JPH10213756A - Optical switching element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical switching element capable of obtaining a display device having bright display and a five visual angle characteristic. SOLUTION: Plural recessed parts 12 are formed on one face side of a substrate 11 consisting of stainless steel or the like so as to be arrayed like a matrix. Holes 13 penetrated from the bottom parts of respective recessed parts 12 to the other face sides are formed on the substrate 11. Respective holes 13 are filled with oil into which dyestuff or pigment is dispersed as fluid 14, which is supported in the holes 13 by surface tension. A pressure diaphragm 16 is joined with the other face side of the substrate 11 and electrostatic valves 15 are arranged so as to be matched with the end parts of respective holes 13. When the valves 15 are opened and the inner pressure of the diaphragm 16 is increased, the fluid in the holes 13 of which valves 15 are opened is moved to one face side of the substrate 11 and covers the surfaces of the recessed parts 12. Consequently an image or the like is displayed on the surface of the substrate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching element applicable to a display panel and the like, and more particularly to an optical switching element suitable as a display device of a portable terminal used outdoors.

[0002]

2. Description of the Related Art In recent years, with the spread of information devices, various display devices have been developed. Above all, since the reflection type display device does not require a light source, it has advantages such as low power consumption and downsizing of the device. Conventionally, as a reflective display device, a liquid crystal display device having a structure in which liquid crystal is sealed between a pair of transparent electrodes and sandwiched between a pair of polarizing plates, and a dye having a rod-like molecular shape between the pair of transparent electrodes. A guest-host type liquid crystal display device in which (a dichroic dye) and a liquid crystal are mixed and sealed has been developed.

[0003]

However, all of the above-mentioned conventional reflection type display devices have a drawback that the efficiency of light utilization is low because the amount of transmitted light is controlled by deflection by liquid crystal. Further, in the liquid crystal display device, since the transmittance of light is controlled by birefringence, a good display can be obtained in front of the display panel, but the contrast when viewed from an oblique direction is reduced, and the viewing angle characteristic is poor. is there.

[0004] It is an object of the present invention to provide an optical switching element capable of providing a display device with a bright display and good viewing angle characteristics.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is to provide a base, a hole penetrating from one side of the base to the other side,
A fluid filled in the hole and supported in the hole by surface tension, and a pressure difference is applied between the one surface side and the other surface side of the base to provide a fluid in the hole. And pressure adjusting means for moving at least a part of the substrate to one surface side of the base.

The above-mentioned problem is solved by a base, a plurality of holes arranged in a matrix and penetrating from one surface of the base to the other surface, and filled in the holes and supported in the holes by surface tension. And a pressure difference between one surface side and the other surface side of the base for each of the fluids in each hole, so that at least a part of the fluid is on one side of the base. And a selective pressure adjusting means for moving the optical switching element to the optical switching element.

Hereinafter, the operation of the present invention will be described. In the present invention, a fluid is filled in a hole provided in the base, and the fluid is supported in the hole by surface tension. Then, by applying a pressure difference between one surface side and the other surface side of the base by the pressure adjusting means to move the fluid in the hole to the one surface side of the base, the one surface side of the base is The perimeter of the hole is covered with this fluid. Therefore, when the fluid is made of, for example, oil in which a dye or a pigment is dispersed, the light reflectance of the portion of the substrate surface covered with the fluid is low. Thereby, a contrast is obtained between a portion of the substrate surface covered with the fluid and a portion not covered with the fluid, and an image or the like can be displayed.

As the fluid, a substance that reflects light, such as mercury, may be used. In this case, a light-absorbing film (such as a black coating film) is formed on the surface of the substrate. Also,
As the fluid, a transparent oil or the like that changes the direction of light reflection by refraction may be used. Also in these cases, a contrast is obtained between a portion of the substrate surface covered with the fluid and a portion not covered with the fluid, and an image or the like can be displayed.

As described above, in the present invention, since the movement of the fluid to the surface of the substrate is controlled and an image or the like is displayed on the surface of the substrate by absorption, reflection or refraction of light by the fluid, liquid crystal is used. Unlike conventional display devices, it has high light use efficiency and excellent viewing angle characteristics.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an optical switching element according to an embodiment of the present invention. The base 11 is made of a plate material having a glossy surface such as stainless steel. On one surface side of the base 11, conical or pyramidal concave portions 12 are arranged in a matrix. Further, the base 11 is provided with holes 13 penetrating from the bottom of each recess 12 to the other surface side. Each of the holes 13 is filled with an oil in which a black dye or pigment is dispersed as a fluid 14. The fluid 14 is supported in the hole 13 by surface tension.

A pressure bulkhead 16 is joined to the lower side of the base 11, and the pressure bulkhead 16 and the hole 1 are formed below the base 11.
The fluid 14 inside 3 forms a closed space which is isolated from the external space. An electrostatic valve 15 is arranged below each hole 13. These electrostatic valves 15
Thereby, the other end of the hole 13 is opened and closed. A bellows (or a diaphragm) 17 is attached to a part of the pressure bulkhead 16.
The pressure of the space inside can be changed.

In the optical switching element of the present embodiment, each recess 12 serves as a pixel, and an image or the like is displayed by the brightness of each pixel. FIG. 2A is a cross-sectional view illustrating an example of the electrostatic valve. The electrostatic valve 15a has a movable piece 21 that is bent at a substantially central position, a support member 22 that swingably supports the movable piece 21 at a substantially central position, and a movable piece 21 that is operated by electrostatic force. Electrodes 23. One end of the movable piece 21 can close the end of the hole 13, and the electrode 23 is arranged corresponding to the other end of the movable piece 21. The electrode 23 is connected to the positive electrode of the power supply 24, the movable piece 21 is connected to one end of the switch 25, and the other end of the switch 25 is connected to the negative electrode of the power 24.

In the electrostatic valve 15a, one end of the movable piece 21 closes the end of the hole 13 when the switch 25 is turned off. When the switch 25 is turned on, the other end of the movable piece 21 is attracted to the electrode 23, and as a result, the end of the hole 13 is opened. FIG. 2B is a cross-sectional view illustrating another example of the electrostatic valve. The electrostatic valve 15b has a flat plate-shaped movable piece 26, one end of which is fixed to the pressure partition 16 and the end of the hole 13 can be closed by the other end, and is arranged in alignment with the other end of the movable piece 26. And an electrode 27 for operating the movable piece 26 by electrostatic force. The movable piece 26 is connected to the positive electrode side of the power supply 29a, and the electrode 27 is connected to the neutral contact c of the switch 28. The first switching contact a of the switching unit 28 is connected to the ground, and the second switching contact b is connected to the positive electrode of the power supply 29b.

The electrostatic valve 15b is provided with a changeover switch unit 28
Is connected to the first switching contact a, the other end of the movable piece 26 is attracted to the electrode 27, whereby the hole 13 is closed by the movable piece 26. When the switch 28 is connected to the second switching contact b, the electrode 27 and the other end of the movable piece 26 are repelled, and the movable piece 26 is bent as shown by a broken line to form a hole. 13 is opened.

Hereinafter, the operation of the thus configured optical switching element of the present embodiment will be described. First,
As shown in FIG. 3, the electrostatic valve 15 of the pixel to be displayed in a dark state is kept open. Then, the current I is applied to the actuator 18.
And the bellows 17 is pushed up to increase the pressure in the closed space inside the pressure partition 16. As a result, the fluid 14 in the hole 13 in which the electrostatic valve 15 is open is pushed out into the recess 12, and covers the surface of the recess 12.

As a result, the reflectance of light on the surface of the concave portion 12 is reduced, and the pixel in that portion is displayed in a dark state. On the other hand, in the hole 13 in which the electrostatic valve 15 is closed, the fluid 14 stays in the hole 13, so that the reflectance of the surface of the concave portion 12 is high. That is, the pixels in that part are displayed brightly. in this way,
In the present embodiment, the reflectance on the surface of the base 11 is controlled for each pixel (recess 12) by opening and closing the electrostatic valve 15, so that an image or the like can be displayed by light and dark. In this case, since almost 100% of the light is reflected on the surface of the concave portion 12 in the pixel where the electrostatic valve 15 is in the closed state, the light use efficiency is high and the display recognizability is high. Further, there is no direction dependency of the viewing angle unlike the liquid crystal display device.

Hereinafter, a method for manufacturing the optical switching element of the present embodiment will be described. First, the thickness is about 100μ
A stainless steel plate having a diameter of about 20 μm is prepared, and a plurality of holes 13 having a diameter of about 20 μm and arranged in a matrix at a pitch of about 100 μm are formed. Next, the concave portion 12 is formed by etching the periphery of the hole 13 on one surface side into a tapered shape.

On the other hand, the pressure barrier 16 is formed by using a silicon substrate.
To form In this case, using a micromachining technique, the electrostatic valve 15 is placed at a position corresponding to each hole 13 of the base 11.
To form A bellows 17 is attached to the pressure bulkhead 16. The bellows 17 may be, for example, a metal sheet that is bent concentrically (corrugated in cross section) or a silicon substrate that is partly thinned by etching.

Next, the substrate 11 is immersed in an ink (fluid) in which a black dye or pigment is dispersed in oil, and the holes 13 are filled with the ink. At this time, after the substrate 11 is lifted from the ink tank, the surface of the substrate 11 is blown as necessary to remove excess ink. The ink is supported in each hole 13 by surface tension. Next, the pressure partition 16 to which the bellows 17 is attached is joined to the lower surface side of the base 11, and the bellows 17 and the electromagnetic actuator 18 are connected. Thereby, the optical switching element of the present embodiment is completed.

It is preferable that the oil used for the fluid is hardly volatilized. For example, a silicon-based (particularly, siloxane-based) oil can be used. Also, mercury may be used as the fluid. in this case,
On the surface of the base 11, a film such as a black polyimide film, which hardly reflects light, is formed so that when mercury is extruded from the hole 13, the light is reflected by the mercury so that the pixel is in a bright state.

Further, a transparent oil may be used as the fluid 14. The light is refracted or reflected by the oil to change the reflection direction, and a contrast is obtained between a portion of the surface of the base 11 covered with the oil and a portion not covered with the oil. Furthermore, in the above-described embodiment, the case where the fluid 14 in the hole 13 is pushed out to the upper side of the base 11 by the bellows 17 has been described. The fluid 14 in the hole 13 may be drawn out onto the base 11 by the pressure of (1). In this case, the same effect as in the above embodiment can be obtained.

[0022]

As described above, in the optical switching element of the present invention, the fluid is arranged in the hole provided in the base, and the fluid is moved from the inside of the hole to the substrate surface by the pressure adjusting means. Thereby, an image or the like is displayed by selectively changing the light reflectance of the substrate surface, so that the light use efficiency is excellent and the viewing angle characteristics from an oblique direction are excellent.
Thus, there is an effect that a display device which is small, consumes little power, and is suitable as a display of a portable terminal can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an optical switching element according to an embodiment of the present invention.

2A is a cross-sectional view illustrating an example of an electrostatic valve, and FIG. 2B is a cross-sectional view illustrating another example of the electrostatic valve.

FIG. 3 is a cross-sectional view illustrating an operation of the optical switching element according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 12 Recess 13 Hole 14 Fluid 15, 15a, 15b Electrostatic valve 16 Pressure partition 17 Bellows 18 Electromagnetic actuator 21, 26 Movable piece 22 Supporting member 23, 27 Electrode 24, 29a, 29b Power supply 25 Switch part

Claims (7)

[Claims] 1. A base, a hole penetrating from one side of the base to the other side, a fluid filled in the hole and supported in the hole by surface tension, and the one of the bases Pressure adjusting means for giving a pressure difference between the surface side and the other surface side to move at least a part of the fluid in the hole to one surface side of the base. Optical switching element. 2. The optical switching element according to claim 1, wherein the fluid is made of a material having a higher light absorptivity than a surface on one side of the base. 3. The optical switching device according to claim 1, wherein the fluid is made of a material having a higher light reflectance than a surface of the substrate on one side. 4. The optical switching device according to claim 1, wherein the fluid is made of a transparent nonvolatile oil. 5. The optical switching element according to claim 1, wherein a concave portion is provided on one side of the base, the concave portion communicating with the hole and storing a fluid moved outside the hole. . 6. A base, a plurality of holes arranged in a matrix and penetrating from one surface of the base to the other surface, and a flow filled in the holes and supported in the holes by surface tension. And applying a pressure difference between one surface side and the other surface side of the base for each fluid in each hole to move at least a portion of the fluid to the one surface side of the base. An optical switching element comprising: a selective pressure adjusting unit. 7. A base, a plurality of holes arranged in a matrix and penetrating from one surface of the base to the other surface, and a flow filled in the holes and supported in the holes by surface tension. And applying a pressure difference between one surface side and the other surface side of the base for each fluid in each hole to move at least a portion of the fluid to the one surface side of the base. Selective pressure adjusting means, wherein the selective pressure adjusting means includes an opening / closing means for opening and closing the other end of the hole for each hole, and a fluid in each hole by opening / closing the opening / closing means. An optical switching element for selectively applying pressure to the optical switching element.