Touch screen for mobile terminal and power saving method thereof

A touch screen of a mobile terminal and a power saving method thereof are provided. The power saving method of a touch screen for a mobile terminal includes determining whether a touch panel is contacted by controlling light emitting elements to emit light with a first scan speed and detecting whether light is received by light receiving elements; and decreasing, if the touch panel is determined not to be contacted for a predetermined time duration, a scan speed from the first scan speed to a second scan speed after lapse of the predetermined time duration. Therefore, if a contact occurs within the predetermined time duration, the contact is detected by executing the scan with the first scan speed, and if no contact is detected before lapse of the predetermined time duration, the scan speed is decreased, whereby electric current waste due to the scan can be minimized.

PRIORITY

This application claims priority to an application entitled “TOUCH SCREEN FOR MOBILE TERMINAL AND POWER SAVING METHOD THEREOF” filed in the Korean Intellectual Property Office on Sep. 12, 2006 and assigned Ser. No. 2006-87894, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a touch screen for a mobile terminal and a power saving method thereof, and in particular, to a touch screen for a mobile terminal and a power saving method thereof that can reduce electric current consumed upon scanning.

2. Description of the Related Art

Nowadays, due to the rapid development of communications technology, voice communication can be performed using a mobile terminal at most times and places. As various functions are added to the mobile terminal, a user can utilize character information, image information, MP3, or games through a screen of a display unit in the mobile terminal. The display unit of the mobile terminal is typically a touch screen enabling input through repeated touching.

Moreover, the touch screen is a display device for executing an instruction by identifying a contact position of a person's finger or material on a visible character on or a specific position on a touch panel without using a key input unit, and process using stored software.

Particularly, the touch screen periodically executes a scan in order to detect whether a material is in contact. For example, a touch screen having 17 light emitting elements and 17 light receiving elements within a touch panel performs a scan that emits and receives light at a frequency of 100 times/second. In the following description, the number of executions of emitting and receiving light per second is referred to as a scan speed.

However, in a conventional touch screen, because a scan is continuously executed with a predetermined scan speed even if no material is in contact, there is a problem that electric current is wasted.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the above problems, and an object of the present invention is to provide a touch screen for a mobile terminal and a power saving method thereof that can minimize electric current waste due to the scan by adjusting a scan speed according to whether the touch screen is contacted.

In accordance with an aspect of the present invention, a power saving method of a touch screen for a mobile terminal includes determining whether a touch panel is contacted by controlling light emitting elements to emit light with a first scan speed and detecting whether light is received by light receiving elements; and decreasing, if a touch panel is determined not to have been contacted for a predetermined time duration, a scan speed from the first scan speed to a second scan speed after lapse of the predetermined time duration.

The scan speed may be immediately decreased from the first scan speed to the second scan speed upon lapse of the predetermined time duration.

Alternatively, the scan speed may be gradually decreased from the first scan speed to the second scan speed after lapse of the predetermined time duration.

Conversely, if the touch panel is further determined not to be contacted after the scan speed attains the second scan speed, the scan speed may be sustained at the second scan speed.

If the touch panel is determined to be contacted, the scan speed may immediately be recovered to the first scan speed.

Preferably, when the quantity of the light receiving elements is 17, the quantity of the light emitting elements is 17, and the first scan speed is 100 times/second, the second scan speed is 10 times/second.

In accordance with another aspect of the present invention, a power saving method of a touch screen for a mobile terminal, includes: determining whether a touch panel is contacted by controlling light emitting elements to emit light with a first scan speed and detecting whether light is received by light receiving elements; gradually decreasing, if a touch panel is determined not to be contacted for a first predetermined time duration, a scan speed after lapse of the first predetermined time duration; determining, after lapse of the first predetermined time duration, whether the touch panel is contacted before lapse of a second predetermined time duration; and sustaining, if the touch panel is determined not to be contacted before lapse of the second predetermined time duration, a scan speed at a second scan speed after lapse of the second predetermined time duration.

The power saving method may further include recovering, if the touch panel is determined to be contacted, the scan speed immediately to the first scan speed.

In accordance with another aspect of the present invention, a touch screen for a mobile terminal includes: a base substrate; a touch panel mounted on a surface of the base substrate; a plurality of light emitting elements arranged on the base substrate around a peripheral edge of the touch panel to radiate light towards the touch panel; a plurality of light receiving elements arranged on the base substrate around the peripheral edge of the touch panel and arranged to be opposite to the light emitting elements to receive light radiated from the light emitting elements; and a controller that determines whether the touch panel is contacted by controlling the light emitting elements to emit light with a first scan speed and detecting whether light is received by the light receiving elements, and decreases, if the touch panel is determined not to be contacted for a predetermined time duration, a scan speed from the first scan speed to a second scan speed after lapse of a predetermined time duration.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

While the present invention may be embodied in many different forms, specific embodiments of the present invention are shown in drawings and are described herein in detail, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

In the following description, a conventional scan speed is a first scan speed and a scan speed in a power saving mode according to the present invention is a second scan speed. The second scan speed is slower than the first scan speed and is a speed within a range that can recognize a physical contact.

FIG. 1is a diagram illustrating a configuration of a touch screen10for a mobile terminal according to an exemplary embodiment of the present invention.

Referring toFIG. 1, the touch screen10is a touch screen that uses infrared rays and includes a base substrate11, touch panel13mounted in the base substrate11, light emitting elements15, light receiving elements17, and controller19.

The base substrate11is a wiring substrate in which a circuit wiring is formed and uses a tape wiring substrate or a printed circuit board (PCB).

The touch panel13is mounted on a surface of the base substrate11and may have a rectangular shape, although numerous other shapes are permitted.

The light emitting elements15and the light receiving elements17of the same quantity are arranged at a peripheral edge of the touch panel13. In the present embodiment, the light emitting elements15are arranged at an upper part and left part of the touch panel13and are spaced apart at predetermined intervals. The light receiving elements17are arranged at a lower part and right part of the touch panel13at a predetermined interval so as to be opposite to the light emitting elements15. As the light emitting element15, an infrared ray light emitting diode (Ir LED) is preferably used and as the light receiving element17, a photo diode preferably is used. Accordingly, light radiated from the light emitting element15to the touch panel13is received by the light receiving element17arranged in a position opposite to the light emitting element15.

The controller19controls operations of the components of the touch screen10. specifically, controller19controls an operation related to scan mode and power saving mode setting and execution. The controller19also controls the light emitting elements15to emit light with a first scan speed and detects whether light is received by the light receiving elements17, and determines whether the touch panel13is contacted. In the present embodiment, a scan direction is counterclockwise. For example, the scan is performed by emitting light from the light emitting elements15in a counterclockwise sequence, beginning from the light emitting element15positioned at the top right corner of the upper part of the touch panel13, and sequentially receiving light by the corresponding light receiving element17opposite to the light emitting element15. However, the scan may alternatively be performed clockwise.

Particularly, the controller19executes a power saving mode that decreases the scan speed from a first scan speed to a second scan speed if the touch panel13is not contacted for a predetermined time duration. If the controller19determines that the touch panel13is contacted again after lapse of the predetermined time duration, the controller19confirms that the touch panel13is contacted by immediately recovering the scan speed from the second scan speed to the first scan speed.

In operation, the controller19can execute either a first power saving mode or a second power saving mode according to a user's setting. In the first power saving mode, the controller19immediately decreases the scan speed from the first scan speed to the second scan speed after lapse of the predetermined time duration. In the second power saving mode, the controller19gradually decreases the scan speed from the first scan speed to the second scan speed during a second predetermined time duration that begins upon lapse of a first predetermined time duration. Conversely, if the touch panel13is determined not to be contacted after lapse of the second predetermined time duration, the scan speed is sustained at the second scan speed.

Therefore, the touch screen10according to an exemplary embodiment of the present invention can minimize electric current wastage due to the scan by decreasing a scan speed when contact is not detected.

FIG. 2is a flowchart illustrating a power saving method of a touch screen according to an the present invention.

As shown inFIGS. 1 and 2, the controller19of the touch screen10determines whether a user input through the touch panel13is to perform a power saving mode setting process in step S21. If an input through the touch panel13is to perform a power saving mode setting process, the power saving mode setting process is executed in step S23. If an input through the touch panel13is not to perform a power saving mode setting process, the controller19determines whether the user input is to execute the power saving mode in step S25. If the input is to execute the power saving mode, a process of selecting a type of the power saving mode is performed in step S27. The controller19determines the selected type of the power saving mode in step S28, and the first power saving mode is executed in step S31or the second power saving mode in step S33is executed according to the user's selection.

If the user input is not to execute the power saving mode at step S25, the controller19executes another function in step S29.

In the power saving method according to the present invention, the power saving mode setting process in step S23is described in detail with reference toFIGS. 1 to 3as follows.

FIG. 3is a flowchart illustrating a power saving mode setting process in the method ofFIG. 2.

The power saving mode setting process in step S23begins with selecting a power saving mode type through user input using the touch panel13in step S231. The user can select the first power saving mode or the second power saving mode, and the controller19determines whether the first or the second power saving mode is selected in step S232.

If the first power saving mode is selected in step S232, the user sets a first predetermined time duration and a second scan speed through user input using the touch panel13in step S237. If the second power saving mode is selected in step S232, the user sets the first and second predetermined time duration and the second scan speed through input using the touch panel13in step S239. It is preferable that the second scan speed is set to a speed within a range that can recognize contact using the touch panel13. For example, if the quantity of the light receiving elements17is 17, the quantity of the light emitting elements15is 17, and the first scan speed is 100 times/second, the second scan speed may be set to 10 times/second.

The first predetermined time duration is a time duration after a time point when a first contact through the touch panel13is detected. When a second contact is not detected before lapse of the first predetermined time duration, the scan speed is differently determined according to the selected power saving mode. In the second power saving mode, the user further sets a second predetermined time duration required to change from the first scan speed to the second scan speed. The reason why the first and second predetermined time durations are set is described in the following first and second power saving mode execution processes in steps S31and S33inFIG. 2.

In the power saving method according to the present invention, the first power saving mode execution process is described in detail with reference toFIGS. 1,2,4, and5.

FIG. 4is a flowchart illustrating a first power saving mode execution process in step S31in the method ofFIG. 2.FIG. 5is a graph showing the change of a scan speed by executing the first power saving mode in the process ofFIG. 4. InFIG. 5, a time point when a contact to the touch panel13is detected occurs at 0 seconds.

The controller19scans with the first scan speed (v1) after a time point (0 seconds) when contact to the touch panel13is detected in step S311, and checks whether a further contact to the touch panel13occurs in step S313. That is, the controller19controls the light emitting elements15to emit light with the first scan speed (v1) and checks whether the touch panel13is contacted by detecting whether light is received by each of the light receiving elements17.

If a further contact is detected, the controller19recognizes the contact in step S315and the process returns to steps S311, so that the time point reverts to 0 seconds and the scan speed is sustained at the first scan speed (v1). Thus if the touch pad13is contacted, at least one light receiving element17that cannot receive light radiated from the light emitting element15is detected. This is detected by the controller19and recognized as a contact.

If a contact is not detected in step S313, the controller19checks whether the first predetermined time duration (t1) has elapsed in step S317. If the first predetermined time duration (t1) has not elapsed, the process returns to step S311and the controller19continues to perform the scan with the first scan speed (v1). If the first predetermined time duration (t1) elapses without a contact being detected, the controller19decreases the scan speed from the first scan speed (v1) to the second scan speed (v2) immediately upon lapse of the first predetermined time duration (t1) in step S319.

The controller19checks whether a contact occurs while scanning with the second scan speed (v2) after lapse of the first predetermined time duration (t1) in step S321. If a contact is not detected, the process goes to step S319and the controller19sustains the scan speed at the second scan speed (v2). However, if a contact is detected at any time point (t2) after lapse of the first predetermined time duration (t1), the controller19recognizes the contact (S323) and the process returns to step S311, so that the scan speed immediately recovers from the second scan speed (v2) to the first scan speed (v1).

In the power saving method according to an exemplary embodiment of the present invention, the second power saving mode execution process is described in detail with reference toFIGS. 1,2,6, and7as follows.

FIG. 6is a flowchart illustrating a second power saving mode execution process in step S33in the method ofFIG. 2.FIG. 7is a graph showing the change of a scan speed by executing the second power saving mode ofFIG. 6.FIG. 7, a time point when a contact to the touch panel13is detected occurs at 0 seconds.

In the second power saving mode execution process ofFIG. 6, because process steps S331through S337describe a process of checking whether the first predetermined time duration (t1) has elapsed in steps S337and are performed similarly to the equivalent steps S311through S317of the first power saving mode execution process ofFIG. 4, only subsequent process steps are described.

If the first predetermined time duration (t1) elapses without a contact being detected, the controller19gradually decreases the scan speed from the first scan speed (v1) after lapse of the first predetermined time duration (t1) in step S339.

The controller19further checks whether a contact occurs after lapse of the first predetermined time duration (t1) in step S341. If a contact is detected at any time point (t2) after lapse of the first predetermined time duration (t1), the controller19recognizes the contact in step S343and the process returns to step S331, so that the scan speed immediately recovers to the first scan speed (v1).

If a contact is not detected at step S341, the controller19checks whether the second predetermined time duration (t2) has elapsed at time point t3in step S345. If the second predetermined time duration (t3) has not elapsed, the process returns to step S339and the controller19continues to gradually decrease the scan speed from the first scan speed (v1).

If the second predetermined time duration (t3) elapses without a contact being detected, the controller19scans with the second scan speed (v2) after lapse of the second predetermined time duration (t3) in step S347. The second scan speed (v2) is a scan speed at the time point when the second predetermined time duration (t3) elapses.

The controller19checks whether a contact occurs while scanning with the second scan speed (v2) after lapse of the second predetermined time duration (t3) in step S349. If a contact is not detected, the process returns to step S347and the controller19sustains the scan speed at the second scan speed (v2). However, if a contact is detected at any time point (t4) after lapse of the second predetermined time duration (t3), the controller19recognizes the contact in step S351and the process returns to step S331, so that the scan speed immediately recovers to the first scan speed (v1).

In the present embodiment, a mobile terminal having a touch screen is exemplified, however the present invention can be applied to other electronic appliances having a touch screen. Further, a rectangular touch screen is exemplified, however the present invention can be applied to a touch screen of another shape. In the second power saving mode, an example in which the scan speed uniformly decreases from the first scan speed to the second scan speed is described, however the scan speed may be decreased in the form of a downward curve or another form. An example in which the scan speed immediately recovers to the first scan speed on detecting a contact is described, however the scan speed may be recovered the first scan speed after a predetermined time duration from detecting a contact.

According to the present invention, if a contact occurs within a predetermined time duration, the contact is detected by performing a scan with a first scan speed as in the related art and, if no contact is detected during the predetermined time duration, the scan speed is decreased from the first scan speed, whereby electric current waste due to the scan can be minimized.