TWI391710B - Liquid optical deflector and method for fabricating the same - Google Patents

Description

Liquid optical refractor and manufacturing method thereof

This invention relates to liquid optical deflectors and methods for making liquid optical refractors.

Electrowetting phenomena are well known in the art. In the electrowetting phenomenon, when the applied voltage between the two liquids changes, the surface tension also changes, causing the liquid to move. In other studies, if the metal surface of the electrode is formed by an insulation film having a thickness of several micrometers, operational reliability can be improved. The electrode can be protected from damage. This improved technique is called electrowetting-on-dielectric (EWOD).

EWOD technology can be used, for example, in Lab-on-a-chip (LOC) or optical applications. Optical applications can have liquid lenses as well as electronic paper. The operating mechanism of the electrowetting phenomenon is as follows. For example, the droplets are placed on a metal substrate having a thin insulating layer thereon. Next, a voltage is applied to the metal substrate, and the contact angle of the droplets with the metal substrate can be changed. When this droplet is used as an optical lens, two liquids having equal densities are used. One liquid is insulating and the other liquid is electrically conductive. Due to the voltage change, the curvature of the interface between the two liquids changes accordingly, resulting in a change in lens focus.

In a conventional application, for example, U.S. Patent No. 6,369,954 has been proposed. FIG. 1 is a cross-sectional view schematically illustrating a conventional lens having a variable focus. In FIG. 1, the insulating liquid droplet 11 is located filled with a conductor liquid. 13 is on the inner surface of the wall of the dielectric chamber 12. Both the insulating liquid 11 and the conductor liquid 13 are transparent and immiscible, have different optical refractive indices, and have substantially the same density. The dielectric 12 naturally has a low wetting relative to the conductor liquid 13. A highly wet surface treatment 14 of the wall of the dielectric chamber relative to the conductor liquid 13 is ensured to surround the contact area 15 between the insulating droplet 11 and the wall of the chamber 12. The surface treatment 14 maintains the positioning of the droplets 11 to prevent the insulating liquid from expanding beyond the desired contact surface. When the system is at rest, the insulating droplets 11 naturally assume the shape specified by reference A. When a voltage V is established between the electrode 16 and the electrode 17, an electric field is generated which, according to the electrowetting principle mentioned above, increases the wetting of the region 15 relative to the conductor liquid 13. Therefore, the conductor liquid 13 moves the insulating liquid droplet 11 and deforms the insulating liquid droplet 11 into a shape specified by the reference B.

However, several other disclosures have been proposed by, for example, WO 2004/051323 and CN 1881003. Conventional liquid optical devices basically require assembly of several parts into the device. Alternatively, in a conventional structure, an indium tin oxide (ITO) electrode and a hydrophobic insulating layer are coated on the inner surface of the glass cavity, and then the glass cavity is adhered to the lower transparent substrate. The device size is about a few millimeters. Usually, it is not easy to align and assemble. The error can be large and the yield is low. Even the device size cannot be reduced. Other equipment structures and manufacturing processes are still under development.

The present invention proposes a liquid optical refractor and its manufacture. The liquid optical refractor includes two conductive electrodes having an insulating wall to form a liquid container for adapting the two liquids. By changing the operating power on the two conductive electrodes The pressure, the angle of the interface between the two liquids can be controlled and then provided for various applications.

A liquid optical refractor of an embodiment of the invention includes a substrate. The electrode layer is disposed on the substrate. An insulating layer is disposed on the electrode layer, wherein the electrode layer has an exposed area. The first electrode wall is vertical from the substrate. The first insulating wall is disposed on a surface of the first electrode wall. The second electrode wall is vertical from the substrate and faces the first electrode wall as a first electrode pair. The second insulating wall is disposed on a surface of the second electrode wall. The sidewall is vertically from the substrate and is at least connected between the first electrode wall and the second electrode wall to form a containing space. The first liquid is filled in the containment space to contact the electrode layer on the substrate. The second liquid is filled in the containment space to have an interface with the first liquid and does not dissolve each other. A cap layer is sealed to the containment space to form an optical refractor unit. Wherein the interface between the first liquid and the second liquid has an angle controlled by a first voltage on the first electrode wall and a second voltage on the second electrode wall.

For another embodiment, the optical refractor array includes a plurality of optical refractor units as described above to form an array.

An embodiment of a method for fabricating a liquid optical refractor includes providing a substrate, wherein the substrate has an electrode layer thereon and an insulating layer disposed on the electrode layer, and the first electrode layer has an exposed region. The first electrode wall is formed to be vertical from the substrate. The first insulating wall is formed on a surface of the first electrode wall. The second electrode wall is formed to be vertical from the substrate and facing the first electrode wall as a first electrode pair. The second insulating wall is formed on a surface of the second electrode wall. The sidewall is formed to be vertical from the substrate and connected to the first electrode wall and the second electrode Between the walls to form a containment space. The first liquid is filled in the containment space to contact the electrode layer on the substrate. The second liquid is filled in the containment space to have an interface with the first liquid and does not dissolve each other. A cap layer is formed for sealing onto the containment space to form an optical refractor unit.

It is to be understood that the foregoing general descriptions

In the present invention, a liquid optical refractor is described. Liquid optical refractors are structures that can be fabricated in small sizes (eg, on the order of microns). Manufacturing costs and time can be at least reduced and yield can be kept high. In the aspect of the invention, the device body can be integrated into a small size. The fabrication process can, for example, use a conductive photopolymer to act as a conductive electrode, and the insulating material can be, for example, a photopolymer. The liquid container can be formed, for example, by a process including a photolithography process, a jet process, a plating process, a screen printing, or an imprint process. In other words, the walls of the liquid container can be formed directly on the substrate with reduced size and increased alignment. Manufacturing costs and speed can be at least improved.

Several embodiments are provided for the purpose of description and are not intended to limit the invention. Further, the embodiments may be combined as appropriate with each other in another embodiment.

2A and 2B are cross-sectional views schematically illustrating lateral and lateral directions of a liquid optical refractor in accordance with an embodiment of the present invention. In FIG. 2A, the liquid optical refractor can, for example, include a lower transparent substrate 100. The electrode layer 102 is disposed on the substrate 100 to serve as, for example, a common electrode. The electrode layer 102 can be grounded, for example, in actual operation. Voltage. The insulating layer 104 is disposed on the electrode layer 102 at a peripheral region of the desired region, wherein the insulating layer 104 on the electrode layer 102 has an opening to expose a region of the electrode layer 102. The first electrode wall 106A and the second electrode wall 106B are disposed on the substrate 100 and are vertical from the substrate 100. The first electrode wall 106A and the second electrode wall 106B are insulated from the electrode layer 102 by the insulating layer 104. Electrode walls 106A, 106B can be, for example, conductive photopolymers. The insulating wall 108 is disposed on the surfaces of the first electrode walls 106A and 106B. Basically, the first electrode wall 106A and the second electrode wall 106B form a parallel electrode pair to later control the liquid interface in the electrowetting mechanism. The material of the insulating layer 108 can be, for example, hydrophobic such that the electrowetting phenomenon can be controlled more easily.

If a liquid container having four vertical walls is used as an example, the other two insulating sidewalls are visible in Figure 2B, but are not visible in Figure 2A. In order to form a liquid container, the walls should be continuously connected to the electrode walls 106A, 106B. The insulating sidewalls 116 are formed to be disposed on the substrate 100 and vertically from the substrate 100 to be connected between the first electrode walls 106A, 106B for forming a containment space. However, the shape of the side wall 108 is not limited to the two wall portions in Fig. 2B. Any shape used to form the side walls of the container can be employed.

The liquid 110 is filled in the containment space to be in contact with the electrode layer 102 on the substrate 100. Liquid 110 includes, for example, water or a conductive solution. Another liquid 112 is filled in the containment space to have an interface with the liquid 110 without being dissolved from each other. Liquid 112 can include, for example, an oil or an insulating liquid. However, in general, for example, one of the two liquids is electrically conductive and the other is insulating. The transparent cap layer 114 is sealed on the containment space to form an optical fold Optical Deflector unit. The two liquids can be selected to form an interface plane in which the tilt angle of the interface can be controlled. Furthermore, the density of the two liquids is preferably substantially the same. Therefore, the refractometer is not affected by gravity.

3 through 5 are cross-sectional views schematically illustrating an operating mechanism in accordance with an embodiment of the present invention. For example, an operating mechanism is described. In FIG. 3, the electrodes 106A and 106B with respect to the common electrode 102 are respectively applied with equal voltages (such as at a voltage of 30 V). In this case, an electric field is generated. The angle of the liquid interface remains horizontal. For normally incident light, the direction of travel is not deflected. In FIG. 4, for example, when the electrode wall 106A is applied with the voltage V ₂ and the electrode wall 106B is applied with the voltage V ₁ , an electric field is generated. The liquid interface 202A is tilted according to the electrowetting phenomenon. Both liquids have different refractive indices. Incident light 200 has an angle of incidence θ ₁ relative to liquid interface 202A, and then the exiting light is deflected to the right. In FIG. 5, when _a voltage V is applied to the electrode 106A and the wall when the voltage V ₂ is applied to the electrode 106B wall, an electric field is generated using another. The liquid interface 202B is tilted according to the electrowetting phenomenon. The incident light 200 has an incident angle θ ₂ with respect to the liquid interface 202B, and then the emitted light is deflected to the left side. Typically, the liquid interface between the first liquid and the second liquid has an angle. This angle can be controlled by applying a first voltage on the electrode wall 106A and a second voltage on the second electrode wall 106B. The tilt angle of the liquid interface can be controlled depending on the value of the applied voltage on the wall of the electrode. At this point, the incident light can be deflected to the desired direction during operation.

In practical applications, for example, liquid optical refractors can be used to scan scanners at different line positions. In addition, the liquid optical refractor can also be three-dimensional A display device is implemented for displaying the left image to the left eye and the right image to the right eye. Furthermore, several liquid optical refractors as light deflection units can be formed into arrays for various uses. Here, all apps are not fully listed.

For the manufacturing process, aspects of the invention provide for the process of forming the walls of a liquid container directly onto a substrate. 6A through 6C and 7 are cross-sectional views schematically illustrating a manufacturing process in accordance with an embodiment of the present invention. A plating seed layer 302 is formed on the substrate 300 by, for example, employing a process based on photolithography and electroplating in FIG. 6A. A mask layer 304, such as a photopolymer layer, is formed on the electroplated seed layer 302 by photolithography. The mask layer 304 has a wall opening 306 to expose the plated seed layer 302. Next, the wall opening 306 is filled with a conductive material 308 by electroplating. In FIG. 6C, one portion of the plating seed layer 302 and the insulating layer 303 are removed, and the conductive material 308 forms a conductive wall with the remaining plating seed layer 302. To form the liquid container, one portion of the mask layer 304 and the remaining portion are also removed (not visible in this cross-sectional view of Figure 6C). The remaining portion of the mask layer 304 acts as an insulating wall that is connected between the conductive walls 308. In addition, the insulating layer 310 is preferably formed on the surface of the conductive walls 308, 302. The two liquids 312 and 314 are required to be filled in the containment space.

In FIG. 7, a substrate 300 having a common electrode layer 301 is formed. The common electrode is a transparent conductive layer such as ITO or any other suitable material. The transparent substrate 400 is disposed on the conductive walls 308, 302 and the insulating walls to seal the liquids 312, 314. Alternatively, as mentioned previously, the wall may also be formed by a printing process or the like. The aforementioned manufacturing process is merely an example. State of the invention As such, the liquid optical refractor can be formed directly on the substrate during the manufacturing process. The walls may also be formed by other various processes to be formed on the substrate.

The conductive walls can be, for example, a plurality of pairs with respect to the structure. 8 to 9 are horizontal cross-sectional views schematically illustrating the structure of a liquid optical refractor according to an embodiment of the present invention. In FIG. 8, for example, three pairs of conductive walls 412 are formed on the insulating wall 410. In this case, more degrees of freedom can be used to control the angle of the liquid interface. Further, as an example in FIG. 9, the conductive walls 420a to 420d may separately form walls of the liquid container, and the conductive walls 420a to 420d are coupled to the smaller insulating portion 422 at the joint portion. An insulating layer 424, such as a hydrophobic material, is formed on the inner surfaces of the conductive walls 420a to 420d. The liquid can then be filled in the containment space.

In other words, the present invention uses a device structure having a suitable material in accordance with the manufacturing process. Manufacturing can be performed more easily without consuming a large amount of labor. The device is formed directly on the substrate and can be formed in a reduced size. Thus, the refractor device can be more easily integrated into the final product, such as a scanner, a stereoscopic display device, and the like.

It will be apparent to those skilled in the art that various modifications and changes can be made in the structure of the invention without departing from the scope of the invention. The modifications and variations of the present invention are intended to cover the modifications and variations of the present invention.

11‧‧‧Insulation droplets / insulating liquid

12‧‧‧Dielectric chamber/dielectric

13‧‧‧Conductor liquid

14‧‧‧ Surface treatment

15‧‧‧Contact area

16‧‧‧Electrode

17‧‧‧Electrode

100‧‧‧Substrate

102‧‧‧electrode layer

104‧‧‧Insulation

106A‧‧‧First electrode wall

106B‧‧‧Second electrode wall

108‧‧‧Insulation wall/insulation/sidewall

110‧‧‧Liquid

112‧‧‧Liquid

114‧‧‧Transparent top cover

116‧‧‧Insulated sidewall

200‧‧‧ incident light

202A‧‧‧Liquid interface

202B‧‧‧Liquid interface

300‧‧‧Substrate

301‧‧‧Common electrode layer

302‧‧‧Electroplating seed layer / conductive wall

303‧‧‧Insulation

304‧‧‧mask layer

306‧‧‧ wall opening

308‧‧‧Conductive material / conductive wall

310‧‧‧Insulation

312‧‧‧Liquid

314‧‧‧Liquid

400‧‧‧Substrate

410‧‧‧Insulated wall

412‧‧‧Electrical wall

420a‧‧‧Electrical wall

420b‧‧‧Electrical wall

420c‧‧‧Electrical wall

420d‧‧‧Electrical wall

422‧‧‧Insulated part

424‧‧‧Insulation

A‧‧‧Reference

B‧‧‧Reference

V‧‧‧ voltage

V ₁ ‧‧‧ voltage

V ₂ ‧‧‧ voltage

θ ₁ ‧‧‧ incident angle

θ ₂ ‧‧‧ incident angle

The drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. Schematic diagram illustrating the implementation of the present invention The examples are used together to explain the principles of the invention.

1 is a process flow diagram that schematically illustrates a method of surface detection in accordance with a preferred embodiment of the present invention.

2A and 2B are cross-sectional views schematically illustrating lateral and lateral directions of a liquid optical refractor in accordance with an embodiment of the present invention.

3 through 5 are cross-sectional views schematically illustrating an operating mechanism in accordance with an embodiment of the present invention.

6A through 6C and 7 are cross-sectional views schematically illustrating a manufacturing process in accordance with an embodiment of the present invention.

8 to 9 are horizontal cross-sectional views schematically illustrating the structure of a liquid optical refractor according to an embodiment of the present invention.

100‧‧‧Substrate

102‧‧‧electrode layer

104‧‧‧Insulation

106A‧‧‧First electrode wall

106B‧‧‧Second electrode wall

108‧‧‧Insulation wall/insulation/sidewall

110‧‧‧Liquid

112‧‧‧Liquid

114‧‧‧Transparent top cover

116‧‧‧Insulated sidewall

Claims (28)

A liquid optical refractor comprising: a substrate; an electrode layer disposed on the substrate; an insulating layer disposed on the electrode layer, wherein the electrode layer has a surface exposed by the insulating layer An exposed area; a first electrode wall that is vertical from the substrate; a first insulating wall disposed on a surface of the first electrode wall; and a second electrode wall that is vertical from the substrate And facing the first electrode wall as a first electrode pair; a second insulating wall disposed on a surface of one of the second electrode walls; a side wall vertically connected to the substrate and connected to at least Between the first electrode wall and the second electrode wall to form a containment space, wherein the material of the sidewall comprises a photopolymer; a first liquid filled in the containment space to be The electrode layer on the substrate is in contact; a second liquid filled in the containment space to have an interface with the first liquid without dissolving each other; and a cap layer sealed to the containment Spatially forming an optical refractor unit, The first liquid and the second liquid to the interface between the substrate relative to the phase angle of a clamp, the angle is from said first A first voltage on the electrode wall and a second voltage on the second electrode wall are controlled. The liquid optical refractor of claim 1, wherein one of the first liquid and the second liquid is a conductive liquid, and the other of the first liquid and the second liquid One is an electrically insulating liquid. The liquid optical refractor of claim 1, wherein one of the first liquid and the second liquid is water, and the other of the first liquid and the second liquid It is oil. The liquid optical refractor of claim 1, wherein the first insulating wall and the second insulating wall are hydrophobic. The liquid optical refractor of claim 1, wherein the first electrode wall is parallel to the second electrode wall. The liquid optical refractor of claim 1, wherein the material of the first electrode wall and the second electrode wall comprises a conductive photopolymer. The liquid optical refractor of claim 1, wherein the first liquid and the second liquid have different refractive indices. The liquid optical refractor of claim 1, wherein the angle of the interface is controlled to have at least two values to deflect the direction of incident light into at least two particular directions. The liquid optical refractor of claim 1, further comprising at least a second electrode pair connected to the sidewall to more control the interface of the two liquids. The liquid optical refractor of claim 1, wherein the substrate, the electrode layer on the substrate, and the cap layer are optically transparent. The liquid optical refractor of claim 1, wherein the first liquid and the second liquid are substantially equal in density. An optical refractor array comprising a plurality of optical refractory units as described in claim 1 wherein the optical refractor units form an array. A method for forming a liquid optical refractor, comprising: providing a substrate, wherein the substrate has an electrode layer thereon and an insulating layer disposed on the electrode layer, and the first electrode layer has An exposed region; forming a first electrode wall that is vertical from the substrate; forming a first insulating wall disposed on a surface of the first electrode wall; forming a second electrode wall from the The substrate is vertical and faces the first electrode wall as a first electrode pair; forming a second insulating wall disposed on a surface of the second electrode wall; forming a sidewall from which the substrate is vertical And connecting between the first electrode wall and the second electrode wall to form a containment space; filling a first liquid in the containment space to contact the electrode layer on the substrate; Filling a second liquid in the containment space to have Determining the interface of the first liquid without dissolving each other; and forming a cap layer for sealing on the containment space to form an optical refractory unit, wherein the first insulating wall and the second insulating wall are Formed from a photopolymer. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall, the first insulating wall, and the second electrode are performed by performing a photolithography process. The wall, the second insulating wall, and the sidewall are formed directly on the substrate. The method for forming a liquid optical refractor according to claim 13 , wherein the first electrode wall, the first insulating wall, and the method are performed by performing a photolithography process and a plating process. The second electrode wall, the second insulating wall, and the sidewall are directly formed on the substrate. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall, the first insulating wall, and the second electrode wall are performed by performing a process including a jet printing process The second insulating wall and the sidewall are directly formed on the substrate. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall, the first insulating wall, and the second electrode are performed by performing a screen printing process. The wall, the second insulating wall, and the sidewall are formed directly on the substrate. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall, the first insulating wall, and the second electrode wall are performed by performing an embossing process. The second A rim wall and the sidewall are formed directly on the substrate. A method for forming a liquid optical refractor according to claim 13 wherein a plurality of said optical refractor units are simultaneously formed to have an array. The method for forming a liquid optical refractor according to claim 13, wherein one of the first liquid and the second liquid is a conductive liquid, and the first liquid and the first The other of the two liquids is an electrically insulating liquid. The method for forming a liquid optical refractor according to claim 13, wherein one of the first liquid and the second liquid is water, and the first liquid and the second The other of the liquids is oil. The method for forming a liquid optical refractor according to claim 13, wherein the first insulating wall and the second insulating wall are formed of a hydrophobic material. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall is formed to be parallel to the second electrode wall. The method for forming a liquid optical refractor according to claim 13, wherein the first electrode wall and the second electrode wall are formed of a conductive photopolymer. The method for forming a liquid optical refractor according to claim 13, wherein the first liquid and the second liquid have no Same refractive index. The method for forming a liquid optical refractor according to claim 13, wherein the substrate, the electrode layer on the substrate, and the cap layer are formed of a light transparent material. A liquid optical refractor comprising: a substrate; an electrode layer disposed on the substrate; an insulating layer disposed on the electrode layer, wherein the electrode layer has a surface exposed by the insulating layer An exposed area; a first electrode wall that is vertical from the substrate; a first insulating wall disposed on a surface of the first electrode wall; and a second electrode wall that is vertical from the substrate And facing the first electrode wall as a first electrode pair; a second insulating wall disposed on a surface of one of the second electrode walls; a side wall vertically connected to the substrate and connected to at least Between the first electrode wall and the second electrode wall to form a containment space; a first liquid filled in the containment space to contact the electrode layer on the substrate; a second liquid filled in the containment space to have an interface with the first liquid without dissolving each other; and a cap layer sealed on the containment space to form an optical refractor unit, Wherein the interface between the first liquid and the second liquid is at an angle with respect to the substrate, the angle being a first voltage on the first electrode wall and the second electrode wall The second voltage control is wherein the material of the first electrode wall and the second electrode wall comprises a conductive photopolymer. A liquid optical refractor comprising: a substrate; an electrode layer disposed on the substrate; an insulating layer disposed on the electrode layer, wherein the electrode layer has a surface exposed by the insulating layer An exposed area; a first electrode wall that is vertical from the substrate; a first insulating wall disposed on a surface of the first electrode wall; and a second electrode wall that is vertical from the substrate And facing the first electrode wall as a first electrode pair; a second insulating wall disposed on a surface of one of the second electrode walls; a side wall vertically connected to the substrate and connected to at least Between the first electrode wall and the second electrode wall to form a containment space; a first liquid filled in the containment space to contact the electrode layer on the substrate; a second liquid filled in the containment space to have an interface with the first liquid without dissolving each other; a cap layer sealed on the containment space to form an optical refractor unit, wherein the interface between the first liquid and the second liquid is at an angle to the substrate, the angle Controlled by a first voltage on the first electrode wall and a second voltage on the second electrode wall, wherein the first electrode wall and the second electrode wall are formed of a conductive photopolymer.