BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a cross-sectional view of one embodiment of an optical mouse having adjustable resolution;
FIG. 2 is an enlarged view of a portion of FIG. 1;
FIG. 3 is an illustration of an embodiment of an actuator; and
FIG. 4 is a diagram of a lens, sensor and navigation surface.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a cross sectional view of optical mouse 10 situated upon navigation surface 11 and with an upper cover removed. Optical mouse 10 includes light emitting diode (LED) 12, imaging lens 13 and image sensor 14. The distance between lens 13 and image sensor 14 is referred to as the sensor distance, while the distance between lens 13 and the navigation surface 11 is referred to as the surface distance, as also shown in FIG. 4. In one embodiment, image resolution of optical mouse 10 can be adjusted by increasing or decreasing the sensor distance and/or surface distance. In one embodiment, the sensor distance and surface distance are independently controlled via a pair of actuators 20, 21, respectively. The sensor and lens positions can be optimized, for example via a controller, in order to provide a desired resolution level.
FIG. 2 is an illustration of portion 200 of optical mouse 10 showing actuator 20 positioned between lens 13 and image sensor 14 and actuator 21 positioned between lens 13 and navigation surface 11. Actuator 20 is used to vary the sensor distance, while actuator 21 is used to vary the surface distance. Actuators 20, 21 may be electromechanical devices or any type of device that can move or refocus the light rays. Actuators 20, 21 can include position sensors for motion control via, for example, an on-board microprocessor. One or more of each of these sensors can be provided and they both can be the same or different from each other.
FIG. 3 is an illustration of actuator 20 having electric motor 30 which rotates threaded drive 31 in the well known fashion. Such a device is commonly referred to as a linear actuator. Rotation of threaded drive 31 causes expansion or contraction (upward or downward motion) of piston 32 and hence an increase or decrease in the sensor distance. Similarly, a second electric linear actuator may be used to adjust the surface distance. These electric linear actuators may be controlled, for example by a microcontroller (not shown), in response to a user's selection of a resolution level.
FIG. 4 illustrates lens 13, sensor 14 and navigation surface 11. The following relationship exists between the surface distance (Dsurface) and the sensor distance (Dsensor):
(1/f)=(1/Dsurface)+(1/Dsensor)
where f is the focal length of the lens. Magnification (M) is the ratio of the sensor distance to the sensor distance:
M=(Dsensor)/(Dsurface)
The image resolution (IR) is a function of M. For example:
IR=M×k, where k is a constant.
A microcontroller may be used to determine appropriate displacement of lens 13 or sensor 14 relative to navigation surface 11 in order to optimize image resolution. The microcontroller may activate actuator 20 and/or actuator 21 to increase or decrease the sensor distance and/or surface distance. The image resolution of optical mouse 10 can be communicated to the computer and displayed to the user. In another embodiment, the user can adjust the positioning of the lens and/or sensor via manipulation of, for example, a finger wheel in order to manually adjust optical resolution.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods, and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, process, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same results as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such process, machines, manufacture, composition of matter, means, methods or steps.
Patent Application
20080042041
