Patent Application
20120235018
This application claims the benefit of Taiwan Patent Application Serial No. 100109214, filed Mar. 17, 2011, the subject matter of which is incorporated herein by reference.
The present invention relates to an optical touch system and an optical touch method, and more particularly to an optical touch system and an optical touch method using retro-reflected and diffuse-reflected rays to implement an optical touch operation.
Nowadays, the demand on the touch technology is progressively increasing because it can provide a user-friendly and intuitive user-machine interface. The basic principle of the touch technology is to detect a position of a touching point within a predetermined touch-sensitive zone.
A scanning-type optical touch technology utilizes optical principles to implement the optical touch operation. Conventionally, the scanning-type optical touch technology is implemented according to the light-sheltering property of the touching object, e.g., a stylus, a finger, etc. The scanning-type optical touch technology employs an incident ray to scan the touch-sensitive zone. Once the incident ray strikes the touching object, the incident ray is sheltered by the touching object. That is, along the light path from the light source to the touching object, a shadow, opposed to the light source, is formed at the backside of the touching object. After the position of the shadow is detected by photodetectors, the position of the touching point can be calculated. However, since this technology needs to install lots of photodetectors or reflective tapes on three edges of the touch-sensitive zone, the fabricating cost is very high.
Another conventional scanning-type optical touch technology is implemented according to the reflective property of the touching object. Depending on the directions of the reflected rays corresponding to an incident ray striking an object, these reflected rays may be classified into a mirror-reflected ray, diffuse-reflected rays and a retro-reflected ray because of specular reflection, diffuse reflection and retro-reflection, respectively. The traveling direction of the retro-reflected ray is opposed to the travelling direction of the incident ray. For implementing the optical touch operation by means of retro-reflection, the incident ray sequentially scan across a range of angle of the touch-sensitive zone. When the incident ray strikes the touching object at a specific angle, a retro-reflected ray is returned back to the light source in a direction reverse to that of the incident ray. According to the scanning mode, the occurrence of the retro-reflected ray detected by the photodetector and/or the scanning angle corresponding to the occurrence of the retro-reflected ray, the position of the touching point can be calculated.
However, the optical touch operation by means of retro-reflection still has some drawbacks. For example, since the intensity of the retro-reflected ray is relatively weak, the use of only the retro-reflected ray to implement the optical touch operation usually results in a low signal-to-noise ratio and fails to accommodate the variation of the retro-reflection from different touching objects. Generally, the intensity of the retro-reflected ray is highly dependent on the shape and the outer surface of the touching object. Moreover, the intensity of the retro-reflected ray from a finger and the intensity of the retro-reflected ray from a touch pen are distinguished. In some situations, the optical touch technology by means of retro-reflection needs a specially-designed touch pen to result in effective detection. That is, the conventional optical touch technology by means of retro-reflection is not user-friendly.
For obviating the drawbacks encountered from the prior art, the present invention provides an optical touch system using retro-reflected and diffuse-reflected rays to implement an optical touch operation. When an incident ray strikes an object, the energy of the incident ray is largely or mostly diffuse-reflected. Consequently, the optical touch operation may be implemented according to the diffuse-reflected ray. Moreover, for increasing the signal-to-noise ratio, the optical touch operation may be implemented according to the diffuse-reflected ray and the retro-reflected ray.
An embodiment of the present invention provides an optical touch system. The optical touch system includes a touch-sensitive zone, a first optical touch module, a second optical touch module and a micro controller unit. The first optical touch module is arranged at a first side of the touch-sensitive zone for providing a first incident ray to the touch-sensitive zone. The second optical touch module is arranged at a second side of the touch-sensitive zone for providing a second incident ray to the touch-sensitive zone. The first incident ray and the second incident ray are alternately provided by the first optical touch module and the second optical touch module. When the first incident ray and the second incident ray strike a touching point within the touch-sensitive zone, a plurality of reflected rays are reflected by the touching object. The reflected rays are detected by the first optical touch module and the second optical touch module, so that a plurality of detecting values are outputted. The micro controller unit receives the detecting values from the first optical touch module and the second optical touch module, thereby calculating a position of the touching point within the touch-sensitive zone.
Another embodiment of the present invention provides an optical touch method for use in an optical touch system including a first optical touch module and a second optical touch module. Firstly, a first incident ray and a second incident ray are alternately provided by the first optical touch module and the second optical touch module, respectively. The light intensities of a plurality of reflected rays produced when the first incident ray and the second incident ray strike a touching object are detected, and thus a plurality of detecting values are acquired. According to the a plurality of detecting values, a position of the touching point within a touch-sensitive zone is calculated.
A further embodiment of the present invention provides an optical touch system. The optical touch system includes a touch-sensitive zone, a first optical touch module and a micro controller unit. The first optical touch module includes a first scanning unit for providing a first incident ray in a first direction, and an external detector for detecting a reflected ray corresponding to the first incident ray in a second direction, wherein the second direction is not parallel with the first direction. The micro controller unit is used for controlling the first optical touch module and receiving a detecting value from the external detector, thereby calculating a position of a touching point within a touch-sensitive zone.
A still embodiment of the present invention provides an optical touch method for use in an optical touch system including a first optical touch module and a second optical touch module. The first optical touch module includes a first scanning unit. The second optical touch module includes a second detector. The optical touch method includes steps of providing a first incident ray in a first direction by the first scanning unit, and allowing the second detector to receive a reflected ray corresponding to the first incident ray in a second direction, wherein the second direction is not parallel with the first direction.
Numerous objects, features and advantages of the present invention will be readily apparent upon a reading of the following detailed description of embodiments of the present invention when taken in conjunction with the accompanying drawings. However, the drawings employed herein are for the purpose of descriptions and should not be regarded as limiting.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
Moreover, according to a first operating signal C1 and a second operating signal C2, the micro controller unit 24 cooperates with the two optical touch modules M1a, M2a to perform a touch control operation. In addition, the detecting module 22 generates a detecting value F to the micro controller unit 24. According to the relation between the first operating signal C1, the second operating signal C2 and the detecting value F, the micro controller unit 24 calculates a position of a touching point. The information associated with the position of a touching point is transmitted to a host (not shown). The operations of the optical touch modules M1a and M2a will be illustrated as follows.
Since the configurations and functions of the optical touch module M2a are similar to those of the optical touch module M1a, only the operations of the optical touch module M1a will be illustrated as follows. The optical touch module M1a comprises a scanning unit 12a, a light source unit LD, a light collecting unit 16a and a detector PD0. The light source unit LD may further comprise an optical mechanism associated with the light source (e.g. LED). The optical mechanism includes for example the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). The light source unit LD provides an initial ray L0 to the scanning unit 12a along an optical axis Ax. Similarly, the light collecting unit 16a (i.e. a basic light collecting unit) may comprise the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). By the light collecting unit 16a, the ray propagating in a predetermined direction Dp is collected to the detector PD0 to be used as a basis of calculating the position of a touching point by the micro controller unit 24.
The scanning unit 12a comprises a mirror 14a and a servo mechanism (not shown in
At a specified time t0, the mirror 14a is rotated such that an angle between the direction D1(t0) of the incident ray Li(t0) and the optical axis Ax is a1(t0). Meanwhile, the direction D1(t0) of the incident ray Li(t0) is the same as the predetermined direction Dp of the ray directed to the light collecting unit 16a. Under this circumstance, the incident ray Li(t0) can be detected by the detector PD0. Once the incident ray Li(t0) is received by the detector PD0, it means that the incident ray in the predetermined direction Dp has been scanned. Consequently, the detecting result of the detector PD0 may be used to indicate the scanning progress (e.g. the start scanning time and the final scanning time). That is, the detecting result of the detector PD0 can be used as a basis of calculating the position of a touching point by the micro controller unit 24.
Please refer to
At the time spot t2, the incident ray Li(t2) just strikes a touching object PT, and thus a reflected ray Ld(t2) is reflected by the touching object PT. The reflected ray Ld(t2) will be received by corresponding detectors PDe of the detecting module 22. The detecting results of these detectors PDe are added, and thus the detecting value F outputted from the detecting module 22 is a local peak value. Obviously, the reflected ray Ld(t2) is one kind of diffuse-reflected ray. Since the diffuse-reflected ray is widespread, a portion of the diffuse-reflected ray can be received by the detecting module 22. As the fraction of the diffuse-reflected ray received by the detecting module 22 increases, the magnitude of the detecting value F increases. That is, during the optical touch operation is implemented, a time difference dt between the time spots t0 and t2 may be acquired according to the time spots between the extreme value and the local peak value of the detecting value F. According to the time difference dt and the scanning mode (i.e. the change profile of the direction of the incident ray with time), the micro controller unit can calculate the angle a between the incident ray Li(t2) and the edge 28 of the touch-sensitive zone 26.
At the time spot t3, the incident ray Li(t3) does not strike a touching object PT, and thus the incident ray Li(t3) is not reflected by the touching object PT. Meanwhile, the detecting value F is restored to the low value. After the scanning action from the direction Dp (at the time spot t0) to a vertical edge of the touch-sensitive zone 26 in the clockwise direction (through the times spots t1˜t3) is performed, the scanning action from the vertical edge to the direction Dp in a counter-clockwise direction will be performed. Moreover, the scanning action in the clockwise direction and the scanning action in the counter-clockwise direction are cyclically performed to continuously scan the touch-sensitive zone 26.
Similarly, the optical touch module M2a and the optical touch module M1a alternately provide the incident ray. That is, when one of the optical touch modules M1a and M2a provides the incident ray, the other does not provide the incident ray. For example, the optical touch module M2a sequentially provides the incident rays Li(t1′), Li(t2′) and Li(t3′) at the time spots t1′, t2′ and t3′. The time spots t1′, t2′ and t3′ are not necessarily equal to the time spots t1, t2 and t3. At the time spot t2′, the incident ray Li(t2′) just strikes the touching object PT, and thus a reflected ray Ld(t2′) is reflected by the touching point PT. Meanwhile, the detecting value F outputted from the detecting module 22 is a local peak value. By the approach of calculating the angle a, the micro controller unit may calculate the angle a′ between the incident ray Li(t2′) and the edge 28 of the touch-sensitive zone 26. According to the angles a and a′ and the distance between the optical touch modules M1a and M2a, the micro controller unit may locate the position of the touching object PT. In this situation, since the reflected ray Ld(t2′) is also one kind of diffuse-reflected ray, a portion of the diffuse-reflected ray can be received by the detecting module 22.
In an exemplary scanning mode, according to the simple harmonic periodic change of a time sequence in a cycle T, the angle between the incident ray and the edge 28 of the touch-sensitive zone 26 is changed from the angle a_min (at the time spot t0) to the angle a_max (at the time spot (t0+T/2)) and then changed to the angle a_min (at the time spot t0+T). That is, the angle of the incident ray at an arbitrary time spot t may be expressed as the formula: a_min+(a_max−a_min)×(1−cos(2×pi×(t−t0)/T))/2, wherein pi is the ratio of a circle's circumference to its diameter, and cos(•) is a cosine function.
At the time spot t2 when the detecting value corresponding to the incident ray of the optical touch module M1a has the local peak value, the angle between the incident ray and the edge 28 of the touch-sensitive zone 26 (i.e. the angle a as shown in
Particularly, in the above formulae, the position of the origin for calculating the angle a is located at the midpoint of the mirror of the optical touch module M1a; the position of the origin for calculating the angle a is located at the midpoint of the mirror of the optical touch module M2a; and the distance between the optical touch modules M1a and M2a denotes the distance between the midpoints of the mirrors of the optical touch module M1a and the optical touch module M2a. In such way, the position of the touching point PT can be calculated by the micro controller unit.
Consequently, the line passing through the midpoints of the mirrors of the optical touch modules M1a and M2a is spaced from the touching object PT by a distance equal to L×tan(a)×tan(a′)/(tan(a)+tan(a′)), wherein L is the distance between the optical touch modules M1a and M2a, and tan(•) is a tangent function.
In a case that there is an offset between the edge 28 of the touch-sensitive zone 26 and the line passing through the midpoints of the mirrors of the optical touch modules M1a and M2a, the offset may be calculated and compensated by the micro controller unit. In such way, the position of the touching object PT within the touch-sensitive zone 26 can be precisely calculated by the micro controller unit.
The above-mentioned formulae are obtained when the edge 28 of the touch-sensitive zone 26 is parallel with the line passing through the midpoints of the mirrors of the optical touch modules M1a and M2a. However, if the edge 28 of the touch-sensitive zone 26 is not parallel with the line passing through the midpoints of the mirrors of the optical touch modules M1a and M2a, the non-parallel condition may be calculated and compensated by the micro controller unit. In such way, the position of the touching object PT within the touch-sensitive zone 26 can be precisely calculated by the micro controller unit.
Please refer to
Moreover, in the basic optical touch structure 10a of
Since the configurations and functions of the optical touch module M2b are similar to those of the optical touch module M1b, only the operations of the optical touch module M1b will be illustrated as follows. The optical touch module M1b comprises a scanning unit 12b, a light source unit LD, two light collecting units 16b, 18b and two detectors PD0, PD1. The light source unit LD may further comprise an optical mechanism associated with the light source (e.g. LED). The optical mechanism includes for example the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). The light source unit LD provides an initial ray L0 to the scanning unit 12b along an optical axis Ax. Similarly, the light collecting unit 16b (i.e. a basic light collecting unit) may comprise the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). By the light collecting unit 16b, the ray propagating in a predetermined direction Dp is collected to the detector PD0 to be used as a basis of calculating the position of a touching point by the micro controller unit.
The scanning unit 12b comprises a mirror 14b and a servo mechanism (not shown in
When the incident ray Li(t) propagating in the direction D1(t) strikes the touching object PT, a reflected ray Ld(t) is reflected by the touching object PT. By the light collecting unit 18b, the reflected ray Ld(t) propagating in the direction D1d(t) is collected to the detector PD1 in order to implement the optical touch operation. The light collecting unit 18b may comprise the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism) in order to collect the a great portion of the reflected ray Ld(t) propagating in the direction D1d(t). An example of the detector PD1 is a photodetector for detecting the intensity of the reflected ray that is collected by the light collecting unit 18b, thereby acquiring the detecting value F.
Like the basic optical touch structure 10a of
In a case that the optical touch module M1b does not provide the incident ray, the optical touch module M2b is responsible for providing the incident ray. For example, the optical touch module M2b sequentially provides the incident rays Li(t1′), Li(t2′) and Li(t3′) at the time spots t1′, t2′ and t3′. At the time spot t2′ when the incident ray Li(t2′) just strikes the touching point PT, a reflected ray Ld(t2′) reflected by the touching point PT will be detected by the optical touch module M2b. According to the detecting values of the optical touch modules M1b and M2b and the scanning mode, the angle between the incident ray Li(t2) and the edge 28 and the angle between the incident ray Li(t2′) and the edge 28 will be calculated. According to the angles and the distance between the optical touch modules M1b and M2b, the position of the touching point PT can be realized. Consequently, the optical touch purpose is achieved.
From the above discussions in
The optical touch module M1c comprises a scanning unit 12c, a light source unit LDc, two light collecting units 16c, 18c and two detectors PD0, PD1. The light source unit LDc may further comprise an optical mechanism associated with the light source (e.g. LED). The optical mechanism includes for example the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). The light source unit LDc provides an initial ray L0 to the scanning unit 12c along an optical axis Ax. Similarly, the light collecting unit 16c (i.e. a basic light collecting unit) may comprise the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism). By the light collecting unit 16c, the ray propagating in a predetermined direction Dp is collected to the detector PD0 to be used as a basis of calculating the position of a touching point by the micro controller unit.
The scanning unit 12c comprises a mirror 14c and a servo mechanism (not shown in
When the incident ray Li(t) propagating in the direction D1(t) strikes the touching object PT, a reflected ray Ld(t) is reflected by the touching object PT. By the light collecting unit 18c, the reflected ray Ld(t) propagating in the direction D1d(t) is collected to the detector PD1 in order to implement the optical touch operation. The light collecting unit 18c can collect the a great portion of the reflected ray Ld(t) propagating in the direction D1d(t). An example of the detector PD1 is a photodetector for detecting the intensity of the reflected ray that is collected by the light collecting unit 18c, thereby acquiring the detecting value F.
Moreover, some examples 181˜183 of the light collecting unit 18c are also shown in
In the above embodiments of
The scanning unit 12d comprises a mirror 14d and a servo mechanism (not shown in
When the incident ray Li(t) propagating in the direction D1(t) strikes the touching object PT, a reflected ray is reflected by the touching object PT. Consequently, a great portion of the diffuse-reflected ray Ld(t) propagating in the direction D1d(t) is received by the light collecting unit 18d and collected to the detector PD1. The light collecting unit 18d may be designed to have the same configuration as the light collecting unit 18b or 18d.
On the other hand, when the incident ray Li(t) strike the touching point PT, a retro-reflected ray Lr(t) is produced because of retro-reflection. The traveling direction of the retro-reflected ray Lr(t) is opposed to the direction D1(t). The retro-reflected ray Lr(t) is directed to the mirror 14d in the direction D1′(t). By the mirror 14d, the retro-reflected ray Lr(t) is reflected back to the light collecting unit 20d along the optical axis Ax. By the light collecting unit 20d, the retro-reflected ray Lr(t) is collected to the detector PD1. The light collecting unit 20d is disposed around the light source unit LD. The light collecting unit 16d may comprise the optical elements for collecting the ray (e.g. a collimating lens or a lens set) and/or the optical elements for changing the path of the ray (e.g. a mirror or a prism), so that the retro-reflected ray Lr(t) is collected to the detector PD1 along the optical axis Ax. In this embodiment, the light collecting unit 16d comprises a light collecting lens with a circular aperture. The initial ray L0 is permitted to pass through the circular aperture. The remaining part of the light collecting lens can collect the retro-reflected ray Lr(t) whose direction is opposed to the direction of the initial ray L0.
From the above discussions, by the light collecting units 18d and 20d, the optical touch module M1d can collect the retro-reflected ray and a great portion of the diffuse-reflected ray. Consequently, the signal-to-noise ratio of the optical touch operation will be enhanced, and a precise optical touch technology will be achieved.
In the basic optical touch structure 10d, the incident ray is alternately provided and detected by the optical touch modules M1d and M2d. For example, the optical touch module M1d sequentially provides the incident rays Li(t1), Li(t2) and Li(t3) at the time spots t1, t2 and t3. At the time spot t2 when the incident ray Li(t2) just strikes the touching object PT, the diffuse-reflected ray Ld(t2) and the retro-reflected ray Lr(t2) reflected by the touching object PT will be detected by the optical touch module M1d. Meanwhile, the detecting value F is a local peak value. Whereas, since the incident rays Li(t1) and Li(t3) provided at the time spots t1 and t3 are not reflected by the touching object PT, the detecting value F is maintained at a low value. Since the retro-reflected ray and a great portion of the diffuse-reflected ray are collected by the optical touch module Mid, the local peak value of the detecting value F become more noticeable. Consequently, the signal-to-noise ratio of the optical touch operation will be enhanced, and the position of the touching point PT can be located more precisely.
In a case that the optical touch module M1d does not provide the incident ray, the optical touch module M2d is responsible for providing the incident ray. For example, the optical touch module M2d sequentially provides the incident rays Li(t1′), Li(t2′) and Li(t3′) at the time spots t1′, t2′ and t3′. At the time spot t2′ when the incident ray Li(t2′) just strikes the touching point PT, a reflected ray Ld(t2′) and a retro-reflected ray Lr(t2′) reflected by the touching object PT will be detected by the optical touch module M2d. According to the detecting values of the optical touch modules M1d and M2d and the scanning mode, the angle between the incident ray Li(t2) and the edge 28 and the angle between the incident ray Li(t2′) and the edge 28 will be calculated. According to the angles and the distance between the optical touch modules M1d and M2d, the position of the touching object PT can be realized. Consequently, the optical touch purpose is achieved.
For example, the optical touch module M1d sequentially provides the incident rays Li(t1), Li(t2) and Li(t3) at the time spots t1, t2 and t3. At the time spot t2 when the incident ray Li(t2) just strikes the touching object PT, the diffuse-reflected ray Ld(t2) and the retro-reflected ray Lr(t2) reflected by the touching object PT will be detected by the optical touch module M1d. At the same time, the diffuse-reflected ray Ld(t2) is also detected by the optical touch module M2d. The detecting values obtained by the optical touch modules M1d and M2d are added, so that the detecting value F is a local peak value. Whereas, since the incident rays Li(t1) and Li(t3) provided at the time spots t1 and t3 are not reflected by the touching object PT, the detecting value F is maintained at a low value. Since the retro-reflected ray and the diffuse-reflected ray are simultaneously collected by the optical touch modules M1d and M2d, the local peak value of the detecting value F become more noticeable. Consequently, the signal-to-noise ratio of the optical touch operation will be enhanced, and the position of the touching object PT can be located more precisely.
In a case that the optical touch module M1d does not provide the incident ray, the optical touch module M2d is responsible for providing the incident ray. For example, the optical touch module M2d sequentially provides the incident rays Li(t1′), Li(t2′) and Li(t3′) at the time spots t1′, t2′ and t3′. At the time spot t2′ when the incident ray Li(t2′) just strikes the touching object PT, a reflected ray Ld(t2′) and a retro-reflected ray Lr(t2′) reflected by the touching object PT will be detected by the optical touch module M2d. At the same time, the diffuse-reflected ray Ld(t2′) is also detected by the optical touch module M1d.
Please refer to
In the embodiments of
From the above description, the optical touch system of the present invention utilizes the diffuse-reflected ray and the retro-reflected ray from the touching point to increase the detecting value. As a consequence, the signal-to-noise ratio and the detecting precision of the optical touch operation are enhanced. Moreover, in comparison with the conventional light-sheltering optical touch technology necessary to install widespread detectors along the three edges of the touch-sensitive zone, the optical touch system of the present invention has a simplified structure and low operating cost.
Moreover, the wavelengths of the rays outputted from the light sources of the present invention are not limited to the visible spectrum (e.g. 400 nm˜780 nm). Nevertheless, the wavelengths of the rays outputted from the light sources can also be applied to the invisible electromagnetic spectrum (e.g. the near infrared spectrum of about 850 nm). That is, wavelengths of the incident ray and the reflected rays mentioned above are in the visible or invisible spectrum. Moreover, the light collecting units used in the optical touch system can be used for collecting the rays in the visible or invisible spectrum.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100109214 | Mar 2011 | TW | national |
