Optical touch device, and light source assembly and display module thereof

An optical touch device includes a sensing area, at least a light source assembly and a light sensing component. The light source assembly is disposed beside the sensing area and includes a plurality of first point light sources configured to sequentially emit a first beam into the sensing area. The light sensing component has a field of view of the entire sensing area and is configured to sense the first beams. A light source assembly and a display module used in the optical touch device are also disclosed.

TECHNICAL FIELD

The present invention relates to a touch device, and more particularly to an optical touch device, and a light source assembly and a display module thereof.

BACKGROUND

In recent years, touch device, due to having advantages of easy operation, has been widely used in many various electronic products such as a mobile phone, tablet computer, digital camera, music player, satellite navigation device and touch screen. Touch devices basically can be categorized into resistive touch devices, capacitive touch devices and optical touch devices, etc.; among which optical touch devices, due to having a better durability and a lower cost, have been getting more and more attentions.

FIG. 1is a schematic top view of a conventional optical touch device. As shown, the optical touch device100includes a plurality of point light sources110disposed in the X-axis direction, a plurality of point light sources120disposed in the Y-axis direction, a plurality of light sensing components130disposed in the X-axis direction and corresponding to the point light sources110in a one-to-one manner and a plurality of light sensing components140disposed in the Y-axis direction and corresponding to the point light sources120in a one-to-one manner. A sensing area102is defined by the point light sources110,120and the light sensing components130,140. The light sensing components130each are configured to sense beam112emitted from its corresponding point light source110; and the light sensing components140each are configured to sense beam122emitted from its corresponding point light source120.

When a user uses his/or her finger50to touch the sensing area102so as to perform a touch operation, some beams112,122respectively emitted from the corresponding point light sources110,120(for example, the point light sources110a,120a) are blocked by the finger50and accordingly some corresponding light sensing components130,140(for example, the light sensing components130a,140a) may sense relatively weak optical signals; and thus, the optical touch device100can determine the position of the finger50according to these relatively weak optical signals. However, because requiring a relatively large number of light sensing components130,140, the conventional optical touch device100has a higher cost.

SUMMARY OF EMBODIMENTS

Therefore, one object of the present invention is to provide an optical touch device having a lower cost.

Another object of the present invention is to provide a light source assembly so as to decrease the associated optical touch device's cost.

Still another object of the present invention is to provide a display module so as to decrease the associated optical touch device's cost.

The present invention provides an optical touch device, which includes a sensing area, at least a light source assembly and a light sensing component. The light source assembly is disposed beside the sensing area and includes a plurality of first point light sources configured to sequentially emit a first beam into the sensing area. The light sensing component has a field of view of the entire sensing area and is configured to sense the first beams.

In an embodiment of the present invention, the sensing area is configured to have a rectangular structure with a first side, a second side, a third side and a fourth side. The first and third sides are configured to be opposite to each other. The second and fourth sides are configured to be opposite to each other. The light source assembly is disposed beside the first side. The light sensing component is disposed in a boundary area between the third and fourth sides.

In an embodiment of the present invention, the optical touch device includes two light source assemblies. The sensing area is configured to have a rectangular structure with a first side, a second side, a third side and a fourth side. The first and third sides are configured to be opposite to each other. The second and fourth sides are configured to be opposite to each other. The light source assembly is disposed beside the first and second sides. The light sensing component is disposed in a boundary area between the third and fourth sides.

In an embodiment of the present invention, the aforementioned optical touch device further includes a display panel and a light guide plate. The display panel has a display surface and a back surface. The sensing area is defined on the display surface. The light guide plate has a light emission surface and a plurality of side surfaces. The light emission surface is opposite to the back surface. The side surfaces are connected to the light emission surface. The light source assembly is configured to be opposite to one of the side surfaces.

In an embodiment of the present invention, the light source assembly further includes a plurality of second point light sources. Each second point light source is configured to provide a second beam. The first beam is an invisible light. The second beam is a visible light.

In an embodiment of the present invention, the first point light sources include infrared light emitting diodes. The second point light sources include white light emitting diodes.

In an embodiment of the present invention, the first point light sources and the second point light sources are arranged alternatively in a same row.

In an embodiment of the present invention, the first point light sources are arranged in a first row, the second point light sources are arranged in a second row.

In an embodiment of the present invention, the first and second rows are configured to be parallel to each other.

In an embodiment of the present invention, the aforementioned optical touch device further includes at least a white light source. The white light source and the light source assembly are disposed to be opposite to two different side surfaces of the light guide plate, respectively.

In an embodiment of the present invention, the first point light sources are arranged in a spaced manner.

In an embodiment of the present invention, the aforementioned optical touch device further includes a substrate. The sensing area is defined above the substrate.

In an embodiment of the present invention, the aforementioned optical touch device further includes a light source control unit electrically connected to the first point light sources and configured to control the first point light sources to emit the first beams sequentially.

In an embodiment of the present invention, the first beam is an invisible light.

In an embodiment of the present invention, the aforementioned light source assembly further includes a carrier board; the first point light sources are disposed on the carrier board.

The present invention further provides a light source assembly of an optical touch device, which includes a plurality of first point light sources and a light source control unit. The first point light sources are disposed on a substrate of the optical touch device. The light source control unit is electrically connected to the first point light sources and configured to control the first point light sources to be switched-on or switched-off sequentially according to a predetermined time sequence.

In an embodiment of the present invention, the aforementioned light source assembly of an optical touch device further includes a plurality of second point light sources disposed on the substrate and electrically connected to the light source control unit. The first point light sources are invisible light sources. The second point light sources are visible light sources. The light source control unit is further configured to control the second point light sources to be switched-on or switched-off.

In an embodiment of the present invention, the first point light sources are invisible light sources.

In an embodiment of the present invention, the aforementioned light source assembly of an optical touch device further includes a carrier board disposed on the substrate. The first point light sources are fixed on the carrier board.

The present invention still provides a display module of an optical touch device, which includes a substrate, a light guide flat plate and a light source assembly. The light guide flat plate is disposed on the substrate. A sensing area is formed above the light guide flat plate. The light source assembly is disposed beside at least a side of the light guide flat plate and includes a plurality of first point light sources and a light source control unit. The light source control unit is electrically connected to the first point light sources and configured to control the first point light sources to be switched-on or switched-off sequentially according to a predetermined time sequence.

In an embodiment of the present invention, the aforementioned display module of an optical touch device further includes a display panel disposed on the light guide flat plate.

In an embodiment of the present invention, the aforementioned light source assembly further includes a plurality of second point light sources disposed on the substrate and electrically connected to the light source control unit. The first point light sources are invisible light sources. The second point light sources are visible light sources. The light source control unit is further configured to control the second point light sources to be switched-on or switched-off.

In an embodiment of the present invention, the first point light sources are invisible light sources.

In an embodiment of the present invention, the light source assembly further includes a carrier board disposed on the substrate. The first point light sources are fixed on the carrier board.

In summary, in the optical touch device, the light source assembly and the display module according to the present invention, because the point light sources are configured to emit beams sequentially, an object's position in the sensing area can be identified by one light sensing component. Thus, the number of the light sensing components in the present invention can decrease and consequently the optical touch device according to the present invention can have a lower cost.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 2is a schematic top view of an optical touch device in accordance with one embodiment of the present invention. As shown, the optical touch device200includes a sensing area230, a light source assembly220and a light sensing component210. The light source assembly220is disposed beside the sensing area230. The light sensing component210is configured to have a field of view (FOV) of the entire sensing area230. The light source assembly220includes a plurality of point light sources221, which are configured to sequentially emit first beams (not shown) into the sensing area230according to a predetermined time sequence; wherein these first beams can be sensed by the light sensing component210. In this embodiment, the first beam is, for example, an invisible light (for example, an infrared light), and accordingly the point light sources221each are an infrared light emitting diode.

The light sensing component210is, for example, disposed above the sensing area230and configured to sense the first beams (also referred as optical signals) emitted from the point light sources221of the light source assembly220. The light source assembly220is disposed above the sensing area230. In another embodiment, the sensing area230is disposed above a light guide plate (not shown) and the light source assembly220is disposed beside the light guide plate; wherein the first beams emitted from the light source assembly220are directed into the sensing area230through the light guide plate.

In this embodiment, the sensing area230is configured to have, for example, a rectangular structure constituted by a first side231, a second side232, a third side233and a fourth side234. The first side231and the third side233are configured to be opposite to each other; the second side232and the fourth side234are configured to be opposite to each other; and specifically the light source assembly220is disposed beside the first side231of the sensing area230. Additionally, in order to sense the first beams, the light sensing component210is disposed at a corner opposite to the first side231. For example, the light sensing component210is disposed in a boundary area between the third side233and the fourth side234.

Besides the point light sources221, the light source assembly220further includes a carrier board223and on which, with no limitation, the point light sources221are disposed. In this embodiment, these point light sources221are arranged in a spaced manner, and an interval D between each two adjacent point light sources221is designed, due to a user usually uses his/or her finger as a media to perform a touch operation, to be a little smaller than a finger width. Specifically, because generally a finger width is about 12 mm, the interval D is designed to be smaller than 12 mm (for example, 10 mm); and thus, the optical touch device200can have a higher sensing accuracy.

The optical touch device200further includes a light source control unit260. The light source control unit260is electrically connected to the point light sources221(specifically, electrically connected to each point light source221) and configured to control the switch-on and switch-off of the point light sources221and thereby controlling the point light sources221to sequentially emit the first beams into the sensing area230, according to a predetermined time sequence. In this embodiment, the light source control unit260is electrically connected to the point light sources221through the carrier board223; however, it is understood that the light source control unit260can be electrically connected to the point light sources221respectively through a plurality of signal wires in an embodiment without the carrier board223. In addition, the duration-time for each point light source221to emit first beam is, with no limitation, about 0.1 ms˜1 ms. In addition, the optical touch device200further includes a substrate240, above which the sensing area230are defined and on which the light sensing component210, the light source assembly220and the light source control unit260are disposed.

In this embodiment, because these point light sources221are configured to emit beams sequentially, accordingly when one point light source221emits beams simultaneously the rest are configured not to emit beams. Thus, by adopting one light sensing component210only, the optical touch device200can determine the position of an object (for example, a user's finger) in the sensing area230. The process of the optical touch device200sensing as well as determining an object's position in the sensing area230will be illustrated in the following with a cooperation of related figures.

FIGS. 3A, 3Bare schematic views for illustrating the process of the optical touch device200sensing and determining an object's position in the sensing area230. As shown inFIG. 3A, firstly the light source control unit260controls the point light sources221a˜221jto sequentially emit beams to scan the sensing area230so as to determine whether or not an object60(for example, a user's finger) existing in the sensing area230; wherein the position of the object60can be determined according to the scan result if the object60is detected. For example, first, the light source control unit260controls the point light source221ato emit the first beam222; and at least a portion of the first beam222accordingly will be expanded in different directions if the first beam222is blocked by the object60. Thus, according to the image of the expansion of the first light beam222captured by the light sensing component210, the position information of the object60is obtained. It is understood that the light source control unit260controls the point light sources221b˜221jto emit first beams222sequentially based on the same manner.

Please refer toFIG. 3B. As shown, the light source control unit260controls the point light source221dto emit the first beam222, the first beam222emitted from the point light source221dwill be blocked by the object60and simultaneously the light sensing component210can sense a partially-bright first beam222and also determine the position of the blocking point of the first beam222; wherein through the position of the blocking point of the first beam222, the object60is determined to be located at a line L1. Moreover, because the optical path L2, for the point light source221dto emit the first beam222, is known information, the position information of the object60(or, the intersection point of the line L1and the optical path L2) can be obtained. Thus, the optical touch device200can determine the position of the object60by adopting one light sensing component210only and consequently can have a lower cost.

It is to be noted that, the first beams222emitted from the point light sources221c,221e, which are adjacent to the point light source221d, may be also blocked partially by the object60and consequently result in inaccurate position information of the object60. Thus, in this embodiment the obtained position information can be further processed by a centroid method or a centric method. For example, the captured brightness information can be referred as weight data and introduced in the calculation of the weighted-average centre position for the obtainment of the more-accurate position of the object60. The centroid or the centric methods are apparent to those ordinarily skilled in the art; no any unnecessary detail will be given here. In addition, the optical touch device200may further include a processing unit270. The processing unit270is electrically connected to the light sensing component210and the light source control unit260and configured to calculate the position of the object60according to the position information obtained from the light sensing component210and the emitting information of the point light sources221(for example, the point light source221d). It is understood that the processing unit270can be integrated into either the light source control unit260or the light sensing component210in another embodiment, and accordingly the light source control unit260and the light sensing component210are configured to be electrically connected to each other.

In addition, the aforementioned embodiment is exemplified by configuring one point light source221to emit beams in one time-interval; however, for saving the scanning time, it is understood that two or more than two point light sources221can be configured to simultaneously emit beams in a same time-interval. In another embodiment, the emission times of two adjacent point light sources221may overlap. For example, if the point light sources221a,221band221care configured to sequentially emit beams and each is configured to have an emission time of 1 ms, the point light sources221a,221bmay have an overlapped emission time of 0.5 ms therebetween and the point light sources221b,221cmay have an overlapped emission time of 0.5 ms therebetween.

It is understood that the aforementioned emission time and beam emitting sequence can be adjusted according to a specific structure, requirements or limitations of the optical touch device200.FIG. 4is a schematic top view of an optical touch device in accordance with another embodiment of the present invention. As shown, the optical touch device300has a structure similar to that of the optical touch device200; the main difference between the two is that the optical touch device300includes two light source assemblies220, which are respectively disposed beside the first side231and the second side232of the sensing area230. The light source control unit260is electrically connected to the two light source assemblies220both so as to control the point light sources221in the two light source assemblies220to emit beams sequentially. According to this structure, the light sensing component210can obtain more position information and consequentially the optical touch device300can have a higher sensing accuracy.

FIG. 5is a schematic top view of an optical touch device in accordance with another embodiment of the present invention.FIG. 6Ais a schematic cross-sectional view of the optical touch device along a line I-I inFIG. 5. Please refer toFIGS. 5, 6Aboth. The optical touch device400is a touch screen and includes a display module401. The display module401includes a substrate240, a light guide plate420and a light source assembly220. The light guide plate420is, for example, a light guide flat plate and disposed on the substrate240. The sensing area230is, for example, formed above the light guide plate420. In addition, the display module401further includes a display panel410disposed on the light guide plate420; wherein the back surface412of the display panel410is opposite to the light emission surface424of the light guide plate420. The display panel410is a penetrating display panel (for example, a liquid crystal display (LCD)). The light source assembly220is opposite to a side surface422, the one connected to the light emission surface424of the light guide plate420, of the light guide plate420. The first beam222provided by the point light source221is configured to firstly emit into the light guide plate420through the side surface422thereof, then emit out from the light guide plate420through the light emission surface424thereof, and then emit through the display panel410. The light sensing component210is configured to sense the first beam222emitting through the display panel410. Specifically, at least a portion of the first beam222accordingly will be expanded in different directions if the first beam222is blocked by an object (not shown). Thus, according to the image of the expansion of the first light beam222captured by the light sensing component210, the position information of the object is obtained. In addition, the light guide plate420and the display panel410may be configured to have an optical film (for example, a prism sheet or a diffuser, and not shown) disposed therebetween; and the light guide plate420and the substrate240are configured to have a reflector (not shown) disposed therebetween. In this embodiment, the sensing area230is, for example, located on a display surface414of the display panel410; and the light sensing component210can sense the position information of an object (not shown) when the object is performing a touch operation on the sensing area230. The means for the obtainment of position information in this embodiment is similar to that in the aforementioned embodiments, no any unnecessary will be given here.

FIG. 6Bis an alternative schematic cross-sectional view of the optical touch device along a line I-I inFIG. 5. As shown, the light source assembly220is disposed above the sensing area230and configured to directly provide the first beam222into the sensing area230without through a light guide plate. A supporting component250is disposed on the substrate240and the light source assembly220is disposed fixedly to the supporting component250; and thereby the light source assembly220is lifted above the sensing area230by the supporting component250.

FIG. 7is a schematic cross-sectional view of the optical touch device along a line II-II inFIG. 5. Please refer toFIGS. 5, 7both. The optical touch device400further includes a white light source480, which is disposed to be opposite to a side surface426, another one connected to the light emission surface424, of the light guide plate420. The white light source480is configured to emit white lights482functioned as display lights for the display panel410; wherein the white lights482emitted from the white light source480are configured to firstly emit into the light guide plate420through the side surface426thereof and then emit out from the light guide plate420through the light emission surface424thereof.

In this embodiment, the white light source480is a lamp; however, the white light source480can be constituted by a plurality of white point light sources (for example, white light emitting diodes) in another embodiment. Additionally, although in this embodiment the optical touch device400is exemplified by one white light source480and one light source assembly220; however, it is understood that the optical touch device400may include more than one white light source480and more than one light source assembly220in other embodiments. For example, the optical touch device400in another embodiment can include two white light sources480and two light source assemblies220, which are respectively disposed to be opposite to two different sides of the light guide plate420.

It is to be noted that the display panel410in the optical touch device400can be omitted in another embodiment if the optical touch device400is not required to provide display features. Moreover, in another embodiment, the white light source480can be integrated into the light source assembly220. For example, as illustrated inFIG. 8, the light source assembly520includes point light sources521,522, which are alternatively arranged in a same row on a carrier board523. Specifically, the point light sources521are configured to emit first beams for the light sensing component. Therefore, the first beam is an invisible light and accordingly the point light sources521are, for example, infrared light emitting diodes and configured to provide infrared lights. The point light sources522are configured to emit second beams functioned as display lights for the display panel. Therefore, the second beam is a visible light, and accordingly the point light sources522are, for example, white light emitting diodes and configured to provide white lights. It is to be noted that inFIG. 5, the white light sources480can be omitted if the light source assembly220is replaced by the light source assembly520as shown inFIG. 8.

In another embodiment as illustrated inFIG. 9, the point light sources521,522are arranged in two rows, respectively. In particular, the point light sources521are arranged in the first row L3and the point light sources522are arranged in the second row L4. In particular, the first row L3and the second row L4are configured to be parallel to each other.

To sum up, in the optical touch device, the light source assembly and the display module according to the present invention, because the point light sources are configured to emit beams sequentially, an object's position in the sensing area can be identified by one light sensing component. Thus, the number of the light sensing components in the present invention can decrease and consequently the optical touch device according to the present invention can have a lower cost.