supported by one spring. With an intermediate electrode and a coupling part with the micro optical element.
An active micro-optical element, which is connected to the micro-optical element by one or more connecting portions. 2. An electrostatic drive type micro-actuator having a micro-actuator and a drive circuit in an array, wherein an intermediate electrode is provided between a lower electrode and an upper electrode, and an applied voltage between the intermediate electrode and a lower electrode or an upper electrode is provided. Has an actuator structure that moves the intermediate electrode, and the intermediate electrode is supported via a spring structure. When the potentials of the lower electrode, the intermediate electrode, and the upper electrode are equal, the distance between the intermediate electrode and the lower electrode, A microactuator characterized in that the intervals between upper electrodes are not equal. 3. An electrostatically driven microactuator having a microactuator and a drive circuit in an array, wherein the potential of at least one intermediate electrode is made equal to the potential of an intermediate electrode of an adjacent microactuator. A microactuator characterized in that when a potential difference occurs between the electrodes and the electrode stops moving downward, a part of the intermediate electrode contacts a part of a column supporting a spring connected to an adjacent intermediate electrode. 4. An active micro-optical element in which a micro-optical element is coupled to a micro-actuator, and the micro-optical element moves by an electrostatically driven micro-actuator having a driving circuit for each micro-actuator. Equalizing the potential of the intermediate electrode of one or more adjacent microactuators;
When a potential difference occurs between the intermediate electrode and the lower electrode, and when moving downward, the bottom surface of the connection portion between the intermediate electrode and the micro optical element, or a part, or the bottom surface of the intermediate electrode is connected to the adjacent intermediate electrode. An active micro-optical element characterized in that it stops when it comes into contact with a part of a column supporting a spring. 5. An active micro-optical element in which a micro-optical element moves by means of a micro-optical element, a micro-actuator, and an electrostatically driven micro-actuator having a drive circuit for each micro-actuator. The intermediate electrode has a coupling portion with the micro-optical element, and the coupling portion couples with the micro-optical element. The coupling portion is formed of a conductor or an insulator, and the bottom surface of the micro-optical element is formed of an insulator. When a potential difference is generated between the intermediate electrode and the lower electrode, and when the micro-optical element moves downward, a part or all of the upper surface of the upper electrode and the lower surface of the micro-optical element come into contact with each other and the micro optical element stops. Active micro optical element. 6. An active micro-optical element having a micro-actuator, a driving circuit, an intermediate electrode between lower and upper electrodes, and a micro-optical element connected to the intermediate electrode moving and performing an optical switching operation. When the optical element moves upward, a stopper for defining the position of the micro optical element is provided above the micro optical element. When the micro optical element comes into contact with the stopper and stops, the upper surface of the intermediate electrode (the surface on the upper electrode side) ) And the lower surface of the upper electrode (surface on the side of the intermediate electrode) do not contact at least over the entire surface. 7. An array of optical micro-elements according to claim 1, 3, 4, 5, 6, which constitutes an array of optical switching elements, and displays an image on said optical switching element array. Characteristic image display device.