BACKGROUND
1. Technical Field
The present disclosure relates to electronic devices, and particularly, to an electronic device with infrared touch input function.
2. Description of the Related Art
An infrared input system often includes a circuit board having a first pair of opposite sides positioned parallel to a first axis and a second pair of opposite sides positioned parallel to a second axis perpendicular to the first axis. The four sides corporately define a generally rectangular touch input area. A linear array of light emitting devices is arranged along each side. A light detection device is positioned at each corner of the circuit board. A controller is coupled to the light emitting devices and the light detection devices. The controller sequentially activates each linear array and activates the light detection devices positioned at the corners of the circuit board opposed to the activated array of light emitting devices. One problem with device using such an infrared input system is that the device is usually thicker than people otherwise expect.
Therefore, a thinner electronic device with infrared touch input function, which overcomes the problems is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is an isometric, exploded view of an electronic device with infrared touch input function in accordance with an exemplary embodiment.
FIG. 2 is an enlarged, isometric view of a light guide of the electronic device in FIG. 1.
FIG. 3 is a cross-sectional view taken along line of FIG. 2.
FIG. 4 is a cross-sectional view showing an infrared emitter and a coupling receiver of the electronic device in FIG. 1.
DETAILED DESCRIPTION
Referring to FIG. 1, an electronic device 200 with infrared touch input function includes an infrared touch module 2, a display panel 3, a front cover 4, and a rear cover 5. The display panel 3 may be a flat panel display defining an information display area. The infrared touch module 2 is mounted between the display panel 3 and the front cover 4. The infrared touch module 2 includes a linear array of infrared emitters 20, a linear array of infrared receivers 21, and a rectangular circuit board 22. In this embodiment, the circuit board 22 is divided into two pairs of oppositely disposed circuit boards 22a, 22b, 22c, and 22d, corporately defining an open area corresponding in size and shape corresponding to the information display area. The circuit boards 22a, 22b, 22c, 22d are arranged around the periphery of the display panel 3. The light emitters 20 are arranged along one side of each pair of adjacent circuit boards 22a, 22b, and the light receivers 21 are arranged along the other one side of each pair of adjacent circuit boards 22c, 22d, and face the light emitters 20. The light receivers 21 respectively receive infrared light from the array of light emitters 20. In an exemplary embodiment, the light emitters 20 are light emitting diodes that emit infrared light, and the light receivers 21 are light phototransistors. The liner array of infrared emitters 20 and receivers 21 are vertically mounted on the circuit boards 22a, 22b, 22c, 22d.
The infrared touch module 2 further includes a plurality of light guides 23, each light guide is mounted on each infrared emitter 20 and each infrared receiver 21, and the light guide 23 on each infrared emitter 20 is operable to guide the light emitted from the infrared emitter 20 to the corresponding infrared receiver 21 via the light guide 23 mounted thereon. Each light guide 23 is transparent.
Referring to FIG. 2, an isometric view of a light guide of the electronic device is illustrated. The light guide 23 includes a base 230 and a guiding portion 233 extending outwardly from the base 230. The bases 230 are vertically mounted on the circuit boards 22a, 22b, 22c, 22d and each respectively correspond to one of the infrared emitters 20 or one of the infrared receivers 21. In an exemplary embodiment, each of the bases 230 includes a pair of supporting legs 231, a space 232 is defined between the two supporting legs 231. The space 232 is used to receive one of the infrared emitters 20 or one of the infrared receivers 21. A plurality of fixing holes 220 are formed in the circuit boards 22, corresponding to the supporting legs 231. Ends of the two supporting legs 231 are fitted into the fixing holes 220, which fix the base 230 on the circuit boards 22a, 22b, 22c, 22d.
Referring also to FIG. 3, the guiding portion 233 of each light guide 23 locates above the corresponding infrared emitter 20 or the corresponding infrared receiver 21. The free end of a guiding portion 233 located above an infrared emitter 20 faces a free end of a guiding portion 233 located above a corresponding infrared receiver 21. The guiding portion 233 located above an infrared emitter 20 guides light beams from the infrared emitter 20 to the corresponding infrared receiver 21. The guiding portion 233 located above an infrared receiver 21 is used to guide light beams received from the corresponding infrared emitter 20 to the infrared receiver 21. Each guiding portion 233 includes a reflective surface 234 used to reflect light from an infrared emitter 20 to a corresponding infrared receiver 21. In an exemplary embodiment, the angle between the reflective surface 234 and the display panel 3 is about 45 degrees.
Referring to FIG. 4, during operation, the light beam from an infrared emitter 20 firstly projects into a light guide 23 located above the infrared emitter 20, and then is reflected by the reflective surface 234 of the light guide 23. The light beam is further transmitted into another light guide 23 located above a coupling infrared receiver 21, and further reflected by the reflective surface 234 of the another light guide 23 to the coupling infrared receiver 21. However, if an object touches the information display area and blocks the light beam, the infrared receiver 21 will not receive the light beam, the infrared receiver 21 feeds back signals to a controller (not shown) and the controller determines the position of the object according to the signal fed back by the infrared receiver 21. Therefore, the infrared emitters 20 and infrared receivers 21 vertically mounted on the circuit board 22 enables an infrared touch function. The thickness between the light guides 23 and the circuit boards 22 can be made thin to realize a very thin electronic device.
It is understood that the present disclosure may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the disclosure is not to be limited to the details given herein.
Patent Application
20110298752
