HK1029422B - User input device for a computer system - Google Patents

Description

User input device for computer system

Background

1. Field of the invention

The present invention relates to a user input device, and more particularly, to a user input device for a computer system.

2. Description of the Prior Art

The user input device of the computer system may take many forms. Two forms of user input devices of interest are touch screens and pen-based screens. Touch screens provide user input by a user touching the display screen with a finger. Pen-based screens provide user input by a user touching the display screen with a stylus or pen.

One conventional approach to providing a touch screen or pen-based screen is to overlay a resistive or capacitive film over the display screen. One problem with conventional thin film processes is that the thin film is easily damaged. Another problem with the conventional thin film approach is that the cost of this approach is too expensive for a standard size or larger display screen because it is measured in squares with circumference. Another problem with the conventional film approach is that a large number of translucent films are overlaid on the display screen. The film then makes the display appear blurred. To compensate, the display screen should provide a light output of greater intensity, but this is not always effective enough. For example, in the case of a portable computer, there is typically no additional light intensity and, if any, will result in additional power consumption, over-stressing the battery of the portable computer.

Another approach to providing a touch screen or pen-based screen is to use groups of infrared Light Emitting Diodes (LEDs) to provide light, and corresponding groups of phototransistors to detect the light. One major problem with the conventional light-based approach is that it requires a large number of components. And these components are too large for use on portable computers. Another problem with the conventional light-based approach is that it does not provide the high resolution required for pen-based screens. In addition, conventional light-based approaches are too expensive due to the large number of components required.

Another approach to providing a touch screen or pen-based screen is to use fiber optic cables, Liquid Crystal Displays (LCDs) as controllable masks, and use a multiplexing scheme. Such a process is described in U.S. patent No.5,196,836. Here, although only one light emitter is used, the diffusion of light output from the optical cable is so severe that a controllable LCD mask is required to sequentially isolate light output from only one optical cable at a time. Light received from the isolated fiber optic cable also needs to be isolated at the receiving end. Given this configuration, the system must scan through each cable using a multiplexing scheme, which makes the method very slow. Furthermore, this method does not produce the high resolution required for pen-based screens and is also quite expensive to manufacture.

Accordingly, there is a need for an improved user input device that can provide high resolution at a modest cost.

Summary of The Invention

The present invention relates generally to user input devices for electronic devices that provide location information using a light grid. Optical gratings are created and processed using waveguides that guide the transmission and reception of light. Optionally, optics may be used to enhance the operation of the user input device. The user input device is particularly suitable for use as a user input device for a computer system or the like.

The invention can be implemented in numerous ways, including as an apparatus, a system, and a method. Several embodiments of the invention are discussed below.

An apparatus according to an embodiment of the invention comprises: a light source; a transmitting waveguide portion optically coupled to receive light from the light source, the transmitting waveguide portion formed of an insulating material and including a plurality of light emitting waveguides, the light emitting waveguides producing a first set of light beams in response to the light received from the light source, the first set of light beams emanating from the light emitting waveguides in a first direction; a receiving waveguide portion disposed apart from the transmitting waveguide in the first direction, the receiving waveguide portion being formed of an insulating material and including a plurality of light receiving waveguides for receiving the first group of light beams emitted from the transmitting waveguide; and a photodetector optically coupled with the receiving waveguide portion, receiving the light from the light receiving waveguide of the receiving waveguide portion, the photodetector measuring the light intensity of the light from the light receiving waveguide of the receiving waveguide portion. This embodiment also includes a lens optically positioned proximate to the transmitting waveguide portion to collimate the first set of light beams emanating from the transmitting waveguide toward a corresponding light receiving waveguide of the receiving waveguide portion.

As an input device for an electronic device, another embodiment of the invention includes: at least one light source; a photodetector for detecting light intensity at the plurality of photodetecting elements; and, a lithographically defined waveguide structure including a plurality of waveguides. The light source couples light into a first set of waveguides of a waveguide structure that generates a grid of light beams (grid of light beams) from the light coupled into the waveguides. The beam grid passes through an input region and is then directed by a second set of waveguides of the waveguide structure to the light detector.

As a method of determining user input with respect to an input device, one embodiment of the invention includes the operations of: providing a light source; generating a plurality of parallel light beams from a light source; simultaneously directing a parallel light beam through an input area of an input device, the input area being positioned relative to the input device; simultaneously receiving the specific parallel light beams after having passed through the input area; determining the light intensity of each of the received parallel light beams; and determining whether there is user input with respect to the input area based on the determined light intensity value.

The advantages of the present invention are numerous. One advantage of the present invention is that high resolution can be achieved. Another advantage of the present invention is that the cost of the input device is modest and significantly lower than conventional designs, since the cost is calculated linearly with the circumference, making the input device particularly advantageous on normal and large-sized displays. Yet another advantage of the present invention is that the display screen strength is not impeded. Yet another advantage of the present invention is that the input device requires few relatively small, inexpensive components that are easily mounted on a two-dimensional surface.

Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

Brief description of the drawings

The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

FIG. 1 is a block diagram of an input position detection system according to one embodiment of the invention;

FIG. 2 is a schematic diagram of a computer system;

FIG. 3 is a schematic diagram of an input device according to one embodiment of the invention;

FIG. 4 is a schematic diagram of an input device in accordance with one embodiment of the present invention;

FIG. 5 shows a schematic diagram of a waveguide arrangement according to an embodiment of the invention;

FIGS. 6A and 6B are cross-sectional views of the waveguide shown in FIG. 5;

fig. 6C is a schematic view showing a structural configuration of a waveguide portion according to an embodiment of the present invention;

FIG. 6D is a flow chart of a fabrication process for fabricating the waveguide shown in FIG. 6C according to one embodiment of the present invention;

FIG. 6E is a schematic diagram showing an output waveguide;

FIG. 6F is a flow chart of a fabrication process for fabricating a waveguide structure according to another embodiment of the present invention;

FIG. 7A is a schematic diagram showing light coupled into a waveguide;

FIG. 7B is a schematic diagram showing a waveguide coupled to a receiver;

FIG. 7C is a block diagram of an ASIC layout for implementing a receiver in accordance with one embodiment of the present invention;

FIG. 8 is a flow diagram of an initialization process in accordance with one embodiment of the invention;

FIG. 9 is a flow diagram of a threshold adjustment process in accordance with one embodiment of the present invention;

FIG. 10A is a flow diagram of a shadow detection process in accordance with one embodiment of the invention;

FIGS. 10B and 10C are diagrams illustrating an example of a shadow detection process according to one embodiment of the invention;

FIGS. 11A and 11B are schematic diagrams showing placement of a microlens proximate to a waveguide to mitigate diffusion of light emitted from the waveguide; and

fig. 12A-12D are schematic diagrams of input devices according to other embodiments of the invention.

Detailed description of the invention

The present invention relates to a user input device for an electronic device that provides positional information using a light grid. Optical gratings are created and processed using waveguides that guide the transmission and reception of light. Optionally, optics may be used to enhance the operation of the user input device. The user input device is particularly suitable for use as a user input device for a computer system or the like.

Embodiments of the present invention are discussed below with reference to fig. 1-12D. However, those of ordinary skill in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments.

Fig. 1 is a block diagram of an input position detection system 100 according to an embodiment of the invention. The input position detection system 100 includes a light source 102 that directs light to a waveguide 104. Waveguide 104 redirects the input light into a plurality of optical beams 106, and the plurality of optical beams 106 are directed through a transmission medium 108 to a waveguide 110. Waveguide 110 directs received optical beam 107 as optical beam 114 to optical receiver 112. The optical receiver 112 then determines whether each light beam 114 received by the optical receiver 112 is "on" or "off" based on the intensity level of the received light for each light beam 114.

The light receiver 112 recognizes those light beams 106 that are blocked (e.g., input by a user) while being directed through the transmission medium 108 as "off light beams. The user's finger (touch input) or stylus (pen-based input) prevents the one or more optical beams 106 from reaching the waveguide 110 and the optical receiver 112. The particular beam or beams 106 that are blocked then provide the position of the user input relative to the beam 106, the beam 106 preferably having a predetermined relative position with respect to the transmission medium 108 (e.g., display screen). Thus, the one or more light beams 114 that the light receiver 112 determines to be "off" indicate the location of the user input.

Optionally, the input position detection system 100 may include a lens 116 (e.g., a polymer microlens array) at the launch end, i.e., proximate the output end of the waveguide 104. The lens 116 is preferably a collimating lens that directs the light beam 106 through the transmission medium 108 to the corresponding waveguide 110. The input position detection system 100 may also include a lens 118 at the receiving end (i.e., near the input end of the waveguide 110). The lenses 118 direct the light beams directed through the transmission medium 108 into the respective waveguides 110.

Fig. 2 is a schematic diagram of a computer system 200. Computer system 200 is representative of a computer system suitable for using an input device in accordance with the present invention. The computer system 200 includes a computer chassis 202 having a CD-ROM drive 204 and a floppy disk drive 206. The computer system 200 also includes a display device 208, a keyboard 210, and a pointing device (e.g., mouse) 212. The computer system 200 shown in FIG. 2 is a desktop computer system in which the display device 208 is typically a separate article of manufacture coupled to the computer chassis 202 by a cable (not shown). The keyboard 210 and pointing device 212 of the computer system 200 enable a user to provide user input to the computer system 200.

As described above, the present invention relates to optical grid-based input devices for use by electronic devices, such as computers. In accordance with one embodiment of the present invention, the input device is placed on the screen area 214 of the display device 208 and secured to the peripheral portion 216 of the display device 208 surrounding the screen portion 214. The input device preferably does not extend beyond or block the screen area 214. Alternatively, the input device may be integral with the display device 208. A user can provide user input to the computer system 200 by blocking certain portions of the light grid generated by the input device. Thus, the input device differs from a conventional touch screen or pen-based screen, but provides location information to the computer system 200 in much the same way. According to another embodiment of the present invention, the input device may be placed on or integral with the display screen of the portable computer. Although the input device according to the invention is preferably placed on or integral with the display screen, it should be appreciated that the input device according to the invention may also be placed on other surfaces than the display screen. For example, the input device may surround a pad, backplane or tablet for pen or touch input.

The input device may also be used in a variety of environments other than user input to a computer system. For example, the input device may be used for robot positioning, where the input device provides robot positioning information. As another example, the input device may be used with a safety or emergency sensor where the interruption of the light beam operates as a switch.

FIG. 3 is a schematic diagram of an input device 300 in accordance with one embodiment of the present invention. Input device 300 is a rectangular structure having a left side 302, a bottom side 304, a right side 306, and a top side 308. The input device 300 generates a plurality of parallel light beams on two sides and the input device 300 receives a plurality of parallel light beams on the other two sides. A light detector associated with input device 300 determines the received light beam to determine a positional reference of any user input with respect to the rectangular structure. Input device 300 includes a waveguide structure that directs light from a light source or to a light detector. The waveguide structure includes waveguide portions 310-316, each waveguide portion 310-316 having a plurality of waveguides. The waveguide operates as an optical channel. In fig. 3, waveguide portions 310 and 312 are shown having a plurality of waveguides 318 and 320, respectively. Each waveguide is used to generate or receive a light beam.

In this embodiment, the input device 300 is placed around the screen area of the display device of the computer system. For example, the input device 300 may be placed around the screen area 214 of the display device 208 of the computer system 200 shown in FIG. 2 by securing the input device 300 to the peripheral portion 216 of the display device 208. Input device 300 may be held in place in various ways. For example, the input device may be fabricated or mounted into the display device, or mechanically secured to a peripheral portion of the display device surrounding the display device 308. In one case, a snap-in plastic frame that can be incorporated into the display device 208 supports the components of the input device 300. Alternatively, in another case where the display device is a flat panel display (e.g., a flat panel display of a portable computer), the assembly of components supporting the display device may be incorporated into a metal bezel surrounding the flat panel display.

Although fig. 3 shows an input device 300 having a rectangular configuration, an input device according to the present invention need not be regular or rectangular. In fact, the waveguide structure used with the input device according to the invention provides flexibility in the shape taken by the input device.

Fig. 4 is a schematic diagram of an input device 400 according to an embodiment of the present invention. Input device 400 is a detailed schematic diagram of input device 300, in which two light sources and two receivers are employed to transmit and receive light grids, respectively. However, FIG. 4 does not show a chassis of an input device 400, such as the input device 300 shown in FIG. 3.

The input device 400 includes a first transmitter 402, a second transmitter 404, a master receiver 406, and a slave receiver 408. In addition, input device 400 includes waveguide portions 410, 412, 414, and 416. The waveguide portions 410 and 416 are arranged such that they are positioned around the periphery of an input area, such as a screen area of a display device. The slave receiver 408 communicates with the master receiver 406, and the master receiver 406 communicates with a host (e.g., the computer system 200).

Input device 400 may also include lens portions 422, 424, 426, and 428, which, although not shown in FIG. 3, are also preferably located within the housing of input device 400. Each of lens portions 422, 424, 426 and 428 correspond to waveguide portions 410, 412, 414 and 416, respectively. The lens portions 422,424, 426 and 428 are arranged proximate to the waveguide portion 410-416 and thus around the periphery of the input area (e.g., the screen area of the display device).

The operation of input device 400 is as follows. When the emitter 402 is activated, light is coupled into the end of the waveguide section 410 adjacent to the emitter 402. The light coupled into waveguide section 410 is then directed to a plurality of waveguides (i.e., optical channels) within waveguide section 410. Each of these waveguides within waveguide section 410 produces a horizontal light beam 418, and horizontal light beam 418 traverses the screen area of the display device to reach waveguide section 412. Waveguide section 412 includes a plurality of waveguides corresponding to the waveguides in waveguide section 410. The light beam 418 from the waveguide section 410 is directed to and aligned with the waveguide in the waveguide section 412 so that the received light beam is directed to the light detecting element from the receiver 408. The slave receiver 408 abuts (or nearly abuts) the end of the waveguide portion 412 so that light is received from each respective waveguide within the waveguide portion 412 at the light detecting element of the slave receiver 408.

Likewise, when emitter 404 is activated, light is coupled into the end of waveguide section 414 adjacent to emitter 404. The light coupled into waveguide section 414 is then directed to a plurality of waveguides (i.e., optical channels) within waveguide section 414. Each of these waveguides within waveguide section 414 produces a vertical light beam 420, and the vertical light beam 420 traverses through the screen area of the display device to reach waveguide section 416. Waveguide section 416 includes a plurality of waveguides corresponding to the waveguides in waveguide section 414. The light beam 420 from the waveguide section 414 is directed to and aligned with the light channel in the waveguide section 416 such that the received light beam is directed to the light detecting element of the main receiver 406. The main receiver 406 abuts (or nearly abuts) the end of the waveguide section 416 so that light is received at the light detecting elements of the main receiver 406 from each respective waveguide within the waveguide section 416.

When input device 400 includes lens portions 418-424, the operation is substantially the same, although enhanced by reducing diffusion. The advantage of using a lens is that the light is collimated so that the beam can traverse a larger screen area and simplifies the fabrication of the waveguide section. The horizontal light beam 418 exiting the waveguide section 410 is collimated by the lens section 422 and then focused again by the lens section 424 so that the horizontal light beam 418 is received by the waveguide in the waveguide section 412. Likewise, the vertical light beam 420 exiting the waveguide section 414 is collimated by the lens section 426 and then focused again by the lens section 428 so that the horizontal light beam 420 is received by the waveguide in the waveguide section 416.

The emitters 402 and 404 are preferably light sources. For example, each receiver 402 and 404 may be a Light Emitting Diode (LED). The wavelength of the light emitted by the emitter may vary over a wide range. However, the wavelength is preferably in the range of 0.38 to 1.10 microns. Preferably, the wavelength of the light is in the range of 0.40 to 0.48 microns. Alternatively, the wavelength of the light is in the range of 0.70 to 0.95. In one embodiment, the LED used as the emitter may be a blue gallium nitride LED having a wavelength of about 0.43 microns. Waveguide section 410 and 416 are described below with reference to fig. 5, 6A, 6B, 6C, and 6D.

The slave receiver 408 and the master receiver 406 may be designed in a number of different ways. For example, receivers 406 and 408 may be implemented by custom Application Specific Integrated Circuits (ASICs) or other circuits with photosensitive regions.

The receivers 406 and 408 are also coupled to or include circuitry that converts the light sensitive measurements from the light sensitive areas into digital quantities and then transmits the digital quantities to the host. This circuitry may be implemented in a number of ways, including on an application specific Integrated Circuit (IC) or on an ASIC or other circuitry that contains the photosensitive region. Regardless of the implementation, receivers 406 and 408 perform processing tasks to operate input device 400. An advantage of using the ASIC approach is that the light sensing devices (light detecting elements) can be formed on the same integrated circuit as the logic elements that perform other processing tasks performed by the receivers 406 and 408. Photosensitive devices can also be made in a number of ways. Charge Coupled Devices (CCDs) are suitable for light detection, but their circuits require more silicon and consume more power than CMOS circuits. CMOS technology does not enable CCD sensors to be fabricated, but other photosensitive devices can be fabricated using CMOS technology, as is known in the art. Additional details of the ASIC method will be discussed below with reference to FIG. 7C.

Fig. 5 shows a schematic diagram of a waveguide arrangement 500 according to an embodiment of the invention. The waveguide arrangement 500 shows the coupling of light from a light source to a receiver through a pair of waveguide sections. The waveguide arrangement 500 is suitable, for example, for the waveguide portions 414 and 416 of the input device 400 shown in fig. 4.

The waveguide arrangement 500 comprises a first waveguide section 502 and a second waveguide section 504 forming a pair of waveguide sections for input in one direction. When light 506 is applied to one end of waveguide section 502, a plurality of light beams 508 are formed and directed toward waveguide section 504 by a plurality of light emitting waveguides (i.e., light emitting channels) in waveguide section 502. Each light beam 508 is directed to a corresponding light receiving waveguide (i.e., light receiving channel) of the waveguide portion 504. The light receiving waveguides of waveguide section 504 then direct the light received from light beam 508 to the end of waveguide section 504 where (for the receiver) a plurality of light beams 510 are generated. Each light beam 510 corresponds to light received in one of the light receiving waveguides of the waveguide portion 504. The input direction for which the waveguide arrangement 500 is useful in determining is perpendicular to the light beam 508 (i.e., the horizontal direction in fig. 5).

Fig. 6A and 6B are cross-sectional views of waveguide portions 504 and 502 shown in fig. 5. In fig. 6A, waveguide portion 600 is shown having a light-receiving side 602 and a light-output end 603. The light receiving side 602 includes a plurality of waveguides (channels) to receive light. In particular, the light receiving side 602 is shown as having a number of light receiving waveguides, here shown as light receiving waveguides 604, 606, 608, 610 and 612. Each of these light receiving waveguides has a corresponding light output waveguide (channel) 614, 616, 618, 620, and 622, respectively, at the light output end 603 of the waveguide portion 600. Light receiving waveguides 604, 606, 608, 610 and 612 and light output waveguides 614, 616, 618, 620 and 622 are inside waveguide portion 600.

In fig. 6B, waveguide section 624 includes a light output edge 626 and a light input 628. The light output side 626 has a plurality of light output waveguides (channels) 630, 632, 634, 636 and 638. Each of the light output waveguides 630, 632, 634, 636 and 638 corresponds to a respective one of the light receiving waveguides 612, 610, 608, 606 and 604 of the waveguide portion 600. The light input 628 of the waveguiding section 624 is shown as having a plurality of light input waveguides (channels), here shown as light input waveguides 640, 642, 644, 646 and 648. Each of the optical input waveguides 640, 642, 644, 646 and 648 has a corresponding optical output waveguide (channel) 630, 632, 634, 636 and 638, respectively, at the optical output edge 626 of the waveguide portion 624. The optical input waveguides 640, 642, 644, 646, and 648 and the optical output waveguides 630, 632, 634, 636, and 638 are inside the waveguide portion 600.

In order to keep the dimensions of the waveguide sections small but allow them to provide high resolution, the waveguide sections preferably comprise a waveguide layer. Fig. 6C is a schematic diagram showing the structural configuration of a waveguide portion 650 according to an embodiment of the present invention. The waveguide portion 650 includes a first substrate 652, a waveguide 654 supported on an upper surface of the first substrate 652, and a waveguide 656 on a lower surface of the first substrate 652. The waveguide portion 650 further includes a second substrate 658 supporting a waveguide 660 on an upper surface of the second substrate 658 and a waveguide 662 on a lower surface of the second substrate 658. The height, width, and shape of the waveguides 660, 656 can vary widely. However, in one suitable embodiment, the height is about 5 microns and the width is about 10 microns, and the shape is rectangular. A polyester layer 664 is then sandwiched between the first and second substrates 652 and 658 and their associated waveguides and holds the waveguide portions 650 together with optical glue. An advantage of the waveguide layer of waveguide section 650 is that it helps provide high resolution. The structural configuration of the waveguide portion 650 is also referred to as a waveguide layer structure. For ease of illustration, the waveguide portion 650 shown in fig. 6C does not show the curvature of the channel shown in fig. 6A and 6B. It is desirable to keep the components (chassis) of the input device to a side height of less than 2 mm. In one embodiment, the single waveguide layer (i.e., glass plate with waveguide) is 760 microns thick, the glass plate is approximately 0.7mm thick, and the dibenzocyclobutene (BCB) layer thickness is variable (e.g., in the range of approximately 0.5 to 50 microns thickness). Thus, the total thickness of the two single waveguide layers of the waveguide sandwich (i.e., the glass plate with the rows of single waveguides on both sides) and a polyester layer (e.g., about 5 mils) between the two waveguide layers is about 4 mm.

Fig. 6D is a flow diagram of a fabrication process 670 for fabricating the waveguide portion 650 shown in fig. 6C, in accordance with one embodiment of the present invention. Initially, the fabrication process 670 yields 672 a sheet of glass. The glass sheet acts as a support substrate for the construction of the individual waveguides. Next, a BCB layer was applied to the first side of 674 glass pieces and a mild bake was performed. BCB is a photosensitive material. The photosensitive BCB is then exposed and developed 676 to form channels. Next, the BCB layer is baked 678. In other words, the channels are formed by a lithographic process. Thereafter, a channel may be formed on the other side of the substrate by the process described below. The glass sheet is turned over 680. The BCB layer is applied to the second side of the 682 glass pieces and gently baked. The photosensitive BCB is then exposed and developed 683 to form the channels. The BCB layer is then baked 684. The glass sheet is then laser cut 685 into individual waveguides. Laser etching and dicing are standard processes. Finally, the two individual waveguides can be merged 686 together with a polyester strip and optical glue (see fig. 6C). The polyester strip serves to separate or isolate the combined individual waveguides from each other. After block 686, the fabrication process 670 is complete and ends.

FIG. 6E is a schematic diagram showing flared waveguides 690, 692, and 694. Flared waveguides may be used at the ends of the transmit and/or receive waveguides. For example, the portion of the light output waveguide 630-638 proximate the light output edge of the waveguide section 624 may be widened or tapered as shown in FIG. 6E. The light diffraction spread of the light can be reduced by widening the light output waveguide. Also, widening the light input waveguide increases the area over which incident light is coupled.

Figure 6F is a flow diagram of a fabrication process 696 for fabricating a waveguide structure according to another embodiment of the invention. In general, a waveguide structure includes a substrate, a low index (index) refractive layer, and a high index refractive layer. In the embodiment discussed with reference to fig. 6D, glass may be used as both the substrate and the low index refractive layer, while the BCB layer may be used as the high index refractive layer.

In any case, the fabrication process 696 is as follows. Initially, a substrate material 696-1 is obtained. Decision block 696-2 then determines whether the refractive index of the substrate material (IOR) is lower than the refractive index of the waveguide material to be used. When the decision block 696-2 determines that the refractive index of the substrate material is not lower than the refractive index of the waveguide material, then 696-3 a material with a low refractive index (low IOR) is obtained. The material is then applied 696-4 to both sides of the substrate. Such an operation is performed if the low IOR material needs to be baked or bent. Thus, the substrate with the material thereon has a refractive index lower than the refractive index of the waveguide material. On the other hand, when the decision block 696-2 determines that the refractive index of the substrate material is lower than the refractive index of the waveguide material, blocks 696-3 and 696-4 are bypassed.

Desirable characteristics of the substrate material include stiffness, low coefficient of thermal expansion, low water adsorption capacity, surface adhesion to waveguide materials of low IOR materials, and low cost. Suitable substrate materials include glass, some plastics, ceramics. Desirable characteristics of low IOR layers include lower IOR than waveguide materials, optical transparency, adhesion to substrate and waveguide materials, application as coatings or as thin film growth, low coefficient of thermal expansion, low water adsorption capacity, and low cost.

After block 696-4 or after block 696-2 when the decision block 696-2 determines that the refractive index of the substrate material is lower than the refractive index of the waveguide material to be used, a piece of waveguide material 696-5 is obtained. Desirable characteristics of waveguide materials include higher IOR than low IOR materials or substrate materials, optical transparency, adhesion to substrate materials and waveguide materials, application as coatings or as thin film growth, low coefficient of thermal expansion, low water absorption, and low cost. The first side 696-6 of the waveguide material is then coated. Once applied, the first side of the waveguide material may be lithographically patterned 696-7 to form individual waveguides. The second side 696-8 of the waveguide material is then coated. Once coated, the second side of the waveguide may be patterned 696-9 to form a single waveguide. Thus, with this process, a single waveguide is made on both sides of the substrate, thereby increasing the pixel density (i.e., resolution) that the waveguide can provide and reducing size requirements and cost (see FIG. 6C). Thereafter, the waveguide portion is sheared 696-10 from the fabricated substrate and waveguide material.

Fig. 7A is a schematic diagram showing light coupled into a waveguide section. As shown, the waveguide portion is waveguide portion 624 shown in fig. 6B. In particular, a Light Emitting Diode (LED)700 includes a light output portion 702 from which light is output 702 according to electrical signals provided to ports 704 and 706 of the LED 700. The light output section 702 abuts (or nearly abuts) the end 628 of the waveguide section 624 to provide light to the waveguide section 624. The LED 700 preferably has a relatively short wavelength, such as a blue LED. More particularly, LED 700 is a 430 nanometer (nm) blue gallium nitride LED, available from Stanley corporation. The output light intensity of the Stanley blue gallium nitride LED was approximately 100 millicandelas. The LEDs enter a T1 package, where the T1 package is a small package approximately 3.2 millimeters (mm) in diameter.

FIG. 7B is a schematic diagram showing optical coupling of a waveguide portion to a receiver. As shown, the waveguide portion is waveguide portion 600 shown in fig. 6A. In particular, waveguide section 600 receives and guides light through its light receiving waveguides 604 and 612 to receivers optically coupled to waveguide section 600. In this illustrated embodiment, the light receiving waveguides 604-612 are optically coupled to a light detection region 708 of an integrated circuit device 710 that operates as a receiver. The integrated circuit device 710 may be attached to (or proximate to) the waveguide portion 600 in various ways. For example, the chassis of the input device (see fig. 3), an adhesive, or some other mechanical structure may provide mechanical support for the integrated circuit device 710 relative to the waveguide portion 600 to provide the desired optical coupling.

Fig. 7C is a block diagram of an ASIC layout 720 for implementing a receiver in accordance with one embodiment of the present invention. ASIC layout 720 includes various functional logic modules. The emitter driver 722 supplies a power supply (PWR) and a Ground (GND) signal to the emitter (light source) to emit light. The clock circuit 724 provides a clock signal to the emitter driver 722 to control the operation of the emitter according to the duty cycle associated with the clock signal. The ASIC layout 720 also includes a photodetector and associated circuitry 726 that detects light received by the receiver. The outputs of the photodetectors and associated circuitry are signals that indicate those pixels that are black in the x and y directions. These output signals are then processed by processing circuit 728. For example, the processing circuitry performs the shading process discussed below. The processing circuit 728 includes a first-in-first-out (FIFO) buffer 730 where data to be sent to the host is temporarily stored. The communication circuit 732 retrieves the data stored in the FIFO buffer 730 and outputs the data to the host. The receiver 720 is electrically connected to the DATA (DATA) and Ground (GND) signals. The processing circuit 728 and the communication circuit 732 also receive a clock signal from the clock circuit 724 for processing in synchronization with the clock signal. The ASIC arrangement 720 also includes initialization circuitry 734 for starting and initializing the photo detector and associated circuitry 726 and processing circuitry 728.

Fig. 8 is a flow diagram of an initialization process 800 in accordance with one embodiment of the invention. The initialization process 800 begins with activating 802 a light source. For example, referring to FIG. 4, light sources 402 and 404 (emitters) will be activated. Next, the light intensity value for each light sensing element is read 804. That is, referring to FIG. 4, the light sensing elements of receivers 406 and 408 operate to measure the light intensity value of the input of each of their light sensing elements. Thereafter, light sensing elements having light intensity values below a predetermined threshold are disabled 806. The disabled optical readout elements are no longer used because they do not correspond to the optical receiving channels of the corresponding waveguides. In other words, the operation of initialization process 800 effectively aligns the light receiving channels of the waveguide with the appropriate light readout elements of receivers 406 and 408. Generally, this process is desirable because it facilitates the manufacture, design, and installation of input device 400, particularly because the channel within the waveguide is very narrow and the receiver will generally include an area of optical readout elements that exceeds the size of the end of the waveguide. For example, in FIG. 7B, the light detection region 708 of the integrated circuit device 710 is larger than the end 603 of the waveguide 600. After block 806, the initialization process 800 is complete and ends.

Fig. 9 is a flow diagram of a threshold adjustment process 900 according to one embodiment of the invention. The threshold adjustment process 900 initially reads 902 the light intensity value for each of the allowed light readout elements under ambient light conditions. An "on" threshold is then determined 904 based on the light intensity values that have been read. Next, an "on" threshold is set 906 in the receiver. For example, the "on" threshold may be set 906 by the ambient current (current) plus n (ambient current-black current), where n is an integer. After block 906, the threshold adjustment process 900 is complete and ends.

The threshold adjustment process 900 is used to periodically and frequently set an "on" threshold amount for the receiver so that the receiver can properly discriminate between "on" and "off conditions. By periodically and frequently updating the "on" threshold amount, the input device is able to compensate for changes in ambient light conditions that may affect the light intensity values measured by the light readout elements. For example, if a computer system user with an input device according to the present invention initially begins using the computer system in the dark and then turns on a light (directing the light toward the waveguide), the ambient light conditions change and the input device cannot operate properly due to such changes in ambient light conditions. Thus, the threshold adjustment process 900 is able to compensate for changes in ambient light conditions so that the input device can function in a reliable manner regardless of ambient light conditions or changes thereto.

FIG. 10A is a flow diagram of a shadow detection process 1000 in accordance with one embodiment of the invention. The detected shadows are associated with a user touch or stylus touch to the input device according to the present invention. A touch of a finger or stylus to a display device having an input device according to the invention mounted thereon causes a shadow to be generated, since a particular light beam generated by the input device will be blocked. Shadows are created because the receiver measures very low intensities for these light sensing elements because certain light beams that cross (i.e., the light grid) across the surface of the screen area are blocked (or interrupted). Since these particular beams are blocked, the receiver then detects these particular beams as "off".

The shadow detection process 1000 initially reads 1002 light intensity values for each allowed light sensing element. Then, for those allowed optical readout elements that are determined to be "off," the identifier is stored 1004. The slave receivers then pass these "off" identifiers of the allowed optical read elements to the master receiver 1006. The master receiver then determines from these identifiers the minimum shadow 1008. By determining the minimum shadow 1008, the input device is able to distinguish stylus or pen inputs from a user's hand touching the screen at the same time. After the minimum shadow 1008 is determined, the coordinate location of the minimum shadow is communicated to the host 1010. Following block 1010, the shadow detection process 1000 is complete and ends.

One example of the shadow detection processing 1000 is explained below with reference to fig. 10B and 10C. In fig. 10B and 10C, the light detection units are numbered 0, 1, 2, 3. In these examples, it is assumed that only those light detection units (e.g., black units) that do not receive light output one signal. In the process, the address of each black cell is sequentially input to one logic array. The logic array then preferably first throws out all but the first and last pixels of any shadow that may be present, leaving only the pattern in memory in a first-in-first-out (FIFO) buffer: the first, the last; the first, the last. For example, for fig. 10B, the FIFO would contain: 3, 6; 12, 12. The process then selects the smallest shadow and outputs its center and width. In this example, 12, 1 are sent to the host. In another example, for FIG. 10C, the FIFO would contain 12, 16, and then 14, 5 would be sent to the host.

By selecting the minimum shadow to be sent to the host, the shadow detection process 1000 can filter out the situation where two objects, such as a stylus and a hand, touch the screen at the same time. By identifying and selecting the smallest shadow, the shadow detection process 1000 can distinguish between two objects and select the desired one. However, this technique does not work when the shadow from the hand covers the shadow of the stylus, but this will not typically happen. The width of the shadow is sent because this gives the width of the stylus. This is useful for calligraphy on a pen screen and potentially useful for measurement applications. In addition, as described above, the input device according to the present invention optionally further includes a lens (e.g., a diffractive lens) to collimate the light output by the transmitting waveguide to the receiving waveguide. The lens may be a single lens or an array of lenses. Assuming that the waveguides are small (e.g., 3-6 microns), the lenses are often referred to as microlenses. Further, the receiving end of the input device may also include a lens (e.g., a diffractive lens) that focuses light into the receiving waveguide.

Fig. 11A and 11B are schematic diagrams showing a microlens placed close to a waveguide to mitigate diffusion of light emitted from the waveguide. In fig. 11A, optical device 1000 places microlens 1102 proximate to the output end of waveguide 1104. The micro-lens 1102 functions to collimate the light emitted from the waveguide 1104. Thus, the beam traversing one input area is the collimated beam 1106. The waveguide 1108 with a flared portion receives the collimated light beam after traversing the input area. The waveguide then directs the received light to a receiver. In fig. 11B, optical device 1110 is similar to optical device 1000 at the transmitting end, except at the receiving end. In particular, the lens 1112 receives the collimated light after traversing the input area. The lens 1112 focuses the received collimated beam onto the waveguide 1114.

The use of lenses serves to simplify the structure of the waveguide, since etching a thick coating of the waveguide is both difficult and time consuming. For example, it may be considered that 5 μm is moderate, 10 μm is somewhat thick, and 20 μm is quite thick. The amount of light diffusion in the waveguide is inversely proportional to the size of the waveguide in that dimension, so a thicker coating means a deeper waveguide, meaning less diffusion. Thus, with the use of a lens, a thinner coating (e.g., 5 microns) can be used for the waveguide. Another advantage of using a lens is that the power (i.e., light intensity) required by the emitter can be reduced.

The lens is typically made of plastic. The lens can be made in several different ways. One method is to deposit droplets of resin on a substrate by an injection device, where the injection device controls the characteristics and location of the droplets. This process provides high quality but is relatively expensive. Therefore, it is preferable for the motherboard fabrication. Another method involves lithographic etching followed by melting and resolidifying the plastic on the substrate. Conventional methods such as high quality molding and embossing can also be used and are relatively inexpensive. Lenses are available from many manufacturers that produce microlens arrays (e.g., TR Labs of Alberta, Canada).

The embodiment of the input device shown in fig. 4 and described above may be a preferred embodiment of the present invention. However, it should be understood that other embodiments of the present invention may be used. In these embodiments, the number of waveguide sections, transmitters and receivers may vary. While more components may be required for a larger perimeter input region, since the manufacture of the components may also provide practical limitations, in general, fewer components are less expensive. Fig. 12A-12D are schematic diagrams of input devices according to other embodiments of the invention. These embodiments show a different arrangement of an input device according to the invention in the same way as in fig. 4. In each embodiment, the dashed lines represent the optical path from the emitter (light source) through the waveguide, through the input region, and into the waveguide. Further, although not shown, these embodiments may include a lens in a manner similar to that shown in fig. 4. Fig. 12A is a schematic diagram of a two transmitter (T1, T2), two receiver (R1, R2) embodiment with a four-section waveguide structure. Fig. 12B is a schematic diagram of one transmitter (T1), one receiver (R1) embodiment with a two-part waveguide structure. Fig. 12C is a schematic diagram of an embodiment of a transmitter (T1), a receiver (R1) with a waveguide structure having a portion. By having only one portion, alignment of the opposing optical waveguide portions is avoided, although manufacturing costs may be higher. Fig. 12D is a schematic diagram of a one-transmitter (T1), four-receiver (R1, R2, R3, R4) embodiment with a waveguide structure having one section. Applying the embodiment shown in fig. 12D, it is possible to cover the case of a large input area. Since the receiver has a limit on the number of waveguides or pixels that can provide light detection, the present invention uses additional receivers to enable tuning to larger perimeter input devices.

The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. Thus, any suitable modifications and equivalents may be resorted to as falling within the scope of the invention.

Claims (33)

1. An apparatus, comprising:

a light source;

it is characterized in that the device further comprises:

a multi-channel transmit waveguide section optically coupled to receive light from the light source, the transmit waveguide section comprising a plurality of light-emitting waveguides that produce a first set of light beams by directing the light received from the light source such that the first set of light beams are simultaneously emitted from the light-emitting waveguides in a first direction;

a multi-channel receive waveguide section spaced from said transmit waveguide in a first direction, said receive waveguide section comprising a plurality of light receive waveguides for simultaneously receiving said first set of light beams from said transmit waveguide; and

a photodetector optically coupled to the receiving waveguide portion, receiving light from the light receiving waveguide of the receiving waveguide portion, the photodetector measuring light intensity of the light from the light receiving waveguide of the receiving waveguide portion.

2. The apparatus of claim 1, wherein the apparatus is an input device of an electronic device.

3. The apparatus of claim 2, wherein an input region is created between the transmit waveguide section and the receive waveguide section.

4. The apparatus of claim 3, wherein a user may provide input to the electronic device by interacting with an input area of the apparatus with a finger or stylus.

5. The apparatus of claim 3, wherein the apparatus is a user input device of a computer system interacting with the input area.

6. The apparatus of claim 1, wherein the photodetector is an integrated circuit having an optical readout region optically coupled to the receiving waveguide portion to receive light from a light receiving waveguide of the receiving waveguide portion.

7. The apparatus of claim 1, wherein the apparatus further comprises:

a lens optically positioned proximate to the transmitting waveguide portion to collimate the first set of light beams emanating from the transmitting waveguide toward a corresponding light receiving waveguide of the receiving waveguide portion.

8. The apparatus of any of claims 1-7, wherein the light emitting waveguide and the light receiving waveguide are lithographically defined waveguides.

9. The apparatus of claim 8, wherein the light emitting waveguide and the light receiving waveguide have rectangular cross-sections.

10. The apparatus of any of claims 1-9, wherein the transmit waveguide section is formed of an insulating material and the receive waveguide is formed of an insulating material.

11. The apparatus of claim 7, wherein the apparatus is an input device for providing user input to a computer system, and

wherein the photodetector is an integrated circuit having an optical readout region optically coupled to the receiving waveguide portion to receive light from the optical channel of the receiving waveguide.

12. The apparatus of claim 1, wherein the transmit waveguide portion is a non-fiber transmit waveguide and the receive waveguide portion is a non-fiber receive waveguide.

13. The apparatus of claim 1, wherein the transmit waveguide section is a multilayer transmit waveguide and the receive waveguide section is a multilayer receive waveguide.

14. The apparatus of claim 1, wherein the transmit waveguide section is a rectangular slab and the receive waveguide section is a rectangular slab.

15. The apparatus of claim 1, wherein the light detector comprises a plurality of light detecting elements that substantially simultaneously detect light intensities of light from at least a first set of light receiving waveguides of the receiving waveguide portion.

16. The apparatus of claim 15, wherein the apparatus is a high resolution input device, such that at least the first set of light beams can be substantially simultaneously directed from the light source through the light emitting waveguide in the emitting waveguide portion, through an input region, then substantially simultaneously received by the light receiving waveguide in the receiving waveguide portion, and then directed to corresponding light detecting elements of the light detector, where light intensities are substantially simultaneously detected.

17. The apparatus of claim 1, wherein the receive transmit waveguide has a flared portion proximate an end of the receive waveguide portion that receives the first set of light beams.

18. The apparatus of claim 13, wherein the multilayer transmit waveguide section comprises at least one low index refractive layer and at least one high index refractive layer, and wherein the multilayer receive waveguide section comprises at least one low index refractive layer and at least one high index refractive layer.

19. An input device of an electronic device, comprising:

at least one light source;

a photodetector for detecting light intensity at the plurality of photodetecting elements; and the number of the first and second groups,

a lithographically defined waveguide structure comprising a plurality of waveguides,

wherein the light source couples light into a first set of waveguides of the waveguide structure, and the waveguide structure couples light guides into the waveguides to produce a beam grid from the light coupled into the waveguides, the beam grid simultaneously traversing an input area and then being directed by a second set of waveguides of the waveguide structure toward a light detecting element of the light detector.

20. The input device as recited in claim 19 wherein the lithographically defined waveguide structure is an insulating material and

wherein the first set of waveguides transmits the optical beam through the input region to corresponding waveguides of the second set of waveguides.

21. The input device of claim 19, 20, wherein the input device further comprises:

a lens optically positioned proximate to the waveguide structure to collimate the light beams emanating from the first set of waveguides.

22. The input device as in claim 21, wherein the lens is a microlens formed in a material positioned proximate to the light exit end of the first set of waveguides from which the light beams emanate.

23. The input device of claim 19, wherein the input device provides user input to a computer system, an

Wherein the photodetector is an integrated circuit having an optical readout region optically coupled to the receiving waveguide portion to receive light from the optical channel of the receiving waveguide.

24. The input device as recited in claim 23 wherein the optical readout area of the integrated circuit includes a plurality of light sensitive cells.

25. The input device as recited in claim 19 wherein the waveguide structure comprises a plurality of waveguide sections.

26. The input device of claim 25, wherein the first waveguide section produces a horizontal beam, the second waveguide section produces a vertical beam, the third waveguide section is positioned opposite the first waveguide section through the input region and receives the horizontal beam from the first waveguide section, and the fourth waveguide section is positioned opposite the third waveguide section through the input region and receives the vertical beam from the second waveguide section.

27. The input device as recited in claim 19 wherein the waveguiding structure is a unitary structure.

28. The input device as recited in claim 19 wherein the electronic device is a computer system having a display device, the display device including a screen area and a peripheral portion, wherein the input device is secured to the peripheral portion of the display device, the input area of the input device being disposed on the screen area of the display device.

29. The input device of claims 23-28, wherein the input device further comprises:

a lens optically positioned proximate to the waveguide structure to collimate the light beams emanating from the first set of waveguides.

30. The input device as recited in claim 19 wherein the lithographically defined waveguide structure is an insulating structure.

31. The input device as in claim 19, wherein the first set of waveguides re-direct light into the waveguides so as to direct the resulting grating of light beams in a direction that is substantially different from a direction in which light is coupled into the first set of waveguides.

32. A method for determining user input with respect to an input device, the method comprising:

(a) providing a light source;

(b) generating a plurality of parallel light beams by directing light from a light source through a plurality of paths of a multi-channel launch waveguide;

(c) simultaneously directing a parallel light beam through an input area of an input device, the input area being positioned relative to the input device;

(d) simultaneously receiving the specific parallel light beams after having passed through the input area;

(e) determining the light intensity of each of the received parallel light beams; and

(f) determining whether there is user input with respect to the input area based on the determined light intensity value.

33. The method of claim 32, wherein the method determines a position of the user input relative to the input device, an

Wherein the method further comprises:

(g) the position of the user input relative to the input device is determined from the determined light intensity values.