Patent Application
20050280781
1. Field of the Invention
The present invention relates generally to the field of image display devices. More particularity, the present invention is directed to an overall architecture and method for the assembly of a rear projection television (TV).
2. Description of the Related Art
Rear projection TV (also called internal projecting TV) is widely utilized for large screen display or related image reception and viewing. As the rear projection TV can significantly magnify a display image through internal image projecting optics, it can solve the problem of display size limitation of a cathode ray tube (CRT) caused by a safety imposed upper limit of its internal coil voltage. Thus, it is well known that the screen size of many rear projection TV often exceeds 50 inches to further elevate visual enjoyment for the viewer.
However, among the structures of the well known rear projection TV units in the market, whether it is a unit based upon a Digital Light Processor (DLP) technology from Texas Instruments or a unit based upon a Liquid Crystal on Silicon (LCOS) technology, the observation is that enclosed within an otherwise very bulky TV housing are a set of precision but light-weighted subassemblies like a projection screen, an optical mechanism, a control electronics module and an audio module. Therefore, in addition to an increased assembly time and cost during manufacturing, the assembled thus bulky rear projection TV units must now be very carefully handled throughout the shipping process and the installation process at the user's site such that the internal subassemblies should not be damaged or their relative alignments should not be disturbed. Thus, regardless of the careful handling, accidents can still happen and this represents a significant disadvantage during shipping and installation of the rear projection TV units.
Another disadvantage of these well known structures in the market is that, for product maintenance after installation where one or more of these subassemblies failed, the user would have to make a service call to insure that the replaced subassemblies are properly positioned and affixed to the TV unit. For example, the position and orientation of either the projection screen or the optical mechanism can affect the displayed image quality, etc. The root cause of the associated consumption of maintenance labor, time and cost mainly comes from an accompanying complex procedure for disassembly and assembly. It is therefore highly desirable to reduce or eliminate the aforementioned disadvantages.
An adjoining-type architecture and method for the assembly of a rear projection TV is proposed according to the invention. The proposed projecting TV enclosure includes a set of interconnectable housing sections. A set of interconnectable subassemblies is also provided for the product function. Each subassembly includes a number of second adjoining devices for detachably adjoining the subassembly to a selected subset of the housing sections. Correspondingly, each housing section includes a number of first adjoining devices for detachably adjoining the housing section to a corresponding subset of the second adjoining devices of the set of interconnectable subassemblies. Hence, this architecture allows the reduction in the time and cost of projecting TV production assembly, the reduction of its shipping volume thus simplifying its shipping and allowing self-assembly by user. And, for product maintenance, the user may purchase and self-assemble only the damaged subassemblies.
To effect the interconnection between any two housing sections, a number of third adjoining devices are provided on one housing section for mating with the same number of fourth adjoining devices provided on the other housing section.
The interconnection among the set of subassemblies can be a mechanical connection, an electrical connection or an optical coupling.
An embodiment of the housing sections includes, expressed with x-y-z coordinates with the y-axis pointing to the top and the z-axis pointing to the front, a bottom housing plate lying in the x-z plane, two lateral housing plates each lying in the y-z plane, a back housing plate lying in the x-y plane, a slanted back housing plate lying in a slanted plane tilted away from the x-y plane toward the z-direction, a top housing plate lying in the x-z plane and a front housing plate lying in the x-y plane so as to leave a projection opening lying in the x-y plane and along the front face of the projecting TV.
An embodiment of the subassemblies includes a control electronics module, an optical mechanism and an audio module all located atop the bottom housing plate, a reflective mirror located beneath a bottom surface of the slanted back housing plate and a projection screen lying in the x-y plane and filling the projection opening.
To form a thinner enclosure of the rear projection TV, multiple reflective mirrors located within the TV enclosure can be employed to effect multiple folding of the video image projection light path. One specific embodiment is a two-mirror system.
The subassemblies also include an IO and power terminal, for the audio and video signal interfacing and power input to the projecting TV, located atop the bottom housing plate.
The optical mechanism includes a body having a lens head that, upon assembly of the housing sections, becomes optically essentially aligned with the reflective mirror and the projection screen such that projected video image lights from the lens head impinge upon the reflective mirror, get reflected and projected to the projection screen for proper viewing.
The effect of any residual optical misalignment can be rendered imperceptible to the user by sizing at least one of the housing sections, the optical mechanism and the reflective mirror making the projected video image 3% to 5% larger than the projection screen. To reduce the effect of any stray image resulting from the projected video image outside the projection screen, all interior surfaces of the rear projection TV not required for the video image projection can be painted black to render these surfaces essentially non-reflective.
In one embodiment, the optical alignment of the lens head is through the optical mechanism body using the combination of an indentation formed on an interior surface of the back housing plate and a locking tab that, being part of the optical mechanism body, upon being locked onto the bottom housing plate with a screw forces the optical mechanism body into a three-point contact registration with the TV enclosure.
During the assembly process, each housing section is first adjoined, through the first adjoining and the second adjoining devices, to a number of corresponding subassemblies. The set of housing sections, together with their now-adjoined set of interconnectable subassemblies, are then assembled through the third adjoining and the fourth adjoining devices to form the projecting TV.
To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated.
Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawing, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
In the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will become obvious to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, materials, components and circuitry have not been described in detail to avoid unnecessary obscuring aspects of the present invention. The detailed description is presented largely in terms of simplified orthogonal and perspective views. These descriptions and representations are the means used by those experienced or skilled in the art to concisely and most effectively convey the substance of their work to others skilled in the art.
Reference herein to “one embodiment” or an “embodiment” means that a particular feature, structure, or characteristics described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the order of process flow representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations of the invention.
Reference is made to
Given the above description, it can be seen that during manufacturing each of the various subassemblies can be adjoined to its corresponding housing segments to form a set of size-wise compact intermediaries without further assembling these intermediaries into the final bulky rear projection TV 100. The set of compact intermediaries can then be shipped, as is, to the end user for self-assembly with reduced shipping volume thus simplified shipping logistics. Clearly, an additional accompanying advantage is the reduction in production assembly time and cost. Furthermore, for product maintenance, the user only needs to purchase and self-assemble the damaged intermediary or intermediaries as well.
Another embodiment of the present invention rear projection TV are illustrated in
Yet another embodiment of the present invention rear projection TV, while not graphically illustrated here, is as follows:
Regardless of the above scheme for optically aligning the lens head 31 with the reflective mirror 12 and the projection screen 20, it nevertheless is an indirect mechanical scheme not based upon a direct image alignment at the projection screen 20. Thus, due to numerous unavoidable dimensional or optical tolerances of the parts constituting the adjoining-type rear projection TV 100, a residual optical misalignment in the form of a likely perceptible image misalignment at the projection screen 20 can still be expected from volume production. To insure user self-assembly of the adjoining-type rear projection TV 100 without any special skills or tools, the effect of this residual optical misalignment can be rendered imperceptible to the user by sizing at least one of the optical mechanism 30, the reflective mirror 12 or section(s) of the TV housing 10 for a projected video image 3% to 5% larger than the projection screen 20. Here, sizing can be a simple dimensional adjustment or a more complex optical adjustment from an otherwise nominal design. For example, adjusting the projection screen 20 slightly forward (+z-direction) from its ideal position would increase the total video image projection light path length hence enlarge the projected video image. For another example, slightly thinning the body of the reflective mirror 12 from its ideal thickness would also increase the total video image projection light path length hence enlarge the projected video image. For a third example, slightly reducing the f-number of the lens head 31 from its ideal value would maintain the total video image projection light path length while enlarging the projected video image, etc. To reduce the effect of any stray image resulting from the small amount of projected video image outside the projection screen 20, all interior surfaces of the adjoining-type rear projection TV 100 not required for the video image projection can be painted black to render these surfaces essentially non-reflective.
To make electrical connections as part of the assembly process, and disassembly process as the case may be, of the adjoining-type rear projection TV 100, the optical mechanism 30 is provided with video input lines 33 terminated with a video input terminal 331 for electrically connecting with corresponding video terminal 431 and video output lines 43 provided on the control electronics module 40. Secondly, the audio module 50 is provided with audio input lines 52 terminated with an audio terminal 521 for electrically connecting with corresponding audio terminal 441 and audio output lines 44 provided on the control electronics module 40. Thirdly, the control electronics module 40 is provided with signal and power lines 42 terminated with an input terminal 421 for electrically connecting with, while not shown here to avoid excessive obscuring details, corresponding output terminal and signal and power lines provided on the control 10 and power terminal 13. In this way, the set of aforementioned advantages of end user self-assembly, reduced shipping volume and simplified shipping logistics, etc. gets expanded to the area of electrical assembly for the adjoining-type rear projection TV 100 as well.
An adjoining-type architecture for the assembly of a rear projection TV through the formation of a set of intermediaries is described with numerous exemplary embodiments. This architecture reduces the projecting TV production assembly time and cost, reduces its shipping volume thus simplifying its shipping and allowing user self-assembly. For product maintenance, this architecture further allows the user to purchase and self-assemble only the damaged subassemblies. However, for those skilled in this field, these exemplary embodiments can be easily adapted and modified to suit additional applications without departing from the spirit and scope of this invention. Thus, it is to be understood that the scope of the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements based upon the same operating principle. The scope of the claims, therefore, should be accorded the broadest interpretations so as to encompass all such modifications and similar arrangements.
