Patent Application
20060043267
Optical pointing devices, such as optical mice, direct movement information to a graphical user interface of a computer by tracking relative movement between a navigation surface, such as a mouse pad, and an image sensor within the optical pointing devices. Light is optically radiated onto the navigation surface by a light source, such as a light emitting diode or a laser. Based on the illumination of the navigation surface, images are obtained using electronic image sensors, which typically contain an array of photodetectors arranged in a pattern. Each photodetector in the array creates an output signal proportional to the intensity of light impinging on that photodetector. The output signals from the photodetector array are processed to generate an image of the navigation surface. By comparing a series of these images over time, the optical mouse develops movement information about movement of the mouse relative to the navigation surface. This movement information, upon processing, enables a corresponding movement of a pointer on the graphical user interface of the computer.
Some optical pointing devices use a coherent light source (e.g., a laser) to illuminate the navigation surface. While coherent light sources enable lower power consumption and more accurate and precise optical navigation, these coherent illumination navigation systems tend to be more sensitive to the presence of contaminants, such as particles of dust, dirt, food, hair, and other substances. Optical pointing devices that use a non-coherent light source (e.g., a light emitting diode) are less affected by contaminants such as dirt and dust because they employ diffuse light patterns which tend to cause the contaminants to remain out of focus in the images. Whichever light source is used, optical pointing devices perform better with less noise, caused by contaminants, scratches, etc.
Once a contaminant becomes fixed to one of the optical surfaces of the optical pointing device (e.g., an imaging lens, illumination lens, etc) and is coherently-illuminated, it becomes a fixed pattern on the image of the navigation surface. For example, with a contaminant present, one or more photodetectors of the photodetector array of the image sensor will generate a fixed output signal having an intensity or location, that does not correspond to an actual surface feature or light pattern on the navigation surface. This fixed pattern acts as noise, distorting image comparison and thereby inhibiting accurate tracking of movement of the optical pointing device relative to the navigation surface. Unfortunately, contaminants are unavoidable during transport or use in dusty environments. Similar negative effects can result from scratches on optical surfaces resulting from exposure to the environment, handling, etc.
Accordingly, optical pointing devices face an on-going challenge to mitigate effects of fixed pattern noise from contaminants and other sources.
One aspect of the invention provides an optical mouse with a replaceable contaminant barrier. The mouse comprises a housing, an optics module, and the replaceable contaminant barrier. The housing has a surface with an optical window. The optics module includes a light source disposed within the housing and configured to direct light out of, and receive light in, through the optical window. The replaceable contaminant barrier is transparent and is removably secured across the optical window.
In the following detailed description, references made to the accompanying drawings, which form a part hereof, and which is illustrated by way of illustrations specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “front,” “back,” etc., is used with reference to the orientation of the figures(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
Embodiments of the present invention mitigate the effects of fixed pattern noise on optical navigation resulting from scratches and/or contaminants, such as particles of dust or dirt. These embodiments enhance optical navigation with both non-coherent light sources and coherent light sources but is especially effective for coherently-illuminated optical mice. In one embodiment, one or more replaceable transparent barriers covers an opening to a cavity of the mouse to prevent dirt from reaching exposed optical surfaces, such as a surface of the imaging lens or illumination lens, within the cavity of the mouse. In another embodiment, a bottom surface of the mouse includes a transparent optical member that seals the cavity of the mouse to prevent the entry of contaminants. The transparent optical member is covered by a replaceable transparent cover that prevents scratching of the transparent optical member, thereby minimizing fixed pattern noise.
Optical mouse 22 is used as a pointing device for a computer (not shown) based upon sliding movement between bottom surface 36 of optical mouse 22 relative to navigation surface 25. In particular, optics module 32 obtains a series of images of navigation surface 25 over time as the mouse 22 moves relative to navigation surface 25. The differences between the images obtained over time is converted into movement information for directing movement of a pointer on a graphical user interface of a computer or other device.
Embodiments of the present invention introduce a replaceable transparent barrier at the bottom surface 36 of optical mouse 22 between the optics module 32 and the navigation surface 25 to prevent contaminants 50 (or features of navigation surface 25) from causing fixed pattern noise that would otherwise degrade the performance of optical mouse 22. These embodiments are described in more detail in association with
Mouse 60 also comprises optics module 80, which includes coherent light source 82, sensor 84, illumination lens 86 with surface 87, and imaging lens 88 with surface 89. Lens surface 87 and lens surface 89 are exposed to the environment and navigation surface 25 via opening 68 in bottom 66 of mouse 60. In another embodiment, opening 68 is formed on a different surface (e.g. top, side) of shell 62 with optics module 80 arranged to emit and receive light through opening 68 in association with navigation surface 25 or an alternative navigation surface that is alignable with opening 68 for optical navigation.
In one form of the invention, light source 82 is a coherent light source 82 that produces at least partially coherent light. In one embodiment, coherent light source 82 comprises a laser light source and produces substantially coherent light in which the coherence length allows interference patterns that are discernable by a sensor, such as sensor 84. Sensor 84 comprises an integrated circuit including one or more of digital input/output circuitry, processing circuitry, analog/digital signal conversion, light source drivers, and a photodetector array. Illumination lens 86 directs coherent light from light source 82 in a focused pattern onto navigation surface 25 while imaging lens 88 receives and directs a pattern of light reflected from navigation surface 25 into sensor 84.
In another form of the invention, light source 82 comprises a non-coherent light source such as a light emitting diode (LED). While non-coherently illuminated optical pointing devices are less sensitive to particle contaminants, embodiments of the present invention can still yield improvements in optical tracking.
Optics module 80 also comprises controller 85 which has logic for controlling the operation of light source 82 and sensor 84, a memory for storing images obtained at sensor 84, and logic for communicating movement information from optics module 80 to an external device, such as a computer, for directing a pointer on a graphical user interface. In some embodiments, controller 85 is incorporated into sensor 84.
In one form of the invention, transparent barrier 90 is a flexible translucent film, such as a thin film plastic material. Barrier 90 includes a top surface 92, a bottom surface 94, adhesive portion 96, and edge 98. Barrier 90 is sized to completely cover opening 68 of mouse 60, extending beyond an edge of opening 68 so that adhesive portion 96 of barrier 90 can removably secure barrier 90 to bottom surface 66 of mouse 60. In one form of the invention, adhesive portion 96 is a pressure sensitive adhesive, so that barrier 90 acts as a tape that is pressable onto, and peelable off of, bottom surface 66 of mouse 60. Moreover, transparent barrier 90 can be formed as one of many different shapes, such as a generally circular member, a generally rectangular member, a generally triangular member, a generally trapezoidal member, a generally polygonal member, as well as other shapes. Some of these shapes are illustrated later in
In one form of the invention, transparent barrier 90 is generally color-free while in another form of the invention, barrier 90 is a colored material. While accounting for the type, color and thickness of its material, barrier 90 is constructed with an index of refraction suitable for passing light from light source 82 to navigation surface 25, and from navigation surface 25 to sensor 84, without substantially altering the illumination pattern from light source 82 and/or images reflected from navigation surface 25.
In one form of the invention, the flexible film forming barrier 90 comprises a material or coating that repels contaminants.
Once barrier 90 becomes scratched or contaminated with dirt, barrier 90 is simply lifted off bottom surface 66 of optical mouse 60, and replaced with a new transparent barrier 90 that is free from scratches and contaminants. New transparent barrier 90 restores optical mouse 60 to its optimal performance by removing scratches and/or contaminants that were fixed to the discarded replaceable barrier 90 and which produces fixed noise patterns.
In one form of the invention, sensor 84 of optical mouse 60 comprises a method for detecting the presence of fixed pattern noise, such as particle contaminants, so that a user is alerted to perform maintenance on optical mouse 60 to remedy the situation. One form of maintenance comprises replacing transparent barrier 90. Accordingly, optical mouse 60 monitors its own operation for degraded performance due to fixed pattern noise and signals a user to replace barrier 90, when appropriate.
Mouse 150 further comprises transparent barrier 152 and shoes 154. Barrier 152 prevents the entry of contaminants 50 into cavity 63 of mouse 22, and onto optical surfaces of lenses 86, 88. Barrier 152 comprises a resilient, semi-rigid member forming securing portion 156, upper surface 158, bottom surface 160, central portion 162 and flange 164. In one form of the invention, barrier 152 comprises a generally circular shape. Securing portion 156 securely engages edge of opening 68 of optical mouse 60 to maintain barrier 152 in a fixed position within opening 68, yet enables removal of barrier 152 at the discretion of the user. Flange 164 extends radially outward from central portion 162 and has a thickness that generally corresponds to the thickness of shoes 154. Contact shoes 154 are disposed on bottom 66 of mouse 150 for maintaining sliding contact with navigation surface 25 and have a thickness that generally maintains opening 68 a small distance above navigation surface 25.
Flange 164 has a thickness generally equal to the thickness of contact shoes 154 so that lower surface 160 of barrier 156 also is positioned for sliding contact with navigation surface 25. In another embodiment, transparent barrier 156 omits flange 164 and includes only central portion 162 that has a thickness (as shown) configured to make lower surface 160 substantially coplanar with a bottom surface of contact pads 154 for contact with navigation surface 25. In one form of the invention, mouse 150 does not include contact shoes 154.
In one form of the invention, transparent barrier 152 preferably made of a material so that upper and lower surfaces 158, 160 are hard, optically smooth surfaces adapted to passing light with minimal interference and that are resistant to scratches, thereby further minimizing fixed pattern noise during optical navigation. Moreover, transparent barrier 152 is constructed of a material to minimize bubbles, voids, volume defects etc, that would otherwise produce effects similar to fixed pattern noise caused by scratches and/or contaminants. In one embodiment, transparent barrier 152 is made of a sapphire material. As previously described for barrier 90, barrier 152 can comprise any one or more of different colored materials, such as designer colors. In one form of the invention, barrier 152 has a color adapted for LED illumination in variegated colors. Finally, transparent barrier 152 can have any one of the shapes previously described for barrier 90 and as illustrated in
When transparent barrier 152 does become scratched or otherwise contributes to undesirable performance of optical mouse 150, transparent barrier 152 is removed from opening 68 of optical mouse 150, discarded, and then replaced with a new transparent barrier 152 that is positioned over opening 68 of mouse. In one form of the invention, as shown in
In use, protective cover 204 prevents scratches from being formed on optical member 202, thereby preserving the optical transmitting quality of optical member 202 as an optical window during extensive use of mouse 200. Instead, scratches from the environment, such as features of navigation surface 25, occur in protective cover 204, which can readily be removed and replaced with a new protective cover 204. In one form of the invention, sensor 84 detects the presence of fixed pattern noise, which can be caused by scratches on protective cover 204, and alerts the user to perform maintenance on optical mouse to remedy the situation. In response, the user simply peels off used transparent cover 204, and pressingly rolls a new scratch-free transparent cover 204 over optical window 202.
In use, transparent barrier 260 operates substantially similar to barrier 152, filling in opening 254 to prevent the entry of contaminants into cavity of mouse 260. Transparent barrier 260 is a replaceable thin flexible member, with securing members 262, 264 being sized and adapted for engaging edge of opening 254 to removably secure barrier 260 within opening 254. As for the other embodiments, once barrier 260 becomes dirty, scratched, and/or covered with undesirable substances (e.g. grease), it is simply removed and replaced with a new barrier 260.
Embodiments of the invention, including those shown and described in association with
Embodiments of the present invention, as shown in
Embodiments of the present invention minimize fixed pattern noise in optical pointing devices by preventing contaminants from reaching exposed optical surfaces within an optical mouse and/or by preventing permanent scratches on an optical window of an optical mouse. With these anti-contamination measures, the performance advantage of coherently-illuminated optical navigation for hand-operated pointing devices are better realized and even non-coherently illuminated optical pointing devices will enjoy enhanced performance.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
