TWI460470B - Electrowetting display device - Google Patents

Description

Electrowetting display device

The present invention relates to an electrowetting display device, and more particularly to an electrowetting display device having multiple gaps.

The electrowetting display device is a display device that utilizes an electric wetting force to control the movement of a non-polar liquid and a polar liquid to achieve a display effect. The electrowetting display device mainly comprises two substrates, two electrodes respectively disposed inside the two substrates, and a non-polar liquid and a polar liquid disposed between the two electrodes and mutually immiscible with each other. The difference in voltage applied between the two electrodes can change the hydrophilic effect of the electrode, thereby changing the contact angle. That is to say, in the absence of a voltage difference, the surface of the electrode is more hydrophobic and oleophilic, and after the application of the voltage difference, the surface of the electrode becomes more hydrophilic and oleophobic, so that the area of the non-polar liquid covering the substrate can be controlled, thereby achieving Control the role of grayscale. However, in the conventional electrowetting display device, since the distance between any two electrodes is uniform, the electric field generated is a uniform electric field, so when continuously displaying pictures having different gray levels, Polar liquids and non-polar liquids can cause a hysteresis phenomenon due to other forces. The retention phenomenon causes the area of the non-polar liquid actually covering the substrate to deviate from the area intended to cover the substrate. As a result, the gray scale performance of the electrowetting display device is not good, which seriously affects the display quality.

It is an object of the present invention to provide an electrowetting display device that solves the problem of poor gray scale performance of conventional electrowetting display devices.

An embodiment of the present invention provides an electrowetting display device having a plurality of pixel regions, and each pixel region includes a pixel peripheral region and an active region. The electrowetting display device comprises a first substrate, a plurality of first electrodes, a hydrophobic layer, a plurality of barrier walls, a second substrate, a plurality of second electrodes, a polar liquid, and a non-polar liquid. The first electrodes are disposed on the first substrate and are respectively located in the pixel region. The hydrophobic layer is disposed on the first electrode. The barrier walls are disposed on the hydrophobic layer and are respectively located in the peripheral regions of the pixels. The second substrate is disposed facing the first substrate. The second electrodes are disposed on the second substrate and are respectively located in the pixel region. Each of the second electrodes includes a first sub-electrode portion and a second sub-electrode portion. Each of the second electrodes is disposed in the corresponding active region and electrically connected to each other, the first sub-electrode portion and the hydrophobic layer have a first distance, the second sub-electrode portion and the hydrophobic layer have a second distance, and the first distance Greater than the second distance. The polar liquid is between the second electrode and the hydrophobic layer, and the second electrode is in contact with the polar liquid. The non-polar liquid is located between the second electrode and the hydrophobic layer.

The second electrode of the electrowetting display device of the present invention has two different gaps between the second electrode and the first electrode, and can accurately and effectively control the position of the polar liquid and the non-polar liquid in the dark state display mode and the bright state display mode. In turn, it improves grayscale performance and improves display quality.

1‧‧‧Electric humidification display device

10P‧‧‧Photo District

10A‧‧‧Active Area

10S‧‧‧ pixels surrounding area

12‧‧‧First substrate

14‧‧‧First electrode

16‧‧‧hydrophobic layer

18‧‧‧ blocking wall

20‧‧‧second substrate

22‧‧‧second electrode

24‧‧‧Polar liquid

26‧‧‧Non-polar liquid

15‧‧‧Insulation

10B‧‧‧Border area

28‧‧‧Box glue

221‧‧‧First sub-electrode

222‧‧‧Second sub-electrode

D1‧‧‧first distance

D2‧‧‧Second distance

42‧‧‧Light source

44‧‧‧Light guide plate

L‧‧‧Light

30‧‧‧Bump structure

1'‧‧‧Electric humidification display device

222M‧‧‧Main electrode section

222A‧‧‧Auxiliary electrode section

1”‧‧‧Electric humidification display device

S1‧‧‧Auxiliary electrode layer

S2‧‧‧Auxiliary electrode layer

S3‧‧‧Auxiliary electrode layer

2‧‧‧Electric humidification display device

32‧‧‧ shading pattern

2'‧‧‧Electric humidification display device

2”‧‧‧Electric humidification display device

3‧‧‧Electric humidification display device

34‧‧‧wavelength conversion layer

L’‧‧ Visible light

3'‧‧‧Electric humidification display

3"‧‧‧Electric humidification display device

Fig. 1 is a schematic view showing the electrowetting display device of the first embodiment of the present invention in a dark state display mode.

Fig. 2 is a schematic view showing the electrowetting display device of the first embodiment of the present invention in a bright state display mode.

FIG. 3 is a schematic view showing an electrowetting display device according to a first variation of the first embodiment of the present invention.

Fig. 4 is a schematic view showing an electrowetting display device according to a second modified embodiment of the first embodiment of the present invention.

Fig. 5 is a schematic view showing the electrowetting display device of the second embodiment of the present invention in a bright state display mode.

Figure 6 is a schematic view showing the electrowetting display device in the dark state display mode of the second embodiment of the present invention.

7 is a diagram showing an electrowetting display device according to a first variation of the second embodiment of the present invention. intention.

FIG. 8 is a schematic view showing an electrowetting display device according to a second variation of the second embodiment of the present invention.

Figure 9 is a schematic view showing the electrowetting display device of the third embodiment of the present invention in a bright state display mode.

Figure 10 is a schematic view showing the electrowetting display device in the dark state display mode according to the third embodiment of the present invention.

11 is a schematic view showing an electrowetting display device according to a first variation of the third embodiment of the present invention.

Figure 12 is a schematic view showing an electrowetting display device according to a second modified embodiment of the third embodiment of the present invention.

The present invention will be further understood by those of ordinary skill in the art to which the present invention pertains. .

Please refer to Figure 1 and Figure 2. 1 and 2 are schematic views of an electrowetting display device according to a first embodiment of the present invention, wherein FIG. 1 is a schematic view showing a dark display mode of the electrowetting display device of the first embodiment, FIG. It is a schematic diagram of the electrowetting display device of the first embodiment in a bright state display mode. As shown in FIGS. 1 and 2, the electrowetting display device 1 of the present embodiment has a plurality of pixel regions 10P, and each of the pixel regions 10P includes an active region 10A and a pixel peripheral region 10S. The active area 10A is a display area, and the pixel peripheral area 10S is an area between adjacent active areas 10A. The electrowetting display device 1 includes a first substrate 12, a plurality of first electrodes 14, a hydrophobic layer 16, a plurality of barrier walls 18, a second substrate 20, a plurality of second electrodes 22, a polar liquid 24, and a non- Polar liquid 26. The first substrate 12 may include a transparent substrate, which may be a rigid transparent substrate such as a glass substrate or a quartz substrate, or a flexible transparent substrate such as a plastic substrate, but is not limited thereto. The first electrodes 14 are disposed on the first substrate 12 and respectively located in the pixel area Within 10P. The first electrode 14 may comprise a transparent electrode, the material of which may be indium tin oxide (ITO), indium tin oxide (IZO) or other suitable transparent conductive material. The first electrode 14 is a pixel electrode, and each of the first electrodes 14 may have an independent pixel voltage. The electrowetting display device 1 can be an active matrix display device or a passive matrix display device. When the electrowetting display device 1 is an active matrix display device, each of the first electrodes 14 can be electrically connected to a corresponding active switching element (not shown) such as a thin film. The crystal elements are electrically connected; when the electrowetting display device 1 is a passive matrix display device, the first electrodes 14 do not need to be connected to the active switching elements, but can be directly connected to the signal lines (not shown). The hydrophobic layer 16 is disposed on the first electrode 14, and the material of the hydrophobic layer 16 may be various materials having hydrophobic properties. In addition, the electrowetting display device 1 can optionally include an insulating layer 15 disposed between the first electrode 14 and the hydrophobic layer 16, but is not limited thereto. The barrier wall 18 is disposed on the hydrophobic layer 16 and located in the pixel peripheral region 10S, respectively, and the barrier wall 18 substantially surrounds the active region 10A. The barrier wall 18 can be fixed to the surface of the hydrophobic layer 16 and in contact with the hydrophobic layer 16, and the barrier wall 18 is not in contact with the second electrode 22. The material of the barrier wall 18 can be, for example, a photoresist or other insulating material. The second substrate 20 is disposed to face the first substrate 12, and the first substrate 12 and the second substrate 20 are adhered by the sealant 28 disposed in the frame region 10B. The second substrate 20 may include a transparent substrate, and the material thereof may be the same as that of the first substrate 12, but is not limited thereto. The second electrode 22 is disposed on the second substrate 20. To be precise, the first electrode 14 and the second electrode 22 are disposed on the inner side surfaces of the first substrate 12 and the second substrate 20, respectively. The second electrodes 22 are respectively located in the pixel region 10P, and the second electrodes 22 are connectable to each other. The second electrode 22 is a common electrode, and each of the second electrodes 22 can have the same common voltage, but is not limited thereto. In addition, each of the second electrodes 22 includes a first sub-electrode portion 221 and a second sub-electrode portion 222 disposed in the corresponding active regions 10A and electrically connected to each other. The first sub-electrode portion 221 has a first distance d1 from the hydrophobic layer 16, the second sub-electrode portion 222 and the hydrophobic layer 16 have a second distance d2, and the first distance d1 is greater than the second distance d2. The polar liquid 24 and the non-polar liquid 26 are located between the second electrode 22 and the hydrophobic layer 16, and the polar liquid 24 and the non-polar liquid 26 are mutually immiscible, and can be sealed to the first substrate 12 and the second substrate by the sealant 28. Between 20. The sealant 28 can be, for example, a UV sealant, or other various types of sealant. In detail, the polar liquid 24 and the non-polar liquid 26 are located in the active region 10A. Therein, wherein the polar liquid 24 is substantially distributed in the space between the first substrate 12 and the second substrate 20, and the non-polar liquid 26 is substantially confined within the space formed by the barrier wall 18. The polar liquid 24 has polarity, which may be, for example, water or other polar liquid having polarity, while the non-polar liquid 26 has no polarity, which may be an ink or other oily liquid that does not have polarity. Additionally, in the present embodiment, the polar liquid 24 includes a light transmissive liquid that permits light to pass through, and the non-polar liquid 26 includes an opaque liquid that blocks light from penetrating.

The electrowetting display device 1 of the present embodiment may further include a light source 42 and a light guide plate 44. The light source 42 can be disposed on one side of the light guide plate 44 and used to guide the light guide plate 44 to the light beam L. The light guide plate 44 is disposed under the first substrate 12 for guiding the light L emitted by the light source 42 to the first substrate. 12. In the present embodiment, the light L emitted by the light source 42 is visible light, that is, the wavelength range thereof is light visible to the human eye. For example, light source 42 can be, for example, a light emitting diode element, a fluorescent tube, or other type of light emitting element. In addition, the light source 42 may also be disposed below the first substrate 12 . The electrowetting display device 1 of the present embodiment can also use an environmental backlight, and in this case, it is not necessary to use a backlight element such as the light source 42 and the light guide plate 44.

In this embodiment, there are two different gaps between the second electrode 22 and the hydrophobic layer 16. The design of the different gaps can be between the first sub-electrode portion 221 and the hydrophobic layer 16 under the same voltage difference. The pressure is not equal to the pressure between the second sub-electrode portion 222 and the hydrophobic layer 16, so that the retention of the polar liquid 24 and the non-polar liquid 26 can be effectively avoided, and the polar liquid 24 and the non-polar liquid 26 can be precisely controlled. The position in the dark state display mode and the bright state display mode. Referring to Formula 1, Equation 1 is the relationship between the pressure, distance, and voltage difference between the second electrode 22 and the hydrophobic layer 16.

P2-P1=(1/2)*CV ² *((1/d2)-(1/d1))........................ . . . Equation 1 where P1 is the pressure between the first sub-electrode portion 221 and the hydrophobic layer 16; P2 is the pressure between the second sub-electrode portion 222 and the hydrophobic layer 16. V is the voltage difference between the first electrode 14 and the second electrode 22; d1 is the first distance; and d2 is the second distance.

As can be seen from Equation 1, when the voltage difference V between the first electrode 14 and the second electrode 22 is the same, the first sub-electrode portion 221 can be adjusted by changing the magnitude relationship between the first distance d1 and the second distance d2. The relationship between the pressure P1 between the hydrophobic layer 16 and the pressure P2 between the second sub-electrode portion 222 and the hydrophobic layer 16. In this way, when the electrowetting display device 1 is driven, the position of the polar liquid 24 and the non-polar liquid 26 in the dark state display mode and the bright state display mode can be controlled more accurately and effectively by using the pressure difference, thereby improving the gray scale performance. , thereby improving display quality.

The electrowetting display device 1 of the present embodiment further includes a plurality of bump structures 30 respectively located in the active region 10A. Each of the bump structures 30 is disposed between the corresponding second sub-electrode portion 222 and the second substrate 20 , but is not disposed between the first sub-electrode portion 221 and the second substrate 20 . Therefore, the second sub-electrode portion 222 is raised by the bump structure 30 and protrudes from the first sub-electrode portion 221 with respect to the lower surface of the first sub-electrode portion 221 . That is, in the present embodiment, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second distance d2 between the second sub-electrode portion 222 and the hydrophobic layer 16 are due to the second sub- A bump structure 30 is provided between the electrode portion 222 and the second substrate 20. The material of the bump structure 30 may be various insulating materials, such as inorganic insulating materials such as yttrium oxide, tantalum nitride, aluminum oxide and titanium oxide, or an organic insulating material.

The operating conditions of the electrowetting display device of the present embodiment in the dark state display mode and the bright state display mode will be described below. It should be noted that the dark state display mode or the bright state display mode refers to a single pixel display mode, that is, each pixel can be independently controlled to a dark state display mode or a bright state depending on the picture to be displayed. Display mode.

As shown in FIG. 1, in the dark state display mode, there is no voltage difference between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22. Will be equal. In this case, the polar liquid 24 (light-transmitting liquid) repels the hydrophobic layer 16, and the non-polar liquid 26 (opaque liquid) adsorbs on the surface of the hydrophobic layer 16 to completely cover the active region 10A, so that it can be shielded by The light L emitted from the light guide plate 44 reaches a dark state display effect.

As shown in FIG. 2, in the bright state display mode, an electric field exists between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22 are not Equal and have a voltage difference. Under this condition, the non-polar liquid 26 (opaque liquid) may be pushed to one side of the barrier wall 18 by the pushing of the electric wetting force to partially cover the active region 10A, and the polar liquid 24 (light transmitting liquid) may be The surface energy changes to cover part of the active area 10A. Therefore, the light L (visible light) emitted from the light guide plate 44 can pass through the polar liquid 24 (light transmitting liquid) to achieve a bright state display effect. In the bright state display mode, the grayscale value (brightness) of each pixel region 10P can be controlled by the magnitude of the voltage difference between the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22, that is, when The larger the voltage difference is, the larger the gray scale value is; the smaller the voltage difference is, the smaller the gray scale value is. Further, since the pixel voltages of the first electrodes 14 of the respective pixel regions 10P are independently controlled, predetermined gray scale values can be respectively displayed.

The electrowetting display device 1 of the embodiment can provide a black and white display function, a monochrome display function or a full color display function. For example, if a black and white display function is to be provided, the light L emitted by the light source 42 may be white light. If a monochrome display function is to be provided, the light L emitted from the light source 42 may be monochromatic light such as red light, green light or blue light. If the full color display function is to be provided, the light source 42 may select a scanning light source, which may sequentially emit different colors of light L, for example, sequentially emitting red light, green light and blue light; or the light L emitted by the light source 42 may be selected. White light, and color filters of different colors (not shown) are respectively disposed in different pixel regions 10P.

The electrowetting display device of the present invention is not limited to the above embodiment. The electrowetting display device of the other preferred embodiments of the present invention will be described in order below, and the same symbols are used to denote the same components in the following embodiments in order to facilitate the comparison of the different embodiments and simplify the description. The description of the differences between the embodiments will be mainly made, and the repeated parts will not be described again.

Please refer to Figure 3. FIG. 3 is a schematic view showing an electrowetting display device according to a first variation of the first embodiment of the present invention. As shown in Fig. 3, in the electrowetting display device 1' of the first modified embodiment, each of the second sub-electrode portions 222 includes a main electrode portion 222M and an auxiliary electrode portion 222A. The main electrode portion 222M of the second sub-electrode portion 222 and the first sub-electrode portion 221 are formed of the same layer of patterned transparent conductive layer, and each auxiliary electrode portion 222A is disposed between the corresponding main electrode portion 222M and the hydrophobic layer 16. . Therefore, the auxiliary electrode portion 222A protrudes from the first sub-electrode portion 221 with respect to the lower surface of the first sub-electrode portion 221 . That is, in the first variant embodiment, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second distance d2 between the second sub-electrode portion 222 and the hydrophobic layer 16 are The auxiliary electrode portion 222A of the two sub-electrode portions 222 is achieved. The operation mode of the dark state display mode and the bright state display mode of the electrowetting display device 1' of the first modified embodiment is the same as that of the first embodiment, and will not be further described herein.

Please refer to Figure 4. Fig. 4 is a schematic view showing an electrowetting display device according to a second modified embodiment of the first embodiment of the present invention. As shown in FIG. 4, unlike the first variation embodiment, in the electrowetting display device 1" of the second variation embodiment, each of the auxiliary electrode portions 222A includes a plurality of auxiliary electrode layers S1, S2, S3 stacked in correspondence. The main electrode portion 222M is disposed between the main electrode portion 222M and the hydrophobic layer 16. The area of the auxiliary electrode layers S1, S2, and S3 is different, for example, the area thereof is arranged in a decreasing manner. That is, the area of the auxiliary electrode layer S3 adjacent to the hydrophobic layer 16 is smaller than the auxiliary portion. The area of the electrode layer S2, and the area of the auxiliary electrode layer S2 is smaller than the area of the auxiliary electrode layer S1 adjacent to the main electrode portion 222M. Similarly, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second sub- Electrode portion 222 and sparse The second distance d2 between the water layers 16 is achieved by the auxiliary electrode portion 222A having a multilayer stacked structure. The operation mode of the dark state display mode and the bright state display mode of the electrowetting display device 1" of the second modified embodiment is the same as that of the first embodiment, and will not be further described herein.

Please refer to Figure 5 and Figure 6. 5 and 6 are schematic views of an electrowetting display device according to a second embodiment of the present invention, wherein FIG. 5 is a schematic view showing the electrowetting display device of the second embodiment in a bright state display mode, FIG. It is a schematic diagram of the electrowetting display device of the second embodiment in a dark state display mode. As shown in FIG. 5 and FIG. 6 , the electrowetting display device 2 of the present embodiment further includes a plurality of light shielding patterns 32 respectively disposed in the active region 10A, and each of the light shielding patterns 32 is only partially partially different from the first embodiment. The corresponding active area 10A is partially covered and the corresponding active area 10A is partially exposed. The light shielding pattern 32 can block the light L. Further, the light L emitted by the light source 42 can be an invisible light. In addition, unlike the first embodiment, in the second embodiment, the polar liquid 24 includes a light transmissive liquid, and the non-polar liquid 26 includes a wavelength converting liquid, wherein the non-polar liquid 26 has a refractive index greater than or equal to the hydrophobic layer 16. The refractive index, and the refractive index of the polar liquid 24 is smaller than the refractive index of the hydrophobic layer 16. For example, the difference in refractive index between the non-polar liquid 26 and the hydrophobic layer 16 may be between 0.1 and 1, but not limited thereto. In addition, in the embodiment, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second distance d2 between the second sub-electrode portion 222 and the hydrophobic layer 16 are due to the second sub-electrode portion. The bump structure 30 is disposed between the 222 and the second substrate 20, but is not limited thereto.

As shown in FIG. 5, in the bright state display mode, there is no voltage difference between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22. Will be equal. In this case, the polar liquid 24 (light transmitting liquid) repels the hydrophobic layer 16, and the non-polar liquid 26 (wavelength converting liquid) adsorbs on the surface of the hydrophobic layer 16 to completely cover the active region 10A. Since the refractive index of the non-polar liquid 26 is greater than or equal to the refractive index of the hydrophobic layer 16, the light L enters and penetrates the non-polar liquid 26 (wavelength converting liquid) in a form of direct penetration or refraction. The wavelength conversion liquid is excited to form a visible light line L', and since the interface between the non-polar liquid 26 and the polar liquid 24 is curved, the visible light line L' can still penetrate the polar liquid 24 to achieve a bright display effect. For example, the pixel region 10P of the electrowetting display device 2 of the present embodiment may include a plurality of pixel regions 10P of different colors, such as a red pixel region, a green pixel region, and a blue pixel region, and are in red. In the pixel area, the green pixel area and the blue pixel area, the color wavelength conversion liquids are respectively a red light-emitting liquid, a green light-emitting liquid and a blue light-emitting liquid, so that a full-color display function can be provided. In addition, in the bright state display mode, the grayscale value (brightness) of each pixel region 10P can be controlled by the magnitude of the voltage difference between the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22, that is, When the voltage difference is larger, the gray scale value is smaller; when the voltage difference is smaller, the gray scale value is larger. Further, since the pixel voltages of the first electrodes 14 of the respective pixel regions 10P are independently controlled, predetermined gray scale values can be respectively displayed.

As shown in FIG. 6, in the dark state display mode, an electric field exists between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22 are not Equal and have a voltage difference. In this case, the non-polar liquid 26 (wavelength converting liquid) is pressed by the electric wetting force to move onto the light shielding pattern 32, and the polar liquid 24 (light transmitting liquid) covers a part of the active area 10A due to the change in surface energy. . The polar liquid 24 (light-transmissive liquid) blocks the light L and provides a dark display. In the present embodiment, since the refractive index of the polar liquid 24 is smaller than the refractive index of the hydrophobic layer 16, the light L (invisible light) emitted from the light guide plate 44 is affected by the polar liquid 24 (light transmitting liquid) due to the total reflection effect. Reflected and unable to penetrate the polar liquid 24 (light transmitting liquid). That is to say, in the dark state display mode, the light L (invisible light line) can not only penetrate the light shielding pattern 32, but also cannot penetrate the polar liquid 24 (light transmitting liquid) due to the total reflection effect, so the wavelength conversion liquid is not excited. It can achieve a dark state display effect that does not emit light.

Please refer to Figure 7. FIG. 7 is a schematic view showing an electrowetting display device according to a first variation of the second embodiment of the present invention. As shown in Fig. 7, the electrowetting in the first variation embodiment In the display device 2', each of the second sub-electrode portions 222 includes a main electrode portion 222M and an auxiliary electrode portion 222A. The main electrode portion 222M of the second sub-electrode portion 222 and the first sub-electrode portion 221 are formed of the same layer of patterned transparent conductive layer, and each of the auxiliary electrode portions 222A is disposed between the corresponding main electrode portion 222M and the hydrophobic layer 16 between. Therefore, the auxiliary electrode portion 222A protrudes from the first sub-electrode portion 221 with respect to the lower surface of the first sub-electrode portion 221 . That is, in the first variant embodiment, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second distance d2 between the second sub-electrode portion 222 and the hydrophobic layer 16 are The auxiliary electrode portion 222A of the two sub-electrode portions 222 is achieved. The operation mode of the dark state display mode and the bright state display mode of the electrowetting display device 2' of the first modified embodiment is the same as that of the second embodiment, and will not be further described herein.

Please refer to Figure 8. FIG. 8 is a schematic view showing an electrowetting display device according to a second variation of the second embodiment of the present invention. As shown in FIG. 8, unlike the first variation embodiment, in the electrowetting display device 2" of the second variation embodiment, each of the auxiliary electrode portions 222A includes a plurality of auxiliary electrode layers S1, S2, S3 stacked in correspondence. The main electrode portion 222M is disposed between the main electrode portion 222M and the hydrophobic layer 16. The area of the auxiliary electrode layers S1, S2, and S3 is different, for example, the area thereof is arranged in a decreasing manner. That is, the area of the auxiliary electrode layer S3 adjacent to the hydrophobic layer 16 is smaller than the auxiliary portion. The area of the electrode layer S2, and the area of the auxiliary electrode layer S2 is smaller than the area of the auxiliary electrode layer S1 adjacent to the main electrode portion 222M. Similarly, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second sub- The second distance d2 between the electrode portion 222 and the hydrophobic layer 16 is achieved by the auxiliary electrode portion 222A having a multi-layer stack structure. The dark state display mode and the bright state display of the electrowetting display device 2" of the second modified embodiment The operation mode of the mode is the same as that of the second embodiment, and will not be described here.

Please refer to Figure 9 and Figure 10. 9 and 10 are schematic views of an electrowetting display device according to a third embodiment of the present invention, wherein FIG. 9 is a schematic view showing the electrowetting display device of the third embodiment in a bright state display mode, FIG. It is a schematic diagram of the electrowetting display device of the third embodiment in a dark state display mode. As shown in FIGS. 9 and 10, unlike the first and second embodiments, The electrowetting display device 3 of the present embodiment includes a wavelength conversion layer 34 disposed on the second substrate 20. In addition, the light L emitted by the light source 42 may be an invisible light, the polar liquid 24 includes a light transmitting liquid, and the non-polar liquid 26 includes a light transmitting liquid, wherein the refractive index of the non-polar liquid 26 is greater than or equal to the refractive index of the hydrophobic layer 16. And the refractive index of the polar liquid 24 is smaller than the refractive index of the hydrophobic layer 16. For example, the difference in refractive index between the non-polar liquid 26 and the hydrophobic layer 16 may be between 0.1 and 1, but not limited thereto.

As shown in FIG. 9, in the bright state display mode, there is no voltage difference between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22. Will be equal. In this case, the polar liquid 24 will repel the hydrophobic layer 16, and the non-polar liquid 26 will adsorb on the surface of the hydrophobic layer 16 to completely cover the active region 10A, since the refractive index of the non-polar liquid 26 is greater than or equal to that of the hydrophobic layer 16. The refractive index, therefore, the light L enters and penetrates the non-polar liquid 26 (translucent liquid) in a form of direct penetration or refraction, and since the interface between the non-polar liquid 26 and the polar liquid 24 is curved, the visible light L' remains The polar liquid 24 can be penetrated and the wavelength conversion layer 34 is excited to form a visible light line L' to achieve a bright state display effect. The pixel region 10P of the electrowetting display device 3 of the present embodiment may include a plurality of pixel regions 10P of different colors, such as a red pixel region, a green pixel region, and a blue pixel region, and in the red pixel region, In the green pixel region and the blue pixel region, the wavelength conversion layer 34 may select wavelength conversion layers of different materials, such as a red light emitting layer, a green light emitting layer and a blue light emitting layer, which may be respectively excited by invisible light lines. Produces red, green and blue light, so full color display is available. In addition, in a variant embodiment, the light L emitted by the light source 42 may also be a visible light having a short wavelength, such as blue light. In this case, the blue pixel region may not be provided with the wavelength conversion layer 34, and in the red pixel region and the green pixel region and the blue pixel region, the wavelength conversion layer 34 may select a wavelength conversion layer of a different material, for example, The red light emitting layer and the green light emitting layer are respectively excited by short-wavelength blue light to generate red light and green light. By the above method, a full color display function can also be provided. In addition, in the bright state display mode, the grayscale value (brightness) of each pixel region 10P can be increased by the voltage difference between the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22. To control, that is, when the voltage difference is smaller, the gray scale value is larger; when the voltage difference is larger, the gray scale value is smaller. Further, since the pixel voltages of the first electrodes 14 of the respective pixel regions 10P are independently controlled, predetermined gray scale values can be respectively displayed.

As shown in FIG. 10, in the dark state display mode, an electric field exists between the first electrode 14 and the second electrode 22, that is, the pixel voltage of the first electrode 14 and the common voltage of the second electrode 22 are not Equal and have a voltage difference. Under this condition, the non-polar liquid 26 is pushed to one side of the barrier wall 18 by the pushing of the electric wetting force to partially cover the active region 10A, and the polar liquid 24 covers the partial active region 10A due to the change in surface energy. The polar liquid 24 blocks the light L to provide a dark display. In the present embodiment, since the refractive index of the polar liquid 24 is smaller than the refractive index of the hydrophobic layer 16, the light L emitted from the light guide plate 44 is reflected by the polar liquid 24 due to the total reflection effect and cannot penetrate the polar liquid 24.

Please refer to Figure 11. 11 is a schematic view showing an electrowetting display device according to a first variation of the third embodiment of the present invention. As shown in Fig. 11, in the electrowetting display device 3' of the first modified embodiment, each of the second sub-electrode portions 222 includes a main electrode portion 222M and an auxiliary electrode portion 222A. The main electrode portion 222M of the second sub-electrode portion 222 and the first sub-electrode portion 221 are formed of the same layer of patterned transparent conductive layer, and each auxiliary electrode portion 222A is disposed between the corresponding main electrode portion 222M and the hydrophobic layer 16. . Therefore, the auxiliary electrode portion 222A protrudes from the first sub-electrode portion 221 with respect to the lower surface of the first sub-electrode portion 221 . That is, in the first variant embodiment, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second distance d2 between the second sub-electrode portion 222 and the hydrophobic layer 16 are The auxiliary electrode portion 222A of the two sub-electrode portions 222 is achieved. The operation mode of the dark state display mode and the bright state display mode of the electrowetting display device 3' of the first modified embodiment is the same as that of the third embodiment, and will not be further described herein.

Please refer to Figure 12. Figure 12 is a diagram showing a second variation of the third embodiment of the present invention. A schematic view of an electrowetting display device of an embodiment. As shown in FIG. 4, unlike the first variation embodiment, in the electrowetting display device 3" of the second variation embodiment, each of the auxiliary electrode portions 222A includes a plurality of auxiliary electrode layers S1, S2, S3 stacked in correspondence. The main electrode portion 222M is disposed between the main electrode portion 222M and the hydrophobic layer 16. The area of the auxiliary electrode layers S1, S2, and S3 is different, for example, the area thereof is arranged in a decreasing manner. That is, the area of the auxiliary electrode layer S3 adjacent to the hydrophobic layer 16 is smaller than the auxiliary portion. The area of the electrode layer S2, and the area of the auxiliary electrode layer S2 is smaller than the area of the auxiliary electrode layer S1 adjacent to the main electrode portion 222M. Similarly, the first distance d1 between the first sub-electrode portion 221 and the hydrophobic layer 16 and the second sub- The second distance d2 between the electrode portion 222 and the hydrophobic layer 16 is achieved by the auxiliary electrode portion 222A having a multi-layer stacked structure. The dark state display mode and the bright state display of the electrowetting display device 3" of the second modified embodiment The operation mode of the mode is the same as that of the third embodiment, and will not be described here.

In summary, the second electrode of the electrowetting display device of the present invention has two different gaps between the second electrode and the first electrode, so that the polar liquid and the non-polar liquid can be accurately and effectively controlled in the dark state display mode and the bright state. Improve the display quality by improving the grayscale performance in the display mode.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

1‧‧‧Electric humidification display device

10P‧‧‧Photo District

10A‧‧‧Active Area

10S‧‧‧ pixels surrounding area

12‧‧‧First substrate

14‧‧‧First electrode

16‧‧‧hydrophobic layer

18‧‧‧ blocking wall

20‧‧‧second substrate

22‧‧‧second electrode

24‧‧‧Polar liquid

26‧‧‧Non-polar liquid

15‧‧‧Insulation

10B‧‧‧Border area

28‧‧‧Box glue

221‧‧‧First sub-electrode

222‧‧‧Second sub-electrode

D1‧‧‧first distance

D2‧‧‧Second distance

42‧‧‧Light source

44‧‧‧Light guide plate

L‧‧‧Light

20‧‧‧Bump structure

Claims (17)

An electrowetting display device having a plurality of pixel regions, wherein each of the pixel regions includes a pixel peripheral region and an active region, the electrowetting display device comprising: a first substrate; and a plurality of first electrodes disposed on The first substrate is located in the pixel regions respectively; a hydrophobic layer is disposed on the first electrodes; a plurality of barrier walls are disposed on the hydrophobic layer and respectively located in the peripheral regions of the pixels; a second substrate disposed opposite the first substrate; a plurality of second electrodes disposed on the second substrate and respectively located in the pixel regions, wherein each of the second electrodes includes a first sub-electrode portion And a second sub-electrode portion, each of the second electrodes is disposed in the corresponding active region and electrically connected to each other, the first sub-electrode portion and the hydrophobic layer have a first distance, and the second sub-electrode portion is The hydrophobic layer has a second distance, and the first distance is greater than the second distance; a polar liquid is located between the second electrode and the hydrophobic layer, wherein the second electrodes are in contact with the polar liquid; a non-polar liquid, located at Two between the electrode and the hydrophobic layer. The electrowetting display device of claim 1, wherein the second electrodes are connected to each other. The electrowetting display device of claim 1, further comprising an insulating layer disposed between the first electrodes and the hydrophobic layer. The electrowetting display device of claim 1, further comprising a plurality of bump structures respectively located in the active regions, wherein each of the bump structures is disposed on the corresponding second sub-electrode portion and the second substrate Between the second sub-electrode portions protruding from the first sub-electrode portion. The electrowetting display device according to claim 1, wherein each of the second sub-electrode portions includes a main electrode portion and an auxiliary electrode portion, and the main electrode portions and the first sub-electrode portions are patterned by the same layer. The transparent conductive layer is formed, and each of the auxiliary electrode portions is disposed between the corresponding main electrode portion and the hydrophobic layer, and the auxiliary electrode portion protrudes from the first sub-electrode portion. The electrowetting display device of claim 5, wherein each of the auxiliary electrode portions comprises a plurality of auxiliary electrode layers stacked between the corresponding main electrode portion and the hydrophobic layer, and adjacent to the auxiliary electrode layer of the hydrophobic layer The area is smaller than the area of the auxiliary electrode layer adjacent to the main electrode portion. The electrowetting display device of claim 1, further comprising: a light source for emitting a light; and a light guide plate disposed under the first substrate for guiding the light emitted by the light source to the light source The first substrate. The electrowetting display device of claim 7, wherein the light comprises a visible light line. The electrowetting display device of claim 8, wherein the polar liquid comprises a light transmissive liquid, and the non-polar liquid comprises an opaque liquid. The electrowetting display device of claim 9, wherein in a dark state display mode, no voltage difference exists between the first electrode and the second electrode, and the non-polar liquid system completely covers the active region to shield The light emitted by the light guide plate; and in a bright state display mode, an electric field exists between the first electrode and the second electrode, and the non-polar liquid is moved to the barrier by pushing of an electrowetting force One side of the wall covers only the active area, so that the visible light emitted by the light guide plate passes through the polar liquid. The electrowetting display device of claim 7, wherein the light comprises an invisible light. The electrowetting display device of claim 11, further comprising a plurality of light shielding patterns respectively disposed in the active regions, wherein each of the light shielding patterns partially covers only the corresponding active region, and the non-polar liquid comprises a wavelength conversion liquid . The electrowetting display device of claim 12, wherein the non-polar liquid has a refractive index greater than or equal to a refractive index of the hydrophobic layer, and the polar liquid has a refractive index smaller than a refractive index of the hydrophobic layer. The electrowetting display device of claim 12, wherein in a bright state display mode, no voltage difference exists between the first electrode and the second electrode, and the non-polar liquid system completely covers the active region, so that The invisible light emitted from the light guide plate enters the non-polar liquid and excites the non-polar liquid to form a visible light line; and in a dark state display mode, an electric field exists between the first electrode and the second electrode, and The non-polar liquid is pushed onto the light-shielding pattern by an electrowetting force so that the invisible light emitted from the light guide plate is blocked by the polar liquid. The electrowetting display device of claim 11, further comprising a wavelength conversion layer disposed on the second substrate, wherein the polar liquid comprises a light transmissive liquid, and the non-polar liquid comprises a light transmissive liquid. The electrowetting display device of claim 15, wherein the non-polar liquid has a refractive index greater than or equal to a refractive index of the hydrophobic layer, and the polar liquid has a refractive index smaller than a refractive index of the hydrophobic layer. The electrowetting display device of claim 15, wherein in a bright state display mode, no voltage difference exists between the first electrode and the second electrode, and the non-polar liquid system completely covers the active region, so that The invisible shot by the light guide plate Light passing through the non-polar liquid and exciting the wavelength conversion layer to form a visible light line; and in a dark state display mode, an electric field exists between the first electrode and the second electrode, and the polar liquid is subjected to an electric wetting force Pushing partially covers the active area to shield the invisible light emitted by the light guide plate.