1. Technical Field
The disclosure relates to an infrared touch input device for use with an information display system, more particularly, relates to an electronic device with infrared touch input function.
2. General Background
It is already known that an infrared input system comprises a circuit board having a first pair of opposed sides positioned parallel to a first axis and a second pair of opposed sides positioned parallel to a second axis, the second axis being perpendicular to the first axis, each of the second pair of sides connecting the first pair of sides, all four sides defining a generally rectangular touch input area, a linear array of light emitting devices along each side, and a light detection device positioned at each corner of the circuit board; and a controller coupled to the light emitting devices and the light detection devices, therein the controller sequentially activates each linear array and activates the light detection devices positioned at corners of the circuit board opposed to the activated array of light emitting devices. The system can discern the location of a touch within the information display area by implementing an algorithm on x, y coordinates detected by the detectors, which is complicated and time consuming.
Therefore, it is necessary to provide a electronic device with infrared touch input function to implement the functions easier.
The CPU 2 is electronically connected to the infrared input device 1 and the display unit 3. The display unit 3 may be a flat panel display having two pairs of oppositely disposed sides defining an information display area. The infrared input device 1 may include a circuit board 12 having two pairs of oppositely disposed sides defining an open area corresponding in size and shape to the information display area. The circuit board 12 includes at least one light detecting device 10 and a linear array of light emitting devices 11 (LED1-LED8).
In an exemplary embodiment, the light detecting devices 10 are infrared phototransistors, the light emitting devices 11 are organic light emitting diodes that emit light in the infrared (IR) range. The light emitting devices 11 can be positioned on one side or two adjacent sides of the circuit board 12. The light detecting device 10 is positioned at one corner of the circuit board 12 and faces the light emitting devices 11 for detecting infrared light emitted by the light emitting devices 11. For example, in the exemplary embodiment, the light detecting device 10 is positioned at the top right corner of the circuit board 12.
The CPU 2 is configured to control the display unit 3 to display a plurality of menu options corresponding to the light emitting devices 11. The number of the menu options displayed will be the same as the number of the light emitting devices 11. As shown in
Taking the control signal 000 as an example, the encoder 14 will control the LED1 to emit infrared light. If the infrared light path between the LED 1 and the light detecting device 10 is not obstructed, the light detecting device 10 will be controlled to send a low voltage to the micro-controller 13. If the infrared light path between the LED 1 and the light detecting device 10 is obstructed blocking the light emitted by the LED 1, the light detecting device 10 will be controlled to send a high voltage to the micro-controller 13. The micro-controller 13 is further configured to determine the menu option touched by the user when the high voltage is received.
In step S11, the encoder 14 controls the Ith light emitting device 11 to emit infrared light. In the exemplary embodiment, the encoder 14 controls the light emitting devices 11 to emit infrared light according to a predetermined sequence. For example, the encoder 14 controls the light emitting devices 11 one by one from LED1 to LED8. In step S12, the micro-processor 13 determines whether the infrared light is received. If yes, the procedure goes to step S13, otherwise, the procedure goes to S14. In step S13, the micro-processor 13 determines the corresponding menu option is not touched, and the procedure goes to S15. In step S14, the micro-processor 13 determines the corresponding menu option is touched by the user, and sends the high voltage to the CPU 2. The CPU 2 performs functions corresponding to the menu option being touched according to the signal, and the procedure goes to S15. In step S15, the micro-processor 13 determines whether I+1 is less than or equal to the total number of the light emitting devices 11, e.g., 8. If yes, the procedure goes to step S11, otherwise, the procedure ends.
In order to avoid misoperation, in one scan, only when the time of the infrared light that is not received by the light detecting device 10 lasts for a predetermined time, the micro-processor 13 sends the high voltage to the CPU 2 to perform the functions corresponding to the menu option. Alternatively, during one circular scan, the micro-processor 13 detects the infrared light from one light emitting device 11 is not received by the light detecting device 10, and in the next one or two successive circular scans, the micro-processor 13 detects the infrared light from the same light emitting device 11 is still not received, the micro-processor 13 sends the high voltage to the CPU 2 to perform the functions corresponding to the menu option.
Although the present disclosure has been specifically described on the basis of an exemplary embodiment thereof, the disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiments without departing from the scope and spirit of the disclosure.
Number | Date | Country | Kind |
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200810304897.1 | Oct 2008 | CN | national |
This application is related to copending applications entitled, “ELECTRONIC DEVICE WITH INFRARED TOUCH INPUT FUNCTION”, filed ______ (Atty. Docket No. US 23305); “ELECTRONIC DEVICE WITH INFRARED TOUCH INPUT FUNCTION”, filed ______ (Atty. Docket No. US23308); and “ELECTRONIC DEVICE WITH INFRARED TOUCH INPUT FUNCTION”, filed ______ (Atty. Docket No. US24653).