WO2005083669A1

WO2005083669A1 - Adjusting brightness of a lcd display using a backlight key of a remote control

Info

Publication number: WO2005083669A1
Application number: PCT/US2004/002140
Authority: WO
Inventors: Valerie Sacrez Liebhold
Original assignee: Thomson Licensing S.A.
Priority date: 2004-01-26
Filing date: 2004-01-26
Publication date: 2005-09-09

Abstract

A remote controller (100) includes a display (120), a backlight, and a backlight key (131), in which the backlight key (131) is used to operate the display (120) and to adjust the brightness of the display (120). The remote control (100) also includes a controller and a memory for storing a plurality of predefined levels. When the controller receives a first signal indicating that the backlight key (131) has been activated, the controller activates the backlight if not being activated, and adjusts the brightness of the display (120) to the next predefined level in response to an occurrence of an event related to operation of the backlight key (131). For example, the event is that the backlight key (131) is activated by being held down and for more than a predetermined time interval.

Description

ADJUSTING BRIGHTNESS OF A LCD DISPLAY USING A BACKLIGHT KEY OF A REMOTE CONTROL

Technical Field of Invention This invention relates to the field of remote control and, more particularly, to a remote control having a display, a backlight, and a backlight key, in which the backlight key is used for both operating the backlight and adjusting the brightness of the display. Background of the Invention Remote controls are used to control electronic devices such as televisions, video cassette recorders, digital versatile disc players, stereos, digital recorders, cable boxes, and camcorders. Most remote controls are wireless, allowing a user to control the desired electronic device from almost anywhere in a room without having to be in physical contact with the electronic device. Recently, some remote controls are provided with a liquid crystal display (LCD) for displaying control information and/or for serving as a graphical user interface. The LCD display normally requires its brightness adjusted according to the light condition of the room where the remote control is used. As such, a remote control with a LCD display normally includes at least a key for adjusting the brightness of the LCD display. This additional key, however, reduces space that may be used for new control functions to control the ever-increasing capabilities, functionalities, and complexity of the electronic devices to be controlled. Thus, there is a need for not dedicating a key to adjust the brightness of a LCD display or any display that requires brightness adjustment in a remote control. Summary of the Invention It is common for a remote control to have a backlight key for activating a backlight in order to illuminates keys on the remote control. According to the principles ofthe invention, the backlight key is also used to adjust the brightness of a display on the remote control. The display may be but not limited to a LCD display. The remote control also includes a controller for activating the backlight and adjusting the brightness ofthe display in response to activation ofthe backlight key. If the backlight has been activated when the backlight key is activated, the controller adjusts the brightness ofthe display. Otherwise, if the backlight has not been activated when the backlight key is activated, the controller activates the backlight, and adjusts the brightness of the display upon occurrence of an event related to operation of the backlight key. For example, if the backlight key is activated by being pressed, the controller adjusts the brightness of the display when the backlight key is pressed again within a first predetermined time interval after the backlight key has been inactivated. The controller will continue to adjust the brightness of the display as long as the backlight key is pressed again within the first predetermined time interval after the backlight key is last inactivated. For a second example, if the backlight key is activated by being held down, the controller will adjust the brightness of the display if the holding down persists for more than a second predetermined time interval. The controller will readjust the brightness of the display if the holding down persists for an additional full interval of the second predetermined time interval. Brief Description of Drawings FIG. 1 illustrates a hand-held infrared remote control that can be used with a television apparatus according to the principles of the invention. FIG. 2 illustrates elements of the hand-held infrared remote control shown in FIG. 1. FIG. 3 illustrates a method for using the backlight key of the remote control shown in FIGs. 1 and 2 to operate the backlight and adjust the display of the remote control according to the principles of the invention. Detailed Description FIG. 1 illustrates a hand-held infrared remote control 100 adapted to function according to the present invention. The infrared remote control 100 illustratively includes channel up key 101 , channel down key 102, volume up key 103, volume down key 104, channel number keys 106-115, mute key 116, go-back key 121 , and a power key 122. The remote control 100 also includes a backlight key 131 for operating a backlight (not shown) and a LCD display 120 for displaying control information and for serving as a graphical user interface. The infrared remote control 100 further comprises an infrared signal generator (not shown) for generating infrared control signals when keys are activated. When a user presses any of the keys 101-104 and 106-121 on the remote control 100 an appropriate user infrared control signal (not shown) is generated by the infrared generator and is transmitted to a controlled device, such as a television apparatus (not shown). The activation of the backlight key 131 , however, does not cause the remote control 100 to generate an infrared control signal. Rather and according to the principles of the invention, the operation of the backlight key 131 causes the remote control 100 to activate/inactivate the backlight or to adjust the brightness of the display 120 or to do both as described below. Illustratively, the remote control 100 also includes other keys not necessary for understanding the principles of this invention: a menu key 123 for displaying a television setup menu, an information key 133 for displaying an on-screen display (OSD), keys (an up arrow key 124, a down arrow 127, a right arrow key 125, and a left arrow key 128) for navigating inside an OSD, an OK key 132 to validate a selection in an OSD, and a clear key 129 for clearing an OSD. Other keys may be added for other functions, and without dedicating a key for adjusting the brightness of the LCD display 120 may leave more room for incorporating these additional keys. Although the illustrated remote control 100 uses an infrared (IR) transmitter to communicate with a controlled electronic device, other methods such as using radio frequencies (RF) and wire connection can be used to achieve the same purpose. Similarly, although a LCD display is illustrated, other display devices such as cathode ray tube (CRT) and plasma displays can be used as well. FIG. 2 illustrates a structure of the remote control 100, which includes a controller 210, a LCD display 220, a switch array 230, a backlight 240, and a memory 250. Other elements such as an IR or RF transmitter are not shown because they are not required for understanding the principles of the invention. The memory 250 is used to store a plurality of predefined levels of brightness, and other control and operational information. The predefined levels are normally arranged in order, preferably in ascending order. One of the predefined levels is set as the default level, so that when the remote control 100 is reset or powered up, the brightness of the LCD display is adjusted to the default level. According to the principles of the invention, the default level can be changed by holding down the backlight key 131 and using the channel up and down keys to select a predefined level in the memory 250. When a user is satisfied with the brightness of the LCD 220, the user releases the backlight key 131 and, in response, the controller 210 stores the selected predefined level as the new default level. Each switch of the switch array 230 corresponds to a button in the remote control 100. Each switch normally is in an open state. When a button is activated, the corresponding switch is closed. The activation of a button includes but not limited to the following two types: pressing and holding down the button. As used herein, a button is pressed if the corresponding switch is held in a close position for less than a second. On the other hand, a button is considered to be held down, if the corresponding switch is held in a close position for one second or more. As used herein, the term "controller" represents various devices including, but not limited to, microprocessors, microcomputers, microcontrollers, and controllers. The controller 210 monitors the state of each switch and performs function in response to the state or change of the state of each switch. For example, if the backlight key 131 is pressed and if the backlight 240 has not been activated, the controller activates the backlight 240. If the backlight key 131 or other keys are not pressed or held down within a first predetermined time interval, for example, two seconds, from the release of the last press, the backlight 240 times out and the controller 210 inactivates the backlight 240. If any key is activated within the first predetermined time interval, the controller 240 resets the timeout value, i.e., the backlight 240 will not be inactivated for another full interval of the first predefined time interval. Continuing the example above, if the backlight 240 is pressed again within the first predetermined time interval, the controller 210 adjusts the brightness of the LCD display 220 to the next predefined level. This process continues so long as the backlight key 131 has been pressed within the predetermined interval from the release of the last press. When the brightness of the LCD display 220 has reached the highest predefined level, the next adjustment puts the brightness of the LCD display to the lowest predefined level. In the case that the backlight 240 has already activated when the backlight button 131 is pressed, the controller 210 resets the timeout value for the backlight 240 and immediately adjusts the brightness of the LCD display 220 to the next predefined level. Similar results can be achieved if the backlight key 131 is activated by being held down. For example, if the backlight has not being activated and the backlight key 131 is held down, the controller 210 activates the backlight 240 and if the holding down persists for more than a second predetermined time interval (preferably the same as the first predetermined time interval), the controller 241 adjusts the brightness of the LCD display 220 to the next predefined level. In fact, for each additional interval of the second predetermined interval the backlight key 131 continues to be held down, the controller 241 readjusts the brightness of the LCD display to the next predefined level. As in the case of pressing the backlight button 131 , the timeout value for the backlight 244 is counted from the time when the backlight button 131 is released. Before the timeout of the backlight 240, if the backlight button is pressed, the controller 210 adjusts the brightness of the LCD display 220 regardless of the type of last activation. Similarly, before the timeout of the backlight 240, if the backlight button is held down, the controller 210 adjusts the brightness of the LCD display 220 to the next predefined level when the duration of the backlight button 131 being held down exceeds the second predefined time interval and for each additional interval of the second predefined time interval that the backlight button 131 continues to be held down, regardless of the type of the last activation. In the above embodiments, the LCD display 220 is turned on when any key has been activated, and is turned off if no key has been activated for a third predetermined time interval, preferably the same as or more than the first predetermined time interval. FIG. 3 summarizes the illustrative operations discussed above. At step 310, the remote control 100 receives a first signal indicating that the backlight button 131 has been activated. In response to the first signal, the controller 210 at step 320 activates the backlight 240 if the backlight 240 has not being activated. Then, at step 330, the controller 210 adjusts the brightness of the LCD display 220 in response to an occurrence of an event related to operation of the backlight key 131. As discussed above, the event can be any one of the following. First, the event can be that the backlight 240 has been activated when the first signal is received and the first signal is generated by pressing the backlight key 131. Second, the event can be that the backlight 240 has not been activated when the first signal is received, a second signal is received within the first predetermined time interval after the release of the first signal, and the second signal is generated by pressing the backlight key 131. Note that the first signal is released when the backlight key 131 is inactivated (released). Lastly, the event can be that the controller 210 detects that the first signal has persisted beyond the second predetermined time interval. This is equivalent to a case discussed above, in which the backlight key 131 has been holding down for more than the second predetermined interval regardless of the type of activation of the backlight key 131. While this invention has been described with regard to a few presently preferred embodiments, those skilled in this art will readily appreciate that many alternative modes and embodiments can be carried out without departing from the spirit and scope of this invention.

Claims

1. A remote control for controlling an electronic device, comprising: a display; a backlight for backlighting the remote control; a first control key; and a controller for activating the backlight and for adjusting the brightness of the display in response to activation of the first control key.

2. The remote control of claim 1 wherein the display is a LCD display.

3. The remote control of claim 1 wherein if the backlight is still activated when the first control key is activated, the controller adjusts the brightness of the display.

4. The remote control of claim 3 wherein the first control key is activated by being pressed.

5. The remote control of claim 4 wherein the controller readjusts the brightness of the display every time the first control key is pressed again within a first predetermined time interval.

6. The remote control of claim 4 wherein the controller readjusts the brightness of the display when the first control key is held down within a first predetermined time interval after the first control key has been inactivated and for more than a second predetermined time interval.

7. The remote control of claim 6 wherein if the holding down persists for one additional interval of the second predetermined time interval, the controller readjusts the brightness of the display.

8. The remote control of claim 3 wherein the first control key is activated by being held down and for more than a second predetermined time interval.

9. The remote control of claim 8 wherein if the holding down persists for one additional interval of the second predetermined time interval, the controller readjusts the brightness of the display.

10. The remote control of claim 8 wherein the controller readjusts the brightness of the display when the backlight key is pressed within a first predetermined time interval after the first control key has been inactivated.

11. The remote control of claim 3 wherein when the brightness of the display reaches a highest level and the controller readjusts the brightness of the display, the brightness of the display is adjusted to a minimum level.

12. The remote control of claim 1 wherein if the remote control is reset, the controller adjusts the brightness of the display to a default level.

13. The remote control of claim 12 wherein the default level is a selected one of a plurality of predefined levels.

14. The remote control of claim 13 wherein the remote control further comprises a channel up key and a channel down key, and the default level is selected by using the channel up and channel down keys to select one of the predefined levels while holding down the first control key.

15. The remote control of claim 1 wherein if the backlight has not been activated when the first control key is activated, the controller activates the backlight.

16. The remote control of claim 15 wherein the controller adjusts the brightness of the display when the first control key is pressed within a first predetermined time interval after the first control key has been inactivated.

17. The remote control of claim 15 wherein the backlight key is activated by being pressed and the controller adjusts the brightness of the display if the first control key is held down within a first predetermined time interval after the first control key has been inactivated and for more than a second predetermined time interval.

18. The remote control of claim 17 wherein if the holding down persists for another interval of the second predetermined time interval, the controller readjusts the brightness of the display.

19. The remote control of claim 17 wherein the first predetermined time interval is equal to the second predetermined time interval.

20. The remote control of claim 15 wherein if the first control key is activated by being held down and for more than a second predetermined time interval, the controller adjusts the brightness of the display.

21. The remote control of claim 15 wherein when the first control key is inactivated for more then the first predetermined time interval, the controller inactivates the backlight.

22. The remote control of claim 1 wherein if the first control key is activated by being held down for more than a second predetermined time interval, the controller adjusts the brightness of the display.

23. The remote control of claim 1 further comprising at least a second key for controlling the electronic device.

24. A method for adjusting brightness of a display in a remote control having a backlight and a backlight key for operating the backlight, the method comprising the steps of: receiving by the remote control a first signal indicating that the backlight key has been activated; activating by the remote control the backlight if the backlight has not been activated; adjusting by the remote control the brightness of the display in response to an occurrence of an event related to operation of the backlight key.

25. The method of claim 24 wherein the event is that the backlight has been activated when the remote control receives the first signal, and the first signal is generated by a user pressing the backlight key.

26. The method of claim 24 wherein the event is that the backlight has not been activated when the remote control receives the first signal, the remote control receives a second signal within a first predetermined time interval after release of the first signal, and the second signal is generated by a user pressing the backlight key.

27. The method of claim 24 wherein the event is that the first signal persists for more than a second predetermined time interval.