WO2017147173A1

WO2017147173A1 - High-precision focus mechanism for a pico projector module

Info

Publication number: WO2017147173A1
Application number: PCT/US2017/018916
Authority: WO
Inventors: Jon Godston; Sung Ook YANG; Lars Gilstrom
Original assignee: Navdy, Inc.
Priority date: 2016-02-22
Filing date: 2017-02-22
Publication date: 2017-08-31

Abstract

A projection system with: (i) a lens housing comprising a lens for projecting an image through the lens toward a projection surface; (ii) a rotatable member adjacent the lens housing, the rotatable member having a length and an axis along the length, wherein the axis is outside of the lens housing and wherein rotation of the rotatable member is around the axis; and (iii) a coupling between the rotatable member and the lens structure, wherein rotation of the rotatable member moves the lens housing along a line parallel to the axis.

Description

TITLE OF THE INVENTION

Title of Invention: HIGH-PRECISION FOCUS MECHANISM FOR A PICO

PROJECTOR MODULE

Technical Field [0001] The preferred embodiments relate to projector focusing and are more particularly directed to the focus mechanism for small projectors, such as pico projectors.

Background Art

[0002] Smaller projectors, sometimes referred to as handheld, pocket projectors, mobile projectors, or pico projectors, include projection technology that fits within a very small form factor (e.g., a few to several inches) yet includes sufficient, and often sophisticated, hardware and/or software so as to project an image to a remote surface. Further, as an image projector, these devices typically include some type of focusing mechanism, the precision of which may depend in part on the image projecting technology (e.g., micromirrors, lasers, liquid crystals) and related factors such as lens, depth of focus, and the like. For certain technologies and devices, therefore, the image projector includes a manual focusing mechanism, for example providing variability given that the surface to which the device will project can be at a varied distance from the portable projector.

[0003] Complexities of focusing of a smaller projector also can arise for certain image generation technologies and where the projection surface to which the device will project is very close to the projector. For example, in vehicle aftermarket systems, various market entrants are offering or developing head-up display (HUD) devices for installation into vehicles and that project various types of information to a projection surface, which may be a screen that is further reflected by way of example to another device, such as an optical combiner. Depending on the configuration of the HUD device, the projection surface may be very close to the projector. For example, for a small projector with a focal distance of about 100 mm, the corresponding projection screen may be at distance of about 100 mm from the projector. At such a distance, however, even small changes in the distance between projector and screen can cause the image to become unfocused. Moreover, any off-axis movement of the projector relative to the projection surface can cause distortions in the projected image.

[0004] Given the above considerations, the prior art includes projectors that can be mounted in a device (e.g., HUD device) that include a manual focus mechanism, as is now illustrated and described in connection with Figures la and lb. Specifically, Figure la illustrates an exploded view, and Figure lb illustrates a top assembled view, of a prior art projector assembly 10. Projector assembly 10 includes a projector engine 12 that may include various electronics so as to perform signal processing so as to develop an image control signal for the image projection technology implemented, where for sake of this discussion projector engine 12 is housed within a physical frame 14 which is shown by way of example. Frame 14 includes a cavity 16 into which is slidably fitted a lens barrel 18, where as known in the art a lens barrel is an outer casing in which a lens (or plural lenses) is positioned, typically such that light is directed through the lens along an axis that passes through the center of the lens and generally through the length of the barrel which has the same axis. Moreover, in a preferred embodiment, within frame 14, and located adjacent sides of cavity 16, are a first pair of holes 20 and a second pair of holes 22, each pair for receiving a respective cylindrical rail pin 24 and 26. More particularly, therefore, lens barrel 18 is located in cavity 16, after which rail pins 24 and 26 are inserted through frame hole pairs 20 and 22. In this regard, note that each pin 24 and 26 also passes through a respective guide member 28 and 30 of lens barrel 18, thereby defining a path of possible front-to-back movement of lens barrel 18, within cavity 16, that is, whereby lens barrel 18 can be moved, by an adjustment mechanism described below, either frontward or backward as its guide members 28 and 30 slide along rail pins 24 and 26, respectively. In this manner, a lens 18_L of lens barrel 18 is moved closer or farther from a cavity aperture 16_A through which lens 18_L projects an image, so as to likewise bring that lens 18_L closer or farther from the projection surface to which it is projecting that image; in this manner, therefore, such movement provides a focusing function, facilitated by an additional mechanism, described below.

[0005] Projector assembly 10 also includes a rotatable focus wheel 32, which by way of example includes a tactile exterior treatment that is shown as circumferentially protruding teeth in Figures la and lb. Wheel 32 includes a centered hole 34, that is, hole 34 is in the center of the generally circular shape of wheel 32, and a wheel axis pin 36 is located vertically through centered hole 34 and seats in a pin hole 38 in frame 14, so as to allow circular rotation of wheel 32 around that axially-positioned axis pin 36. Wheel 32 also includes a cam 39 positioned atop the generally circular perimeter of wheel 32, but in order to have a camming effect, note that cam 39 is a circular region that is not concentric relative to centered hole 34, so that the off-centered positioning of cam 38 is such that one portion of its perimeter is much farther from centered hole 34 (and axis pin 36) than the rest of cam 39; as a result, this farther portion provides an extending portion relative to centered hole 34, so that as wheel 32 is rotated, the extended portion of cam 38 effectively operates as a lobe by converting the rotation of wheel 32 into a variable linear movement. Further in this regard and as shown in Figure lb, once assembled, cam 39 fits within a bearing region 40 that is part of lens barrel 18. Hence, as wheel 32 is rotated, the extending portion of cam 38 bears against the inner sidewall of bearing region 40, thereby pushing that bearing region sidewall, and hence pushing lens barrel 18, either forward or backward within cavity 16.

[0006] Given the preceding, in the prior art use of projector assembly 10, frame 14 is mounted relative to a projection surface and wheel 32 is rotated so as to focus on image on the projection surface. For devices in which the projection surface is fixed, then typically this focusing operation is done by a manufacturer, after which a glue or the like is applied to wheel 32 in an effort to retain lens barrel 18 in the final focused position. This approach, while useful in some applications, has various drawbacks. As one example, the movement of wheel 32 is generally achieved by movement of the protruding teeth around its perimeter, and as such the ability to move at small increments is difficult and can take additional time and also lack precision. Precision loss may be a considerable issue, particularly where the distance to the projection screen is small, such as in the above-introduced example of including a projector in a HUD device, in which case a change of 0.1 mm can have a detectable effect in projected image quality. Thus, the prior art may well be directed more to focusing where the projection surface is considerably farther, thereby permitting greater tolerance in the adjustment resulting from wheel 32. As another drawback example, rotation of cam 39 produces forces in directions that may oppose a strict linear front-to-back (or back-to-front) movement of lens barrel 18, so that lens barrel 18 could move to project in a direction that is not parallel to its rail pins 24 and 26; such misalignment can create distortions on the image as it appears at the projection surface. As still another drawback, when glue is used to permanently set the position of wheel 32, the wheel 32 may not thereafter be adjusted a second time, thereby preventing the ability to later change focus, if needed. Still further, if the glue is not sufficient or degrades over time, wheel 32 may be freed to move, perhaps even slightly, which again can affect image focus, particularly for close-positioned projection surfaces.

[0007] The preferred embodiments, therefore, seek to improve on small projectors and the devices (e.g., HUD display) into which they are positioned, as further explored below.

Disclosure of Invention

[0008] In one preferred embodiment, there is a projection system. The system comprises: (i) a lens housing comprising a lens for projecting an image through the lens toward a projection surface; (ii) a rotatable member adjacent the lens housing, the rotatable member having a length and an axis along the length, wherein the axis is outside of the lens housing and wherein rotation of the rotatable member is around the axis; and (iii) a coupling between the rotatable member and the lens structure, wherein rotation of the rotatable member moves the lens housing along a line parallel to the axis.

[0009] Other preferred embodiments, aspects and benefits are described and claimed.

Brief Description of Drawings

[0010] The preferred embodiments will be described in detail below by referring to the accompanying drawings:

[0011] Figure la illustrates an exploded view, and Figure lb illustrates a top assembled view, of a prior art projector assembly.

[0012] Figure 2 illustrates a perspective view of an automotive application of a head- up display (HUD) device according to preferred embodiments.

[0013] Figure 3 a illustrates a side view of an HUD device constructed according to a preferred embodiment.

[0014] Figure 3b illustrates a side cross-sectional view of an HUD device according to a preferred embodiment, illustrating light paths in its operation.

[0015] Figure 3c illustrates a rear cross-sectional view of an HUD device constructed according to a preferred embodiment.

[0016] Figure 4a illustrates a partially exploded view of preferred embodiment projector assembly.

[0017] Figure 4b illustrates a bottom perspective view of lens barrel 408 from Figure 4a.

[0018] Figure 4c illustrates a top partially-assembled view of a preferred embodiment projector assembly.

[0019] Figure 5 illustrates a bottom perspective view of a preferred embodiment projector assembly.

[0020] Figure 6 illustrates a bottom perspective view of a preferred embodiment projector assembly after a dust cover is affixed in place. [0021] Figures 7a and 7b illustrate perspective side and partially exploded views of a preferred embodiment HUD device into which a preferred embodiment projector assembly is located.

Description of Embodiments

[0023] By way of introduction, Figures la and lb were discussed above in this document, and the reader is assumed to be familiar with the various aspects of that discussion. Further, the one or more preferred embodiments described in this specification are implemented into an automotive head-up display, as it is contemplated that such implementation is particularly advantageous in that context. However, it is also contemplated that inventive concepts may be beneficially applied to many other applications. Accordingly, it is to be understood that the following description is provided by way of example only, and is not intended to limit the inventive scope as claimed.

[0024] For purposes of this description, a projector module for use with a head-up display device mounted to an automobile dashboard is provided according to these embodiments. An example of a head-up display suitable for use with an input device according to these embodiments is described in co-pending U.S. application S.N. 14/806,530 filed July 22, 2015, which published as U.S. Patent Application Publication No. US 2016/0025973, commonly assigned herewith and incorporated herein by reference.

[0025] In a contemplated preferred embodiment wherein the projector module, according to preferred embodiments, is included in a head-up display device, greater assurance is provided at time of manufacture, and during subsequent use, that the focal distance between the projector and a screen (e.g., within the HUD device) will be properly adjusted at remain at its proper point; moreover, as shown below, preferred embodiments further provide for a more user-friendly or accessible apparatus for readjusting the focal distance, were that to become necessary. The construction and adjustment of such a module according to preferred embodiments is further illustrated and described in the following pages. [0026] As will be apparent from this description and as noted above, the preferred embodiments described herein relate to a see-through display device commonly known as a "head-up display" or "HUD." Figure 2 illustrates the general application of devices according to these embodiments in an automotive context. As shown in Figure 2, HUD device 200 in this context sits on top of a car dashboard DSH, typically in view by a driver DRV above the speedometer and other gauges or operational displays (not shown) provided within dashboard DSH, and above a steering wheel SWH. HUD device 200 provides a see-through image that displays information relevant to driver DRV while driving the vehicle, without blocking the view of the road through windshield WSH. [0027] As will be evident from the following description, HUD device 200 according to a preferred embodiment is constructed so as to be portable, easily placed atop dashboard DSH of a variety of vehicles, and easily removable for use in another vehicle or for security purposes, such as when driver DRV is parking the car in a public parking area. As such, in these embodiments HUD device 200 is constructed to have a compact size so that it can sit on top of dashboard DSH, without significantly interfering with the driver's view.

[0028] The cross-sectional view of Figure 3a schematically illustrates the various components of HUD device 200 according to some embodiments. As shown in that Figure, housing 202 encloses control electronics 204, for example as may be mounted on one or more printed circuit boards, which carry out the data and image processing involved in the operation of HUD device 200 as will be described below.

[0029] Housing 202 also encloses a projector engine 206 which, for purposes of this description, refers to a projection module or assembly, including the optics, light modulation, and light source devices necessary to project an image suitable for use in HUD device 200 and having an improved manual focusing apparatus and method, for use at manufacture and potentially thereafter, according to preferred embodiments. The optics included in projector engine 206 are contemplated to include some or all of the appropriate lenses, mirrors, light homogenization devices, polarization devices, filters such as dichroic filters that combine light, and such other optical devices known in the art and included in the construction of a modern projector. Light modulation devices included in projector engine 206 may be any one of a number of types, including those known in the art as digital micromirror array devices (DMD) such as the DLP™ device from Texas Instruments Incorporated, liquid crystal on silicon (LCOS) light modulators, and transmissive LCD displays such as those used in LCD projectors or other type of spatial light modulator; other types of light modulation device suitable for use in some embodiments include a laser beam scanning (LBS) projector, in which a laser light source is modulated electronically or otherwise and the laser beam is scanned by one or more moving mirrors to scan the image, and any other form of image projection. The light source included in projector engine 206 may be one or more LEDs, one or more lasers, or other sources of light. For example, red, green, and blue LEDs or lasers are commonly used with DMD and LCOS modulators, to support what is known as a "full color" display, but of course other colors of light may additionally or alternatively be used. In any of these technologies, projector engine 206 is contemplated to also include the appropriate electronics for controlling these elements, as known in the art. Lastly, while various figures depict projector engine 206 elevated relative to electronics 204, in a preferred embodiment projector engine 206 may be affixed along the bottom of housing 206, so as to relate it directly to a same structure as a screen 208, as further discussed below.

[0030] Projector engine 206 projects images rearwardly (i.e., toward driver DRV) to a curved screen 208 mounted near the rear edge of housing 202 in this embodiment. As will be described in detail below, screen 208 is a reflective surface, for example a high- gain curved reflective surface, positioned relative to projector engine 206, so that the light projected by projector engine 206 forms a "real" (i.e., human viewable) image on screen 208. Preferred embodiments involving various constructions of screen 208 will be described in further detail below. [0031] According to preferred embodiments, screen 208 reflects the real image it displays (as received from engine 206) in a forward direction (i.e., toward the windshield) to a combiner 210. Combiner 210 according to preferred embodiments is a semi- transparent curved element that combines light from two directions, namely that transmitted through windshield WSH and that reflected from screen 208, to form a combined "virtual" image that is viewable by driver DRV in the arrangement of Figure 2. Combiner 210 is semi-transparent in the sense that road conditions and other visual information ahead of the vehicle (i.e., light entering through windshield WSH) can be seen by driver DRV through combiner 210, but on which the images projected by projector engine 206 and reflected by screen 208 also will be visible to driver DRV. Further in this regard, Figure 3 a shows combiner 210 as physically coupled to housing 202 by way of a hinge 212, and screen 208 is preferably physically coupled directly to housing 202 and even further, directly to the same portion of the housing (e.g., bottom subassembly) as is projector engine 206. In an alternative preferred embodiment, screen 208 may be physically coupled to housing 202 by way of a hinge (not shown). Hinge 212 enables the angle of combiner 210 to be rotationally adjusted about its axis, so as to receive the image reflected by screen 208. This adjustability ensures good visibility of the image displayed to driver DRV for a variety of dashboard DSH geometries (i.e., regardless of the flatness of the top surface of dashboard DSH) and with minimal distortion of the image, as will be described in further detail below.

[0032] Figure 3b illustrates a side elevation view of the basic optical path according to some preferred embodiments. As shown in Figure 3b, projector engine 206 projects light on image path IMG 206 toward screen 208 to form a real (human-viewable) image at screen 208. That image is reflected by screen 208 on image path IMG 208 to combiner 210, and in turn partially reflected by combiner 210 to be visible to driver DRV along a center line-of-sight CLOS. As noted above, combiner 210 is constructed to be semi- transparent to external light such as received through windshield WSH; this semi- transparency also connotes that combiner 210 is semi-reflective to the light reflected by screen 208. These properties may be attained by coatings on the surfaces of combiner 210. For example, the surface of combiner 210 may have a 30% reflective coating, in which case 30% of the reflected light from screen 208 will be reflected toward driver DRV, while roughly 70% of the external light received through windshield WSH will be transmitted through combiner 210 to be visible to driver DRV.

[0033] Because the image projected on screen 208 by projector engine 206 is a "real" image, it is useful for projector engine 206 to be constructed and arranged to project that image so as to be focused on screen 208. In this example, screen 208 is placed in the focal plane of the lens of projector engine 206. In one example in which the lens of projector engine 206 has a focal distance of about 100 mm, screen 208 is placed at distance of about 100 mm from projector engine 206. For projector engine 206 constructed as a DMD or LCOS light modulator type projector, a focus adjustment may be required at manufacture that then remains fixed in place for system use, as further detailed later. It also will be understood by one skilled in the art that because lasers have much narrower bandwidths/linewidths at a given center frequency, the use of lasers can provide better performance with such optical elements at screen 208 such as bandpass filters.

[0034] According to some embodiments, screen 208 is constructed to have a curved surface. In one preferred embodiment, the curved surface is convex (i.e., curved toward) relative to the received light image from projector engine 206, where the convex shape may be spherical, substantially spherical, or biconic (e.g., cylindrically convex). In an alternative preferred embodiment, the curved surface may be concave relative to the received light image from projector engine 206, although such an approach may create bright spots or regions in the depiction of the screen image captured by combiner 210. In any event, the degree of curvature of screen 206 is selected so that the light rays reflected from the surface of screen 208 to combiner 210, and reflected from combiner 210, are focused at the eye pupils of driver DRV and with preferably a minimal amount of varying brightness and/or distortion. In addition, as known in the art, spherical surfaces are concave (from an inner perspective) or convex (from an outer perspective) surfaces that approximate a section of the surface of a sphere. The term "substantially spherical", for purposes of this description, refers to a surface that is not perfectly spherical but is sufficiently close to being spherical so as to behave similarly to a perfectly spherical surface within the context of these embodiments. Referring to the driver's view of Figure 3b, if the projected image from projector engine 206 is as designed for a flat screen with no projection lens offset, that image would appear at screen 208 as slightly "keystoned" (wider at the top than at the bottom) because of the tilt of screen 208, and slightly barrel distorted (smaller at the outsides of the screen than in the center) because of the curvature of screen 208. When reflected to and appearing at combiner 210, the apparent barrel distortion would be further increased by the optical effect of the curvature of combiner 210 since the outside of curved screen 208 is farther away from combiner 210 than is the center of screen 208. In some embodiments, however, screen 208 is constructed to have a "substantially spherical" surface, meaning that the surface behaves similarly to one that is perfectly spherical for purposes of preferred embodiments, but is not perfectly spherical, specifically by being slightly aspherical so as to help correct for the keystone distortion or barrel distortion, or both, resulting from the tilt and curvature of the inner surface of screen 208. In another preferred embodiment, screen 208 is constructed to have a convex cylindrical surface. Alternatively or in addition, distortions may be corrected for optically by the design of the projector lens in projector engine 206, or by also making combiner 210 slightly aspherical (while remaining "substantially spherical" as defined above), or by digital processing of the image being projected to pre-distort the image so it will look correct at combiner 210 as viewed by driver DRV, or by a combination of these techniques. [0035] According to preferred embodiments, screen 208 is constructed to have a high screen "gain", in the optical sense. As known in the art, screen gain is a measure of the peak brightness of light reflected in a direction normal to the screen surface. As commonly understood in the art of projection screens, screen gain is typically a relative measure, where a gain of 1.0 refers to a screen that reflects light at the same brightness at which it is projected onto the screen with perfect uniformity from all viewing angles, with no light absorbed and all light re-radiated. Gain is typically measured from the vantage point where the screen is at its brightest, which is directly in front of and perpendicular to the tangent of the screen at that point. As such, the measurement of gain at this point is known as "Peak Gain at Zero Degrees Viewing Axis". Surfaces having a gain of 1.0 include a block of magnesium carbonate (MgCO3) and a matte white screen. A screen having a gain above 1.0 will reflect brighter light than that projected; for example, a screen rated at a gain of 1.5 reflects 50% more light in the direction normal to the screen than a screen rated at a gain of 1.0. However, screens with a gain greater than 1.0 do not reflect light at the same brightness at all viewing angles. Rather, if one moves to the side so as to view the screen at an angle, the brightness of the projected image will drop.

[0036] Figure 3c illustrates HUD device 200 from the rear (i.e., from the viewpoint of driver DRV of Figure 2). As evident from Figure 3c, driver DRV sees the back surface of housing 202, within which screen 208 (Figure 3a) is disposed so as to face projector engine 206 (shown in shadow in Figure 3c). Because of the construction and arrangement of screen 208 and combiner 210, the image presented by the light projected by projector engine 206 forms image IMG 206 (not shown) at screen 208. This image IMG 206 will reflect from screen 208 and appear on combiner 210 as image IMG 210, as shown in Figure 3c. Image IMG 210 thus presents graphics and other visual information generated by control electronics 204 within housing 202 as appropriate for the particular functions being executed, in a manner that is visible to driver DRV. The height of the back of housing 202 serves to block light emitted by projector engine 206 from directly reaching driver DRV, as evident in the view of Figure 3c. And as discussed above and in further detail below, because combiner 210 is semi-transparent according to these embodiments, driver DRV will be able to see the road ahead through combiner 210, with image IMG 210 effectively overlaid onto that view of the road. [0037] Figures 3a through 3c also illustrate various auxiliary components of HUD device 200 that may be implemented in various embodiments. Rear-facing camera 216 is mounted, in this embodiment, on the back (i.e., driver facing side) of housing 202, and as such is aimed at driver DRV. Image data acquired by rear-facing camera 216 are communicated to control electronics 204, which processes those data to identify gestures made by driver DRV and carry out various control functions responsive to those identified gestures. To enable this function in nighttime conditions, rear-facing camera 216 is sensitive to infrared light, and an infrared illuminant 218 (e.g., an LED emitting infrared light) is mounted on the driver-side surface of housing 202 and also facing driver DRV. Other gesture-detection technologies alternatively may be implemented in place of or in addition to rear-facing camera 216, examples of which include depth sensors, photometric stereo sensors, and dual camera arrangements. Other aspects also may be included on the driver- side surface of housing 202, including an on/off button 220 and a status indicator (e.g., LED) 222. [0038] A front-facing camera 21 OF may be provided in some embodiments, for example mounted to the top edge of combiner 210 and aimed in the direction of windshield WSH. In these embodiments, front-facing camera 210F communicates image data pertaining to the location of the vehicle within or among lanes of the roadway, road conditions, or other environmental parameters visible through windshield WSH to control electronics 204, which in turn generates information for display at combiner 210 in response to that information. Figure 3a also shows ambient light sensor 224 mounted on housing 202, which will communicate the level of ambient light to control electronics 204, in some embodiments; more than one such ambient light sensor 224 may be implemented in HUD device 200 if desired. If ambient light sensor 224 is implemented, control electronics 204 can adjust the brightness and other attributes of the light projected by projector engine 206, typically to increase brightness of the displayed images under bright ambient conditions and reduce brightness at nighttime. [0039] HUD device 200 further includes apparatus for communication in combination with various functions in the automotive context, where such communications may be wired, wireless, or both. In one example, HUD device 200 includes wireless communications functionality as part of or in conjunction with its control electronics 204, operable to carry out wireless transmission and receipt according to a conventional technology such as Bluetooth or other near-field communications (NFC) types for local communication with nearby devices (i.e., in the vehicle); longer-range communication capability such as cellular, satellite, FM and other radio communications may additionally or alternatively be implemented. In this example, the communications may be with a smartphone SPH (see Figure 2), which will typically be personal to driver DRV and include the appropriate software for communicating with HUD device 200. By way of this communication with smartphone SPH, HUD device 200 will be capable of displaying online-accessible information regarding traffic, weather conditions, text messages, email, and the like. The wireless functionality of HUD device 200 also is operable to communicate with a remote wireless device in the vehicle as preferred embodiments also contemplate such a device, as may be affixed to steering wheel SWH and operated by the driver DRV for providing scrolling and selection commands, among others, by manipulation of a rotary knob and/or selectable/depressible button the on the wireless device. The system of the embodiment shown in Figures 3a-3c also may include one or more rear cameras RCM, which may be deployed within the automobile, for example on the exterior rear of the vehicle, or internally to the vehicle such as on its ceiling or behind the driver's seat; communication between HUD device 200 and rear camera RCM allows HUD device 200 to display images on combiner 210 showing views from behind the vehicle or of the interior behind driver DRV, as the case may be, without requiring driver DRV to physically turn around or take her eyes off the road. Wired communications may be effected in various manners, such as via USB port (not shown) or other wired communication with an on-board diagnostic port OBDP of the vehicle in which HUD device 200 is installed; by way of this connection, information regarding the operating parameters or condition of the vehicle, either directly or in combination with navigation information (distance to next filling station) can be displayed to driver DRV at combiner 210. It is contemplated that those skilled in the art having reference to this specification will be readily capable of implementing these functions, and additionally or alternatively other functions beyond those described, as desired, without undue experimentation.

[0040] Various of the generalized operations of HUD device 200 should be apparent to one skilled in the art from the preceding, and note that HUD device 200 is further operable in response to response to driver commands, whether communicated by the above-referenced remote wireless device, by hand gesture, or by voice. Specifically, after a power-on sequence, such as may be commenced by a user pressing on/off button 220 and/or a button on the wireless device, or via a communication from another source (e.g., vehicle OBD port), device 200 executes appropriate initialization routines by electronics 204, which may include by system CPU, so as to perform power-on self-test sequences, and the like. The CPU also executes appropriate routines to pair its communications with the various devices in its vicinity, including smartphone SPH and perhaps certain functions of the vehicle, including the vehicle audio system, the on-board diagnostic port OBDP, rear-mounted vehicle camera RCM, and the like, as available and enabled for this installation. Following power-on, control electronics 204 places HUD device 200 in a default condition that forwards the corresponding image data to projector engine 206 for display at combiner 210. It is contemplated that this default condition may be to display the current velocity of the vehicle, or the current location on a navigation system map, or even simply a "splash" screen at combiner 210 in the field of view of driver DRV. At this point in its operation, HUD device 200 is ready to receive commands from driver DRV, or to respond to incoming communications. It is contemplated that rear-facing camera(s) 216 and other functions associated with control electronics 204 are operable, in this default state, to receive input from driver DRV or over the communications network, as appropriate. [0041] According to this embodiment, driver DRV can invoke a function by HUD device 200 by operation of the remote wireless device, or by making a pre-determined hand gesture that is detected by rear-facing camera 216. This "home" gesture may be a "thumbs-up" gesture, a "two-fingers up" gesture, or some other distinctive hand position or motion, preferably made by driver DRV above steering wheel SWH (Figure 2) so as to be in the field of view of rear-facing camera 216. Rear-facing camera 216 forwards images to the system CPU, which in response executes image recognition routines to detect the pre-determined "home" gesture for indicating that driver DRV wishes to present a command to HUD device 200. Upon detecting the pre-determined "home" gesture, the system CPU activates a command wait routine, which could anticipate another command from the remote wireless device or could be an audio command listener routine, whereupon control electronics 204 issues the data to projector engine 206 to display a "listening" image at combiner 210. Appropriate speech recognition routines are then executed by the system CPU to detect the content of a voice command received over audio detecting apparatus, where for example HUD device 200 also may include a microphone or may communicate with smartphone SPH in a manner to avail of the microphone included with the latter. According to this embodiment, a relatively wide range of wireless or audio commands may be available for execution by the system CPU (e.g., "search" for executing an Internet search for a type of business; "tweet" for creating a short text message to be posted on the TWITTER social network, via smartphone SPH; "text" for creating a text message to be sent to a contact via the telecommunications network; "call" for making a telephone call via smartphone SPH; and other such commands including invocation of a navigation function). In response to receiving one of these commands, the system CPU executes the corresponding command and HUD device 200 displays the corresponding content on combiner 210. Of course, additional displays and wireless selections therefrom, or voice commands or hand gestures, may be required in the execution of a command. It is contemplated that those skilled in the art having reference to this specification will be readily able to implement such functionality as appropriate for a particular implementation.

[0042] Following execution of the above, control electronics 204 then returns to await further instruction or to respond to incoming communications, as the case may be, with the then-current image being displayed at combiner 210. The then-current image may be the default state, or it may be the result of a different command, for example navigation information regarding the next turn to be made toward the desired destination.

[0043] In response to receiving an external communication, for example as communicated by the connected device (smartphone SPH) in response to it receiving a communication, control electronics 204 produces and displays a notification at combiner 210 corresponding to that external communication. Again as examples of notifications displayed by HUD device 200 in response to receiving an external communication, such could include: (i) the notification for a "tweet" received over the TWITTER social network, the profile photo of the "tweeter" and their screen name, and images; (ii) the notifications for an incoming phone call; and (iii) notifications for an incoming text message.

[0044] It is contemplated that those skilled in the art having reference to this specification will be readily able to recognize additional functions as may be provided by HUD device 200 and its control electronics 204, either itself or by way of a connected device such as smartphone SPH, and to realize those functions in a particular implementation, without undue experimentation. Still further, HUD device 200 may function primarily as a simple display device for an attached computing device, such as smartphone SPH, in which case control electronics 204 would generate the appropriate graphics data to serve as a display for applications running on the attached computing device. In this arrangement, HUD device 200 would then leverage features implemented on that attached computing device, which may include connection to the internet, GPS, or other forms of communication, and could be realized by way of less circuitry than in more computationally capable implementations, retaining as little as only that functionality involved in operating the display, for example the functionality for controlling projector engine 206 in response to ambient light sensors to adjust the brightness. In other embodiments, HUD device 200 itself could be a complete computing platform on its own, or it may have some intermediate level of functionality in which some of the computing is carried out by control electronics 204 with other operations performed on the attached computing device.

[0045] Having described numerous aspects of HUD device 200, attention is now turned to preferred embodiments directed toward the above-introduced projector engine 206. Specifically, Figure 4a illustrates a partially exploded view of preferred embodiment projector assembly 400, which may represent a part or all of projector engine 206 described above. Projector assembly 400 includes a projector engine (not separately shown) that, like the prior art or with added innovation thereto, may include various electronics such as image projection technology to generate an image (e.g., micromirrors, lasers, liquid crystals) as well as circuitry for performing signal processing so as to develop an image control signal for that image projection technology. In any event, for sake of this discussion the projector engine is housed within a physical frame 404, which is shown by way of example. The outer form factor of frame 404 is illustrated by way of example and may vary based on various details, including the items it houses and the device into which it is to be affixed; for sake of the present illustration, however, of note is that frame 404 includes a cavity 406 into which is slidably fitted a lens barrel 408. Lens barrel 408 includes a projector focusing lens within a housing that may be constructed of various materials (e.g., hard plastic). As illustrated and discussed below, the slidable relationship, between lens barrel 408 and cavity 406, is facilitated in part by plural (e.g., two) alignment ribs 408AR along the bottom of lens barrel 408, as shown in the bottom perspective view of lens barrel 408 in Figure 4b. In a preferred embodiment, alignment ribs 408AR are oriented with a majority length of each rib parallel to the direction (i.e., front-to-back/back-to-front) in which lens barrel 408 is to move within cavity 406. Thus, alignment ribs 408AR cooperate with respective slots 408_RS in the bottom of frame 404 (shown in Figure 5), where such slots 408_RS are dimensioned just larger than the width of alignment ribs 408AR SO as to retain and guide movement of lens barrel 408, within cavity 406, in a linear direction. Additionally, and as shown in Figures 4a-4c, lens barrel 408 also include a drive extension 408_DE, which is a portion of the barrel upon which a force is applied so as to move barrel 408 within cavity 406; in a preferred embodiment, drive extension 408_DE extends perpendicularly from a majority length axis 408AX of barrel 408, and drive extension 408_DE includes a threaded (or threadable) hole 408_H. As later described, on assembly, drive extension 408_DE is to be located within a secondary cavity 410 of frame 404, where secondary cavity 410 communicates with cavity 406 and is defined between two sidewalls 412 and 414.

[0046] Continuing in Figure 4a, one of three additional assembly-related components of projector assembly 400 is a customized screw 416. Screw 416 may be metal or other materials and has a head 416_SH and threads as are customary for screws, and is of a length so as to span across secondary cavity 410, that is, between preferably unthreaded holes 412_H and 414_H in each of respective sidewalls 412 and 414. Moreover, screw 416 includes additional attributes in connection with preferred embodiments. As one such attribute, immediately adjacent screw head 416_SH, and along the length of screw 416, is a first unthreaded portion 416^, having a length at least as long as the thickness of sidewall 414 and an outer diameter slightly smaller than that of hole 414_H, so that ultimately first unthreaded portion 416_UP1 may rotate freely, yet with minimal off-axis movement, within hole 414_H. Moreover, with screw 416 passing through hole 414_H, ultimately an O-ring 418 will fit around a part of unthreaded portion 416_UP1 that extends beyond sidewall 414 and into secondary cavity 410, so preferably the dimensions of unthreaded portion 416_UP1 and O-ring 418 are developed to cooperate with one another in this regard. With one end of first unthreaded portion 416_UP1 terminating at the backside of the screw head 416_SH, the opposite end of first unthreaded portion 416 upi ends at a circumferential (or annular) recess 416_CR, that is, recess 416_CR represents a length of the screw having a smaller diameter than that of first unthreaded portion 416_UP1. In a preferred embodiment, ultimately an e-clip 420 will fit within recess 416_CR, so preferably the dimensions of recess 416_CR are formed so as to cooperate with, and retain in place, e- clip 420. With recess 416_CR terminating at one end with first unthreaded portion 416^, it terminates at its other end with a span of threads, which preferably span a majority of the length of screw 416, such as a length of approximately 2mm or more. For reasons further apparent below, the threaded portion of screw 416 includes fine threads with a thread pitch of 0.5 or less, and indeed preferably 0.35 (or less), meaning a full turn of the screw 360 degrees advances (or retracts) the screw in other devices, or in the preferred embodiments a thing with which the screw cooperates, a distance of 0.35mm. As a final attribute, screw 416 also has a second unthreaded portion 416up₂ at its distal end that is opposite screw head 416_SH, where preferably the length of second unthreaded portion 416up₂ is greater than the thickness of sidewall 412 and has a diameter that is slightly smaller than that of hole 412_H, so that ultimately second unthreaded portion 416up₂ may rotate freely, yet with minimal off-axis movement, within hole 412_H. Lastly, completing Figure 4a, projector assembly 400 includes a dust cover 422, which is shaped so as to fit within a slight same-shaped recess in frame 404 and to cover cavity 406 and secondary cavity 410 (both side and bottom), once the remaining components shown in Figure 4a are assembled together, as further appreciated from the discussion below relative to Figure 4c.

[0047] Figure 4c illustrates a top partially-assembled view of a projector assembly 400, where the components from Figure 4a have been assembled, with the exception of dust cover 422. With respect to the assembly, therefore, lens barrel 408 is inserted into cavity 406 leading first by positioning drive extension 408_DE toward cavity 406 so that it may then protrude, from cavity 406 through secondary cavity 410 of frame 404. Next, the tip of screw 416, that is, second unthreaded portion 416up₂ is directed through hole 414_H, starting first from outside secondary cavity 410 and toward the back of frame 400 and in the direction of secondary cavity 410; once, or as, second unthreaded portion 416UP2 extends through hole 414 but before it reaches threaded hole 408_H of the lens barrel drive extension 408_DE, O-ring 418 is positioned over second unthreaded portion 416UP2 and directed past the screw threads and to first unthreaded portion 416^, that is, to seat adjacent the inner side of sidewall 414. Further in this regard, note that O-ring 418 positioned as such will ultimately bear against the inner side of sidewall 414, thereby providing a retention force against inadvertent rotation of screw 416. Next, second unthreaded portion 416up₂ is directed to threaded hole 408_H of lens barrel drive extension 408_DE, and if not already then screw 416 is rotated along its length, such as via a screwdriver or other driver device to its head 416_SH, so that the screw threads cooperate with the threads of threaded hole 408_H and so that second unthreaded portion 416up₂ eventually passes entirely through threaded hole 408_H and reaches, and passes through, hole 412_H. Finally, e-clip 420 is then positioned (e.g., snap fitted around) circumferential recess 416_CR and adjacent O-ring 418.

[0048] To further appreciate the above described assembly, Figure 5 illustrates a bottom perspective view of projector assembly 400. From the bottom perspective, one skilled in the art will further appreciate the location of screw 416, namely, with the majority of its length in secondary cavity 410, its head 416_SH outside cavity 410 and adjacent sidewall 414, and its second unthreaded portion 416up₂ extending through sidewall 412. Moreover, screw 416 passes through the threaded hole of drive extension 408_DE and, by turning screw head 416_SH, screw 416 can rotate freely within the holes of sidewalls 412 and 414, while the screw itself is axially retained in place by e-clip 420, so that rotation of screw 416 about its longitudinal axis causes drive extension 408_DE, and hence the entirety of lens barrel 408, to move either forward or backward within cavity 410, depending on the direction of rotation of the screw. Moreover, from Figure 5, also evident is that front/back movement of lens barrel 408 is further steered by its alignment ribs 408AR, which fit into respective rib slots 404_RS. Further in this regard, therefore, note that the preferred embodiment combination of ribs 408AR fitting into rib slots 404_RS provides various benefits over the prior art's use of two lateral pins along which a barrel lens slides. Such benefits include: (i) lower cost - due to fewer parts (no separate pins are required) and fewer assembly steps (pins no longer need to be assembled); and (ii) increased precision - due to fewer parts in the assembly (i.e., avoids additional tolerance build-up). In view of the preceding, therefore, with lens barrel 408 movement in the forward or backward direction, the image projected by the lens is brought in or out of focus, relative to the projection surface to which that image is projected.

[0049] To further appreciate the above described functionality, Figure 6 illustrates a bottom perspective view of projector assembly 400 after dust cover 422 is affixed in place relative to the corresponding recess shown atop frame 404 in Figure 4a, and further wrapping around and below secondary cavity 410. Again from this perspective, also visible are alignment ribs 408AR positioned into respective rib slots 404_RS, and screw head 416_SH, abutting sidewall 414; further, in the example illustrated, the drive of screw head 416_SH is shown by way of example as a Phillips drive, while others (e.g., hex, torx, square, hex, Frearson, etc.) are contemplated and may be even preferred for purposes of tight fit and potentially automated engagement with a tool and focus operation. In any event, by coupling a tool with a corresponding drive shape to screw head 416_SH, screw 416 is rotatable about its majority length (i.e., longitudinal) axis which, in response to the direction of rotation, will cause drive extension 408_DE and lens barrel 408 (shown in earlier Figures) to move either forward or backward in a focusing manner; thus, lens barrel 408 has its own barrel axis 408AX down the centered length of the barrel and through its lens, while screw 416 has its own screw axis in parallel, but not co-linear, with barrel axis 408AX and the screw longitudinal axis is also outside of the lens barrel. Thus, unlike the prior art with a knob rotating about an axis in a direction other than line of movement of the lens (or also unlike larger camera systems with a concentric hand-turned focusing mechanism having an axis co-linear with the lens center and inside the lens barrel), the preferred embodiments provide a mechanism external from, and not concentrically around, the lens barrel, yet providing a translational force that is parallel to the longitudinal axis of the rotating adjustment screw. Further in this regard, note various improvements over the prior art. For example, a tool is used to drive the movement of lens barrel 408, which should provide greater precision in such movement and hence in the available granularity of focus. As another example, such granularity and precision are also influenced by the screw pitch, and using a small pitch as noted above therefore allows for extreme fine turning in the amount of rotations (or partial singular rotation) and the corresponding translated linear movement of lens barrel 408. By way of further illustration, with a preferred embodiment thread pitch of 0.35, then screw head 416_SH may be rotated one quarter turn (i.e., 90 degrees), in which case lens barrel 408 moves only 0.0875 mm (i.e., 0.35 * ¼ = 0.0875). Such precision, particularly with such predictable accuracy and finite control, is not provided in the above-described prior art approach. Still further, a fine threaded screw, as in the preferred embodiment, also includes a steep ramp angle, meaning physical disturbances to assembly 400 are less likely to cause the screw to rotate, such as in response to bumps, vibrations, drops, and the like, as that steepness provides a relatively increased resistance to rotational movement of the screw; as a result, there is no need or preferred embodiment use of any adhesive to hold the screw in place, yet the focus is mostly assured of remaining as set by the manufacturer. Still further, without the need or use of an adhesive, as was necessitated in the prior art, then assembly 400 may be refocused at a later time or date, again by turning screw 416, if needed or desired, and likewise lens barrel 408 also may be more readily replaced, if necessary.

[0050] Figures 7a and 7b illustrate perspective side and partially exploded views of HUD device 200, into which projector assembly 400 is located. In a preferred embodiment, HUD device 200 includes a top housing subassembly 700^ and a bottom housing subassembly 700_BHS, where ultimately the two housing subassemblies are affixed together (in the vertical direction from the view of Figures 7a- 7b), such as by screws (not shown) inserted upward from the bottom , and through the metal substructure, of bottom housing subassembly 700_BHS, SO as to then be received in respective receptacles beneath the upper surface of top housing subassembly 700^. Looking to the inclusion of projector assembly 400, note that earlier illustrations of its frame 414 include various holes, cutouts, and recesses through which screws or other fasteners may be inserted, and while not explicitly shown in Figures 7a- 7b, one skilled in the art will appreciate that such affixation may be readily implemented, thereby attaching projector assembly 400 to bottom housing subassembly 700_BHS- Thus, in Figure 7b, projector assembly 400 is shown as so attached, where its lens barrel is then adjacent a projection tunnel subassembly 702, such that projector assembly 400 projects light beans through projection tunnel subassembly 702 toward, and to be reflected by, screen 208. Moreover, as discussed in detail earlier, the real image thusly on screen 208 is further reflected to combiner 210. In all events, therefore, with the adjustable focus of preferred embodiments as detailed above, the distance along these reflective paths may be adjusted, so as to properly focus the projected image onto screen 208 and, hence, to be reflected further, as a focused image, to combiner 210.

[0051] Given the preceding, the preferred embodiments provide an improved pico projector module for use, or in combination, with a display device. Preferred embodiments may include various features and benefits, as have been described, and others may be ascertained by one skilled in the art. The inventive scope, therefore, is demonstrated by the teachings herein and is further guided by the following claims.

Claims

Claims: What is claimed is:

1. A projection system, comprising:

a lens housing comprising a lens for projecting an image through the lens toward a projection surface;

a rotatable member adjacent the lens housing, the rotatable member having a length and an axis along the length, wherein the axis is outside of the lens housing and wherein rotation of the rotatable member is around the axis; and

a coupling between the rotatable member and the lens structure, wherein rotation of the rotatable member moves the lens housing along a line parallel to the axis.

2. The projection system of claim 1 wherein the rotatable member comprises a screw.

3. The projection system of claim 2 wherein the screw comprises a thread pitch of 0.35 or lower.

4. The projection system of claim 2 wherein the coupling comprises a member having a threaded aperture for cooperating with threads on the screw.

5. The projection system of claim 1 :

wherein the lens housing comprises an exterior guide mechanism; and further comprising an assembly frame, wherein the assembly frame comprises apparatus for abutting the exterior guide mechanism.

6. The projection system of claim 5 :

wherein the exterior guide mechanism comprises a plurality of protruding ridges; and

wherein the apparatus for abutting comprises a plurality of apertures, wherein each aperture in the plurality of apertures is for abutting a respective protruding ridge in the plurality of protruding ribs.

7. The projection system of claim 1 and further comprising an assembly frame, wherein the rotatable member rotates with the length fixed from axial movement between two positions of the assembly frame.

8. The projection system of claim 7 wherein the rotatable member comprises a screw having a length and comprises:

a head;

threads along a majority of the length;

a first unthreaded portion supported by a first cylindrical aperture in the assembly frame; and

a second unthreaded portion supported by a second cylindrical aperture in the assembly frame.

9. The projection system of claim 1 :

wherein the rotatable member comprises a circumferential recess; and further comprising a clip located in the circumferential recess for fixing the rotatable member from axial movement between two positions of the assembly frame.

10. The projection system of claim 9 and further comprising an O-ring between the clip and a wall of the assembly frame.

11. The projection system of claim 10 wherein the rotatable member comprises a screw having a length and comprises:

a head;

threads along a majority of the length; and

an unthreaded portion between the threads and the head.

12. The projection system of claim 11 wherein the unthreaded portion is between the circumferential recess and the head.

13. The projection system of claim 1 wherein a full 360 degree rotation of the rotatable member is for moving the lens housing a distance of 0.5 mm or less.

14. The projection system of claim 1 wherein a full 360 degree rotation of the rotatable member is for moving the lens housing a distance of 0.35 mm or less.

15. The projection system of claim 1 further comprising:

an assembly frame, wherein the lens housing is slidably disposed in the assembly frame and the rotatable member is supported within the assembly frame; and a device subassembly coupled to the assembly frame.

16. The projection system of claim 15 and further comprising a screen for receiving an image projected by the lens in the lens housing, wherein the screen is coupled to the device subassembly.

17. The projection system of claim 15 wherein the device subassembly comprises:

a first screen for receiving an image projected by the lens in the lens housing; a combiner for receiving a reflection of the image from the first screen; and circuitry for projecting an image through the lens in the lens housing.

18. The projection system of claim 1 further comprising:

an assembly frame, wherein the lens housing is slidably disposed in the assembly frame and the rotatable member is supported within the frame; and

a head up display device subassembly coupled to the assembly frame.