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Publication numberUS20070080956 A1
Publication typeApplication
Application numberUS 11/536,403
Publication dateApr 12, 2007
Filing dateSep 28, 2006
Priority dateOct 7, 2005
Also published asUS7525078, US7935917, US8227740, US8537149, US20070080282, US20090179243, US20090309009, US20110096026
Publication number11536403, 536403, US 2007/0080956 A1, US 2007/080956 A1, US 20070080956 A1, US 20070080956A1, US 2007080956 A1, US 2007080956A1, US-A1-20070080956, US-A1-2007080956, US2007/0080956A1, US2007/080956A1, US20070080956 A1, US20070080956A1, US2007080956 A1, US2007080956A1
InventorsSen-Shyong Fann
Original AssigneeIntegrated Digital Technologies, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Interactive Display Devices And Methods Of Making The Same
US 20070080956 A1
Abstract
An interactive display device in one example may include: a first substrate and a second substrate spaced apart from each other for providing a display area; a plurality of display control elements in a first matrix over the first substrate; a plurality of first data lines over the first substrate, each of the first data lines being coupled with one or more corresponding display control elements; and a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with one or more corresponding display control elements. Additionally, the interactive display device may further include: a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information; a plurality of second data lines over the first substrate, each of the second data lines being coupled with one or more corresponding photo sensors; and a plurality of second scan lines over the first substrate, each of the second scan lines being coupled with one or more corresponding photo sensors for activating the at least one corresponding photo sensor.
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Claims(21)
1. An interactive display device comprising:
a first substrate and a second substrate spaced apart from each other for providing a display area;
a plurality of display control elements in a first matrix over the first substrate, the display control elements controlling the information displayed by the display area;
a plurality of first data lines over the first substrate, each of the first data lines being coupled with at least one corresponding display control element;
a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with at least one corresponding display control element;
a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information;
a plurality of second data lines over the first substrate, each of the second data lines being coupled with at least one corresponding photo sensor; and
a plurality of second scan lines over the first substrate, each of the second scan lines being coupled with at least one corresponding photo sensor for activating the at least one corresponding photo sensor.
2. The interactive display device according to claim 1, wherein the interactive display device is coupled to a computing system that is capable of providing the information being displayed by the display area and being controlled by the input information received by the interactive display device.
3. The interactive display device according to claim 1, wherein at least some of the first scan lines also act as the second scan lines.
4. The interactive display device according to claim 1, wherein at least some of the first data lines also act as the second data lines.
5. The interactive display device according to claim 1, wherein each of the photo sensors comprises a photo transistor comprising:
a gate coupled to a corresponding second scan line;
a drain region coupled to one of a voltage source or the gate terminal; and
a source region coupled to a corresponding second data line.
6. The interactive display device according to claim 1, wherein each of the photo sensors comprises a photo transistor comprising:
a photo transistor gate coupled to a voltage source;
a photo transistor drain region coupled to the voltage source; and
a photo transistor source region; and
a switching transistor comprising:
a switching transistor gate coupled to a corresponding second scan line;
a switching transistor drain region coupled to the photo transistor source region; and
a switching transistor source region coupled to a corresponding second data line.
7. The interactive display device according to claim 1, wherein the first matrix and the second matrix are arranged so that the number of the display control elements in a horizontal direction is x times the number of the photo sensors in the horizontal direction and the number of the display control elements in a vertical direction is y times the number of the photo sensors in the vertical direction, wherein each of x and y is an integer.
8. The interactive display device according to claim 1, wherein the photo sensors provide location information of at least one of a light beam projected onto the interactive display device and an object or a shadow of the object on or near the interactive display device, wherein at least one of the light beam and the object provides an input information to the interactive display device.
9. The interactive display device according to claim 1, wherein each of the photo sensors comprises a dual-transistor photo transistor having a gate, two source regions, and one shared drain region.
10. The interactive display device according to claim 1, wherein the photo sensors and the display control elements comprise semiconductor components that are fabricated together.
11. The interactive display device according to claim 1, wherein the second data lines are coupled to an object shadow analysis circuit.
12. An interactive display device comprising:
a first substrate and a second substrate spaced apart from each other for providing a display area;
a plurality of display control elements in a first matrix over the first substrate, the display control elements controlling the information displayed by the display area;
a plurality of first data lines over the first substrate, each of the first data lines being coupled with at least one corresponding display control element;
a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with at least one corresponding display control element;
a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information, wherein at least some of the first scan lines are coupled to at least one corresponding photo sensor for activating the at least one corresponding photo sensor; and
a plurality of second data lines over the first substrate, each of the second data lines being coupled with at least one corresponding photo sensor.
13. The interactive display device according to claim 12, wherein the interactive display device is coupled to a computing system that is capable of providing the information being displayed by the display area and being controlled by the input information received by the interactive display device.
14. The interactive display device according to claim 12, wherein each of the photo sensors comprises a photo transistor comprising:
a gate coupled to a corresponding first scan line;
a drain region coupled to one of a voltage source or the gate terminal; and
a source region coupled to a corresponding second data line.
15. The interactive display device according to claim 12, wherein each of the photo sensors comprises a photo transistor comprising:
a photo transistor gate coupled to a voltage source;
a photo transistor drain region coupled to the voltage source; and
a photo transistor source region; and
a switching transistor comprising:
a switching transistor gate coupled to a corresponding first scan line;
a switching transistor drain region coupled to the photo transistor source region; and
a switching transistor source region coupled to a corresponding second data line.
16. The interactive display device according to claim 12, wherein the first matrix and the second matrix are arranged so that the number of the display control elements in a horizontal direction is x times the number of the photo sensors in the horizontal direction and the number of the display control elements in a vertical direction is y times the number of the photo sensors in the vertical direction, wherein each of x and y is an integer.
17. The interactive display device according to claim 12, wherein the photo sensors provide location information of at least one of a light beam projected onto the interactive display device and an object or a shadow of the object on or near the interactive display device, wherein at least one of the light beam and the object provides an input information to the interactive display device.
18. The interactive display device according to claim 12, wherein each of the photo sensors comprises a dual-transistor photo transistor having a gate, two source regions, and one shared drain region.
19. The interactive display device according to claim 12, wherein the photo sensors and the display control elements comprise semiconductor components that are fabricated together.
20. The interactive display device according to claim 12, wherein the second data lines are coupled to an object shadow analysis circuit.
21. An interactive display device comprising:
a first substrate and a second substrate spaced apart from each other for providing a display area;
a plurality of display control elements in a first matrix over the first substrate, the display control elements controlling the information displayed by the display area;
a plurality of first data lines over the first substrate, each of the first data lines being coupled with at least one corresponding display control element;
a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with at least one corresponding display control elements;
a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information, wherein the second matrix overlap with a portion of the first matrix so that some of the photo sensors are adjacent to or in the proximity of some of the display control elements.
Description
    RELATED FIELD OF THE INVENTION
  • [0001]
    The invention relates to a display device. More specifically, the invention relates to interactive display devices and methods of making the same.
  • BACKGROUND OF THE INVENTION
  • [0002]
    Display devices traditionally serve the role of displaying the information or the output from a system, while other input device or devices provide inputs to the system. Interactive devices, such as a touch panel that can receive a user's input via touching the display panel, combines both output and input functions and allow a user to interact with the display or the system coupled to the display. As an example, devices such as personal digital assistants (PDAs), mobile phones, personal computers (PCs), tablet PCs (PC), etc. have incorporated touch panels for providing users with more choices in providing inputs to or operate a system.
  • [0003]
    Conventional touch panels or touch screens have a number of different designs, such as resistive type, surface-wave type, capacitive type, and infrared-ray type designs. However, all of these designs typically require combining a display device with a separate touch panel sheet or structure, which may affect the quality of the display, increase the weight and size of an existing display device, and, usually unavoidably, significantly increase the manufacturing cost and time of the combined device. Additionally, the various designs also have associated drawbacks. For example, certain touch panel designs require the panel to first store a received input information in a capacitor before such information is subsequently read. Such requirement, in some examples, may occupy additional area by having additional touch panel structure that provides the input-maintaining capacitors. The design is not ideal, as it may reduce the aperture ratio of a display device when area is limited and display efficiency or brightness is desired. Additionally, depending on the panel design and the dynamic ranges of input information, the capacitors associated with the touch panel may not provide adequate dynamic ranges for storing and identifying all ranges of inputs. As another example, some designs may be vulnerable to non-input noises, such as noises caused by the ambient light, the back light of the displayed information itself, and other forms of electrical, magnetic, or electromagnetic influence.
  • [0004]
    Therefore, there is a need for a display device that is interactive while providing some advantages over or resolve one or more drawbacks of traditional touch panels. For example, there may be a need for interactive display devices with simplified manufacturing processes, reduced sizes or thicknesses, or increased dynamic ranges in receiving input devices of different kinds or levels.
  • BRIEF SUMMARY OF THE INVENTION
  • [0005]
    Examples consistent with the present invention may provide an interactive display device. In one example, the interactive display device may include: a first substrate and a second substrate spaced apart from each other for providing a display area; a plurality of display control elements in a first matrix over the first substrate; a plurality of first data lines over the first substrate, each of the first data lines being coupled with one or more corresponding display control elements; and a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with one or more corresponding display control elements. Additionally, the interactive display device may further include: a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information; a plurality of second data lines over the first substrate, each of the second data lines being coupled with one or more corresponding photo sensors; and a plurality of second scan lines over the first substrate, each of the second scan lines being coupled with one or more corresponding photo sensors for activating the at least one corresponding photo sensor.
  • [0006]
    In another example, an interactive display device may include: a first substrate and a second substrate spaced apart from each other for providing a display area; a plurality of display control elements in a first matrix over the first substrate; a plurality of first data lines over the first substrate, each of the first data lines being coupled with one or more corresponding display control elements; a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with one or more corresponding display control elements. The display control element may further include: a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information; and a plurality of second data lines over the first substrate, each of the second data lines being coupled with one or more corresponding photo sensors. In this example, some of the first scan lines may be coupled to one or more corresponding photo sensors for activating the corresponding photo sensors.
  • [0007]
    In still another example, an interactive display device may include: a first substrate and a second substrate spaced apart from each other for providing a display area; a plurality of display control elements in a first matrix over the first substrate; a plurality of first data lines over the first substrate, each of the first data lines being coupled with one or more corresponding display control elements; a plurality of first scan lines over the first substrate, each of the first scan lines being coupled with one or more corresponding display control elements; a plurality of photo sensors in a second matrix over the first substrate, the photo sensors providing an interface for receiving input information, wherein the second matrix overlap with a portion of the first matrix so that some of the photo sensors are adjacent to or in the proximity of some of the display control elements.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0008]
    FIG. 1 is a schematic diagram illustrating an interactive display in examples consistent with the invention;
  • [0009]
    FIG. 2A is a schematic diagram illustrating an example of photo sensors used in an interactive display device in examples consistent with the invention;
  • [0010]
    FIG. 2B is a schematic diagram illustrating another example of photo sensors of used in an interactive display device in examples consistent with the invention;
  • [0011]
    FIG. 3A is a cross-sectional diagram illustrating an exemplary structure of a photo transistor;
  • [0012]
    FIG. 3B is an top view of the photo transistor illustrated in FIG. 3A;
  • [0013]
    FIG. 3C is a top view showing a possible arrangement of photo sensor regions without sharing a common drain;
  • [0014]
    FIG. 4A is a cross-sectional diagram illustrating an exemplary structure of a photo sensor;
  • [0015]
    FIG. 4B is a top view of the photo sensor illustrated in FIG. 4A; and
  • [0016]
    FIG. 4C is a top view showing a possible arrangement of photo sensor regions of without sharing a common drain.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0017]
    Examples consistent with the invention may provide interactive display devices and the methods of forming interactive display devices. The interactive display devices may have display control elements arranged in a first matrix and photo sensors arranged in a second matrix. In some examples, the photo sensors may be fabricated together with display control elements such as transistors or thin-film transistors (“TFTs”) without requiring additional semiconductor layers or structures to be formed over a substrate. In other words, some examples allow the input or interactive function of a display device be incorporated into a display device without complicating the fabrication process or significantly increasing the fabrication cost. In some examples, a transistor having its gate and drain electrically coupled or two or more transistors with similar configuration may be used for proving photo transistors without occupying too much substrate area. In some examples, interactive display devices may use the input information for various applications, including recognizing hand-writings, recognizing other inputted characters or drawings, and identifying tapping, different forms of tapping or touching, or multi-tapping for different applications. Additionally, interactive display devices may accept various forms of input devices or instruments, including a pen, a stylus, a finger, or any other instruments.
  • [0018]
    FIG. 1 is a schematic diagram illustrating examples of an interactive display device consistent with the invention. Referring to FIG. 1, interactive display device 200 may include two substrates 202 and 204 spaced apart from each other for providing a display area therebetween. In addition, display device 200 may include a number of display control elements 210 arranged in a first matrix over substrate 202, and display control elements 210 may control the information displayed by the display area. Display device 200 also include a number of first data lines 212 over substrate 202, and each of first data lines 212 may be coupled with at least one corresponding display control element 210. In the example illustrated in FIG. 1, all the display control elements 210 in the same horizontal level (along the x direction) may be coupled to one data line 212 that extends horizontally. Display device 200 also include a number of first scan lines 214 over substrate 202, and each of the first scan lines 214 may be coupled with at least one corresponding display control element 210. In the example illustrated in FIG. 1, all the display control elements 210 along the same vertical line (along the y direction) may be coupled to one scan line 214 that extends vertically.
  • [0019]
    In addition to display control elements 210, display device 200 may also include a number of photo sensors 220 arranged in a second matrix over the first substrate, and the photo sensors 220 may serve as an interface for receiving input information. Display device 200 may also include a number of second data lines 222 (dashed, x-direction lines) over substrate 202, and each of the second data lines 222 may be coupled with at least one corresponding photo sensor. In one example, although the interactive display device 200 may use separate data lines in many applications, some of the first data lines 212 may be shared or used as some of the second data lines 222, depending on the design. In addition, in the example illustrated in FIG. 1, all the photo sensors 220 in the same horizontal level (along the x direction) may be coupled to one data line that extends horizontally. Display device 200 may also include a number of second scan lines 224 (dashed, y-direction lines) over substrate 202, and each of the second scan lines 224 may be coupled with at least one corresponding photo sensor 220 for activating the at least one corresponding photo sensor 220. In one example, some of the first scan lines 214 may be shared or used as some of the second scan lines 224, depending on the design. In addition, in the example illustrated in FIG. 1, all the photo sensors 220 in the same vertical position (along the y direction) may be coupled to one scan line 224 that extends vertically.
  • [0020]
    In some examples, interactive display device 200 may be coupled to a computing system that is capable of providing the information being displayed by the display area and being controlled by the input information received by the interactive display device. Also, by using appropriate processing or sensing circuit, photo sensors 220 may provide location information of a light beam projected onto interactive display device 200 or of an object or a shadow of the object on or near the interactive display device. In other words, the light beam or the object may provide input information to interactive display device 200.
  • [0021]
    FIG. 2A illustrates an example of photo sensors that may be used in interactive display device 200 described above. Referring to FIG. 2A, each of photo sensors 110, 120, 130, and 140 may be arranged in a second matrix in combination with other display elements that are not shown in FIG. 2A. Taking photo sensor 110 as an example, it may include a photo transistor having gate terminal 11 g, drain terminal 11 d, and source terminal 11 s. Source terminal 11 s may be coupled to a corresponding data line 1D. Gate terminal 11 g may be coupled to a corresponding scan line 1G, which may also be referred to as a gate line in this example. Drain terminal 11 d may be coupled gate terminal 11 g, which is coupled to scan line 1G in the illustrated example. Alternatively, drain terminal 11 d may be coupled to a separate voltage source, which may provide a voltage such as VDD for operating photo sensor 110. In one example, scan line 1G controls when the corresponding photo sensor or photo sensors 110 and 130 in the illustrated example in FIG. 2A, are activated. The voltage provided to scan line 1G or a separate voltage source coupled to the drain terminals of photo sensors, or photo sensors 110 and 130 in the illustrated example in FIG. 2A, provides a bias level that allows the photo sensors to sense the illumination level or light intensity at or near where the photo sensors are by varying their current flows based on the illumination level. In one example, the activating bias or scan line voltage can be about 10 to 15 volts and the non-activating scan line voltage can be about 0 volts to −10 volts. However, these voltages may vary depending on the voltage sources or driving circuits available to the interactive display device and the design or the components used for the interactive display device.
  • [0022]
    Referring to FIG. 2A, when photo sensor 110 is activated by scan line 1G, first current 1C would flow from source terminal 11 s to indicate the illumination level or light intensity at that location. In other words, the light intensity at or near pixel area 11 can be detected from the level of first current 1C when photo sensor 110 is activated or “scanned” by scan line 1G. Similarly, scan line 1G may activate photo sensor 130 at the same time and the current flowing from its source terminal output through data line 2D may indicate the illumination level at or near pixel area 13. As an example, if pixel area 11 is covered or shadowed by an object from ambient light, first current 1C may be zero or minimal. In contrast, if pixel area 11 is illuminated by ambient light or a pointed light beam, first current 1C may be significant. In a similar manner, when scan line 1G is not but scan line 2G is driven or provided with an activating voltage, second current 2C would flow from the source terminal of photo sensor 120 to indicate the illumination level or light intensity at that location.
  • [0023]
    Accordingly, in this example, viewing an interactive display device as a whole, the illumination levels at various areas of the display device may be obtained by scanning all the scan lines, usually sequentially. And the current flowing through the photo sensors connected to the same data line may be read out at different timing and processed accordingly, such as by a processing or sensing circuit, which is illustrated in FIG. 2A. As a result, with an appropriate current sensing or processing circuit, the input from a light beam projected onto the display device or an object, such as a pen, a finger, a stylus, or other devices, touching or near the surface of the display device may be received.
  • [0024]
    FIG. 2B illustrates another example of photo sensors that may be used in interactive display device 200 described above. Referring to FIG. 2B, each of the photo sensors for pixel areas 21, 22, 23, and 24 may be arranged in a second matrix in combination with other display elements that are not shown in FIG. 2B. Taking the photo sensor for pixel area 21 as an example, it may include photo transistor 211 and switching transistor 212. Photo transistor 211 may detect the illumination level at the location, and switching transistor 212 may control when the detected information is read and output an associated sensing or processing circuitry. Other photo sensors may be arranged similarly. Taking photo transistor 211 as an example, it has source terminal 211 s coupled to drain terminal 212 d of the corresponding switch transistor 212. Gate terminal 211 g of photo transistor 211 is coupled to a biased voltage source, and drain terminal 211 d of photo transistor 211 can be coupled to the same biased voltage source or a separate voltage source.
  • [0025]
    Referring to FIG. 2B, in one example, scan line 1G controls when the corresponding photo sensor or photo sensors for pixel areas 21 and 23 in the illustrated example, are activated. The voltage provided to scan line 1G or a separate voltage source coupled to the gate terminals of the switching transistors of those photo sensors allows the photo sensors to sense the illumination level or light intensity at or near where the photo sensors are. In one example, the activating scan line voltage can be about 10 to 15 volts and the non-activating scan line voltage can be about 0 volts to −10 volts. However, these voltages may be varied depending on the voltage sources or driving circuits available to the interactive display device and the design or the components used for the interactive display device.
  • [0026]
    Referring to FIG. 2B, when the photo sensor for pixel area 21 is activated by scan line 1G, first current 1C would flow from source terminal 211 s, through switching transistor 212, to indicate the illumination level or light intensity at that location. In other words, the light intensity at or near the pixel area 21 can be detected from the level of first current 1C when switching transistor 212 is activated or “scanned” by scan line 1G. Similarly, scan line 1G may activate the photo sensor for pixel area 23 at the same time and the current flowing from the source terminal of the corresponding photo transistor through data line 2D may indicate the illumination level at or near pixel area 23. As an example, if pixel area 21 is covered or shadowed by an object from ambient light, first current 1C may be zero or minimal. In contrast, if pixel area 21 is illuminated by ambient light or a pointed light beam, first current 1C may be significant. In a similar manner, when scan line 1G is not but scan line 2G is driven or provided with an activating voltage, second current 2C would flow from the source terminal of photo sensor 221 through switching transistor 222 to indicate the illumination level or light intensity at that location.
  • [0027]
    Accordingly, in this example, viewing an interactive display device as a whole, the illumination levels at various areas of the display device may be obtained by scanning all the scan lines, usually sequentially. And the current flowing through the photo sensors connected to the same data line may be read out at different timing and processed accordingly, such as by a processing or sensing circuit, which is illustrated in FIG. 2B. As a result, with an appropriate current sensing or processing circuit, the input from a light beam projected onto the display device or an object, such as a pen, a finger, a stylus, or other devices, touching or near the surface of the display device may be received.
  • [0028]
    FIG. 3A is an exemplary cross-sectional diagram illustrating a possible structure of a photo transistor. The illustrated structure may provide a functional photo transistor using only a limited semiconductor area, thereby achieving a high “area efficiency.” Referring to FIG. 3A, photo transistor 61 may include a dual-transistor, flipped (upside-down) structure in the illustrated example. Specifically, photo transistor 61 may include common or shared gate 61 b, gate dielectric layer 61 h above common gate 61 b, channel region 61 g above gate dielectric layer 61 h, and two source regions 61 a and common or shared drain region 61 c above channel region 61 g, with common drain region 61 c between the two source regions 61 a and spaced apart from each of the two source regions 61 a horizontally. Common gate 61 b may include a conductive material such as polysilicon or metal, and the two source regions 61 a and common drain region 61 c may include doped silicon. Additionally, channel region 61 g may include an amorphous silicon layer, and gate dielectric layer 61 h may include a dielectric layer, such as a silicon nitride layer. In one example, common gate 61 b may be electrically coupled to common drain region 61 c, which may eliminate a parasitic capacitance commonly presented between non-coupled gate and drain region. Also, by having the dual transistor or dual source region structure, the effective channel width of the photo transistor may be doubled without occupying the area of two full photo transistors.
  • [0029]
    FIG. 3B is an exemplary top view illustrating the location of different regions of photo transistor 61 illustrated in FIG. 3A. Referring to FIG. 3B, drain region 61 c is spaced apart from two source regions 61 a, and gate 61 b lies approximately under drain region 61 c and extends roughly between two source regions. With the structure, two photo transistors with a channel width of 1W, or effectively one photo transistor with an equivalent channel width of 2W, may be provided. In contrast, FIG. 3C shows an exemplary top view illustrating the possible location of different regions of photo transistor 62, which may be viewed as two separate but parallel-coupled photo transistors, one at the left and the other at the right. Referring to FIG. 3C, the photo transistor at the left may include source region 62 a, gate 62 b, and drain 62 c, and the photo transistor at the right may include source region 62 d, gate 62 e, and drain region 62 f. Compared to the photo transistor having electrically-coupled drain and gate as illustrated in FIG. 3B, the photo transistor illustrated in FIG. 3C occupies a bigger surface area while providing a similar photo transistor with the same channel width of 2W.
  • [0030]
    In some examples, the display function for an interactive display device may be controlled by transistors, such as thin-film transistors (TFTs). One example of the display device includes an LCD (liquid crystal display) or TFT-LCD. As an example, the fabrication of an LCD panel involves forming transistors and other components over one substrate and combining the substrate with another substrate to enclose liquid crystal, which may be controlled by control elements such as TFTs, between the two substrates. In this and some other examples, the photo sensors and other display control elements of an interactive display device may be fabricated together during the fabrication process, such as a fabrication process involving forming semiconductor layers over a substrate. In other words, the input function or interactive part of the display device may be incorporated into a regular display device without burdening or complicating the manufacturing process of display devices. Furthermore, because the interactive display devices in those examples would not require a separate sheet for providing the touch panel or panel input function, the display quality and reliability of the display devices may be improved.
  • [0031]
    FIG. 4A illustrates an exemplary cross-sectional view of a photo sensor structure that was illustrated in FIG. 2B. Referring to FIG. 4A, photo sensor 71 may include (1) a switching transistor including gate 71 e, drain region 71 d, and source region 71 f; and (2) a photo transistor including common or shared gate 71 b, source regions 71 a, and common or shared drain region 71 c. In this example, the photo transistor may similarly have a dual transistor structure by sharing common drain region 71 c and common gate 71 b to reduce the areas occupied by a photo transistor having an equivalent channel width of 2W, as illustrated above in association with FIG. 3A. Gate dielectric layer 71 h and channel region 71 g may be provided between the gates and the source and drain regions as illustrated in FIG. 4A. The materials for gates, source and drain regions, gate dielectric layer, and channel region may be the same or similar to the example described in association with FIG. 3A. In this example, gate 71 b may be electrically coupled to the shared drain regions 71 c in some examples, which may eliminate the parasitic capacitance that is usually presented between non-electrically-coupled gate and drain.
  • [0032]
    FIG. 4B is an exemplary top view illustrating the location of different regions of the photo transistor illustrated in FIG. 4A. Referring to FIG. 4B, as a part of the photo transistor of photo sensor 71, drain region 71 c is spaced apart from two source regions 71 a and 71 d, and gate 71 b lies approximately under drain region 71 c and extends roughly between two source regions 71 a and 71 d. As part of the switching transistor of photo sensor 71, drain region 71 d is spaced apart from source region 71 f, and gate 71 e lies under the two regions and extends roughly between the two regions. With such structure for the photo transistor, two photo transistors with a channel width of 1W, or effectively one photo transistor with an equivalent channel width of 2W, may be provided. In contrast, FIG. 4C shows an exemplary top view illustrating the possible location of different regions of a photo transistor and a switching transistor. Referring to FIG. 4C, a photo transistor may be viewed as two separate but parallel-coupled photo transistors, one at the left (72 a, 72 b, 72 c) and the other at the right (72 d, 72 e, 72 f), and a switching transistor (72 a, 72 g, and 72 h) may be appended to the photo transistor by sharing a common source region 72 a. In particular, the photo transistor at the left may include source region 72 a, gate 72 b, and drain 72 c, and the photo transistor at the right may include source region 72 d, gate 72 e, and drain terminal 72 f. Additionally, the switching transistor may include drain region 72 a, gate 72 g, and source 72 h. Compared to the electrically coupled gate-drain photo transistor illustrated in FIG. 4B, the photo transistor illustrated in FIG. 4C occupies a bigger surface area while providing the same photo transistor with a channel width of 2W.
  • [0033]
    As illustrated above, examples consistent with the invention provide interactive display devices and the methods of forming interactive display devices. In some examples, the photo sensors may be fabricated together with display control elements such as transistors or thin-film transistors without requiring additional semiconductor layer to be formed over a substrate. As an example, conventional processes of fabricating TFT-LCDs can be modified to make interactive display devices by modifying a few pattern-defining masks, such as the masks for defining the TFTs and related components. Accordingly, the input or interactive function of a display device may be added without complicating the fabrication process or significantly increasing the fabrication cost. Furthermore, effective channel widths of photo sensors or photo transistors may be increased with the illustrated structures without requiring too much additional substrate area.
  • [0034]
    Although the display control elements and the photo sensors may be fabricated together, they do not need to be distributed over a display device with the same density. That is, the density of the photo sensors may be lower than the density of display control elements. In other words, the first matrix containing display control elements and the second matrix containing the photo sensors can be arranged so that the second matrix generally overlaps with only a portion of the first matrix. In one example, the number of the display control elements in a horizontal direction is x times the number of the photo sensors in the horizontal direction and the number of the display control elements in a vertical direction is y times the number of the photo sensors in the vertical direction. Each of x and y may be integer in one example. For example, for a display device having a resolution of 12801024 pixels, the number of photo sensors can be 320256 in one example or 256128 in another example. And various other designs of photo sensor distributions may be used depending on designs, applications, or various other design considerations.
  • [0035]
    It will be appreciated by those skilled in the art that changes could be made to the examples described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular examples disclosed, but it is intended to cover modifications within the spirit and scope of the present invention.
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Classifications
U.S. Classification345/207, 257/E27.149
International ClassificationG09G5/00
Cooperative ClassificationH01L27/14681, G06F3/042, G06F3/0412
European ClassificationG06F3/041D, H01L27/146T, G06F3/042
Legal Events
DateCodeEventDescription
Sep 28, 2006ASAssignment
Owner name: INTEGRATED DIGITAL TECHNOLOGIES, INC., TAIWAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FANN, SEN-SHYONG;REEL/FRAME:018334/0971
Effective date: 20060913