WO2000055673A9

WO2000055673A9 - Headset boom for image display module

Info

Publication number: WO2000055673A9
Application number: PCT/US2000/007250
Authority: WO
Inventors: Gary Mcclary; Adrian Sesto; Karl Armagost; Kevin Schehrer
Original assignee: Colorado Microdisplay Inc
Priority date: 1999-03-17
Filing date: 2000-03-17
Publication date: 2002-04-04
Also published as: WO2000055673A1; AU3761200A

Abstract

A headset boom for carrying an image display module. The boom is telescoping and movable laterally with respect to the wearer's head. The boom is rotatable 360 degrees so that the display module can be selectively placed before either eye of the wearer. The boom includes a ball joint on which an image display module can be mounted such that the image display module is pivotable about at least three axes with respect to the boom.

Description

HEADSET BOOM FOR IMAGE DISPLAY MODULE

This application claims priority of provisional application number 60/124,786, filed March 17, 1999.

FIELD OF THE INVENTION

The invention relates generally to headset devices and more, particularly, to headsets for image display devices.

BACKGROUND OF THE INVENTION

Head-mounted display or display headset devices are devices that are mounted on a human head and that deliver an image, such as from a cathode ray tube or liquid crystal display, visible to one or both eyes. Head-mounted display devices have found many uses from video games to military applications. For example, such devices are used in the Air Force for flight simulation. These devices are made up of typically bulky binocular goggles that restrict the field of view of each eye to the image displayed in front of the goggles.

Another example of a head-mounted display device is the Honeywell Integrated Helmet and Display Sighting System (IHADSS) deployed by the U.S. Army on the AH-64 Apache helicopter. The IHADSS features a monocular display mounted on the side of the pilot's helmet and linked to infrared sensors and weapons visible to the pilot's eye. The IHADSS provides a monochrome image with user-accessible adjustments. It is attached to a helicopter flight helmet and is certified by the Army as crash- worthy. The display is not interchangeable between eyes to accommodate, for example, a user's preference for use with a dominant eye. Further, the device is not easily adjustable to fit different head sizes and viewing angles. Although, the display arm of the device provides some up /down adjustment, the primary adjustment limitation is the helmet to which the display is affixed. Users of the IHADSS are only those that possess a head size that fits the helmet. Accordingly, a commercial application of such a device, with different size helmets and differently positioned displays would be a costly venture resulting in a costly product.

Commercial applications of head-mounted display devices include uses for virtual reality simulation. These devices are similar in operation to the flight simulation displays used by the Air Force, with the exception that the new designs are lighter weight and not as bulky on the human head. Similar to the Air Force displays, these devices provide a binocular display to the user and limit the user's entire field of view of each eye to the image on the display.

What is needed is a lightweight, adjustable, and portable headset that can be used with an image display apparatus and that provides a stable support for an image display module. A support providing a comfortable and secure fit to the user's head and allowing free movement of the user's head without slipping and without inadvertent movement of the display module relative to the user's eye is desired. Also, a headset is needed that allows the display module to be easily moved from one eye to the other.

SUMMARY OF THE INVENTION

In one embodiment, a headset boom for carrying an image display module includes an arm having a proximal portion and a distal portion. A hub is operatively associated with the proximal portion of the arm. The hub is configured for rotatable connection to an axle and is rotatable 360 degrees about the axle. The hub is frictionally engaged with the axle.

Other features of the present invention are disclosed in the accompanying drawings and the detailed description which follows. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

FIGURE 1 is a perspective view of a headset including a headset boom embodying the present invention;

FIGURE 2 is another perspective view of the headset of FIGURE 1;

FIGURE 3 is yet another perspective view of the headset of FIGURE 1;

FIGURE 4 is a right side elevational view of the headset of FIGURE 1;

FIGURE 5 is an enlarged partial perspective view showing details of the hub of the boom;

FIGURE 6 is a partial perspective view of the headset showing the axle on which the boom is attached;

FIGURE 7 is a perspective view of a stabilizer assembly and detent frame;

FIGURE 8 is a top plan view of the headset of FIGURE 1;

FIGURE 9 is a partial side view of a support plate rotated to a wearing position;

FIGURE 10 is a partial side view of a support plate rotated to a storage position;

FIGURE 11 is a partial back elevational view of the headset of FIGURE 1;

FIGURE 12 is a cross-sectional view taken along line 5-5 of FIGURE 11;

FIGURE 13 is a cutaway view of a pivot plate and a support plate;

FIGURE 14 is a subassembly view of a pivot plate and a detent wheel;

FIGURE 15 is a perspective view of the subassembly including a pivot plate, detent wheel, and detent frame;

FIGURE 16 is a perspective view of the subassembly including a detent wheel and a detent frame; FIGURE 17 is a partial perspective view of a detent mechanism on a support member;

FIGURE 18 is a partial perspective view of the subassembly including a detent mechanism on a support member assembled with a detent frame.

FIGURE 19 is a left side elevational view of the headset of FIGURE 1;

FIGURE 20 is a front elevational view of the headset of FIGURE 1; and

FIGURE 21 is a bottom plan view of the headset of FIGURE 1.

DETAILED DESCRIPTION

A headset including a headset boom embodying the present invention is adapted to hold an image display module in front of one of the eyes of the wearer of the headset. The boom carries the image display module in position in front of the wearer's eye. The boom is rotatable over 360° so that the user can selectively position the display module in front of his dominant eye by rotating the boom and turning the headset around. The boom is preferably movable from left to right to provide further adjustment relative to the user's eye. Also, the boom includes a ball joint on which the display module is mounted. The display module can be adjusted about at least two axes relative to the boom.

The headset preferably includes four contact points at the sides of the wearer's head. Two contact points are provided at each side of the head. The four contact points compensate for the torque of the boom with the display module on its end. Also, the four contact points distribute the force of contact more evenly to the wearer's head, thus increasing the comfort of the wearer.

One example of an image display module is a liquid crystal on silicon ("LCOS") virtual image microdisplay. More particularly, the exemplary display module can be an LCOS reflective liquid crystal display with optics. The optics create a magnified virtual image of the LCOS, which comprises the object plane. The user of the headset observes the magnified virtual image. The image display module can also be of the type that is "see-through", i.e. an image is displayed on a surface that is transparent or translucent. The user can focus his eye on the image plane, or he can focus past the image plane. This type of display module allows the user to switch between observing the displayed image and his surroundings without moving the display module away from his eye. It allows the user to superpose the virtual image on the real world as seen through the transmissive optics.

A headset 100 shown in FIGURE 1. Headset 100 includes a support member 110 having a first end 112, a second end 114, and an arcuate central portion 116 extending between the first end 112 and the second end 114. Preferably, support member 110 is a lightweight construction of a flexible flat band of metal, sized and shaped to fit human heads of a selected size range, i.e. adults or children. Support member 110 is preferably flexible enough to accommodate most sizes of human heads in a particular selected range, yet stiff enough to provide adequate force to keep the headset 100 firmly yet comfortably secured to the wearer's head.

A top pad 120 can be provided on the central portion 116 of the support member 110. Top pad 120 can include a cushion 121 on the underside of central portion 116. Top pad 120 is preferably a semi-hard rubber material that is flexible enough to conform to the arcuate shape of support member 110, yet rigid enough to provide additional stability at the top of the headset wearer's head.

Top pad 120 preferably includes an elongated center section 122 that is adapted to be attached to the central portion 116 of support member 110. In one embodiment, center section 122 defines a longitudinal groove 124 that cooperates with a longitudinal channel 126 within the center section 122. Channel 126 is preferably shaped to receive central portion 116 of support member 110. Alternatively, other means of attaching top pad 120 to support member 110, such as clips or adhesive, can be used. Top pad 120 can also be molded onto support member 110. Alternatively, top pad 120 can be unitary or integral with support member 110. For example, support member 110 can be made of molded plastic, and top pad 120 can be formed together with support member 110.

Top pad 120 can also include forwardly and rearwardly extending wings 128. Wings 128 provide additional width to top pad 120 for additional stability. Wings 128 help to further distribute force at the top of the wearer's head by providing additional torque. The added width due to wings 128 helps keep the support member 110 from slipping forward or backward on the wearer's head during sudden movements of the head.

Headset 100 also includes a first housing 130 on the first end 112 of support member 110 and a second housing 140 on the second end 114 of support member 110. First housing 130 includes an outer side 132 and an inner side 134 (shown in FIGURE 2). Similarly, second housing 140 includes an outer side 142 (shown in FIGURE 2) and an inner side 144.

First and second ends 112 and 114 are slidably received into first and second housings 130 and 140, respectively, to provide an additional adjustment of the headset 100 to more comfortably fit the wearer's head. Detent mechanisms can be provided in first and second housings 130 and 140, as described below. Alternatively, first and second housings 130 and 140 can be fixedly attached to the respective first and second ends 112 and 114 of support member 110.

FIGURE 1 also shows a first stabilizer assembly 170 attached to the inner side of the first housing 130. A second stabilizer assembly 270 is attached to the inner side 144 of second housing 140. First stabilizer assembly 170 includes a first support plate 190, and second stabilizer assembly includes a second support plate 290.

As shown in FIGURE 1, a boom 150 is provided at the outer side 132 of first housing 130 in the preferred embodiment. Alternatively, in another embodiment of headset 100, boom 150 can be provided at the first end 112 of a support member 110 that does not include a first housing 130. Boom 150 includes a proximal portion 152 and a distal portion 154. The proximal and distal portions 152 and 154 are preferably slidable in relation to each other. The slidable proximal and distal portions 152 and 154 provide the telescoping feature of the boom 150 of the preferred embodiment.

An image display module 102 can be secured to the distal portion of boom 150. Preferably, module 102 defines a socket 105 that accepts a ball joint 156 on the distal portion 154 of boom 150. Preferably, the display module 102 is sufficiently small in the plane orthogonal to the optic axis so that the user can see around the display module.

Image display module 102 can include a lens 103 that faces the wearer's eye when the headset 100 is worn. Telescoping boom 150 allows the user to adjust the distance between the lens 103 and the eye. Boom 150 preferably includes a friction element (not shown) between proximal and distal portions 152 and 154 that hinders slippage between the telescoping portions 152 and 154 under the weight of the display module 102 or during typical movements of the head.

Boom 150 also preferably includes a cable guide 158 that holds a cable 104 that provides power and data signals to the display module 102. Alternatively, the image display module can receive signals through wireless means, such as radio frequency signals.

FIGURE 3 shows headset 100 having boom 150 pivotally coupled to a hub 160 at a boom pivot axis 162. Boom 150 can thus pivot toward and away from the headset 100 wearer's head in the direction of arrows A- A in FIGURE 3. Arrows A- A indicate a generally side-to-side movement of boom 150 relative to the user's head. Boom pivot point 162 is preferably provided with sufficient friction such that boom 150 is held in place during normal head movements of the wearer.

Hub 160 is rotatably coupled to the outer side 132 of first housing 130. Hub 160 can be coupled to first end 112 of support member 110 in an alternative embodiment. As shown in FIGURE 4, hub 160 is preferably rotatable 360° around its axis in the direction of arrows B-B. Full rotation of hub 160 allows boom 150 with display module 102 to be flipped from one side of the headset 100 to the other. The headset 100 can then be turned around and used with the display module 102 positioned in front of either the right or left eye of the user. The user can selectively position the display module 102 in front of his dominant eye or his non-dominant eye, as desired.

FIGURE 5 shows proximal end portion 152 of boom 150 pivotally attached to hub 160 at boom pivot axis 162. Hub 160 includes a cylindrical main hub body 163 and a hinge portion 165 extending generally radially from hub body 163. Hinge portion 165 cooperates with proximal portion 152 of boom 150 at boom pivot axis 162. A boom hinge pin 169 extends through proximal portion 152 and hinge portion

165 to pivotally couple boom 150 to hub 160.

Hub 160 is pivotally coupled to first housing 130. A boom axle 166 extends from first housing 130 and cooperates with hub 160. Hub 160 and boom axle 166 are preferably frictionally engaged such that boom 150 with display module 102 remains in a selected position notwithstanding the torque resulting from the weight of the display module 102 and the length of boom 150.

The frictional engagement of hub 160 to boom axle 166 is preferably provided by a soft or semi-rigid annular collar 164, preferably made of synthetic material such as plastic or rubber, in contact with the outer diameter of boom axle 166 and the inner diameter of hub 160. The inner diameter of annular collar 164 rotates with hub

166 relative to boom axle 166. The friction and lever-arm at the outer diameter of annular collar 164 is preferably such that slippage takes place at the contact between axle 166 and annular collar 164. An alternative embodiment of the hub 160 can include a ratchet or detent mechanism or any mechanical mechanism known in the art that allows selective rotation of the hub 160 and positioning of boom 150, yet can provide a holding mechanism to hold the hub 160 and boom 150 in place. Boom axles 166 defines a groove 167 near its end. Groove 167 is exposed when collar 164 of hub 160 is fully seated onto boom axle 166. A snap ring 168 is seated into groove 167 to hold hub 160 on boom axle 166.

FIGURE 6 shows boom axle 166 extending from first housing 130. FIGURE 7 shows the mechanisms of the interior of first housing 130 (FIGURE 6), including boom axle 166 extending from frame member 131.

In an alternative embodiment, a headset can include a second boom coupled to the second end of the support member or to a second housing at the second end of the support member. A dual-boom headset can provide a binocular display with two display modules. The display need not be binocular, however. Each display module of a dual-boom headset can display a different image. For example, a split- screen computer display can be provided, or 3-dimensional images can be provided.

Yet another alternative embodiment includes a U-shaped boom carrying either one or two display modules. In the case of a U-shaped boom with one display module, the module can be slidably disposed on the boom such that it can be moved from one eye to the other according to the user's preference. In any of the alternative embodiments, the second boom (or boom-end) can be coupled to the support member in the same manner as described above.

FIGURE 8 shows another feature of headset 100. Four side contact points 118 that contact the head of the wearer provide additional comfort to the wearer and stabilization of headset during side-to-side movement of the head. Four side contact points 118 are provided, with two contact points 118 on each side of the head. The four side contact points 118 are provided by a first stabilizer assembly 170 and a second stabilizer assembly 270.

As shown in FIGURE 8, first stabilizer assembly 170 includes a first support plate 190. First support plate 190 includes a forwardly extending portion 191, a rearwardly extending portion 193, and a middle portion 195 between the forwardly and rearwardly extending portions 191 and 193. In the preferred embodiment, middle portion 195 is adjacent to first pivot plate 180. Forwardly extending portion 191 extends forwardly and downwardly relative to middle portion 195. Conversely, rearwardly extending portion 193 extends rearwardly and downwardly relative to middle portion 195.

Preferably stabilizer assemblies 170 and 270 are symmetric. Stabilizer assemblies 170 and 270 may alternatively be asymmetric so that the forwardly extending portion 191 and the rearwardly extending portion 193 are of different lengths relative to the middle portion 195.

First support plate 190 can also include pads 198 on its inner side 194. Pads 198 are preferably located at forwardly extending portion 191 and rearwardly extending portion 193.

First support plate 190 thus provides two contact points 118 to the side of the head of the wearer of headset 100. The contact points 118 are generally to the front and back of the ear of the wearer and may be above the ear. Because the headset 100 does not obstruct the ear, other devices that are placed on the ear such as a telephone handset, for example, can be used without removing the headset 100. Alternatively, an earpiece (not shown) can be provided or attached to the headset 100.

The headset 100 of the preferred embodiment also includes a second stabilizer assembly 270 on the second housing 140. The construction and operation of second stabilizer assembly 270 is preferably identical to those of first stabilizer assembly 170. Alternatively, second stabilizer assembly 270 can be a mirror image of first stabilizer assembly 170. Yet another alternative embodiment of headset 100 has a single contact point 118 or pad 198 at the second end 114 of support member 110.

Preferably, four contact points 118 are provided by the two stabilizer assemblies 170 and 270. The contact points are preferably spread apart to compensate for the torque created by the boom 150 and display module 102. Thus, the force on the head of the wearer is spread out such that the headset can be worn comfortably. FIGURE 9 shows first support plate 190 coupled to first pivot plate 180 at first offset pivot point 184. First support plate 190 includes forwardly extending portion 191, rearwardly extending portion 193, and middle portion 195 between forwardly extending portion 191 and rearwardly extending portion 193. Inner side 194 is shown having pads 198 attached hereto. Pads 198 are preferably attached at forwardly and rearwardly extending portions 191 and 193.

FIGURE 9 shows first support plate 190 in a wearing position. As described below, first support plate 190 can be rotated to a storage position.

FIGURE 10 shows first support plate 190 pivoted about first pivot point 184 to a storage position which is about 90° from a wearing position (FIGURE 9). First support plate 190 defines a recess (not shown) on its outer side (not shown) that cooperates with a protrusion 186 on first pivot plate 180. When protrusion 186 is seated within the recess, first support plate 190 is held in its wearable position. Referring again to FIGURE 1, when both first and second support plates 190 and 290 are pivoted to a storage position and boom 150 is rotated into the plane of support member 110, headset 100 becomes compact and easily stored.

FIGURE 11 shows hub 160 including a cover 161 that is preferably a truncated, spherical body. Cover 160 can define a cable channel 163. Hub 160 is coupled to the outer side 132 of first housing 130 in the exemplary embodiment of headset 100 shown in FIGURE 11.

First stabilizer assembly 170 is preferably coupled to the inner side 134 of first housing 130. First stabilizer assembly 170 has a vertical axis and a horizontal axis and is pivotable about each axis. First stabilizer assembly 170 includes a first pivot plate 180 and a first support plate 190 coupled to first pivot plate 180. First pivot plate 180 cooperates with first housing 130 via a first hinge member 182 extending from first pivot plate 180. First hinge member 182 swivels or is pivotable about its vertical axis. The vertical axis of first hinge member 182 is generally vertical with respect to the wearer. The vertical axis is generally parallel to the first housing 130 or first end (not shown) of support member 110.

As shown in FIGURE 12, first housing 130 defines a hole 136 into which first hinge member 182 extends. Hole 136 has an hourglass shape. The horizontal axis of the first stabilizer assembly 170 (FIGURE 11) passes through the narrow portion of the hourglass shape. First hinge member 182 is pivotable in the direction of arrows C-C about the horizontal axis within the bounds of the hourglass-shaped hole 136. The pivoting of the first hinge member 182 about the horizontal axis corresponds to the pivoting of the first stabilizer assembly 170 in the plane generally parallel to the side of the wearer's head.

FIGURE 13 shows first stabilizer assembly 170 including first pivot plate 180 and first support plate 190. Pivot plate 180 has hinge member 182 extending in the direction away from first support plate 190. First hinge member 182 cooperates with a pin 183 to provide pivoting of the first stabilizer assembly 170 about a vertical axis that is coaxial with pin 183.

First support plate 190 defines a recess 196 on its outer side 192. A corresponding protrusion 186 ( FIGURE 10) on first pivot plate 180 cooperates with recess 196 to releasably hold first support plate 190 in the wearing position.

FIGURE 14 shows first pivot plate 180 pivotally attached to detent wheel 187 via hinge member 182. Hinge member 182 is pivotally attached via pin 183 to socket 188 of detent wheel 187. Detent wheel includes protrusions 189 extending outwardly from detent wheel 187 and preferably diametrically opposed from each other. FIGURE 14 shows a detent wheel that includes two protrusions 189. Alternatively, any selected number of protrusions 189 may be provided on detent wheel 187.

FIGURE 15 shows first pivot plate 180 assembled to detent wheel 187. Detent wheel 187 is seated within detent frame 200 and has pin 183 in hinge member 182. Detent frame 200 defines a generally circular cavity 202 that defines corresponding detents 204 that accept protrusions 189 of detent wheel 187. First pivot plate 180 together with first support plate (not shown) can be rotated about a horizontal axis which is defined by the central axis of detent wheel 187. First pivot plate 180 can be selectively positioned and is held in place by the detent mechanism described above.

First pivot plate 180 includes a first offset pivot point 184. Referring again to FIGURE 13, a first support plate 190 is pivotally attached to the first pivot plate 180 at the first offset pivot point 184. First support plate 190 is pivotable about the first offset pivot point 184 with respect to the first pivot plate 180. Protrusion 186 is shown in FIGURE 15 extending from first pivot plate 180.

FIGURE 16 shows detent frame 200 with detent wheel 187 seated in cavity 202. Pin 183 is shown extending through socket 188 of detent wheel 187.

FIGURE 17 shows a support member detent mechanism 210. Support member detent mechanism 210 is attached to either first end 112 (as shown) or second end (not shown) of support member 110. Detent mechanism 210 includes a body 211 fixedly attached to a first end 112 of support member 110. Arm 212 extends from body 211. As shown in FIGURE 17, arm 212 extends along an edge of body 211 and has a free end 214 that includes a protrusion 216 extending therefrom.

Detent mechanism 210 cooperates with detent frame 200 as shown in FIGURE 18. Detent frame 200, along with the stabilizer assembly and housing (not shown), are slidable with respect to the first end 112 of the support member 110. Detent frame 200 defines an elongated opening 206. Arm 212 extending from detent mechanism 210 includes a protrusion 216 that cooperates with serrated edge 208 of opening 206. Detent mechanism 210 and detent frame 200 provide adjustability of the first and second stabilizer assemblies 170 and 270 with respect to the support member 110.

The detent mechanisms associated with the first pivot plate 180 and the support member 110 provide adjustability of those portions of the headset 100 that a user may selectively adjust and desire to leave in the same position. Other movable portions of the headset 100 are held in place by frictional force. These pieces, such as the boom 150 and stabilizer assemblies 170 and 270 are typically moved by the user during use of the headset 100.

FIGURES 19-21 show headset 100 including image module 102 on boom 150 and the various axes about which image module 102 can be pivoted on the ball joint (not shown) of boom 150. FIGURE 19 illustrates that module 102 can be pivoted in the direction of arrows X-X. FIGURE 20 illustrates that module 102 can be pivoted in the direction of arrows Y-Y. FIGURE 21 illustrates that module 102 can be pivoted in the direction of arrows Z-Z. Thus, image display module can be adjusted in at least three axes relative to boom 150.

Other auxiliary component can be provided on headset 100. For example, an occluder may be provided to cover part or all of the field of view that is seen by the eye that is not observing the image from the display module 102. The occluder can be attached to the display module or to the headset support member and is preferably of a physical size and shape that occludes a field of view in the eye that is not observing the display corresponding to the field of view that comprises the image in the eye that is observing the image from the display module 102. While viewing the image from the display module 102, binocular rivalry is suppressed, and when looking around the display module 102 at the surrounding environment, normal binocular vision is obtained. Referring to FIGURE 2, the occluder can be attached to the outer side 142 of the second housing 140, which is independent of the display module 102 and boom 150 which are attached to the outer side 132 of the first housing 130. The occluder is preferably opaque and dark although it can also be translucent and of any color.

Other features that may be provided on headset 100 are a microphone or audio speakers attached to headset 100.

Thus, a headset including a boom for carrying an image display module has been described. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Claims

CLAIMSWhat is claimed is:

1. A headset boom for carrying an image display module, the boom comprising: an elongated arm having a proximal portion and a distal portion; and a hub operatively associated with the proximal portion of the arm, the hub configured for rotatable connection to an axle, wherein the arm is rotatable 360 degrees around the axle, and wherein the hub is frictionally engaged with the axle.

2. The headset boom of claim 1 wherein the hub includes a hinge portion, and wherein the proximal portion of the arm is pivotally connected to the hub via the hinge portion such that the arm is pivotable laterally with respect to the hub.

3. The headset boom of claim 2 wherein the arm is telescoping such that the proximal portion and the distal portion are slidable with respect to each other.

4. The headset boom of claim 1 wherein the distal portion includes a distal end having a ball joint, wherein an image display module mounted on the ball joint can be pivoted in at least three axes relative to the boom.

5. A headset boom for carrying an image display module, the boom comprising: an elongated arm having a proximal portion and a distal portion, the distal portion having a ball joint, wherein an image display module mounted on the ball joint can be pivoted in at least three axes relative to the boom; a hub operatively associated with the proximal portion of the arm, the hub configured for rotatable connection to an axle, wherein the arm is rotatable 360 degrees around the axle; a hinge portion extending from the hub, wherein the proximal portion of the arm is pivotally connected to the hub via the hinge portion such that the arm is pivotable laterally with respect to the hub.

6. The headset boom of claim 5 wherein the arm is telescoping such that the proximal portion and the distal portion are slidable with respect to each other.

7. The headset boom of claim 5 wherein the hub is frictionally engaged with the axle.

8. The headset boom of claim 5 wherein the hub is engaged with the axle via a detent mechanism.

9. The headset boom of claim 5 wherein the arm is telescoping such that the proximal portion and the distal portion are slidable with respect to each other, and wherein the hub is frictionally engaged with the axle.