Patent Description:
Display technology has significantly improved. Today, displays, such as organic light-emitting diode (OLED) displays, are bendable and may be folded or rolled onto itself. Many portable electronic device have incorporated these displays to create foldable or rollable devices. For example, many smartphones and tablets include foldable displays to open and close similar to a book.

Foldable and rollable devices typically include screen state detection in order to detect whether the device is open with the display being unfolded or unrolled, or closed with the display being folded or rolled. The device may, for example, turn the display on or off depending on whether the device is open or closed.

Various techniques may be used to perform screen state detection. For example, capacitive sensing, switch mechanisms, and magnetic and optical solutions are common techniques to perform screen state detection. These solutions, however, involve complex algorithms, have high power consumptions, and often suffer from noise in a surrounding environment.

For example, <CIT> discloses a capacitive coupling based proximity sensor.

<CIT> discloses a pressure sensor for use in a folding structure that includes a foldable piezoelectric film.

<CIT> discloses a slide type mobile phone that uses a capacitance sensor for detecting the open and closed condition.

Therefore, it is an aim to overcome the drawbacks of the prior art.

According to the invention, a device and a method for performing screen state detection for a bendable display are provided, as defined in the attached claims.

The screen state detection may be used in conjunction with, for example, foldable and rollable display devices. The device includes a stimulus electrode that transmits a key signal, a receiving electrode that detects electrostatic charge variation, and an electrostatic charge variation sensor that measures the variation of electrostatic charge received by the receiving electrode. The device decodes the sequence of the measured electrostatic charge variation to determine whether the key signal has been received by the receiving electrode. The device determines the bendable display is in a closed state (e.g., folded or rolled) when the key signal has been received by the receiving electrode.

In the drawings, identical reference numbers identify similar features or elements. The size and relative positions of features in the drawings are not necessarily drawn to scale.

Hereinafter, a device and method that performs screen state detection for a bendable display are described. The device and method utilize an electrostatic charge variation sensor to detect whether the display is in an open state or a closed state. The electrostatic charge variation sensor provides a low cost and low power solution for screen state detection.

<FIG> is a block diagram of a device <NUM> according to an embodiment. The device <NUM> may be any type of electronic device with a bendable display, such as a foldable or rollable mobile device, electronic reader, cellular phone, and tablet. The device <NUM> includes a display <NUM>, a processor <NUM>, an electrostatic charge variation sensor <NUM>, a stimulus electrode <NUM>, and a receiving electrode <NUM>. The device <NUM> may include an equal number of stimulus and receiving electrodes.

The display <NUM> is a bendable display that may be bent (e.g., folded or rolled) onto itself. When the display <NUM> is in an open state, the display <NUM> is unbent (e.g., unfolded or unrolled). When the display <NUM> is in a closed state, the display <NUM> is bent (e.g., folded or rolled) on to itself. The display <NUM> may be any type of flexible display, such as a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, and an electronic ink display.

The processor <NUM> is electrically coupled to the electrostatic charge variation sensor <NUM>. The processor <NUM> receives electrostatic charge variation data from the electrostatic charge variation sensor <NUM>. The electrostatic charge variation data indicates measurements by the electrostatic charge variation sensor <NUM>. As will be discussed in further detail below, the processor <NUM> decodes and validates the electrostatic charge variation data in order to determine whether the display <NUM> is in an open state or a closed state. The processor <NUM> may be any type of processor, controller, or microcontroller that is able to process data.

The electrostatic charge variation sensor <NUM> is electrically coupled also to the stimulus electrode <NUM>, and the receiving electrode <NUM>. The electrostatic charge variation sensor <NUM> may be embedded in a multi-sensor device that includes a plurality of different sensors (e.g., motion sensors, optical sensor, pressure sensors, etc.). The electrostatic charge variation sensor <NUM> measures variation of electrostatic charge (i.e., a change in electrostatic charge) on the receiving electrode <NUM>. Measurement is made in a passive mode by a high impedance stage of the electrostatic charge variation sensor <NUM>, without internal source of electric charges variation. The electrostatic charge variation sensor <NUM> provides the measured electrostatic charge variation as electrostatic charge variation data to the processor <NUM>.

The electrostatic charge variation sensor <NUM> includes a first input Q+ (a positive terminal) and a second input Q- (a negative terminal). The electrostatic charge variation sensor <NUM> measures electrostatic charge variation on the receiving electrode <NUM> via the first input Q+ and the second input Q-. For example, the electrostatic charge variation sensor <NUM> measures electrostatic charge variation as a differential between signals received by the first input Q+ and the second input Q-. It is noted that an electrostatic charge variation measurement may not be based on a single data point. Rather, the electrostatic charge variation sensor <NUM> may have a sampling rate, for example, in the range of <NUM> hertz to <NUM> hertz, and determine an electrostatic charge variation measurement based on multiple measurements. For example, a capacitor <NUM> may be electrically coupled between the first input Q+ and the second input Q-. The capacitor <NUM> may receive and stores the electrostatic charge received by the receiving electrode <NUM>. In this case, the electrostatic charge variation sensor <NUM> measures electrostatic charge stored in the capacitor <NUM>.

The electrostatic charge variation sensor <NUM> includes various electronic components (e.g., capacitors, resistors, amplifiers, etc.) to measure electrostatic charge variation. The electrostatic charge variation sensor <NUM>, for example, includes an analog-to-digital converter to convert the measured electrostatic charge variation signal to a digital value, and output electrostatic charge variation data as a digital value.

The electrostatic charge variation sensor <NUM> also generates and transmits a key signal to the stimulus electrode <NUM>. As will be discussed in further detail below, the key signal is a signal that is encoded with a key. The processor <NUM> determines that the display <NUM> is in a closed state upon determining that the key signal has been received by the receiving electrode <NUM>.

The stimulus electrode <NUM> is made of a conductive material, such as copper. The stimulus electrode <NUM> receives the key signal from the electrostatic charge variation sensor <NUM>, and transmits the key signal. The stimulus electrode <NUM> transmits the key signal repeatedly (e.g., every <NUM> to <NUM> milliseconds). The stimulus electrode <NUM> may pause transmission after every transmission of the key signal, for example for <NUM> to <NUM> milliseconds.

The geometry of the stimulus electrode <NUM> determines the directivity of the electrode. For example, the stimulus electrode <NUM> is square or rectangular in shape.

The receiving electrode <NUM> is electrically coupled to the first input Q+ and to the second input Q- of the electrostatic charge variation sensor <NUM> via the capacitor <NUM>. The receiving electrode <NUM> is made of a conductive material, such as copper. The receiving electrode <NUM> receives an electrostatic charge variation in a surrounding environment. The electrostatic charge variation may be generated from a wide variety of sources, such as motion by a person, a presence of an alternating current (AC) power line, and the key signal being transmitted by the stimulus electrode <NUM>.

When the receiving electrode <NUM> is in proximity to the stimulus electrode <NUM> (e.g., within <NUM> to <NUM> millimeters of the stimulus electrode <NUM>), the receiving electrode <NUM> receives the key signal transmitted by the stimulus electrode <NUM>. As will be discussed in further detail below, the receiving electrode <NUM> receiving the key signal indicates that the display <NUM> is in a closed state.

The geometry of the receiving electrode <NUM> determines the sensitivity of the electrode. For example, the receiving electrode <NUM> is square or rectangular in shape.

As will be discussed in further detail below, the stimulus electrode <NUM> and the receiving electrode <NUM> are positioned within a casing of the device <NUM> and directly underlie the display <NUM>. Thereby, The a stimulus electrode <NUM>, and the receiving electrode <NUM> are hidden.

In <FIG>, the electrostatic charge variation sensor <NUM> generates and transmits a key signal to the stimulus electrode <NUM>, which in turn transmits the key signal repeatedly. However, the key signal may be generated by other components within the device <NUM> as well, as shone in <FIG> disclosed herein.

Similar to the device shown in <FIG>, the device <NUM> in <FIG> includes the display <NUM>, the processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, and the receiving electrode <NUM>. However, in contrast to <FIG>, the processor <NUM> generates and transmits the key signal to the stimulus electrode <NUM> instead of the electrostatic charge variation sensor <NUM>. As such, the processor <NUM> both generates and transmits the key signal, and decodes and validates the electrostatic charge variation data. Here, the electrostatic charge variation sensor <NUM> does not need to be informed of the key used to generate the key signal.

<FIG> shows the device <NUM> in an open state. <FIG> shows the device <NUM> of <FIG> in a closed state. <FIG> show a case where the device <NUM> is a foldable device. It is beneficial to review <FIG> together.

As discussed above, the device <NUM> includes the display <NUM>, the processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, and the receiving electrode <NUM>. The processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, and the receiving electrode <NUM> are positioned within a casing or housing <NUM> of the device <NUM>. The casing <NUM> encloses internal components of the device <NUM>.

In particular, here, the device <NUM> is configured to be folded at a portion <NUM> of the display <NUM>.

The stimulus electrode <NUM> is positioned on an opposite side of the portion <NUM> with respect to the processor <NUM>, the electrostatic charge variation sensor <NUM>, and the receiving electrode <NUM>. Stated differently, the stimulus electrode <NUM> is positioned at a first end of the display <NUM>, and the processor <NUM>, the electrostatic charge variation sensor <NUM>, and the receiving electrode <NUM> are positioned at a second end, opposite to the first end, of the display <NUM>. Further, the processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, and the receiving electrode <NUM> directly underlie the display <NUM>. For example, the processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, and the receiving electrode <NUM> are on a printed circuit board positioned on a surface of the casing <NUM> that faces the display <NUM>.

The device <NUM> also includes shields 26A, 26B. The shields 26A, 26B prevent or reduce noise in a surrounding environment from interfering with signals transmitted by the stimulus electrode <NUM> and signals received by the receiving electrode <NUM>. The shields <NUM> may be grounded. In <FIG>, shields 26A, 26B are respectively aligned with the stimulus electrode <NUM> and the receiving electrode <NUM>, and are spaced from the display <NUM> by the stimulus electrode <NUM> and the receiving electrode <NUM>, but the arrangement may be different.

As shown in <FIG>, in an open state, the display <NUM> is unfolded and is flat. A first end of the display <NUM> is spaced from a second end, opposite to the first end, of the display <NUM>. The stimulus electrode <NUM> and the receiving electrode <NUM> do not face each other. The sides of the stimulus electrode <NUM> and the receiving electrode <NUM> that face the display <NUM> are facing the same direction. In the open state, the receiving electrode <NUM> is unable to receive and detect the key signal generated by the stimulus electrode <NUM>.

The display <NUM> may be folded in a direction <NUM> (<FIG>).

<FIG> shows the display <NUM> in a closed state, folded onto itself. The first end is closer to the second end in the closed state than the in the open state. The display <NUM> is bent at the portion <NUM>. The sides of the stimulus electrode <NUM> and the receiving electrode <NUM> that face the display <NUM> are facing each other, and the stimulus electrode <NUM> and the receiving electrode <NUM> are directly aligned with each other. Further, the shield 26A behind the stimulus electrode <NUM> (i.e., directly overlying the stimulus electrode <NUM> in <FIG>) is spaced from the shield 26B behind the receiving electrode <NUM> (i.e., directly underlying the receiving electrode <NUM> in <FIG>) by the stimulus electrode <NUM> and the receiving electrode <NUM>. In the closed state, the stimulus electrode <NUM> and the receiving electrode <NUM> are in close proximity to each other (e.g., within <NUM> to <NUM> millimeters of each other) such that the receiving electrode <NUM> is able to receive and detect the key signal transmitted by the stimulus electrode <NUM>.

<FIG> is the device <NUM> in an open state according to another embodiment. <FIG> shows the device <NUM> of <FIG> in a closed state. <FIG> show a case where the device <NUM> is a rollable device. It is beneficial to review <FIG> together.

Similar to the embodiment shown in <FIG>, the device <NUM> in <FIG> include the display <NUM>, the processor <NUM>, the electrostatic charge variation sensor <NUM>, the stimulus electrode <NUM>, the receiving electrode <NUM>, and shield 26A. However, in contrast to the embodiment shown in <FIG>, the display <NUM> is a rollable display that is positioned between a first casing <NUM> and a second casing <NUM>, and couples the first casing <NUM> and the second casing <NUM> to each other. The stimulus electrode <NUM> and a shield 26B are positioned within the first casing <NUM>; and the processor <NUM>, the electrostatic charge variation sensor <NUM>, the receiving electrode <NUM>, and the shield 26B are positioned in the second casing <NUM>. The sides of the stimulus electrode <NUM> and the receiving electrode <NUM> that face the display <NUM> are facing each other.

As shown in <FIG>, in an open state, the display <NUM> is unrolled and is flat. The stimulus electrode <NUM> and the receiving electrode <NUM> are spaced from each other by the display <NUM>. The stimulus electrode <NUM> and the receiving electrode <NUM> are spaced from each other by a sufficient distance such that the receiving electrode <NUM> is unable to receive and detect the key signal generated by the stimulus electrode <NUM>.

As shown in <FIG>, in a closed state, the display <NUM> is rolled on to itself in a direction <NUM>. The first casing <NUM> and the second casing <NUM> are immediately adjacent to each other (e.g., physically contact each other), and the stimulus electrode <NUM> and the receiving electrode <NUM> are directly aligned with each other. Further, the shield 26A adjacent to the stimulus electrode <NUM> (i.e., within the first casing <NUM>) is spaced from the shield 26B adjacent to the receiving electrode <NUM> (i.e., within the second casing <NUM>) by the stimulus electrode <NUM> and the receiving electrode <NUM>. The stimulus electrode <NUM> and the receiving electrode <NUM> are in close proximity to each other (e.g., within <NUM> to <NUM> millimeters of each other) such that the receiving electrode <NUM> is able to receive and detect the key signal transmitted by the stimulus electrode <NUM>.

<FIG> is a flow diagram of a possible method <NUM> for performing screen state. The method <NUM> is performed by the device <NUM>.

In block <NUM>, screen detection is initialized. For example, screen detection is performed periodically at fixed intervals. In an alternative, screen detection may be started in response to movement being detected by motion sensors (e.g., accelerometer, gyroscope, etc.) of the device <NUM>.

In block <NUM>, a key is selected. The key is a data word that includes a plurality of bits. For example, the key may be <NUM>. In the device <NUM> shown in <FIG>, the key is selected by the electrostatic charge variation sensor <NUM>. In the device <NUM> shown in <FIG>, the key is selected by the processor <NUM>.

In block <NUM>, a key signal is generated and transmitted from the stimulus electrode <NUM>. The key signal is a signal that is encoded with the key generated in block <NUM>. In the device <NUM> shown in <FIG>, the key signal is generated by the electrostatic charge variation sensor <NUM>. In the device <NUM> shown in <FIG>, the key signal is generated by the processor <NUM>.

The key signal is generated by interleaving zeroes into the key. For example, the key of <NUM> is modified to <NUM>, and <NUM> is encoded in the key signal. As a result, the key signal has twice as many bits as the key (e.g., an <NUM> bit key interleaved with zeroes will have <NUM> bits). Zeroes are interleaved into the key because the electrostatic charge variation sensor <NUM> measures electrostatic charge variation or change on the receiving electrode <NUM>. As such, in order for <NUM> bit to be detected properly by the electrostatic charge variation sensor <NUM>, the key signal should switch from a <NUM> bit to a <NUM> bit.

Each bit of the key signal is transmitted from the stimulus electrode <NUM> serially. For example, a bit of the key signal may be transmitted every <NUM> to <NUM> milliseconds. Upon transmission of the entire key signal (e.g., all the bits of <NUM>), transmission of the key signal is repeated. For example, the key signal may be transmitted every <NUM> to <NUM> milliseconds. The stimulus electrode <NUM> may pause transmission after every transmission of the key signal, for example for <NUM> to <NUM> milliseconds.

Blocks <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are performed concurrently with blocks <NUM> and <NUM>. In block <NUM>, the processor <NUM> receives electrostatic charge variation data from the electrostatic charge variation sensor <NUM>. Specifically, the receiving electrode <NUM> detects and receives electrostatic charges in a surrounding environment, the electrostatic charge variation sensor <NUM> measures electrostatic charge variations on the receiving electrode <NUM>, and the processor <NUM> receives measurements of the electrostatic charge variations by the electrostatic charge variation sensor <NUM> as the electrostatic charge variation data.

The electrostatic charge variation sensor <NUM> may measure electrostatic charge variation synchronously with transmission of a bit of the key signal by the stimulus electrode <NUM>. For example, the stimulus electrode <NUM> transmits a bit of the key signal every <NUM> milliseconds, and the electrostatic charge variation sensor <NUM> outputs an electrostatic charge variation measurement every <NUM> milliseconds (i.e., after every transmission of a bit).

As noted above, an electrostatic charge variation measurement may not be based on a single data point. Rather, the electrostatic charge variation sensor <NUM> may have a sampling rate, for example, in the range of <NUM> hertz to <NUM> hertz, and determine an electrostatic charge variation measurement based on multiple measurements. Thus, for a bit that is transmitted every <NUM> milliseconds, the electrostatic charge variation will make, for example, <NUM> to <NUM> measurements before outputting an electrostatic charge variation measurement.

In block <NUM>, the processor <NUM> decodes electrostatic charge variation data received from the electrostatic charge variation sensor <NUM>. The processor <NUM> decodes electrostatic charge variation data to extract a bit pattern of the electrostatic data. For example, the processor <NUM> determines a zero bit has been received by the receiving electrode <NUM> in a case where the electrostatic data indicates the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge variation) below a threshold value, and determines a <NUM> bit has been received by the receiving electrode <NUM> in a case where the electrostatic data indicates the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge variation) equal to or greater than the threshold value.

The processor <NUM> may collect electrostatic charge variation data over a period of time, and decode the electrostatic charge variation data after all of the bits of the key signal have been received. For example, in a case where the key signal has <NUM> bits, the processor <NUM> may collect <NUM> bits worth of electrostatic charge variation data, and decode the data after transmission of the last bit (the <NUM>th bit).

In block <NUM>, the processor <NUM> determines whether the decoded electrostatic charge variation data matches the key used to generate the key signal in block <NUM>. For example, the processor <NUM> determines whether the decoded electrostatic charge variation data has a bit pattern of <NUM>.

As discussed above with respect to <FIG> and <FIG>, the receiving electrode <NUM> will receive the key signal transmitted by the stimulus electrode <NUM> in a closed state. Thus, in a case where the device <NUM> is in a closed state, the decoded electrostatic charge variation data will match the key in block <NUM>. Accordingly, in a case where the decoded electrostatic charge variation data matches the key in block <NUM>, the method <NUM> moves to block <NUM> in which the processor <NUM> determines the device <NUM> is in a closed state.

Conversely, as discussed above with respect to <FIG> and <FIG>, the receiving electrode <NUM> will not receive the key signal transmitted by the stimulus electrode <NUM> when the device <NUM> is in an open state. Thus, in a case where the device <NUM> is in an open state, the decoded electrostatic charge variation data will not match the key in block <NUM>. Accordingly, in a case where the decoded electrostatic charge variation data does not match the key in block <NUM>, the method <NUM> moves to block <NUM> in which the processor <NUM> determines the device <NUM> is in an open state.

In some cases, the processor <NUM> is unable to determine whether the decoded electrostatic charge variation data matches the key in block <NUM>. For example, the electrostatic charge variation data may be unreadable because the electrostatic data is saturated or noisy due to, for example, a person touching the device. In this case, no decision may be made by the processor <NUM> in block <NUM>, and the method <NUM> returns to block <NUM> in which additional electrostatic charge variation data is received by the processor <NUM>. The display status (open state or closed state) of the device <NUM> does not change.

Upon determining the closed state in block <NUM> or the open state in block <NUM>, the determined state may be outputted for further processing. For example, a power state of the device <NUM> may be adjusted based on whether the device <NUM> is in the closed state or the open state.

<FIG> is a flow diagram of a method <NUM> for performing screen state detection according to another solution. In contrast to the method <NUM> shown in <FIG>, the method <NUM> determines whether the device <NUM> is in a closed state or an open state based on a number of valid signals and a number of invalid signals received by the receiving electrode <NUM>.

In block <NUM>, similar to block <NUM> in <FIG>, an N bit key is generated. As discussed above, the key is a data word that includes a plurality of bits. For example, the key may be <NUM>. In <FIG>, the key is generated by the electrostatic charge variation sensor <NUM>. In <FIG>, the key is generated by the processor <NUM>.

In block <NUM>, similar to block <NUM> in <FIG>, a 2N bit key signal is generated and transmitted from the stimulus electrode <NUM>. In the <FIG>, the key signal is generated by the electrostatic charge variation sensor <NUM>. In <FIG>, the key signal is generated by the processor <NUM>.

As discussed above, the key signal may be generated by interleaving zeroes into the key. For example, the key of <NUM> is modified to <NUM>, and <NUM> is encoded in the key signal. As a result, the key signal includes 2N bits, which is twice as many bits as the N bit key generated in block <NUM>.

Further, as discussed above, each bit of the key signal is transmitted from the stimulus electrode <NUM> serially. For example, a bit of the key signal may be transmitted every <NUM> to <NUM> milliseconds. Upon transmission of the entire key signal (e.g., all the bits of <NUM>), transmission of the key signal is repeated. For example, the key signal may be transmitted every <NUM> to <NUM> milliseconds.

In block <NUM>, the receiving electrode <NUM> detects and receives electrostatic charge in a surrounding environment, and the electrostatic charge variation sensor <NUM> measures electrostatic charge variation received on the receiving electrode <NUM>.

In block <NUM>, the processor <NUM> determines whether a transmission count is equal to 2N, which is the number of bits included in the key signal. The transmission count indicates a total number of potential or candidate bits of the key signal that have been currently transmitted by the stimulus electrode <NUM>. The transmission count is initialized at zero (i.e., the transmission count is zero when the method <NUM> is started at block <NUM>), and is incremented in block <NUM>, which will be discussed in further detail below.

In a case where the transmission count is not equal to 2N, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> receives electrostatic charge variation data from the electrostatic charge variation sensor <NUM>. The electrostatic charge variation data indicates the measurement of the electrostatic charge variation in block <NUM>. Stated differently, the electrostatic charge variation is a measurement of a potential bit of the key signal.

In block <NUM>, the processor <NUM> filters the electrostatic charge variation data to remove certain frequencies from the electrostatic charge variation data (e.g., noise, electrostatic charge variation caused by unwanted sources, such as an AC power line, etc.). The processor <NUM> may apply a low pass filter, a high pass filter, a band pass filter, or a combination thereof to the electrostatic charge variation data.

In block <NUM>, the processor <NUM> determines whether the electrostatic charge variation data is saturated. If the electrostatic charge variation data is saturated, the electrostatic charge variation on the receiving electrode <NUM> is outside of a readable range of the electrostatic charge variation sensor <NUM>. Saturation of the electrostatic data may be caused by, for example, a person touching the receiving electrode <NUM>.

For example, the processor <NUM> determines the electrostatic charge variation data is saturated in a case where the electrostatic charge variation data indicates the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge variation) in block <NUM> that is greater than a threshold value for a determined period of time. The processor <NUM> may determine the electrostatic charge variation data as unsaturated in a case where the electrostatic charge variation data indicates the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge variation) in block <NUM> that is not greater than the threshold value for the determined period of time.

In a case where the electrostatic charge variation data is saturated, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines that reception by the receiving electrode <NUM> is saturated. Consequently, the display status (open state or closed state) of the device <NUM> does not change. The method <NUM> then moves to block <NUM>.

In block <NUM>, the transmission count is reset to zero, along with a valid signal count and an invalid signal count. The valid signal count and the invalid signal count will be discussed in further detail below with respect to blocks <NUM> and <NUM>, respectively. By resetting the transmission count, the valid signal count, and the invalid signal count to zero, the processor <NUM> restarts checking reception of the key signal at a first, initial bit. The method <NUM> then returns to block <NUM> where the receiving electrode <NUM> detects and receives another electrostatic charge variation in a surrounding environment, and the electrostatic charge variation sensor <NUM> measures the electrostatic charge variation on the receiving electrode <NUM>.

Returning to block <NUM>, in a case where the electrostatic charge variation data is unsaturated, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines whether the electrostatic charge variation data is valid or invalid.

In one embodiment, the processor <NUM> determines the electrostatic charge variation data is valid in a case where the electrostatic charge variation data indicates the (<NUM>) the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge) in block <NUM> that is greater than a threshold value, and (<NUM>) the receiving electrode <NUM> received the electrostatic charge variation in block <NUM> in a determined time slot (e.g., a time slot in which the stimulus electrode <NUM> transmits a bit of the key signal).

The processor <NUM> may determine the electrostatic charge variation data is invalid in a case where the electrostatic charge variation data indicates the (<NUM>) the electrostatic charge variation sensor <NUM> measured an electrostatic charge variation (e.g., measured a voltage level of the electrostatic charge variation in block <NUM>) in block <NUM> that is not greater than the threshold value, or (<NUM>) the receiving electrode <NUM> received the electrostatic charge variation in block <NUM> outside of the determined time slot.

The threshold value in block <NUM> may be less than the threshold value used in block <NUM>.

In a case where the electrostatic charge variation data is valid, the method <NUM> moves to block <NUM>. In block <NUM>, a valid signal count is incremented. The valid signal count indicates a total number of valid electrostatic data that has been generated by the electrostatic charge variation sensor <NUM>. The valid signal count is initialized at zero (i.e., the valid signal count is zero when the method <NUM> is started at block <NUM>). The method <NUM> then moves to block <NUM>.

In block <NUM>, the transmission count, which was discussed with respect to block <NUM>, is incremented. The method <NUM> then moves back to block <NUM> to detect and receive another electrostatic charge variation in the surrounding environment.

Returning to block <NUM>, in a case where the electrostatic charge variation data is invalid, the method <NUM> moves to block <NUM>. In block <NUM>, an invalid signal count is incremented. The invalid signal count indicates a total number of invalid electrostatic data that has been generated by the electrostatic charge variation sensor <NUM>. The invalid signal count is initialized at zero (i.e., the invalid signal count is zero when the method <NUM> is started at block <NUM>). The method <NUM> then moves to block <NUM>.

As discussed above, in block <NUM>, the transmission count is incremented. The method <NUM> then moves back to block <NUM> to detect and receive another electrostatic charge variation in the surrounding environment.

Returning to block <NUM>, in a case where the transmission count is equal to 2N, the method moves to block <NUM>. When the transmission count is 2N the receiving electrode <NUM> has possibly received all of the 2N bits of the key signal. In block <NUM>, the processor <NUM> determines whether the invalid signal count is less than an invalid signal threshold.

In a case where the invalid signal count is not less than the invalid signal threshold, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines the reception signal received by the receiving electrode <NUM> is too noisy. Consequently, the display status (open state or closed state) of the device <NUM> does not change. The method <NUM> then moves to block <NUM>.

As discussed above, in block <NUM>, the transmission count, the valid signal count, and the invalid signal count are reset to zero. By resetting the transmission count, the valid signal count, and the invalid signal count to zero, the processor <NUM> restarts checking reception of the key signal at a first, initial bit. The method <NUM> then moves back to block <NUM> to detect and receive another electrostatic charge variation in the surrounding environment.

Returning to block <NUM>, in a case where the invalid signal count is less than the invalid signal threshold, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines whether the valid signal count is greater than a valid signal threshold.

In a case where the valid signal count is not greater than the valid signal threshold, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines that the device <NUM> is in an open state as discussed above. The method <NUM> then moves to block <NUM>, where the transmission count, the valid signal count, and the invalid signal count are reset to zero.

Returning to block <NUM>, in a case where the valid signal count is greater than the valid signal threshold, the method <NUM> moves to block <NUM>. In block <NUM>, the processor <NUM> determines that the device <NUM> is in a closed state as discussed above. The method <NUM> then moves to block <NUM>, where the transmission count, the valid signal count, and the invalid signal count are reset to zero.

In the discussion above, the device <NUM> includes a stimulus electrode <NUM> and a corresponding receiving electrode <NUM>. However, the device <NUM> may include any number of stimulus and receiving electrodes. For example, <FIG> shows the device <NUM> in an open state according to another embodiment disclosed herein. <FIG> shows the device <NUM> of <FIG> in a closed state. The device <NUM> shown in <FIG> is the same as the device <NUM> shown in <FIG>, except that the device <NUM> of <FIG> includes two stimulus electrodes <NUM> adjacent to each other, and two receiving electrodes <NUM> adjacent to each other. In the closed state, each of the stimulus electrodes <NUM> are aligned with a respective receiving electrode <NUM>. The stimulus electrodes <NUM> concurrently transmit key signals, and the receiving electrodes <NUM> concurrently receive electrostatic charge.

Including two stimulus electrodes <NUM> and two receiving electrodes <NUM> as shown in <FIG> allows a differential configuration for both reception and transmission. Here, a first key signal (e.g., <NUM>) is transmitted from a first stimulus electrode (e.g., leftmost stimulus electrode in <FIG>), and a second key signal that is complementary to the first key signal (e.g., <NUM>) is transmitted from a second stimulus electrode (e.g., rightmost stimulus electrode in <FIG>). In the closed state as shown in <FIG>, a first receiving electrode (e.g., leftmost receiving electrode in <FIG>) receives the first key signal from the first stimulus electrode, and a second receiving electrode (e.g., rightmost stimulus electrode in <FIG>) receives the second key signal from the second stimulus electrode. The first receiving electrode is electrically coupled to the first input Q+ (the positive terminal) of the electrostatic charge variation sensor <NUM>, and the second receiving electrode 12B is electrically coupled to the second input Q- (the negative terminal) of the electrostatic charge variation sensor <NUM>. As such, the electrostatic charge variation sensor <NUM> measures electrostatic charge variation as a differential between signals received by the first input Q+ and the second input Q-.

As the electrostatic charge variation sensor <NUM> measures the difference between the first input Q+ and the second input Q-, noise, which is common to both inputs, will be canceled or at least strongly attenuated. Further, as the first and key signals are complementary and opposite in phase at the first input Q+ and the second input Q-, the data signal will be doubled. As a result, the signal to noise ratio of the device <NUM> is greatly improved.

The various embodiments disclosed herein provide devices and methods for performing screen state detection. The screen state detection may be used in conjunction with any device having a bendable display. The device and method utilizes an electrostatic charge variation sensor to detect whether the display is in an open state or a closed state.

Claim 1:
A device, comprising:
a bendable display (<NUM>);
a first stimulus electrode (<NUM>) configured to transmit a first key signal;
a first receiving electrode (<NUM>) configured to receive an electrostatic charge variation in a surrounding environment;
an electrostatic charge variation sensor (<NUM>) configured to measure the electrostatic charge variation, and generate electrostatic charge variation data based on the measured electrostatic charge variation; and
a processor (<NUM>) configured to determine whether the bendable display is in an open state or a closed state based on the electrostatic charge variation data and the first key signal,
wherein the processor (<NUM>) is configured to determine the bendable display is in the open state in a case where the electrostatic charge variation data does not match a key included in the first key signal, and determine the bendable display is in the closed state in a case where the electrostatic charge variation data matches a key included in the first key signal,
wherein in the open state, the first stimulus electrode and first receiving electrode are spaced from each other, and in the closed state, the first stimulus electrode and first receiving electrode are in close proximity to each other such that the receiving electrode is able to receive and detect the key signal transmitted by the stimulus electrode.