Patent Application
20100245264
1. Field of Invention
The present disclosure relates to a touch panel. More particularly, the present disclosure relates to a touch panel including optical detection means.
2. Description of Related Art
“Touch panel” is a device that can detect the presence and location of a touch within the detection region. Various types of touch panel, such as a resistive touch panel, a capacitive touch panel, and an optical touch panel, have been developed for such purpose.
One embodiment of the present invention relates to a touch panel including optical detecting means.
According to one embodiment of the present invention, an optical detection apparatus includes a first and second scanning devices, a first and second detectors, and a processing unit. The first and second scanning devices are respectively positioned to scan a detection region with a first and second light beams, in which incident angles of the first and second light beams respectively vary with time and the wavelength of the first light beam is different from the wavelength of the second light beam. The first and second detectors are respectively positioned to detect a first and second time signals upon which the first and second light beams are respectively reflected by a touch within the detection region. The processing unit is operative to determine a location of the touch within the detection region by the first and second time signals and the incident angles of the first and second light beams by way of triangulation.
According to another embodiment of the present invention, an optical detection method includes the following steps of:
(1) scanning a detection region respectively with a first and second light beams, in which incident angles of the first and second light beams respectively vary with time, and the wavelength of the first light beam is different from the wavelength of the second light beam;
(2) detecting a first and second time signals upon which the first and second light beams are respectively reflected by a touch within the detection region; and
(3) determining a location of the touch within the detection region by the first and second time signals, and the incident angles of the first and second light beams by way of triangulation.
Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Specifically, the first scanning device 110 includes a light source 112, a mirror 114 and a rotating actuator 116. The light source 112 is operative to generate the first light beam F. The mirror 114 is positioned to receive the first light beam F and subsequently direct the first light beam F into the detection region 500. The rotating actuator 116 is coupled to the mirror 114 for rotating the mirror 114 and thereby varying the incident angle α of the first light beam F in accordance with a driving signal provided by a controller, such as a motor controller integrated circuit (IC). That is, the incident angle α of the first light beam F can vary with time (as shown in
Similarly, the second scanning device 120 includes a light source 122, a mirror 124 and a rotating actuator 126. The light source 122 is operative to generate the second light beam S. The mirror 124 is positioned to receive the second light beam S and subsequently direct the second light beam S into the detection region 500. The rotating actuator 126 is coupled to the mirror 124 for rotating the mirror 124 and thereby varying the incident angle β of the second light beam S in accordance with a driving signal provided by a controller, such as a motor controller integrated circuit (IC). That is, the incident angle β of the second light beam S can vary with time as well.
The light sources 112/122 may be laser diodes, for example 780 nm laser diodes (such as ADL-78101-TL available from Arima Lasers Corporation), 808 nm laser diodes (such as ADL-80Y01-TL available from Arima Lasers Corporation) or 850 nm laser diodes (such as ADL-85051-TL available from Arima Lasers Corporation), such that both the first light beam F and the second light beam S are collimated light beams. In the present embodiment, the light source 112 may be a 780 nm laser diode, and the light source 122 may be an 850 nm laser diode. Accordingly, the wavelength of the first light beam F is 780 nm, and the wavelength of the second light beam S is 850 nm.
It is appreciated that many other devices may be used as the light sources 112/122, for instance, light emitting diodes may be substituted for the laser diodes as the light sources 112/122.
The first scanning device 110 and the second scanning device 120 may be spaced apart from each other by a pre-determined distance. More particularly, the mirrors 114/124 may be spaced apart from each other by a pre-determined distance, for example the length L of the top side of the detection region 500.
The first detector 130 may include a narrow band pass filter 132 and a photodetector 134. The narrow band pass filter 132 is positioned to distinguish the first light beam F from the second light beam S. The photodetector 134 is positioned to convert the first light beam F into the first time signal. As shown in
Similarly, the second detector 140 may include a narrow band pass filter 142 and a photodetector 144 as well. The narrow band pass filter 142 is positioned to distinguish the second light beam S from the first light beam F. The photodetector 144 is positioned to convert the second light beam S into the second time signal. The second time signal may also be a pulse, which indicates the time when the second light beam S is received by the photodetector 144, i.e. the time when the second light beam S is reflected by the touch 300.
The photodetectors 134/144 may be photodiodes. It is appreciated that many other devices may be used as the photodetectors 134/144, for instance, phototransistors may be substituted for the photodiodes as the photodetectors 134/144.
Since the incident angle α of the first light beam F is a function of time (as shown in
The coordinates and distance to the touch 300 can be found by calculating the length L of the top side of the detection region 500, given the incident angle α of the first light beam F at the time when the first light beam F is reflected by the touch 300 and the incident angle β of the second light beam S at the time when the second light beam S is reflected by the touch 300. Specifically, the distance D between the top side of the detection region 500 and the touch 300 may be obtained by the following Formula I:
D=U(1/tan α+1/tan β) Formula I
Thereafter, the distance LR between the right side of the detection region 500 and the touch 300 may be obtained by the following Formula II:
LR=D cot β Formula II
Therefore, the location of the touch 300 may be described as (LR,D) by the Cartesian coordinate system.
In use, the optical detection apparatus 100 may be integrated into a display panel 200 (as shown in
As shown in
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.
