CN101876871B - Image display system and input position judgment method - Google Patents

Abstract

The invention relates to an image display system and an input position judgment method. The touch panel further comprises a processing circuit, a first scanning circuit and a second scanning circuit. The first scanning circuit scans each capacitor bank. The second scanning circuit scans the capacitor modules of a specific capacitor bank. Therefore, the processing circuit generates an input signal related to a position on the touch panel.

Description

Image display system and input position judgment method

technical field

The present invention relates to an image display system; in particular, the image display system of the present invention includes a touch panel, and uses a two-stage scanning method to generate input signals related to positions on the touch panel.

Background technique

In the known technology, the capacitive touch panel is seldom directly arranged on the screen or the display device, especially used on the thinner display device, such as the liquid crystal screen and the like. The reason is that the known capacitive touch panel has insufficient resolution. In other words, if the contact area is too small, such as the tip of a stylus, the capacitive touch panel may not be able to distinguish.

In addition, when a capacitive touch panel is placed on a thin display device, parasitic capacitance and noise will be generated between the touch panel and the display device, and there is a problem that line-by-line (line-by-line) cannot be used due to frequency limitations. line) scanning problem.

Contents of the invention

The object of the present invention is to provide an image display system, which has a capacitive touch panel arranged on a display device, and scans the touch panel in a two-stage manner. The first stage scans a larger area on the panel. Aim, and then scan a smaller range on the panel in the latter stage.

In one embodiment, the image display system includes a capacitive touch panel, the touch panel includes a plurality of capacitor banks, and each capacitor bank includes a plurality of capacitor modules. The touch panel further includes a processing circuit, a first scanning circuit, and a second scanning circuit. The processing circuit selectively electrically connects each capacitor bank and the capacitor modules of each capacitor bank. The first scanning circuit is connected with each capacitor bank and scans each capacitor bank sequentially, so the processing circuit is sequentially connected to each capacitor bank to measure the capacitance value of each capacitor bank, and according to the measured capacitance value, A specific capacitor bank within the capacitor bank is identified. The second scanning circuit is connected with the processing circuit and the capacitor modules of the specific capacitor bank. The second scanning circuit sequentially scans the capacitor modules of the specific capacitor bank, so that the processing circuit is sequentially connected to each capacitor module of the specific capacitor bank to measure each capacitor. Capacitance values of the group modules, and at least one specific capacitor module in the specific capacitor group is identified according to the measured capacitance value, thereby generating an input signal related to a position on the touch panel. Alternatively, the specific capacitor bank is touched by the user so that the capacitance value of the specific capacitor bank measured by the processing circuit is greater than a predetermined value.

In an embodiment of the method, it includes: (a) sequentially turning on the processing circuit and each capacitor bank to measure the capacitance value of each capacitor bank; (b) according to the capacitance value measured in step (a), identifying At least one specific capacitor bank in the plurality of capacitor banks; (c) turning on each capacitor module of the processing circuit and the specific capacitor bank in turn to measure the capacitance value of each capacitor bank module; (d) according to step (c) Identify at least one specific capacitor module by the measured capacitance value; and (e) determine an input position on the touch panel according to the position of the specific capacitor module.

Description of drawings

Fig. 1 shows a display system according to an embodiment of the present invention

Fig. 2a shows a touch panel circuit according to an embodiment of the present invention;

FIG. 2b shows characteristics of a sensing capacitor and a parasitic capacitor of a touch panel according to an embodiment of the present invention;

Fig. 2c shows a touch panel circuit according to an embodiment of the present invention; and

Fig. 2d shows a touch panel circuit according to an embodiment of the present invention.

Explanation of main component symbols

Display system 1 Electronic device 10

Display device 100 Capacitive touch panel 200

Capacitor bank 202, EA-EG

Capacitor module 2022, EA1-EG3

First scanning circuit 204 Second scanning circuit 206

Processing circuit 208 Charge and discharge circuit 2082

Noise Suppression Circuit 2084 Sense Capacitor Cs

Parasitic capacitor Cp sampling capacitor Cx

Scanning line L1-LN, S1-Sm, SWX Object to be measured TOB

Transistor switches T1-TN, T11-TNm, TX, RT1-RTN, RT11-RTNm, RTX

Detailed ways

The invention discloses a capacitive touch panel applied to a display device of an image display system. In particular, the touch panel uses more than two-stage scanning methods to determine the user's input position on the touch panel. In order to make the description of the present invention more detailed and complete, reference may be made to the following description together with FIG. 1 to FIG. 2d.

Referring to FIG. 1, FIG. 1 shows a display system 1 according to an embodiment of the present invention, the display system includes an electronic device 10 having a display device 100 (such as a liquid crystal display device or an OLED display device), especially a capacitive touch The control panel 200 is installed on the display device 100. The display device 100 also includes a power supply (not shown) for the operation of the touch panel 200, and the user can observe the information provided by the display device 100 through the capacitive touch panel 200. image.

In this embodiment, the electronic device 10 with the display device 100 can be applied to mobile phones, digital cameras, personal digital assistants (PDAs), notebook computers, desktop computers, televisions, car displays, aviation displays, global Positioning system (GPS) or portable digital video disk (DVD) player.

FIG. 2 a shows a circuit of a capacitive touch panel 200 according to an embodiment of the present invention. In this embodiment, the capacitive touch panel 200 includes a plurality of capacitor banks 202 , a first scanning circuit 204 , a second scanning circuit 206 and a processing circuit 208 . Wherein, each capacitor bank 202 also includes a plurality of capacitor modules 2022, and each capacitor module 2022 includes a variable sensing capacitor Cs, and the electrode of the variable sensing capacitor Cs can be implemented as a transparent electrode, and its material can be Indium Tin Oxide (ITO for short). When the capacitor module 2022 is touched by a finger or a stylus, the capacitance of the sensing capacitor Cs changes. This part is well known to those skilled in the art and will not be repeated here.

However, it should be noted that there is a parasitic capacitor Cp between the electrode of the capacitor module 2022 and the common electrode PV of the display device 100 or an electrode adjacent to the capacitor module 2022, and the parasitic capacitor Cp is fabricated on the touch panel 200 and arranged on the display device 100. , where the capacitance value of the parasitic capacitor Cp is approximately fixed. FIG. 2b shows a schematic diagram of the relationship between the capacitance value change caused by the contact area of the capacitor module 2022 by the object TOB to be measured, wherein the X-axis represents the capacitance value, and the Y-axis represents the contacted area of the capacitor module 2022. As the touched area of the capacitor module 2022 increases, the capacitance of the sensing capacitor Cs increases accordingly, and the stored electricity also changes accordingly.

The processing circuit 208 includes a charging and discharging circuit 2082 . The charging and discharging circuit 2082 charges and discharges the capacitor module 2022 . It is worth mentioning that the aforementioned parasitic capacitor Cp will also affect the sensing capacitor Cs, but as shown in FIG. And change.

The charging and discharging circuit 2082 will provide a charging voltage V to charge the capacitor module 2022, and provide a fixed current I to discharge the capacitor module 2022, and the charging and discharging time of the charging and discharging circuit 2082 is a certain value. And when the processing circuit 208 is connected to the capacitor module 2022, the equivalent voltage of the capacitor module 2022 can be measured at node A, and when the capacitor module 2022 is touched by the object TOB to be measured, the change of the capacitance value of the sensing capacitor Cs Will affect the equivalent voltage of node A.

In another embodiment, the processing circuit 208 further includes a noise suppression circuit 2084, and the noise suppression circuit 2084 mainly includes a sampling capacitor Cx. It is used to store the electricity flowing out of the capacitor module 2022, and thereby measure the capacitance value or the change of the capacitance value of the capacitor module 2022. As mentioned above, the capacitor module 2022 will inevitably contain a parasitic capacitor Cp, and the parasitic capacitor Cp is formed relative to the common electrode PV of the display device 100, and when the common electrode PV has noise, it will make the capacitor module 2022 The electricity stored in the sampling capacitor Cx is affected by noise, so the capacitance value of the capacitor module 2022 cannot be accurately measured. Therefore, in this embodiment, one end of the sampling capacitor Cx is connected to the capacitor module 2022 , and the other end of the sampling capacitor Cx is connected to the common electrode PV of the display device 100 . As shown in the figure, both ends of the sampling capacitor Cx are affected by the common electrode PV and cancel each other out. Therefore, when the common electrode PV is noisy, the sampling capacitor Cx can still accurately measure the capacitance value of the capacitor module 2022 or Capacitance value changes.

FIG. 2c shows a detailed circuit of the capacitive touch panel 200 according to an embodiment of the present invention. Each capacitor bank (eg, EA) includes a plurality of capacitor modules, eg, three capacitor modules (EA1-EA3). In this embodiment, each capacitor module includes a transparent electrode with a width between 0.1 mm and 0.5 mm, and the transparent electrode can be in any shape other than the strip shape.

The touch panel 200 adopts two-stage scanning. The first stage scan is for the capacitor banks EA-EG, and the second stage is for the capacitor modules in a particular capacitor bank. It will be further explained as follows.

first stage scan

Referring to FIG. 2c, the first scanning circuit 204 provides a plurality of area scanning lines (L1-L7), which are respectively connected to capacitor banks (EA-EG), and the number of capacitor banks corresponds to the number of scanning lines of the first scanning circuit 204. The scanning signal of the first scanning circuit 204 is sequentially sent to the capacitor bank EA, the capacitor bank EB, and finally to the capacitor bank EG. When receiving the scan signal from the first scan circuit 204 , the capacitor banks EA-EG are sequentially connected to the processing circuit 208 . In this embodiment, the term that the capacitor bank is connected to the processing circuit 208 means that the capacitor modules in the capacitor bank are connected to the processing circuit 208 together. The processing circuit 208 can measure the capacitance of the capacitor bank according to the electricity stored in the entire capacitor module in the capacitor bank.

As shown in FIG. 2c, when the object to be measured TOB touches the capacitor banks EC, ED and EE, the capacitance value of the capacitor module will change, for example, greater than a predetermined value, and then be detected by the processing circuit 208 in the previously described manner. If detected, the processing circuit 208 records the capacitor banks EC, ED and EE as "specific capacitor banks" for the next stage of scanning. In another embodiment, the processing circuit 208 additionally records the previous capacitor bank (capacitor bank EB) and the latter capacitor bank (capacitor bank EF) for the next stage of scanning.

second stage scan

Corresponding to the number of capacitor modules in each capacitor bank, the second scan circuit 206 provides three block scan lines ( S1 - S3 ), which are sequentially connected to the capacitor modules ( EA1 - EG3 ) in the capacitor bank ( EA - EG ). Taking the capacitor bank EA as an example, the block scanning line S1 is connected to the capacitor module EA1, the block scanning line S2 is connected to the capacitor module EA2, and the block scanning line S3 is connected to the capacitor module EA3. -S3 is in turn connected to the capacitor modules (EB1-EG3) in the capacitor bank (EB-EG).

In the "second stage scan", the second scan circuit 206 does not scan all the capacitor modules (EA1-EG3), relatively, the second scan circuit 206 only sends a scan signal to the previous stage scan The processing circuit 208 records the capacitor modules of the particular capacitor banks EC, ED, and EE, or adds the capacitor modules of the preceding and following capacitor banks EB and EF. When the scanning signal from the second scanning circuit 206 is received, the capacitor module of the above-mentioned capacitor bank is connected to the processing circuit 208, and the processing circuit 208 can measure the capacitance according to the electric quantity stored in the capacitance module (EB1-EF3). value. As shown in FIG. 2c, when the object TOB to be measured touches the capacitor modules EC2, EC3, ED1, ED2, ED3, EE1 and EE2, its capacitance value will change, for example greater than a predetermined value, and then be detected by the processing circuit 208 Detected, the processing circuit 208 records the capacitor modules EC2, EC3, ED1, ED2, ED3, EE1 and EE2 as "specific capacitor modules", thereby determining the touched position on the touch panel 200 to generate an input Signal.

In one embodiment, the average positions of the capacitor modules EC2, EC3, ED1, ED2, ED3, EE1 and EE2 can be calculated, or two positions can be further selected from the capacitor modules EC2, EC3, ED1, ED2, ED3, EE1 and EE2. The farthest capacitor module (namely the capacitor module EC2 and the capacitor module EE2 ), and then calculate the center point O of the two capacitor modules EC2 and EE2 , thereby determine the touched position on the touch panel 200 .

It can also be understood from the above embodiments that the panel 200 can allow at least two capacitor modules to be touched or two capacitor banks to be touched. Taking FIG. 2c as an example, the capacitor bank EC has touched capacitor modules EC2 and EC3 , the capacitor bank ED has touched capacitor modules ED1-ED3, and the capacitor bank EE has touched capacitor modules EE1 and EE2. However, those familiar with this technical field should be able to understand that the above-mentioned embodiments are used for illustrative purposes only, and are not intended to limit the number of touched capacitor banks or capacitor modules in the present invention; that is, more than one capacitor module Embodiments that are touched, or that have touched capacitor modules in both capacitor banks (which may or may not be adjacent), are within the scope of the present invention.

It should be noted that, in other embodiments, the first scanning circuit 204 and the second scanning circuit 206 can be integrated into the signal/control circuit (not shown in the figure) of the display device 100, and save the cost of the touch panel 200. The number of pins (Pin) increased due to the need for area scan lines (L1-L7) and block scan lines (S1-S3), such as area scan lines (L1-L7) and block scan lines (S1-S3) The existing signal/control pins in the display device 100 can be directly used without adding additional pins to provide scanning.

In addition, referring to FIG. 2d, in this embodiment, the capacitive touch panel 200 is provided with a switching unit, including a plurality of switching switches TX, each switching switch TX is controlled by a switching scanning line SWX, and corresponds to a capacitor module, which enables a signal/control signal (such as an additional scan signal) to scan the capacitor bank arranged along the X direction (or Y direction) by switching the switch TX. This method of scanning the X direction and the Y direction separately will obtain more accurate judgment results.

The embodiment of Fig. 2d is further described below. The switching unit corresponds to the capacitor modules EA1 to ENm of the capacitor bank (EA-EN), and the capacitor modules EA1 to ENm are respectively provided with transistor switches TX and RTX. The transistor switch TX and RTX are opposite phases, for example, the transistor switch TX is an n-type transistor, and the transistor switch RTX is a p-type transistor. The transistor switches TX and RTX are related to the X direction, and are controlled by the X direction scan line SWX. In this embodiment, the capacitor banks (EA-EN) are all arranged along the X direction, so when receiving the scanning signal of the scanning line SWX in the X direction, all the switches TX in the capacitor bank (EA-EN) are turned on, And all switch RTX is off.

Taking the capacitor bank EA as an example, the first scanning circuit 204 is provided with a plurality of transistor switches T1 and RT1, and each of the transistor switches T1 and RT1 corresponds to the capacitor modules EA1-EAm in the capacitor bank EA respectively, and is controlled by the area scanning line L1. control. The second scanning circuit 206 includes a plurality of transistor switches T11-T1m and RT11-RT1m, wherein the transistor switches T11-T1m are set corresponding to the capacitor modules EA1-EAm respectively, and the transistor switches RT11-RT1m are also respectively set corresponding to the capacitor modules EA1-EAm, and The transistor switches T11 and RT11 are controlled by the block scan line S1, and the transistor switches T1m and RT1m are controlled by the block scan line Sm. In addition, the transistor switch T1 and RT1 are opposite phases, for example, the transistor switch T1 is an n-type transistor, and the transistor switch RT1 is a p-type transistor; the transistor switch T11-T1m and RT11-RT1m are opposite phases, such as the transistor switch T11-T1m is an type transistors, and the transistor switches RT11-RT1m are p-type transistors. Taking the capacitor module EA1 as an example, the transistor switches T1 and T11 are connected in series with the transistor switch TX. Therefore, when the transistor switches T1, T11, and TX are all turned on, the capacitor module EA1 is connected to the processing circuit 208, and the transistor switches RT1 and RT11 are turned on. , and RTX are connected in parallel with each other, and when only one of them is turned on, the capacitor module EA1 is grounded. Other capacitor modules can refer to the capacitor module EA1 , which are provided in the form of icons, and will not be described in detail here.

During the first stage of scanning, all switches TX and T11-TNm are turned on, and all switches RTX and RT11-RTNm are turned off. At this time, the area scanning lines L1-Ln of the first scanning circuit 204 turn on the transistor switches T1-TN in turn to conduct the processing circuit 208 and the capacitor bank (EA-EN), and the processing circuit 208 measures the capacitor bank (EA-EN). ), and in this example, the processing circuit 208 determines that the capacitance value of the capacitor bank EA is greater than a predetermined value according to the measured capacitance value or capacitance value change, so the capacitor bank EA is further selected for the next step phase scan.

The second stage scan is only for the capacitor bank EA, wherein all the switches TX and T1 of the capacitor bank EA are turned on, and all the switches RTX and RT1 are turned off. At this time, the block scanning lines S1-Sm of the second scanning circuit 206 turn on the transistor switches T11-T1m in the capacitor bank EA in turn, and conduct the processing circuit 208 and the capacitor modules EA1 to EAm, and the processing circuit 208 measures the capacitor modules EA1 to EAm. At least one of the capacitor modules EA1 to EAm is selected to generate an input signal when the capacitance of the EAm changes or the capacitance changes.

According to the above settings, the embodiment of the present invention provides a capacitive touch panel integrated on the display device, which has advantages over the resistive touch panel, for example, according to the embodiment of the present invention, the display device does not increase The thickness also solves the problem of parasitic capacitance and noise interference. In addition, through two-stage scanning, it also solves the problem of insufficient resolution of known capacitive touch panels.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention; all other equivalent changes or modifications that do not deviate from the spirit disclosed in the present invention should be included in the following within the scope of the patent application.

Claims (12)

1. an image display system, comprises a capacitance type touch-control panel, and described contact panel comprises:

A plurality of capacitor groups, each capacitor group also comprises a plurality of capacitor modules;

One treatment circuit, the optionally capacitor module of each capacitor group of electrically connect and each capacitor group;

One first sweep circuit, link with each capacitor group, scan successively each capacitor group, therefore described treatment circuit successively with each capacitor group conducting to measure the capacitance of each capacitor group, and according to measured capacitance, at least one particular comparator group in a plurality of capacitor groups described in identification; And

One second sweep circuit, link with the capacitor module of described treatment circuit and described particular comparator group, described the second sweep circuit scans the capacitor module of described particular comparator group successively, therefore described treatment circuit successively with each capacitor module conducting of described particular comparator group to measure the capacitance of each capacitor pack module, and according to measured capacitance, at least one particular comparator module in particular comparator group described in identification, to produce the input signal relevant to a position on described contact panel;

One display device, described display device comprises described contact panel and a power supply supply, wherein said display device has community electrode, described each capacitor module of common electrode electrically connect, and described treatment circuit also comprises a sampling capacitor device, described sampling capacitor device one end is each capacitor group of electrically connect and each capacitor module optionally, common electrode described in other end electrically connect.

2. system according to claim 1, wherein, the capacitance that described treatment circuit measures described particular comparator group is greater than a predetermined value.

3. system according to claim 1, wherein, described the first sweep circuit also links the capacitor module of each capacitor, and described the first sweep circuit comprises many first sweep traces;

Wherein, the capacitor module of different capacitors group links the first different sweep traces, and the capacitor module of same capacitor group links same the first sweep trace.

4. system according to claim 1, wherein, described the second sweep circuit comprises many second sweep traces, and in same capacitor group, different capacitors module links the second different sweep traces, and same the second sweep trace links the capacitor module of different capacitors group.

5. system according to claim 1, wherein, each capacitor module comprises an electrode, and corresponding each capacitor module, described the first sweep circuit comprises one first switch, and described the first switch links described electrode and described treatment circuit;

Wherein, when described the first sweep circuit scans, the first switch of the capacitor module in corresponding same capacitor group is together opened.

6. system according to claim 5, wherein, each capacitor module of corresponding described particular comparator group, described the second sweep circuit comprises a second switch, in order to link described electrode and described treatment circuit, and described second switch is connected with described the first switch;

Wherein, when described the second sweep circuit scans, the second switch of the capacitor module of corresponding described particular comparator group only has a unlatching at every turn.

7. system according to claim 6, wherein, each capacitor module of corresponding described particular comparator group, described the first sweep circuit comprises one the 3rd switch, and described the second sweep circuit also comprises one the 4th switch, described the 3rd switch and described the 4th switch in parallel, described the 3rd switch difference ground connection and the described electrode of link, described the 4th switch is ground connection and the described electrode of link respectively;

Wherein said the 3rd switch and described the first switch inverse, and described the 4th switch and described second switch are anti-phase.

8. system according to claim 7, wherein, described a plurality of capacitor groups are arranged along a predetermined direction;

Wherein, corresponding each capacitor module, described contact panel also comprises one the 5th switch, described the 5th switch links described electrode and described treatment circuit, described the 5th switch is connected with described the first switch and described second switch, the 5th switch of each capacitor module is relevant to described predetermined direction, and together opens or close;

Corresponding each capacitor module, described contact panel also comprises one the 6th switch, described the 6th switch and described the 3rd switch and described the 4th switch in parallel, described the 6th switch is ground connection and the described electrode of link respectively, and described the 6th switch and described the 5th switch inverse.

9. system according to claim 1, also comprise an electronic installation, described electronic installation comprises described display device, and wherein said electronic installation is a mobile phone, a digital camera, a personal digital assistant, a mobile computer, a desktop PC, a TV, a GPS, a vehicle display, a display, a digital frame or a Portable DVD projector for aviation.

10. an input position judging method, be applied to a capacitance type touch-control panel, described contact panel comprises a plurality of capacitor groups, each capacitor group comprises a plurality of capacitor modules, described contact panel also comprises a treatment circuit, described treatment circuit is the capacitor module of each capacitor group of electrically connect and each capacitor group optionally, and described method comprises:

(a) treatment circuit and each capacitor group described in conducting successively, to measure the capacitance of each capacitor group;

(b) capacitance measuring according to step (a), at least one particular comparator group in a plurality of capacitor groups described in identification;

(c) each capacitor module for the treatment of circuit and described particular comparator group described in conducting successively, to measure the capacitance of each capacitor pack module, capacitor module electrically connect community electrode described in each wherein, described treatment circuit comprises a sampling capacitor device, common electrode described in described sampling capacitor device electrically connect, described method also comprises optionally sampling capacitor device and each capacitor group and each capacitor module described in electrically connect, to suppress noise;

(d) capacitance measuring according to step (c), at least one particular comparator module of identification; And

(e), according to the position of described particular comparator module, judge the input position on described contact panel.

11. methods according to claim 10, wherein, in step (d), the plural particular comparator module of identification;

Wherein step (e) also comprises: according to the position of two distances particular comparator module farthest, calculate the central point of described two distances particular comparator module farthest, to judge described input position.

12. methods according to claim 10, wherein, step (b) also comprises: according to the order of step (a), one of particular comparator group front capacitor group and a rear capacitor group described in identification, and step (c) also comprises: successively treatment circuit and described particular comparator group described in conducting, described front capacitor group, with each capacitor module of described rear capacitor group.