The present invention relates generally to video and image projection, and in particular to projectors for use in compact handheld devices.
Perennial improvements in digital electronics, as described by Moore's Law, delivered forth the ubiquitous personal computer which has computing power comparable to supercomputers of the not so distant past, and for which a myriad of business, engineering, communication, entertainment and other applications have been developed.
At present, the unceasing progress in digital electronics has further progressed computer technology and brought forth handheld devices (e.g., smartphones) with sufficient computing power to run many of the most popular applications that have been run on personal computers. However, one limiting factor in migration of many applications to handheld devices, is the limited screen size of handheld devices, which makes protracted use of many applications (e.g., spreadsheets, text editing) impractical if not impossible.
It has previously been proposed to incorporate a small video projector within handheld electronic devices.
The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to projectors. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
It will be appreciated that embodiments of the invention described herein may be comprised of one or more conventional processors and unique stored program instructions that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of image processing for video projection described herein. The non-processor circuits may include, but are not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method to perform image processing for video projection. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.
Referring to the graph it is seen that for microdisplays ranging from 320×240 up to 1920×1200 the shortest dimension varies from about 2 mm to about 18 mm. In reviewing the graph 300 it should be kept in mind that handheld electronic devices are typically between 5 mm and 20 mm thick and that some high end models are characterized by thickness in the lower end of this range. In the case of clamshell or slider type devices a projector would typically be accommodated in one of two relatively moveable parts of the device, and the thickness of these parts is on average one-half of the total thickness. Moreover, a few millimeters must be added to the ordinate of the graph 300 to allow for the thickness of, at least, the housing walls of the handheld device, if not for other supporting structure as well. In a tight fit in a thin handheld device (or thin part of a multi-part, e.g., clam, slide type device) the height of the spatial light modulator will typically be at least 80% of the thickness of the part of the housing of the handheld device, in which the spatial light modulator is accommodated.
The spatial light modulator 400 has a plurality of oblong pixels 402 arranged in a plurality of columns 404 of pixels and a plurality of rows 406 of pixels. Each pixel has the same aspect ratio as a factor by which an aspect ratio of the spatial light modulator 400 is increased relative to a standard video format.
A controller 612 is coupled to the spatial light modulator 400 and the light source. The controller 612 drives the spatial light modulator according to video information. Optionally, in the case of a field sequential color system the controller 612 also drives the light source (which can include multiple separate color light sources) to periodically emit colors in coordination with the video information supplied to the spatial light modulator 400.
The design of anamorphic lenses is known to persons of ordinary skill in the art and is discussed in various books such as, for example, “Modern Optical Engineering” by Warren J. Smith, McGraw Hill 1990.
Table I describes the lens 700.
The lens 700 was designed for an image modulator having an aspect ratio of 6:1. The high aspect ratio is apparent by comparing the width of the dimension of the of spatial light modulator 400 shown in
In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.