TWI432834B - Touch panel and touch display device - Google Patents

Description

Touch panel and touch display device

The invention relates to a touch panel and a touch display device.

With the rapid development of flat panel display technology and the decreasing manufacturing cost, flat panel display devices with low radiation, small thickness and low power consumption are increasingly favored by consumers, and thus are widely used in electronic products.

In order to meet the needs of modern people for a more convenient and more intuitive human-machine interface, various flat panel display devices with touch functions, namely touch display devices, have been gradually introduced in the market in recent years. Generally, the touch display device can be divided into an external type and an in-line type. The external touch display device is attached with a touch panel on the basis of the conventional flat display device; and the built-in touch display device directly integrates the touch panel into the display panel (such as the liquid crystal panel) by means of in-line integration. in. At present, there are many types of touch panels, including resistive, capacitive, infrared, and surface acoustic wave types.

The conventional touch display device generally adopts a two-dimensional touch technology, and the user can apply a touch action to the touch panel through a finger or a stylus to obtain an operation command. When the touch action is applied, the function module inside the touch display device can detect the plane (two-dimensional) coordinates of the position (ie, the touch position) pointed by the touch action, that is, the X coordinate and the Y coordinate. And correspondingly controlling the signal according to the plane coordinate to control the touch display device or using the electronic product of the touch display device to perform corresponding operations.

The touch display device using the two-dimensional touch technology can realize an intuitive and convenient man-machine interface, but it is mainly used in the flat display technology. With the development of three-dimensional (stereo) display technology, the touch panel and the touch display device using the two-dimensional touch technology in the prior art are difficult to meet the control needs of the three-dimensional display technology.

In view of this, it is necessary to provide a touch surface that can realize three-dimensional touch. Board and touch display device.

A touch panel includes a first electrode layer, a dielectric layer and a second electrode layer, wherein the dielectric layer is disposed between the first electrode layer and the second electrode layer, and the dielectric layer comprises a polymer dispersion Liquid crystal film.

A touch display device includes a touch panel and a detecting circuit. The touch panel includes a first electrode layer, a dielectric layer and a second electrode layer. The dielectric layer is disposed on the first electrode layer and Between the two electrode layers, the dielectric layer comprises a polymer dispersed liquid crystal material, and the detecting circuit is connected to one of the first electrode layer and the second electrode layer, and is used for detecting a three-dimensional coordinate of the touch position.

Compared with the prior art, the touch panel and the touch display device of the present invention change the dielectric layer correspondingly by the change of the dielectric constant between the first electrode layer and the second electrode layer, for example, The polymer-dispersed liquid crystal film can realize three-dimensional touch, thereby satisfying the user's touch operation requirements in the three-dimensional display technology.

Please refer to FIG. 1, which is a schematic exploded view of an embodiment of a touch panel of the present invention. The touch panel 100 includes a first substrate 11 , a first electrode layer 12 , a dielectric layer 13 , a second electrode layer 14 , and a second substrate 15 which are stacked in this order from bottom to top. The outer surface of the second substrate 15 (ie, the surface away from the second electrode layer 14) serves as a touch surface of the touch panel 100, and the user can apply touch to the touch panel 100 through the touch surface. Action to give an operation command to it.

The first substrate 11 and the second substrate 15 are both insulating substrates, wherein the second substrate 15 can be deformed by an external force, for example, when a user applies a touch action to a position of the touch surface thereof. The position pointed by the touch action will be recessed toward the first substrate 11. Specifically, the material used for the second substrate 15 may be one of the following materials: Poly Ethylene Terephthalate (PET), Polycarbonate (PC), Polymethyl methacrylate Fat (Poly Methyl Meth) Acrylate, PMMA), Poly Imide (PI), Poly Ethylene (PE). The material of the first substrate 11 can be the same as the second substrate.

Referring to FIG. 2-4, FIG. 2 and FIG. 3 are schematic diagrams showing the planar structure of the first electrode layer 12 and the second electrode layer 14, respectively, and FIG. 4 is a schematic diagram of the first electrode layer 12 and the second electrode layer 14 being merged. .

The first electrode layer 12 includes a plurality of first electrode lines 121 arranged in parallel, and the second electrode layer 14 includes a plurality of second electrode lines 141 spaced apart from each other and perpendicular to the first electrode lines 121. Specifically, in the present embodiment, the first electrode line 121 extends in the first direction (Y-axis direction), and the second electrode line 141 extends in the second direction (extending in the X-axis direction). Thereby, a plurality of overlapping regions are formed between the first electrode line 121 and the second electrode line 141. Assuming that the line widths of the first electrode line 121 and the second electrode line 141 are both w, the area S of the overlap region is approximately w2. That is, for the touch panel 100, the area of the overlapping area is a fixed value.

In the touch panel 100, each overlapping area can serve as a touch sensing point. Moreover, in each of the overlapping regions, the first electrode line 121, the second electrode line 141, and the dielectric layer 13 sandwiched therebetween form an overlapping capacitor 16. Assuming that the dielectric constant of the dielectric layer 13 is ε and its thickness is d in the overlap region, the capacitance C of the overlap capacitor 16 can be calculated by the following formula: C = ε s / 4 π kd Wherein k is a dielectric constant, and the dielectric constant ε of the dielectric layer 13 is a dielectric constant along the direction of the electric field of the overlapping capacitor 16. In the present embodiment, the dielectric constant ε of the dielectric layer 13 is Refers to the dielectric constant of the dielectric layer 13 in the vertical direction. Since the area s of the overlap capacitor 16 is a fixed value, the capacitance value C of the overlap capacitor is mainly determined by the dielectric constant ε and the thickness d of the dielectric layer 13 in the overlap region.

In the present invention, the thickness of the dielectric layer 13 changes under the action of an external force. For example, when a user applies a touch action, the thickness of the dielectric layer 13 is reduced, and the dielectric constant of the dielectric layer 13 is reduced. ε can follow Its thickness increases as it decreases. By using the material having the above characteristics, the capacitance value C of the overlap capacitor 16 can be correspondingly changed in accordance with the change in the thickness of the dielectric layer 13.

Please refer to FIG. 5 , which is a schematic structural diagram of the dielectric layer 13 . The dielectric layer 13 may be a polymer dispersed liquid crystal film. The polymer dispersed liquid crystal film mainly comprises a polymer material and a liquid crystal material, wherein the polymer material may be a material having a vertical alignment function to a Twisted Nematic (TN) liquid crystal.

Specifically, the polymer dispersed film can be obtained by first mixing a polymer prepolymer with a nematic liquid crystal material; then, polymerizing the polymer and the liquid crystal mixture during the polymerization. The polymer is separated from the liquid crystal material; and after the polymerization process is completed, the liquid crystal material is dispersed in the polymer material by droplets. The liquid crystal droplets 131 can be made into a spherical shape by controlling the process parameters of the above polymerization process, and the size of the liquid crystal droplets 131 is on the order of micrometers.

In the polymer dispersed liquid crystal film, each of the liquid crystal droplets 131 includes a plurality of liquid crystal molecules. Since the polymer material has a vertical alignment function to the liquid crystal material, the liquid crystal molecules will be arranged in a central radiation in each of the spherical liquid crystal droplets 131.

When the dielectric layer 13 is subjected to an external force (for example, a user applies a touch action to the touch panel 100), as shown in FIG. 6, the thickness of the dielectric layer 13 at the position pointed by the external force is affected by the external force. It becomes smaller, thereby forcing the liquid crystal droplets 131 at the position to be deformed (see Fig. 7), and the degree of deformation is determined by the magnitude of the external force. Thereby, the liquid crystal droplets 131 are changed from a spherical shape to an ellipsoidal shape, and since the polymer material has a vertical alignment function to the liquid crystal material, when the liquid crystal droplets 131 are changed from a spherical shape to an ellipsoidal shape, The arrangement of the liquid crystal molecules inside thereof will shift from the central radiation arrangement to the vertical parallel arrangement. In addition, since the liquid crystal molecules have the property of dielectric anisotropy, when the liquid crystal molecules inside the liquid crystal droplets 131 are arranged When the column mode is changed, the dielectric constant ε of the dielectric layer 13 also changes.

Specifically, when the dielectric layer 13 is subjected to an external force, the liquid crystal droplets 131 at which the external force is directed will change from a spherical shape to an ellipsoidal shape, which will cause the dielectric layer 13 to be vertically in the position. The dielectric constant increases, that is, the dielectric constant ε at the position increases. Further, the amount of increase in the dielectric constant ε is related to the degree of deformation of the liquid crystal droplets 131, that is, the amount of increase in the dielectric constant ε is determined by the magnitude of the external force.

According to the formula C=ε s/4 π kd, it can be seen that when the user applies a touch action to the touch panel, the thickness of the dielectric layer 13 at the corresponding touch position becomes small, corresponding to the touch position. In the case of the overlapping capacitance, the thickness d of the dielectric sandwiched between the first electrode line 121 and the second electrode line 141 is decreased, and the dielectric constant ε is increased, thereby causing the capacitance value of the overlapping capacitor 16 C increases. Moreover, the amount of increase in the capacitance value C corresponds to the amount of thickness reduction of the dielectric layer 13 at the touch position.

Based on the above structure, in the touch panel 100, the first electrode layer 12 and the second electrode layer 14 overlap each other to form a plurality of overlapping capacitors 16 , and the closer to the center point of the position pointed by the touch action, The greater the degree of deformation of the corresponding liquid crystal droplets 131, the greater the amount of change in the capacitance value C. Therefore, by detecting the overlap capacitance 16 with the largest change in the capacitance value C in the touch panel 100, the plane coordinates of the touch position pointed by the touch action, that is, the X coordinate and the Y coordinate can be obtained. On the other hand, by detecting the specific capacitance value C of the overlapping capacitance corresponding to the touch position, the thickness reduction of the dielectric layer 13 at the touch position can be calculated, that is, the touch action is calculated. Z coordinate of the touch position.

It can be seen that the touch panel 100 of the present invention has a dielectric layer 13 corresponding to a change in dielectric constant with a change in thickness between the first electrode layer 12 and the second electrode layer 14, such as polymer dispersion. The liquid crystal film can realize three-dimensional touch, thereby satisfying the user's touch operation requirements in the three-dimensional display technology.

Please refer to FIG. 8 , which is a schematic structural diagram of a circuit of an embodiment of a touch display device according to the present invention. The touch display device 10 can include the touch panel 100 of the above embodiment and a peripheral circuit for performing three-dimensional coordinate detection on the touch panel 100. For the structure of the touch panel 100, refer to the detailed description of the above embodiments, and details are not described herein again. The peripheral circuit may include a drive circuit 21, a detection circuit 22, and a control circuit 23. The driving circuit 21 is connected to the first electrode line 121 of the touch panel 100 for sequentially outputting the scanning signal to the first electrode line 121. The detecting circuit 22 is connected to the second electrode line 141 of the touch panel for detecting the output signal of the second electrode line 141, and calculating the touch position pointed by the touch action applied by the user according to the output signal. The three-dimensional coordinates. The control circuit 23 is respectively connected to the driving circuit 21 and the detecting circuit 22, and is used for controlling the scanning timing of the driving circuit 21 on the one hand, and for generating corresponding correspondence according to the three-dimensional coordinate information provided by the detecting circuit 22 on the other hand. Control signal.

In addition, in a specific embodiment, the touch display device 10 may further include a display panel connectable to the control circuit 23. The display panel can be a liquid crystal panel or other flat display panel, and can receive the control signal according to the control signal provided by the control circuit 23, and display the corresponding picture according to the control signal.

When the touch display device 10 is in operation, the control circuit 23 generates timing signals and supplies them to the driving circuit 21 and the detecting circuit 22, respectively. The driving circuit 21 generates scan signals according to the timing signals and supplies them to the first electrode lines 121 respectively. When the touch panel 100 is not touch-applied, each of the internal overlapping capacitors 16 has an initial capacitance value. Under the action of the scanning signal, the overlapping capacitor 16 outputs an inductive signal, such as a voltage signal, to the detecting circuit 22 through its corresponding second electrode line 141.

When the user applies a touch action to the touch panel 100, the dielectric layer 13 will be recessed at the position (ie, the touch position) pointed by the touch action by the external force provided by the touch action. To make the dielectric The thickness of the layer 13 is reduced at the touch position, and the dielectric constant ε is increased, so that the capacitance value of the overlap capacitor 16 corresponding to the touch position is increased. Therefore, the sensing signal outputted by the overlapping capacitor 16 to the detecting circuit 22 through the second electrode line 141 is changed, and the amount of change of the sensing signal corresponds to the overlapping capacitor 16 being affected by the touch action. The amount of increase in capacitance. The detecting circuit 22 outputs an inductive signal according to the plurality of second electrode lines 141, and combined with the timing signal provided by the control circuit 23, the amount of change of the sensing signal outputted by each touch sensing point is obtained, and the amount of the sensing signal is changed according to the sensing signal. The capacitance value change amount of the corresponding overlap capacitor 16 is calculated. Further, the detecting circuit 22 can perform the address sensing from the touch sensing point with the largest change in the capacitance value from the above calculation result, and obtain the X coordinate and the Y coordinate corresponding to the touch position. In addition, since the dielectric constant ε of the dielectric layer 13 is affected by the thickness d thereof, by looking up the correspondence table of the dielectric constant ε and the thickness d of the dielectric layer set in advance, and combining the formula C=ε s/4 π Kd, the thickness change of the dielectric layer 13 at the touch position can be calculated, thereby obtaining the Z coordinate of the touch position.

The detection circuit 22 can supply the detected three-dimensional coordinates (X, Y, Z) to the control circuit 23. The control circuit 23 can further know the specific content of the touch action applied by the user according to the three-dimensional coordinates (X, Y, Z), and output corresponding control signals to control the display panel to display the corresponding picture.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make equivalent modifications or variations in accordance with the spirit of the present invention. All should be covered by the following patent application.

100‧‧‧ touch panel

11‧‧‧First substrate

12‧‧‧First electrode layer

13‧‧‧ dielectric layer

14‧‧‧Second electrode layer

15‧‧‧second substrate

16‧‧‧Overlapped capacitor

121‧‧‧First electrode line

131‧‧‧LCD droplets

141‧‧‧Second electrode line

21‧‧‧Drive circuit

22‧‧‧Detection circuit

23‧‧‧Control circuit

1 is a schematic exploded view of an embodiment of a touch panel of the present invention.

2-4 are schematic diagrams showing the planar structure of the first electrode layer and the second electrode layer of the touch panel shown in FIG.

FIG. 5 is a schematic structural view of a dielectric layer of the touch panel shown in FIG. 1. FIG.

6 is a schematic side view showing the touch panel of FIG. 1 when a touch action is applied.

FIG. 7 is a schematic diagram showing a process of changing liquid crystal droplets of a dielectric layer when the touch panel shown in FIG. 1 is touched.

FIG. 8 is a schematic structural diagram of a circuit of an embodiment of a touch display device according to the present invention.

100‧‧‧ touch panel

11‧‧‧First substrate

12‧‧‧First electrode layer

13‧‧‧ dielectric layer

14‧‧‧Second electrode layer

15‧‧‧second substrate

Claims (8)

A touch panel includes a first electrode layer, a dielectric layer and a second electrode layer. The dielectric layer is disposed between the first electrode layer and the second electrode layer and forms a plurality of overlapping capacitors. Wherein, the dielectric layer comprises a polymer dispersed liquid crystal film, and a dielectric constant of the polymer dispersed liquid crystal film increases in a vertical direction as the thickness decreases, and the overlap of the capacitance value in the touch panel is detected to be the largest. The capacitor can obtain the X coordinate and the Y coordinate of the touch position pointed by the touch action. By detecting the capacitance value of the overlap capacitance corresponding to the touch position, the thickness of the dielectric layer at the touch position can be calculated. A small amount, and calculate the Z coordinate of the touch position pointed by the touch action. The touch panel of claim 1, wherein the polymer dispersed liquid crystal film comprises a plurality of liquid crystal droplets, the liquid crystal droplets are dispersedly disposed inside the polymer material, and the polymer material is used for the The liquid crystal molecules inside the liquid crystal droplets are vertically aligned. The touch panel of claim 1, wherein the arrangement of the liquid crystal molecules can be changed when the polymer dispersed liquid crystal film is subjected to an external force. A touch display device includes a touch panel and a detecting circuit. The touch panel includes a first electrode layer, a dielectric layer and a second electrode layer. The dielectric layer is disposed on the first electrode layer and Forming a plurality of overlapping capacitors between the second electrode layers, wherein a dielectric constant of the dielectric layer in a vertical direction increases as the thickness decreases, the dielectric layer comprises a polymer dispersed liquid crystal material, and the detecting circuit is connected to One of the first electrode layer and the second electrode layer, and the detecting circuit is configured to detect a three-dimensional coordinate of the touch position, and obtain a touch by detecting an overlapping capacitance of the largest change in the capacitance value of the touch panel. The X coordinate and the Y coordinate of the touch position pointed by the action can be calculated by detecting the capacitance value of the overlapping capacitance corresponding to the touch position, and the thickness reduction of the dielectric layer at the touch position can be calculated, and the The Z coordinate of the touch position pointed by the touch action. The touch display device of claim 4, wherein the polymer dispersed liquid crystal material comprises a plurality of liquid crystal droplets dispersed in a polymer material, and the polymer material is used for the liquid crystal The liquid crystal molecules inside the droplets are vertically aligned. The touch display device according to any one of claims 4 to 5, wherein the first electrode layer comprises a plurality of first electrode lines, and the second electrode layer comprises a plurality of second electrode lines, the first electrode A plurality of touch detection points are included between the line and the second electrode line, and the detection circuit determines the three-dimensional coordinates of the touch position according to the capacitance of the touch detection point. The touch display device of claim 6, wherein the detecting circuit determines the touch position by detecting a touch detection point whose capacitance value changes the most before and after the touch operation is applied to the touch panel. The X coordinate and the Y coordinate. The touch display device of claim 7, wherein the detecting circuit determines the specific capacitance change amount before and after the touch panel is touched by the touch detection point whose maximum change in the capacitance value is Z coordinate of the touch position.