CN103376546B - light modulation device - Google Patents

Abstract

The present invention discloses a light modulation device. The light modulation device comprises: a first substrate and a second substrate arranged opposite to each other; a first electrode arranged on the first substrate; a first hydrophobic dielectric layer covering the first electrode; a second hydrophobic dielectric layer arranged on the second substrate; a first protrusion and a second protrusion respectively arranged on the first substrate; a second electrode arranged on the first substrate, wherein the first electrode and the second electrode are respectively close to the second protrusion and the first protrusion; a first liquid and a second liquid arranged between the first substrate and the second substrate, wherein when no voltage is applied to the first electrode and the second electrode, the first liquid is located directly above the second electrode, and the interface between the first liquid and the second liquid is located above the first electrode.

Description

light modulation device

technical field

The invention relates to a light modulation device, in particular to a light modulation device using electrowetting technology.

Background technique

Electro-wetting (electro-wetting) technology is widely used in displays (displays) or liquid optical deflectors ( liquid deflector) and other fields.

However, the traditional electro-wetting display (EWD) technology is normally black (normally black), and this feature is applied to displays or smart windows, which will consume energy for a long time. demand. In addition, the traditional liquid optical deflector structure uses side electrodes to control the distribution of polar solution and non-polar solution to deflect light. However, the process of the lateral electrodes of the traditional liquid optical deflector is difficult and complicated, the yield rate is low and the cost is high, so it is not easy to be commercialized.

Therefore, there is a need in this technical field for a light modulation device using electrowetting technology to solve the above problems.

Contents of the invention

The present invention provides a light modulation device, comprising: a first substrate and a second substrate, arranged opposite to each other; a first electrode, arranged on the first substrate; a first hydrophobic dielectric layer, covering the first electrode; Two hydrophobic dielectric layers are arranged on the above-mentioned second substrate; the first protrusion and the second protrusion are respectively arranged on the above-mentioned first substrate; the second electrode is arranged on the above-mentioned first substrate, wherein the above-mentioned The first electrode and the second electrode are respectively close to the second protrusion and the first protrusion; the first liquid and the second liquid are arranged between the first substrate and the second substrate, wherein the first When no voltage is applied to the electrode and the second electrode, the first liquid is located directly above the second electrode, and an interface between the first liquid and the second liquid is located above the first electrode.

The present invention also provides a light modulation device, comprising: a first substrate and a second substrate, arranged opposite to each other; a first electrode, arranged on the first substrate; a first hydrophobic dielectric layer, covering the first electrode; The second hydrophobic dielectric layer is disposed on the second substrate; the first protrusion and the second protrusion are respectively disposed on the first substrate; the second electrode is disposed on the first substrate, wherein The first electrode and the second electrode are respectively close to the second protrusion and the first protrusion; the first liquid and the second liquid are arranged between the first substrate and the second substrate, wherein the first When no voltage is applied to the first electrode and the second electrode, the first liquid is located directly above the second electrode, and an interface between the first liquid and the second liquid is located above the first electrode; the third The electrodes are disposed on the second substrate and opposite to the second electrodes.

Description of drawings

Fig. 1a is a cross-sectional view of an optical modulation device according to an embodiment of the present invention when no voltage is applied;

Fig. 1b is a cross-sectional view of an optical modulation device according to an embodiment of the present invention when a voltage is applied;

2 is a cross-sectional view of an optical modulation device according to another embodiment of the present invention when no voltage is applied;

Fig. 3a is a cross-sectional view of an optical modulation device according to another embodiment of the present invention when no voltage is applied;

Fig. 3b is a cross-sectional view of an optical modulation device according to another embodiment of the present invention when a voltage is applied;

FIG. 4 is a cross-sectional view of a light modulation device according to yet another embodiment of the present invention when no voltage is applied.

[Description of reference signs for main components]

500a, 500b, 500c, 500d Electrowetting display elements;

200 The first substrate;

201, 228, b1, b2 top surface;

203 bottom surface;

202 Second substrate;

204 first electrode;

206, 226 Second electrode;

208 The first hydrophobic dielectric layer;

212 second hydrophobic dielectric layer;

210 The first protrusion;

218 Second protrusion;

214 first liquid;

216 Second liquid;

220, 240, 238 Power supply;

222, 242, 244 Positive pole;

224 Negative pole;

236, 236b interface;

236a Surface;

232 the third electrode;

300 pixels;

300a, 300b sub-pixels;

h1, h2 Height.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

In the drawings or text descriptions of the specification, similar or identical elements or parts all use the same reference signs. And in the drawings, the shape or thickness of the embodiments may be exaggerated to simplify or facilitate labeling. Moreover, the part of each element in the accompanying drawings will be described separately. It should be noted that the elements not shown or described in the drawings are well known to those skilled in the art. In addition, the specific embodiment is only A specific method used in the present invention is disclosed, which is not intended to limit the present invention.

An embodiment of the present invention provides a light modulation device, which is fabricated into a normally transparent electrowetting display or electrowetting optics by using two sets of planar electrodes, edge hydrophilic barriers, and central hydrophobic barriers disposed on the same substrate. Deflector (liquid deflector). It is also possible to place the materials needed to display the color in the polar solution to form a colored polar solution.

FIG. 1a is a cross-sectional view of a light modulation device 500a when no voltage is applied according to an embodiment of the present invention. The light modulation device 500a of this embodiment may be a normally transparent electrowetting display, which includes a first substrate 200 and a second substrate 202 disposed opposite to each other. In an embodiment of the present invention, the first substrate 200 and the second substrate 202 can be a rigid substrate, and its material can include glass, polymer substrate or metal. In another embodiment of the present invention, the first substrate 200 and the second substrate 202 can be flexible soft substrates, and their materials can include polyethylene terephthalate (poly (ethylene terephthalate), PET), polyethylene Ethylene naphthalate (Polyethylenenaphthalate, PEN), polycarbonate (Polycarbonate, PC), polyethersulfone (Polyethersulfone, PES) or polyimide (Polyimide, PI).

As shown in FIG. 1 a , the first electrode 204 is disposed on the top surface 201 of the first substrate 200 . In an embodiment of the present invention, the first electrode 204 may include metal or oxide, such as aluminum, silver, indium tin oxide (ITO), molybdenum tungsten (MoW) or indium zinc oxide ( indium zinc oxide, IZO). The first hydrophobic dielectric layer 208 is disposed on the top surface 201 of the first substrate 200 and covers the first electrode 204 . In addition, the second hydrophobic dielectric layer 212 is disposed on the bottom surface 203 of the second substrate 202 and covers the second substrate 202 . In an embodiment of the present invention, the first hydrophobic dielectric layer 208 and the second hydrophobic dielectric layer 212 are generally composed of a dielectric layer and a hydrophobic layer, and the material of the dielectric layer may include silicon oxide (SiO _x ) , silicon nitride (SiN _x ), silicon oxynitride, aluminum oxide (Al ₂ O ₃ ), tantalum oxide (Ta ₂ O ₃ ), titanium oxide (TiO ₂ ), barium titanate (BaTiO ₃ ), polybiased Vinylidene difluoride (polyvinylidene difluoride, PVDF), a combination of the above materials, or other polymer layers with a dielectric coefficient greater than 2. The hydrophobic layer may include fluorine-containing polymers, diamond-like carbon films or self-polymerizing silane molecules. The fluorine-containing polymer is, for example, TeflonAF-1600 (Dupont), the fluorine-containing polymer with the trade name "Cytop" (company: ASAHI Glass CO., LTD) or the trade name "Cytonix" fluorine-containing polymer (company: Cytonixcorporation) . The self-polymerizing silane molecules include octadecyltrichlorosilane (octadecyltrichlorosilane, OTS), 3,3,3-trifluoropropylmethyl dichlorosilane (3,3,3trifluoro-propylmethyl dichlorosilane, PMDCS), thirteen Fluorine-1,1,2,2-tetrahydrooctyl trichlorosilane (tridecafluoro-1,1,2,2-tetrahydrooctyl trichlorosilane, FOTS), heptadecafluoro-1,1,2,2-tetrahydrodecane Alkyl trichlorosilane (heptadecafluoro-1, 1, 2, 2-tetrahydrodecyltrichlorosilane, FDTS), decanyl trichlorosilane (dodecyl trichlorosilane, DDTCS), dimethyldichlorosilane (dimethyldichlorosilane, DDMS), vinyl eleven Alkyl trichlorosilane (vinylundecyl tirchlorosilane, V11TCS) or aminopropyl trimethoxysilane (aminopropyl trimethoxysilane, APTMS). In an embodiment of the present invention, the first hydrophobic dielectric layer 208 and the second hydrophobic dielectric layer 212 may be dielectric/insulating layers with hydrophobic (hydrophobic) surfaces, or dielectric/insulating hydrophobic layers, or Composite layer composed of hydrophobic layer and dielectric/insulating layer stacked.

As shown in FIG. 1a, the light modulation device 500a further includes a first protrusion 210 and a second protrusion 218, which are disposed above the first substrate 200, respectively. In this embodiment, the first protrusion 210 and the second protrusion 218 can be regarded as a pixel barrier of the electrowetting display, wherein the first protrusion 210 is used to define a pixel (pixel) 300 of the electrowetting display The shape of the pixel 300 defined by the first protrusion 210 may include a rectangle, a square, a triangle, a circle, a sector and a hexagon. In one embodiment, the second protrusion 218 is disposed in the middle of the pixel 300 defined by the first protrusion 210 to divide the single pixel 300 into two sub-pixels 300a, 300b. Therefore, and the first protrusion 210 surrounds the second protrusion 218 . In an embodiment of the present invention, the bottom surface b1 of the first protrusion 210 is coplanar with the bottom surface b2 of the second protrusion 218 , and both of them will contact the top surface 228 of the first hydrophobic dielectric layer 208 , and the second protrusion 218 is in contact with the top surface 228 of the first hydrophobic dielectric layer 208 . The height h2 of the second protrusion 218 is lower than the height h1 of the first protrusion 210 .

In another embodiment of the present invention, a patterning process may be optionally performed on the first hydrophobic dielectric layer 208 to form a hydrophobic dielectric pattern (not shown), and then the first protrusions 210 and The second protrusion 218 is disposed above the first substrate 200 . In more detail, in another embodiment of the present invention, when the first hydrophobic dielectric layer 208 is, for example, a dielectric/insulating layer with a hydrophobic (hydrophobic) surface, or a single hydrophobic layer with a dielectric/insulating property In the layer structure, after forming the hydrophobic dielectric pattern, the bottom surfaces b1 and b2 of the first protrusions 210 and the second protrusions 218 will contact the top surface 201 of the first substrate 200 . In yet another embodiment of the present invention, when the first hydrophobic dielectric layer 208 is a composite layer structure formed by stacking a hydrophobic layer and a dielectric/insulating layer, because it can be only for the hydrophobic layer or for the hydrophobic layer and the dielectric/insulation layer Both insulating layers are patterned, so after forming the hydrophobic dielectric pattern, the bottom surfaces b1 and b2 of the first protrusion 210 and the second protrusion 218 will contact the dielectric/dielectric layer of the first hydrophobic dielectric layer 208. The top surface of the insulating layer or the top surface 201 of the first substrate 200 .

In an embodiment of the present invention, the material of the first protrusion 210 and the second protrusion 218 may be ultraviolet (UV) hardening or thermal hardening photoresist material, and its chemical structure may contain polyethylene glycol groups (polyethylene glycol-), polyurethane group (polyurethane-), polyamide group (polyamide-), or poly(2-hydroxy ethylmethacrylate) group (poly(2-hydroxy ethylmethacrylate)- based) and other groups, such as polyepoxide, polyethylene glycol, polyurethane, polyamide, poly 2-hydroxyethyl methacrylate ( poly(2-hydroxy ethyl methacrylate) and other series.

In an embodiment of the present invention, the contact angle of the second protrusion 218 to water is designed to be greater than the contact angle of the first protrusion 210 to water. That is, the first protrusion 210 is made more hydrophilic, and the second protrusion 218 is made less hydrophilic or more lipophilic.

Please refer to FIG. 1 a again, the second electrode 206 is disposed on the first substrate 200 . In this embodiment, the second electrode 206 is disposed on the top surface 228 of the first hydrophobic dielectric layer 208, and since the second protrusion 218 divides the pixel 300 into two sub-pixels 300a, 300b, each sub-pixel A first electrode 204 and a second electrode 206 are provided in each pixel 300a or 300b, and the first electrode 204 and the second electrode 206 in each sub-pixel 300a or 300b are respectively close to the second protrusion 218 and the first protrusion 210 . However, the embodiment of the present invention does not limit the number of the first electrodes 204 and the second electrodes 206, which may depend on the design of the light modulation device. In the embodiment of the present invention, the first electrode 204 can be regarded as a pixel electrode, and the second electrode 206 can be regarded as a common electrode. No electrodes are disposed on the second substrate 202 .

As shown in FIG. 1 a , the light modulation device 500 a includes a first liquid 214 and a second liquid 216 located between the first substrate 200 and the second substrate 202 . In an embodiment of the present invention, the first liquid 214 may be a polar liquid, and the second liquid 216 may be a weak polar liquid or a non-polar liquid. In an embodiment of the present invention, the first liquid 214 may include water, aqueous solution or alcohols, and electrolytes such as potassium chloride (KCl) or sodium chloride (NaCl) may be added to the first liquid 214 to To increase ionic conductivity, in addition, a surfactant can also be added to reduce the surface tension of the solution. In an embodiment of the present invention, the second liquid 216 may include silicon oil, C ₁₀ -C ₁₆ alkanes, dyes or pigments. The C ₁₀ -C ₁₆ alkanes are, for example, decane, dodecane, tetradecane or hexadecane. Thus, when no voltage is applied to the first electrode 204 and the second electrode 206, the first liquid 214 is in contact with the more hydrophilic first protrusion 210, and the second liquid 216 is in contact with the less hydrophilic or more lipophilic second protrusion 210. The protrusions 218 make contact, and the second liquid 216 is surrounded by the first liquid 214 . In an embodiment of the present invention, the volume ratio of the first liquid 214 and the second liquid 216 in the pixel 300 can be further designed so that when no voltage is applied to the first electrode 204 and the second electrode 206 ( FIG. 1 a ), the first The liquid 214 is located directly above the second electrode 206 , and an interface 236 between the first liquid 214 and the second liquid 216 is designed to be located above the first electrode 204 . Moreover, in this embodiment, the first liquid 214 is in direct contact with the second electrode 206 . In an embodiment of the present invention, pigments or dyes can be added to the first liquid 214 to be distributed in the first liquid 214 to make the first liquid 214 present a desired color and make the second liquid 216 transparent. When no voltage is applied to the first electrode 204 and the second electrode 206 of the light modulation device 500a, the transparent second liquid 216 (weakly polar liquid or non-polar liquid) is substantially filled in the non-polar region of the pixel 300 of the light modulation device 500a. The edge regions, thus the pixels 300 of the light modulating device 500a appear substantially transparent.

Fig. 1b is a cross-sectional view of the light modulation device 500a when a voltage is applied. As shown in FIG. 1b, in an embodiment of the present invention, when the first electrode 204 (pixel electrode) is connected to the positive pole 222 of the power supply 220, and the second electrode 206 (common electrode) is connected to the negative pole 224 of the power supply 220, The more hydrophilic first liquid 214 (polar liquid) will be pulled down (closer to the first substrate 200 ) to cover the first electrode 204 and the second electrode 206 of the two sub-pixels 300a, 300b. Note that the surface 236 a of the first liquid 214 is convex. Since the second protrusions 218 are less hydrophilic or more lipophilic, the first liquid 214 will not climb up and cover the second protrusions 218 . In embodiments where the first liquid 214 is added with a pigment or dye, the pixels 300 of the light modulation device 500a will exhibit a color when a voltage is applied. According to the above properties, the light modulation device 500a of an embodiment of the present invention is called a normally transparent electrowetting display.

2 is a cross-sectional view of an optical modulation device 500b according to another embodiment of the present invention when no voltage is applied. The difference between it and the optical modulation device 500a shown in FIG. 1a is that the second electrode 226 of the optical modulation device 500b is set Between the first substrate 200 and the first hydrophobic dielectric layer 208 , and coplanar with the first electrode 204 . Therefore, when no voltage is applied to the light modulation device 500b, the first liquid 214 is located directly above the second electrode 206, but is not in direct contact with the second electrode 206.

Fig. 3a is a cross-sectional view of a light modulation device 500c according to another embodiment of the present invention when no voltage is applied. The light modulation device 500c of this embodiment can be an electrowetting optical deflector (liquid deflector), which differs from the light modulation device 500a shown in FIG. A third electrode 232 is provided. As shown in FIG. 3 a , the third electrode 232 is disposed between the second substrate 202 and the second hydrophobic dielectric layer 212 , and is disposed opposite to the second electrode 206 . In addition, the third electrode 232 is close to the first protrusion 210 . In this embodiment, the first electrode 204 and the third electrode 232 can be regarded as a pixel electrode respectively, and the second electrode 206 can be regarded as a common electrode. In this embodiment, the volume ratio of the first liquid 214 and the second liquid 216 in the pixel 300 can be further designed so that the first electrode 204, the second electrode 206 and the third electrode 232 can , the first liquid 214 is located directly above the second electrode 206 and directly below the third electrode 232 . Moreover, an interface 236 between the first liquid 214 and the second liquid 216 is located above the first electrode 204 . In addition, in this embodiment, the first liquid 214 is in direct contact with the second electrode 206 . Therefore, when no voltage is applied to the first electrode 204, the second electrode 206, and the third electrode 232, the less hydrophilic or more lipophilic second liquid 216 substantially fills the non-edge region of the pixel 300 of the light modulation device 500c , and the thickness of the second liquid 216 in the pixel 300 is uniform. Therefore, when the light is irradiated to the light modulating device 500c to which no voltage is applied, most of the light will pass through the second liquid 216 with a uniform thickness without being deflected.

Fig. 3b is a cross-sectional view of the light modulation device 500c when a voltage is applied. As shown in Figure 3b, in this embodiment, when the first electrode 204 (pixel electrode) is connected to the positive pole 242 of the power supply 240, the third electrode 232 (pixel electrode) is connected to the positive pole 244 of another power supply 238, and the second When the electrode 206 (common electrode) is connected to the negative poles of the power supply 240 and the power supply 238, the more hydrophilic first liquid 214 (polar liquid) will be pulled down (close to the first substrate 200) to cover the two sub-pixels 300a, 300b The first electrode 204 and the second electrode 206 . Note that the interface 236 b between the first liquid 214 and the second liquid 216 extends from the third electrode 232 toward the second protrusion 218 . In this embodiment, the interface 236b can be a slope or a curved surface. Since the second protrusions 218 are less hydrophilic or more lipophilic, the first liquid 214 will not climb up and cover the second protrusions 218 . Therefore, when a voltage is applied to the first electrode 204, the second electrode 206, and the third electrode 232, the second liquid 216 (weak polar liquid or non-polar liquid) in the pixel 300 of the light modulation device 500c will be absorbed by the first Liquid 214 is squeezed into a different shape (second liquid 216 has a middle thickness greater than edge thickness). Therefore, when light is irradiated to the light modulating device 500c that applies a voltage, most of the light will be deflected by the second liquid 216 having the property of a convex lens. According to the above properties, the light modulation device 500c according to one embodiment of the present invention can be used as an electrowetting optical deflector (liquid deflector).

FIG. 4 is a cross-sectional view of a light modulation device 500d according to yet another embodiment of the present invention when no voltage is applied. The difference between it and the light modulation device 500c shown in FIG. 3a is that the second electrode 226 of the light modulation device 500d It is disposed between the first substrate 200 and the first hydrophobic dielectric layer 208 , and is coplanar with the first electrode 204 . Therefore, when no voltage is applied to the light modulation device 500 b , the first liquid 214 is located directly above the second electrode 206 and directly below the third electrode 232 , but is not in direct contact with the second electrode 206 .

An embodiment of the present invention provides a light modulation device, which uses electrowetting technology, and is equipped with two sets of planar electrodes arranged on the same substrate, plus a hydrophilic high barrier wall located at the edge of the pixel and a hydrophobic low barrier wall located at the center of the pixel, Made into an electrowetting display. When no voltage is applied to the first electrode and the second electrode of the light modulation device of the embodiment of the present invention, the transparent second liquid (polar liquid) is substantially filled in the non-edge area of the pixel of the light modulation device, so the light modulation The device's pixels appear largely transparent. When a voltage is applied to the first electrode and the second electrode of the light modulation device according to the embodiment of the present invention, the more hydrophilic colored first liquid (polar liquid) will be pulled down to cover the first electrode and the second electrode, so that the light A modulation device's pixels take on color when a voltage is applied. According to the above properties, the light modulation device of an embodiment of the present invention can be used as a normally transparent electrowetting display. Compared with the known normally black (normally black) electrowetting display, the light modulation device of the embodiment of the present invention can greatly reduce the power consumption.

In addition, the light modulation device according to the embodiment of the present invention can also be provided with a third electrode opposite to the second electrode on another substrate to form an electrowetting optical deflector. When no voltage is applied to the first electrode, the second electrode and the third electrode of the light modulation device according to the embodiment of the present invention, most of the light will pass through the second liquid (weak polar liquid or non-polar liquid) with uniform thickness without causing deflection. When the first electrode, the second electrode and the third electrode of the light modulation device of the embodiment of the present invention apply a voltage, the second liquid in the pixel of the light modulation device will be squeezed by the first liquid (polar liquid) to a similar The shape of the convex lens deflects light. Compared with the known electrowetting optical deflectors, the electrodes of the light modulation device in the embodiment of the present invention are all fabricated on a flat substrate, which can avoid the disadvantages of complex process and poor uniformity in fabricating the known lateral electrodes, and the process is stable High compatibility, and compatible with the current panel technology, great potential for commercialization.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (15)

1. A light modulation device, comprising: a first substrate and a second substrate, which are arranged opposite to each other; a first electrode disposed on the first substrate; a first hydrophobic dielectric layer covering the first electrode; a second hydrophobic dielectric layer disposed on the second substrate; a first protrusion and a second protrusion are respectively disposed on the first substrate; and The first liquid and the second liquid are arranged between the first substrate and the second substrate, characterized in that: The light modulation device further includes a second electrode disposed on the first substrate, the first electrode and the second electrode are respectively adjacent to the second protrusion and the first protrusion; and When no voltage is applied to the first electrode and the second electrode, the first liquid is located directly above the second electrode, and an interface between the first liquid and the second liquid is located above the first electrode . 2. The light modulation device according to claim 1, wherein the first liquid is a polar liquid, and the second liquid is a weak polar liquid or a non-polar liquid. 3. The light modulation device as claimed in claim 1, wherein the first protrusion surrounds the second protrusion. 4. The light modulating device as claimed in claim 1, wherein the bottom surface of the first protrusion is coplanar with the bottom surface of the second protrusion. 5. The light modulating device as claimed in claim 1, wherein bottom surfaces of the first protrusion and the second protrusion contact the first hydrophobic dielectric layer. 6. The light modulating device as claimed in claim 1, wherein bottom surfaces of the first protrusion and the second protrusion contact the first substrate. 7. The light modulation device as claimed in claim 1, wherein the height of the second protrusion is lower than that of the first protrusion. 8. The light modulation device as claimed in claim 1, wherein the second electrode is disposed on the first hydrophobic dielectric layer, and the first liquid is in direct contact with the second electrode. 9. The light modulation device as claimed in claim 1, wherein the second electrode is disposed between the first substrate and the first hydrophobic dielectric layer, and is coplanar with the first electrode. 10. The light modulation device according to claim 9, wherein the first electrode is a pixel electrode, and the second electrode is a common electrode. 11. The light modulation device as claimed in claim 1, wherein the contact angle of the second protrusion to water is larger than the contact angle of the first protrusion to water. 12. The light modulation device as claimed in claim 1, wherein no electrodes are disposed on the second substrate. 13. The light modulation device of claim 1, further comprising: The third electrode is arranged on the second substrate and opposite to the second electrode. 14. The light modulation device as claimed in claim 13, wherein the third electrode is disposed between the second substrate and the second hydrophobic dielectric layer. 15. The light modulation device as claimed in claim 1, further comprising a pigment or a dye distributed in the first liquid.