Patent Application
20120218226
1. Technical Field
The present disclosure relates to photoelectric devices, and particularly, to a light directing element and an infrared touch screen device having the same.
2. Description of the Related Art
An infrared touch panel 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 touch panel is that there are many light emitting devices and light detection devices, thus increasing costs. A plurality of optical elements, such as mirrors, are used to reduce the numbers of the light emitting devices and light detection devices, but the uniformity and the intensity of the light reflected by the optical elements is deadened.
Therefore, there is room for improvement within the art.
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of a light directing element and an infrared touch screen device having the same. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
In this embodiment, the light directing element 14 extends along the side 101, and the infrared emitter 13 is positioned adjacent to the curved surface 140 of the light directing element 14. The infrared emitter 12 is arranged in a manner such that light paths of the infrared light beams emitted therefrom between the infrared emitter 12 and the outwardly curved surface 140 of the light directing element 14 are located outside the touch screen 100. The outwardly curved surface 140 is configured to collimate the infrared light beams emitted from the infrared emitter 12 into parallel infrared light beams. The plurality of reflective slanted surfaces 141 are aligned with the respective infrared receiver 13, configured to receive and reflect corresponding portions of the collimated parallel beams to the respective infrared receiver 13. In the embodiment, the number of reflective slanted surfaces 141 is equal to the number of the infrared receivers 13.
The reflective slanted surfaces 141 are spaced from each other and parallel to each other. In this embodiment, the light directing element 14 is a light guide. The light directing element 14 further includes a plurality of step surfaces 142, and interconnected between the plurality of reflective slanted surfaces 141.
Because the intensity of the divergent beams emitted by the infrared emitter 12 decreases gradually from the center to the periphery of the divergent beams. In the embodiment, the reflective slanted surfaces 141 are arranged in such a manner to reflect the central portion of the light beams (hereinafter “central reflective slanted surfaces 141”) having the smallest size. So that the sizes of the other reflective slanted surfaces 141 at the opposite sides increases gradually from the size of the central reflective slanted surfaces 141. As a result, each infrared receiver 13 receives substantially the same intensity of light beams, thereby allowing the touch screen 11 to have substantially the same touch sensitivity.
In a second embodiment, because of principle of the reversibility of the light path, the infrared receivers 13 arranged at the side 102 are replaced by the same number of infrared emitters 12. The infrared emitter 12 arranged at the side 101 is replaced by an infrared receiver 13.
Referring to
In a fourth embodiment, because of principle of the reversibility of the light path, the infrared receivers 13 arranged at the side 102 are replaced by the same number of infrared emitters 12, and the infrared emitters 12 arranged at the side 101 are replaced by an infrared receivers 13.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110047864.5 | Feb 2011 | CN | national |
