CA2490344A1 - Binocular head mounted display system - Google Patents
Binocular head mounted display system Download PDFInfo
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- CA2490344A1 CA2490344A1 CA002490344A CA2490344A CA2490344A1 CA 2490344 A1 CA2490344 A1 CA 2490344A1 CA 002490344 A CA002490344 A CA 002490344A CA 2490344 A CA2490344 A CA 2490344A CA 2490344 A1 CA2490344 A1 CA 2490344A1
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Abstract
A binocular head mounted display unit (10) utilizing a single display (28) and binocular optical system (30) is shown for projecting as enlarged image of displayed information in the direct line of the user's eyes, while maintaining the ~ peripheral vision free from obstruction to allow the user to selectively focus on the virtual image or not. The binocular optical system (30) directs the user's eyes inward at an angle that is natural for a person viewing an object at a distance that is less than infinity. Further, the binocular optical system (30) automatically compensates for variations in the interpupillary distances of various users, wherein those variations may be as great as one inch. This head mounted display unit (10) is suitable for a variety of applications, including virtual reality applications, as well as a display for a compact portable computer.
Description
TEC~IICl~ FIELD
The present invention is directed to a head mounted display systea and more particularly to a single display, binocular system that projacta an image in the direct line of eight of th~~.
user's~eyes while maintaining the user's peripheral vision relatively tree from obstruction to allow the user to selectively focus on the virtual image or not.
:o eaC~cc~eov~D o~ Tae i8va~=o~r Binocular head mounted display systems allow a user to view an image or images o!
displayed information with both eyes. Typical binocular head mounted display systems include two displays, one !or each o! the user's eyes, as well as two sets of identical optics so as to be very costly and heavy. 8laocular head mounted display systems that include only a single display are also known. Both types,ot systems typically direct the user's eyu such thtt the axes of the eyes are parallel'tor .viewing a projsctad image focused at infinity.
For virtual reality applications in which the user is to be totally immersed in the video image, these binocular systems are further formed so that the ussr~s field of view is completely blocked, the user being unable to see anything but the displayed image.
These known systems have a number of problems. For exempla, it has bean found that with head mounted display systems in which the user cannot focus on anything but the projected imaga,leys fatigue often occurs. Such systems can cause feelings of claustrophobia because the usar~s view is completely enclosed and fallings of anxiety because the user can hear things going on in his surroundings but is not able to eea what is happening. With these systems the user can also experience "sea sickness" when the motion of the image that hs is viewing does not coincide with the motion that the user s body is experiencing.
Binocular systems in which the ussr~s eyes i5 era directed such that the axes of the eyes are parallel hays been found to~eoritributs to sys fatigue when the image is focused at less than infinity. Eye fatigue and feelings of discomfort result because it is.unnatural for a ZO personas ayes to ba such that the axes o! the eyes era parallel when viewing an image that is only two or three lest away.
Known binocular systans era typically designed for users having a particular "average"
25 or "normal~ intarpupillary distance (hereinafter referred to. as iPOj. Because the IPD of users can vary considerably, these systems era usable only by a vary limited portion of the population and era not suitable for general consumer 30 applications.. If a user has an IPD that varies considerably from the average IFD for which the system is designed hi: eye will ba off of the axis o! the optical systu. Usar~s who err off-axis typically see right eye end left aye images 35 that do not lima up. That' may also see distortions in the image wbaraia one lids of the imago will look bigger than the other side, - . ~ and/or a part of the imago will ba in focus whils other parts of the imago will ba out of.
focus. Further, a portion o! the imago depictsd on the display may ba cut off whan.viawad off axis through the optics of the systsm.
~n accordance with the psasant iirver~tion, .
tha~disadvantagas of prior~binocular head mountad,display systems have bean overcome. Tha .- head mounted display systsm of the prassnt invantion~ia a single display binoculas systas that is usably by a.larga portion o! tba .
population without modification. The bud . .
mounted display systsm of the present invention is suitable !os applications requiring the user to comfortably focus at lass than infinity, as well as applications raquirinQ the user to locus at infinity, and is further suitable for 20~ applications requiring tha_usar to vises his surroundings while viewing the projected imago, . as well as for virtual reality applications.
More particularly, the head mounted display . system o! the present ~invantion includes a Z 5 support to mount the display system o~n a war s head; a single video image source, such as a display, that is mounted on the support; and a compact binoculas optical system of ainiaal weight for projecting an enlarged virtual imaqa 30 of the video from the imago source at a distance.
from the user that is graatas than the actual path length o! the~optical system. Because the optical system is compact and.light-weight, the support may be similar to the frame o! a pair of 35 glasses or other conventional eyawaas and doss not require the support to tsks the lors o! a helmet or other substantial arrangemsnt in order ' 60713-621D
to act as a counter weight for the optics as in - . known.systsms.
Ons feature of the binocular optical systa~
' projscts a of the present invention is that it virtual image in the central field o! vise o!
each of the usars ayes, wharaia the optical systea and support are such as to maintain at least a portion of the peripheral view o! each o! the usars ayes free Eros obstruction.
eacauss at least a portion o! the peripheral view of each of tha~usera.eya, is free frog obstruction, the usar~csn selectively focus on the projected image or not to minisias os substantially aliminati aye fatigue. P~rthas, because the user is visually cognisant o! his surroundings while he is viewing the virtual ' image, feelings o! anxiety and claustrophobia are eliminated. It is also notad,~that because ' the user can selectively view his. surroundings,.
the system o! the present invention dou not promote feelings of "sea sickness" as frequently encountered with othir systems.
although the user can siaultansously view his surroundings as wall as the virtual image with the head mounted display~systea o! the present invention, it has bean found that~ths _ present systsa creates a feeling ol.total immersion in the video image. Therefore the systes is suitable for virtual reality . ' applications without having the probleas ..
associated with binocular head mounted display -systems typically used for such applications:
This lasling o! total immersion in the video image with the systaa o! the present invention . 35 is quits surprising since heretofore it vas thought that-for total immersion, the user should not sea anything but t~u projected video -image. It has lurthsr been found that because the user has at least some vision of the raal ' world, as~wall as the virtual image, the thras-dimensional cuss in the real world cause the.
user to perceive that the virtual image has 5 depth, i.a. is three dimensional without . requiring a stereo imago source.
Another feature of the binocular optical systea of the present invention is that it includes a right eye optical contarlina path and a left eye optical centerline path with at lsast .
one optical element~in each of these paths, ..
wherein the right .yi and left aye optical centerline paths,ara angled in towards the virtual image perceived by the user. Because ~i5 the optical, centerline paths of the syst~a era angle fn towards the virtual imago, the ussr~s eyes era directed inward at sn angle that is natural !or a person viewing an object at a distance that is leas than infinity as opposed to being directed ao that the axai of the eyes era parallel. With the usar~a eyes directed naturally inward to~tha location of the virtual imago, the head mounted display system o!' the -present invention is more comfortable and less eye straining than prior systeaa.
. l~ further feature of the binocular optical system o! the present invantion is that it automatically compensates !or variations in the interpupillary distance of diffasent uaass, wherein those variations may bs as great as one inch. Therefore, the head mounted display system of the present invention is suitable for use by a vast majority of the population without requiring manual adjustment to any o! the optical elements. ~h one embodiment, variations in intarpupillary distance are automatically compensated for utilizing in each o! tho right eye and left eye paths a pries that bends the ~ .
6. .
light from any location along the width thereof, representing various positions of users' eyes with different IPDs, towards a centrsl area on a concave raflactos. This concave reflector focuses the light path free the .user's right acrd loft eyes to the soma point on the display, which. is preferably the center of the display, in.anothar embodiment, a focusing lens is disposed in each of the right eye and left aye 1o optical paths, such that light at any location ~ .
along the width, i.e.,diamatar,~ of the lens . , representing various positions of users' eyes, is focused on the same point, mirrors bairrq disposed in each of the sight~aya and loft ayd, optical paths to direct the path of the light from the user's eyes through t~h~ respactiw larses to the same point on the display. In accordance with a further feature o! the present invention, the binocular optical system may ZO include a semi-transparent reflector into which , the user looks to view the virtual image in a portion of his field o! view. The display say further include a brightness control allowing the brightness of the display to ba varied to cause the virtual image to block that portion of the_ user's llald of view in which the image is projectad;'to cause the virtual image to be superimposed on the real world in that portion of the user's field of view in which the image is projected so that both the image and the real . ~ world in that portion can ba simultaneously scan by the user; or ~to .cause ~tha virtual image to bs . . .
extinguished Eros that~portion of tb~ user's field of view so that the user spas the real world, but doss not sae the virtual image at all. This feature can also be accomplished by providing a display which can bs controlled so that light does not pass from the display in a defined area or window thereof. in~hen this light blocking feature of the display is actuated, a window into the real world is provided through the displayed image and when not actuated, the image is seen in its entirety.
The head mounted display system of the present invention is suitable for any application requiring the viewing of displayed information. Because of a number of ' the features noted above, the system of the present invention is eminently suitable for a computer display.
Therefore, in accordance with the present invention, the head mounted display system forms the display of a computer, the electronics of which are housed in a keyboard housing.
The keyboard is designed to be compact, and in one embodiment is foldable. The keyboard may also include a mounting surface for the head mounted display unit so that the computer can be easily carried. Because the head mounted display is compact and lightweight, the overall weight and size of the computer in accordance with the present invention is greatly reduced over prior portable computer systems. The image viewed by the user with the computer display of the present invention can be as large or larger than the image depicted on conventional non-portable computer displays, unlike the displays of typical portable computers. Further, because the head mounted display is a personal display unit, only the user can see what is being displayed on his computer so as to allow the user to work on confidential information while in a public setting, such as on an airplane.
According to one aspect of the present invention, there is provided a head mounted display system comprising:
7a a support to mount the display system on a user's head; a first prism mounted on said support in a right-eye optical path; a second prism mounted on said support in a left-eye optical path; a display mounted on said support for displaying video information; and a reflector shaped to project an enlarged image of said video at a distance from the user, said reflector being mounted on said support in each of said right-eye and left-eye optical paths, wherein said first and second prisms bend the right-eye and left-eye 20' optical paths from a user's eye towards each other and said reflector in each path focuses light traveling along the respective optical paths onto the same point relative to said display.
According to another aspect of the present invention, there is provided a head mounted display as recited as described herein wherein said display is the only display of the system.
These and other objects, advantages, an$ novel features of the present invention, as well as details of an illustrated embodiment thereof, . will be mots fully understood frog the following . description and the drawing.
BRIE! DESCRIPTIO11 O! THE DRAIIINa Fig. 1 is a perspective view of a head mounted display system and keyboard in accordance with the present invention forming a portable computer=
Fig. 2 is an exploded, perspective view of a head mounted display system in accordance with .
one embodiment o! the present invention;
Fig. 3 is a back perspective view of the head mounted display system,depictsd iwFig. a;
Fig: 4 is a side view o! the head mounted display system depicted in Fig. Zp.
Fig. 5 is a top view o! tZia optics and display o! the system shown in Fig. Z=
Fig. 6 is a schematic illustration o! the convergence angle o! the ussr~s.syss when the image is focused at~less than infinity with the system depicted in Fig. 5i .
Fig. 7 is a top view o! a schematic illustrating the usar~s side peripheral vision that is maintained unobstructed by ttia optical system o! the present invention;
FiQ. 8 is a front view o! a schematic illustrating the users side and lower , peripheral vision that is maintained unobstructed by the optical system o! the present invention=
Fig. 9 is a bottom view o! the head mounted.
display system depicted in Fig. Z modified with the addition of a~movabla eye block so as to make the systea monocular=
Fig. 1o ii a top view of the optics of Fig.
5 modified in accordance with another embodiment o! the head mounted display systu of the present invention 9.
Fig. 11 3s a top view o! the optics and, .~ ~ display for a head mounted display systea in accordance with still another embodiment o! the present invention;
Fig. iz is an exploded, perspective view o!
a folded embodiment o! the head mounted display systea shown in Fig. z; , , Fig. 13 is.a top view of the optics fos a further embodiment o! the head mounted display ' . 10 system of the present invention,depicting alternative locations !or the mounting of the display used therein;~.
F'ig. 14. is a side view o! a folded .
embodiment of the head~mounted display systes;
.
depicted in Fig . 13; ' Fig. 15 is a schematic diagraa o! the optics in accordance with a lurther embodiment 'o! the head mounted display systea o! the present invention wherein dotted lines represent Z0 mirror folds o! the systes;
Fig. 16 is a perspective view o! a keyboard as shown in Fig. 1 partially folded;
Fig. 17 is a perspeatiw.viw o! the keyboard o! Fig. 16 folded=
Z5 ~ Fig. 18 is a top perspective view o! the bottom housing and hinge assembly o! the keyboard o! Fig. 16; ' Fig. 19 is an exploded, perspectiv~.view of the hinge assembly o! the keyboasd depicted in 30 Fig. 16;
Fig. 20 is a~perspectiw view illustrating .
another embodiment.o! the foldable keyboard o!
the present invention;
Fig. zi is a back view o! the keyboard o!
35 Fig. Z0 illustrating as alternative hinge arrangement;~
Fig. Z~ is a partial aids viw o! the hinge arrangement o! Fig.~Zi wherein the hinge is in a non-folded position; ~ ~.
Fiq.~Z3 is a partial side view of the hinge illustrated in Fig. ZZ in the folded position;
Fig. 24 is a perspective view of aw 5 alternative embodiment of the foldable keyboard of the present invention including a mounting surtacs for the head mounted display unit;, Fig. s5 is a bottom view of the portable , computer system depicted it Fig. Z4; and Fig. Z6 is a perspective view of a hud mounted display system mounted on the keyboard , .
of. Fig. Z4 in its folded position.
DEBCRIPTIOlI O! T8a PREFERRED EMHODIME11'! . ' .
Tha head mounted display unit 10 o!-ths i5 present invention as shown in Fig. i.includ~s.~a frame iz that is worn on a usar~s head and that supports a display Z8 and associated binocular optics, as discussed in detail balov for the various embodiments.thereol. The lrasa IZ may alto support the drive electronics for the .
display and a pair. of earphones 1~, 16 that _ . provide. audio for the unit ~10. As is wll~
known, the drive electronics !or the display era =esponaivs to standard video input signals to . Z5 , drive the display to depict video information.
To reduce the weight of the head mounted display unit 10 and to allow tha~head counted display unit 10 to provide a.univsraal video display.
that may receive video inputs froaa any one of a number of.souscas,.tha video input signal , generator is preferably a separate, reaota unit.. .
Tha~video input signal ganasatos may~talca the form of a.talevision tuner, video camera, video player, video game, computes, or other device that generates a video input signal. For example, as shown in Fig. 1, the head mounted ii, i I
display unit 10'forms the display of a computer,. the electronics for which are housed within a keyboard housing 18. Although the head mounted display system may be coupled to the video input signal generator and/or audio generator by a cable 20, as shown, the unit 10 need not be physically connected to the video/sudio.input signal generator. For example, the'video and audio input signals may be RF
modulated and'transmitted from the remote unit to a head mounted display unit 10 that includes an.RF receiver.
A binocular head.mounted display system .in accordance with one embodiment of the present inventior~ is depicted in Figs. 2-6. In this embodiment, the frame Z2 of the head mounted'display unit 10 includes a top cover 22 and a bottom cover 24 forming a housing for a circuit board 26 on which may be mounted the drive electronics for the display 28 and the speakers 14 and 16 and/or an RF receiver.
The bottom. cover 24 forma a support for mounting the display 28 and the optics for the unit~l0 which include a semi-'reflective visor~36 and a prism 30. .
More particularly, the display 28 may be a liquid crystal display. or the like for depicting video inforanation on a surface 40 that faces the inner surface 42 of the reflective visor 36. The display 28 preferably has VGA~.
resolution so as to be suitable for displaying standard ' computer generated alphanumeric information and video graphic images. It is noted that liquid crystal displays are typically configured with a . ..
iZ , back light such that the light shines through the display from the back thereof. When the.
liquid crystal display is viewed from the front, an imago appears in the proper orientation when driven by conventional signals that~ars used to~.
drive a CRT, lor,exampla. This typo of conventional liquid~,crystal display is w hereinatter~referred to as a right-handed~~.
display. In ths~embodiment o! the optical .system depicted in Figs.. 2-6, the information depicted on the display ZB.is-reflected by'tha visor 36 so that it may be viewed by a user.
Because the optical system includes an odd number of reflectors, the imago which would bs lean by the user,. il a conventionally mounted right-handed liquid crystal display were employed, would ba reversed from right to ~lsft.
Although this reversal may not be noticeable for non-text video information, alphane~aric text . displayed backwards would not b~ readable by a user. This problem can ba overcome by inserting another reflector ~in the optical path, although ~~ the additional reflector increases the weight of the unit: Another option i~ to control the imago source to output a reversed imagi. This option would, however, require non-standas~d aid .
complicated~electronics. In the preferred embodiment, the reversal of the imago is corrected by removing the back light lros the back surface of a conventional "right-handed~~
liquid crystal display= mounting the liquid crystal display in a reverse right-to-felt orientation so that it forms a loft-handed.
display with the conventional back of the display forming the viewabls image surface 40 and mounting.tha back light on the conventional front sur~aca o! the display. When the liquid crystal display is oriented in this manner, it 13 .
may bs driven in a conventional mannsr such that - . the image, when viewed directly, will appear in a reverse orientation. ~Howevar, vhan a usas~
views the image as iellected from the display by the visor 36, alphanumeric taxt~will appear in the proper right-to-felt orientation.
The binocular optical system of the ~' , embodiment o! Figs. Z-6 includss prism elements 3Z and 34 disposed respectively its a sight-aye path 50 and a felt-eye path 5= so as to had light from any position along the width, 11, 0!
the prise 3Z,~ 34 towards a central aria ~ o! the visor 36. The visor 36 is a concave ratlsctor that directs both the right-aye optical. .~
centerline path and the felt-sya optical centerline path to the same point oa the lees o!
the display Z6. whsn~th~;imag~ o! thi information depicted on the display Z~ is to appear at optical inlit~ity, the display should be located with respect to the rsllactive visor 36 such that the local point o! the visor 36 is at the center o! thi.display.
When the image ol,tha information depicted on the display is to appaar.at lass than infinity, such as !or viawinQ displayed alF,hanumaric information, the display Zt is~
located at a distance tros the visor 36 that is less than the focal length o! the visor.36, wherein the optical centerline os chic! ray .54 0! tba visor intersects the cantsr o! the.
display. In this later instance, the prisms 3=
and 34 are mounted on the bottom cover Z4 so that the optical centerline o! iach pries 3=, 34 is angled in towards the location o! the virtual image to thereby cause the users eyes to angle in slightly to view ttia virtual image. The angle o! each o! the prisms 3Z and 34 and the angle of the ussr~s aye when looxing.in towards the virtual imags is referred to as the convergence angle B. The convergence angZa I is shown in Fig. 6 with respect to the axis 56 0l the eye wham looking straight ahead. Tha convergence angle is selected to ba approximately equal to the natural inward~anqla o! the eyss.whan viewing an object at the same distance Iron the user as the distance that the virtual imago appears. Tha convargencs angle is ' very small being on the order o! Z~-4~ for a virtual imago that appears approximately two feat or .75 m from the uses. ~1s the virtual image is moved closer to optical infinity, the convergence angle is reduced to faro. It has bean found that'by angling the right-ayi and left-eys optical centerline paths slightly in towards the location o! the virtual imaQs, aye fatigue is reduced. This is because ~tha~usas is use to angling his eyes is towards.a real object a0 that is located at a distancs that is less than optical infinity.
In accordance with an important feature o!
the present invention, the optical systas~~is such as to project a virtual image in the direct ,25 lira o! sight and central field o! viw o! each o! the usar~s ayes so that the displayed information can ba the main locus of the usar~s attention, however the optical systsa and support era also such as to maintain at least a 30 ~ portion o! the peripheral view o! oach of the.
user s eyes free from obstruction. 1~s shown in Figs. 7 and 8, tha.axit surface o! the optical elements) closast~to the usar~s ayes, which in the case of Fig. Z is the pries 30, is 35 repzesantad by the line a8 whare~ll and 8~
respectively represent the locations o! the .
outer side edges of the closet optical . elamant(s). The exit surlao~ o! the closest 60713-6'21D ~ .
' ~ is '. optical element(s~ is preferably approximately .
' Z0 mm from the user~i eyes. Ths distance float .
~~ A to 8 is preferably on the order~100 ma so that "
'. a user having an IPD o! approximately =.s-inches ' . 5 or , 64~ mm need only mow , an eye to the iidi ' ' ' through an angle~a to focus ow his surroundings - ' , irr~his aide peripheral vision. The angle a will ' vary for usars'having ditlesent IpOs but i~ ~.
. ~ generally in the range of 5~ - is~. iii order to ~' maintain a subatarrtial porti~ of the uset~s , .
. lovor,peripheral~vision unobstructed, thi~lowes~, .~ .
edge ~E ~o! the closest ~ optical ~slemant preteral~~y , . does not extend significantly below the bottom . o! the uaer~s'ey~. For example, the distance d '15 from the center o! the~closest optical~~ilement to the lower edge E thereof is-oa the:ordit o1~9 ' ~ - is mm.
with the system depicted in Figs. ?-i, the , ussr has side peripheral vision and a .
considerable amount ot,lowes pesipharal vision.
The lower peripheral vision is important.ao as to allow the user to be able to-vinr the keyboasd 18 or another dwice.such as a medical .
or industrial instrument without obstruction.
Eecause at least a portion of the peripheral ' view o! each o! the-usar'a~eyes is lrse~lrom . obstruction, the user can selectively locw oti the projected virtual image or not to minimise or substantially eliminate eye fatigue. .
~FVrther, because the user is visually cognizant of his surroundings while hs is . viewiral the ' , .
virtual image, feelinga~ot anxiety and . claustrophobia are eliminated. It is also . noted, that because the user cao selectively 3s view his surroundings, thi systu 'o! the present invention does not~promote feeling~~ot "spa ~ .
sickness" as frequently encountered with other systeas. -Although the user can simultaneously view his surroundings, as well as the virtual image of the head mounted.display systeri o! the W
present invention, it has bean found that the present system creates a Pealing o! total immersion in the video imago. It has further been~Pound that because the user has at least sours vision of the real world,. as well as the virtual imago, the three-dimensional cue: in the real world cause the user to perceive that the virtual image has depth, i.~., is thras-dimensional, without requiring a stereo image source.
Tha visor 36 is preferably a semi- ' transparent reflector, being on.tha order o! 808.
rellectiw so that the user can sas the raal'~
world through the visor 36. In a preferred embodiment of the invention, the display Z8 includes a brightness control, such as a brightness control knob 65 mounted on the frame iZ o! the head mountad~display unit 10, or mounted on the keyboard housing 18. Tha brightness control 65 allows the brightness o!
the display Z8 to be varied, such that.tha display 28, wham operating nsar its brightest level, results in a virtual image that completely blocks that portion o! the usar~s Field o! view in which the imaga.is projected.
Hy dimming the brightness o! the display ZB, the virtual imago appears to ba superimposed on the real world in that portion o! the us~r~s field o! view in whic~i the image is projected so that both the image and the real world behind the imago can ba simultaneously seen by. the user.
By completely dimming the display, the virtual imago can ba extinguished lroa that portion o!
the usar~s Field o! view so that the ussr-can sea the real world, but the user does not sad the virtual image at all: It i* noted that a ' ~ window into the real world through the displayed image can also be accomplished by providing a display which can be controlled. so that light does not pass frog the display in a defined area or window thereof. When.the light blocking feature of the display is actuated, a window into the real world in the area o! the blocked display -light is provided through the displayed ' image, and when not actuated,°ths imago is seen in its entirety. -Th~ binocular optical systea shown in Figs.
The present invention is directed to a head mounted display systea and more particularly to a single display, binocular system that projacta an image in the direct line of eight of th~~.
user's~eyes while maintaining the user's peripheral vision relatively tree from obstruction to allow the user to selectively focus on the virtual image or not.
:o eaC~cc~eov~D o~ Tae i8va~=o~r Binocular head mounted display systems allow a user to view an image or images o!
displayed information with both eyes. Typical binocular head mounted display systems include two displays, one !or each o! the user's eyes, as well as two sets of identical optics so as to be very costly and heavy. 8laocular head mounted display systems that include only a single display are also known. Both types,ot systems typically direct the user's eyu such thtt the axes of the eyes are parallel'tor .viewing a projsctad image focused at infinity.
For virtual reality applications in which the user is to be totally immersed in the video image, these binocular systems are further formed so that the ussr~s field of view is completely blocked, the user being unable to see anything but the displayed image.
These known systems have a number of problems. For exempla, it has bean found that with head mounted display systems in which the user cannot focus on anything but the projected imaga,leys fatigue often occurs. Such systems can cause feelings of claustrophobia because the usar~s view is completely enclosed and fallings of anxiety because the user can hear things going on in his surroundings but is not able to eea what is happening. With these systems the user can also experience "sea sickness" when the motion of the image that hs is viewing does not coincide with the motion that the user s body is experiencing.
Binocular systems in which the ussr~s eyes i5 era directed such that the axes of the eyes are parallel hays been found to~eoritributs to sys fatigue when the image is focused at less than infinity. Eye fatigue and feelings of discomfort result because it is.unnatural for a ZO personas ayes to ba such that the axes o! the eyes era parallel when viewing an image that is only two or three lest away.
Known binocular systans era typically designed for users having a particular "average"
25 or "normal~ intarpupillary distance (hereinafter referred to. as iPOj. Because the IPD of users can vary considerably, these systems era usable only by a vary limited portion of the population and era not suitable for general consumer 30 applications.. If a user has an IPD that varies considerably from the average IFD for which the system is designed hi: eye will ba off of the axis o! the optical systu. Usar~s who err off-axis typically see right eye end left aye images 35 that do not lima up. That' may also see distortions in the image wbaraia one lids of the imago will look bigger than the other side, - . ~ and/or a part of the imago will ba in focus whils other parts of the imago will ba out of.
focus. Further, a portion o! the imago depictsd on the display may ba cut off whan.viawad off axis through the optics of the systsm.
~n accordance with the psasant iirver~tion, .
tha~disadvantagas of prior~binocular head mountad,display systems have bean overcome. Tha .- head mounted display systsm of the prassnt invantion~ia a single display binoculas systas that is usably by a.larga portion o! tba .
population without modification. The bud . .
mounted display systsm of the present invention is suitable !os applications requiring the user to comfortably focus at lass than infinity, as well as applications raquirinQ the user to locus at infinity, and is further suitable for 20~ applications requiring tha_usar to vises his surroundings while viewing the projected imago, . as well as for virtual reality applications.
More particularly, the head mounted display . system o! the present ~invantion includes a Z 5 support to mount the display system o~n a war s head; a single video image source, such as a display, that is mounted on the support; and a compact binoculas optical system of ainiaal weight for projecting an enlarged virtual imaqa 30 of the video from the imago source at a distance.
from the user that is graatas than the actual path length o! the~optical system. Because the optical system is compact and.light-weight, the support may be similar to the frame o! a pair of 35 glasses or other conventional eyawaas and doss not require the support to tsks the lors o! a helmet or other substantial arrangemsnt in order ' 60713-621D
to act as a counter weight for the optics as in - . known.systsms.
Ons feature of the binocular optical systa~
' projscts a of the present invention is that it virtual image in the central field o! vise o!
each of the usars ayes, wharaia the optical systea and support are such as to maintain at least a portion of the peripheral view o! each o! the usars ayes free Eros obstruction.
eacauss at least a portion o! the peripheral view of each of tha~usera.eya, is free frog obstruction, the usar~csn selectively focus on the projected image or not to minisias os substantially aliminati aye fatigue. P~rthas, because the user is visually cognisant o! his surroundings while he is viewing the virtual ' image, feelings o! anxiety and claustrophobia are eliminated. It is also notad,~that because ' the user can selectively view his. surroundings,.
the system o! the present invention dou not promote feelings of "sea sickness" as frequently encountered with othir systems.
although the user can siaultansously view his surroundings as wall as the virtual image with the head mounted display~systea o! the present invention, it has bean found that~ths _ present systsa creates a feeling ol.total immersion in the video image. Therefore the systes is suitable for virtual reality . ' applications without having the probleas ..
associated with binocular head mounted display -systems typically used for such applications:
This lasling o! total immersion in the video image with the systaa o! the present invention . 35 is quits surprising since heretofore it vas thought that-for total immersion, the user should not sea anything but t~u projected video -image. It has lurthsr been found that because the user has at least some vision of the raal ' world, as~wall as the virtual image, the thras-dimensional cuss in the real world cause the.
user to perceive that the virtual image has 5 depth, i.a. is three dimensional without . requiring a stereo imago source.
Another feature of the binocular optical systea of the present invention is that it includes a right eye optical contarlina path and a left eye optical centerline path with at lsast .
one optical element~in each of these paths, ..
wherein the right .yi and left aye optical centerline paths,ara angled in towards the virtual image perceived by the user. Because ~i5 the optical, centerline paths of the syst~a era angle fn towards the virtual imago, the ussr~s eyes era directed inward at sn angle that is natural !or a person viewing an object at a distance that is leas than infinity as opposed to being directed ao that the axai of the eyes era parallel. With the usar~a eyes directed naturally inward to~tha location of the virtual imago, the head mounted display system o!' the -present invention is more comfortable and less eye straining than prior systeaa.
. l~ further feature of the binocular optical system o! the present invantion is that it automatically compensates !or variations in the interpupillary distance of diffasent uaass, wherein those variations may bs as great as one inch. Therefore, the head mounted display system of the present invention is suitable for use by a vast majority of the population without requiring manual adjustment to any o! the optical elements. ~h one embodiment, variations in intarpupillary distance are automatically compensated for utilizing in each o! tho right eye and left eye paths a pries that bends the ~ .
6. .
light from any location along the width thereof, representing various positions of users' eyes with different IPDs, towards a centrsl area on a concave raflactos. This concave reflector focuses the light path free the .user's right acrd loft eyes to the soma point on the display, which. is preferably the center of the display, in.anothar embodiment, a focusing lens is disposed in each of the right eye and left aye 1o optical paths, such that light at any location ~ .
along the width, i.e.,diamatar,~ of the lens . , representing various positions of users' eyes, is focused on the same point, mirrors bairrq disposed in each of the sight~aya and loft ayd, optical paths to direct the path of the light from the user's eyes through t~h~ respactiw larses to the same point on the display. In accordance with a further feature o! the present invention, the binocular optical system may ZO include a semi-transparent reflector into which , the user looks to view the virtual image in a portion of his field o! view. The display say further include a brightness control allowing the brightness of the display to ba varied to cause the virtual image to block that portion of the_ user's llald of view in which the image is projectad;'to cause the virtual image to be superimposed on the real world in that portion of the user's field of view in which the image is projected so that both the image and the real . ~ world in that portion can ba simultaneously scan by the user; or ~to .cause ~tha virtual image to bs . . .
extinguished Eros that~portion of tb~ user's field of view so that the user spas the real world, but doss not sae the virtual image at all. This feature can also be accomplished by providing a display which can bs controlled so that light does not pass from the display in a defined area or window thereof. in~hen this light blocking feature of the display is actuated, a window into the real world is provided through the displayed image and when not actuated, the image is seen in its entirety.
The head mounted display system of the present invention is suitable for any application requiring the viewing of displayed information. Because of a number of ' the features noted above, the system of the present invention is eminently suitable for a computer display.
Therefore, in accordance with the present invention, the head mounted display system forms the display of a computer, the electronics of which are housed in a keyboard housing.
The keyboard is designed to be compact, and in one embodiment is foldable. The keyboard may also include a mounting surface for the head mounted display unit so that the computer can be easily carried. Because the head mounted display is compact and lightweight, the overall weight and size of the computer in accordance with the present invention is greatly reduced over prior portable computer systems. The image viewed by the user with the computer display of the present invention can be as large or larger than the image depicted on conventional non-portable computer displays, unlike the displays of typical portable computers. Further, because the head mounted display is a personal display unit, only the user can see what is being displayed on his computer so as to allow the user to work on confidential information while in a public setting, such as on an airplane.
According to one aspect of the present invention, there is provided a head mounted display system comprising:
7a a support to mount the display system on a user's head; a first prism mounted on said support in a right-eye optical path; a second prism mounted on said support in a left-eye optical path; a display mounted on said support for displaying video information; and a reflector shaped to project an enlarged image of said video at a distance from the user, said reflector being mounted on said support in each of said right-eye and left-eye optical paths, wherein said first and second prisms bend the right-eye and left-eye 20' optical paths from a user's eye towards each other and said reflector in each path focuses light traveling along the respective optical paths onto the same point relative to said display.
According to another aspect of the present invention, there is provided a head mounted display as recited as described herein wherein said display is the only display of the system.
These and other objects, advantages, an$ novel features of the present invention, as well as details of an illustrated embodiment thereof, . will be mots fully understood frog the following . description and the drawing.
BRIE! DESCRIPTIO11 O! THE DRAIIINa Fig. 1 is a perspective view of a head mounted display system and keyboard in accordance with the present invention forming a portable computer=
Fig. 2 is an exploded, perspective view of a head mounted display system in accordance with .
one embodiment o! the present invention;
Fig. 3 is a back perspective view of the head mounted display system,depictsd iwFig. a;
Fig: 4 is a side view o! the head mounted display system depicted in Fig. Zp.
Fig. 5 is a top view o! tZia optics and display o! the system shown in Fig. Z=
Fig. 6 is a schematic illustration o! the convergence angle o! the ussr~s.syss when the image is focused at~less than infinity with the system depicted in Fig. 5i .
Fig. 7 is a top view o! a schematic illustrating the usar~s side peripheral vision that is maintained unobstructed by ttia optical system o! the present invention;
FiQ. 8 is a front view o! a schematic illustrating the users side and lower , peripheral vision that is maintained unobstructed by the optical system o! the present invention=
Fig. 9 is a bottom view o! the head mounted.
display system depicted in Fig. Z modified with the addition of a~movabla eye block so as to make the systea monocular=
Fig. 1o ii a top view of the optics of Fig.
5 modified in accordance with another embodiment o! the head mounted display systu of the present invention 9.
Fig. 11 3s a top view o! the optics and, .~ ~ display for a head mounted display systea in accordance with still another embodiment o! the present invention;
Fig. iz is an exploded, perspective view o!
a folded embodiment o! the head mounted display systea shown in Fig. z; , , Fig. 13 is.a top view of the optics fos a further embodiment o! the head mounted display ' . 10 system of the present invention,depicting alternative locations !or the mounting of the display used therein;~.
F'ig. 14. is a side view o! a folded .
embodiment of the head~mounted display systes;
.
depicted in Fig . 13; ' Fig. 15 is a schematic diagraa o! the optics in accordance with a lurther embodiment 'o! the head mounted display systea o! the present invention wherein dotted lines represent Z0 mirror folds o! the systes;
Fig. 16 is a perspective view o! a keyboard as shown in Fig. 1 partially folded;
Fig. 17 is a perspeatiw.viw o! the keyboard o! Fig. 16 folded=
Z5 ~ Fig. 18 is a top perspective view o! the bottom housing and hinge assembly o! the keyboard o! Fig. 16; ' Fig. 19 is an exploded, perspectiv~.view of the hinge assembly o! the keyboasd depicted in 30 Fig. 16;
Fig. 20 is a~perspectiw view illustrating .
another embodiment.o! the foldable keyboard o!
the present invention;
Fig. zi is a back view o! the keyboard o!
35 Fig. Z0 illustrating as alternative hinge arrangement;~
Fig. Z~ is a partial aids viw o! the hinge arrangement o! Fig.~Zi wherein the hinge is in a non-folded position; ~ ~.
Fiq.~Z3 is a partial side view of the hinge illustrated in Fig. ZZ in the folded position;
Fig. 24 is a perspective view of aw 5 alternative embodiment of the foldable keyboard of the present invention including a mounting surtacs for the head mounted display unit;, Fig. s5 is a bottom view of the portable , computer system depicted it Fig. Z4; and Fig. Z6 is a perspective view of a hud mounted display system mounted on the keyboard , .
of. Fig. Z4 in its folded position.
DEBCRIPTIOlI O! T8a PREFERRED EMHODIME11'! . ' .
Tha head mounted display unit 10 o!-ths i5 present invention as shown in Fig. i.includ~s.~a frame iz that is worn on a usar~s head and that supports a display Z8 and associated binocular optics, as discussed in detail balov for the various embodiments.thereol. The lrasa IZ may alto support the drive electronics for the .
display and a pair. of earphones 1~, 16 that _ . provide. audio for the unit ~10. As is wll~
known, the drive electronics !or the display era =esponaivs to standard video input signals to . Z5 , drive the display to depict video information.
To reduce the weight of the head mounted display unit 10 and to allow tha~head counted display unit 10 to provide a.univsraal video display.
that may receive video inputs froaa any one of a number of.souscas,.tha video input signal , generator is preferably a separate, reaota unit.. .
Tha~video input signal ganasatos may~talca the form of a.talevision tuner, video camera, video player, video game, computes, or other device that generates a video input signal. For example, as shown in Fig. 1, the head mounted ii, i I
display unit 10'forms the display of a computer,. the electronics for which are housed within a keyboard housing 18. Although the head mounted display system may be coupled to the video input signal generator and/or audio generator by a cable 20, as shown, the unit 10 need not be physically connected to the video/sudio.input signal generator. For example, the'video and audio input signals may be RF
modulated and'transmitted from the remote unit to a head mounted display unit 10 that includes an.RF receiver.
A binocular head.mounted display system .in accordance with one embodiment of the present inventior~ is depicted in Figs. 2-6. In this embodiment, the frame Z2 of the head mounted'display unit 10 includes a top cover 22 and a bottom cover 24 forming a housing for a circuit board 26 on which may be mounted the drive electronics for the display 28 and the speakers 14 and 16 and/or an RF receiver.
The bottom. cover 24 forma a support for mounting the display 28 and the optics for the unit~l0 which include a semi-'reflective visor~36 and a prism 30. .
More particularly, the display 28 may be a liquid crystal display. or the like for depicting video inforanation on a surface 40 that faces the inner surface 42 of the reflective visor 36. The display 28 preferably has VGA~.
resolution so as to be suitable for displaying standard ' computer generated alphanumeric information and video graphic images. It is noted that liquid crystal displays are typically configured with a . ..
iZ , back light such that the light shines through the display from the back thereof. When the.
liquid crystal display is viewed from the front, an imago appears in the proper orientation when driven by conventional signals that~ars used to~.
drive a CRT, lor,exampla. This typo of conventional liquid~,crystal display is w hereinatter~referred to as a right-handed~~.
display. In ths~embodiment o! the optical .system depicted in Figs.. 2-6, the information depicted on the display ZB.is-reflected by'tha visor 36 so that it may be viewed by a user.
Because the optical system includes an odd number of reflectors, the imago which would bs lean by the user,. il a conventionally mounted right-handed liquid crystal display were employed, would ba reversed from right to ~lsft.
Although this reversal may not be noticeable for non-text video information, alphane~aric text . displayed backwards would not b~ readable by a user. This problem can ba overcome by inserting another reflector ~in the optical path, although ~~ the additional reflector increases the weight of the unit: Another option i~ to control the imago source to output a reversed imagi. This option would, however, require non-standas~d aid .
complicated~electronics. In the preferred embodiment, the reversal of the imago is corrected by removing the back light lros the back surface of a conventional "right-handed~~
liquid crystal display= mounting the liquid crystal display in a reverse right-to-felt orientation so that it forms a loft-handed.
display with the conventional back of the display forming the viewabls image surface 40 and mounting.tha back light on the conventional front sur~aca o! the display. When the liquid crystal display is oriented in this manner, it 13 .
may bs driven in a conventional mannsr such that - . the image, when viewed directly, will appear in a reverse orientation. ~Howevar, vhan a usas~
views the image as iellected from the display by the visor 36, alphanumeric taxt~will appear in the proper right-to-felt orientation.
The binocular optical system of the ~' , embodiment o! Figs. Z-6 includss prism elements 3Z and 34 disposed respectively its a sight-aye path 50 and a felt-eye path 5= so as to had light from any position along the width, 11, 0!
the prise 3Z,~ 34 towards a central aria ~ o! the visor 36. The visor 36 is a concave ratlsctor that directs both the right-aye optical. .~
centerline path and the felt-sya optical centerline path to the same point oa the lees o!
the display Z6. whsn~th~;imag~ o! thi information depicted on the display Z~ is to appear at optical inlit~ity, the display should be located with respect to the rsllactive visor 36 such that the local point o! the visor 36 is at the center o! thi.display.
When the image ol,tha information depicted on the display is to appaar.at lass than infinity, such as !or viawinQ displayed alF,hanumaric information, the display Zt is~
located at a distance tros the visor 36 that is less than the focal length o! the visor.36, wherein the optical centerline os chic! ray .54 0! tba visor intersects the cantsr o! the.
display. In this later instance, the prisms 3=
and 34 are mounted on the bottom cover Z4 so that the optical centerline o! iach pries 3=, 34 is angled in towards the location o! the virtual image to thereby cause the users eyes to angle in slightly to view ttia virtual image. The angle o! each o! the prisms 3Z and 34 and the angle of the ussr~s aye when looxing.in towards the virtual imags is referred to as the convergence angle B. The convergence angZa I is shown in Fig. 6 with respect to the axis 56 0l the eye wham looking straight ahead. Tha convergence angle is selected to ba approximately equal to the natural inward~anqla o! the eyss.whan viewing an object at the same distance Iron the user as the distance that the virtual imago appears. Tha convargencs angle is ' very small being on the order o! Z~-4~ for a virtual imago that appears approximately two feat or .75 m from the uses. ~1s the virtual image is moved closer to optical infinity, the convergence angle is reduced to faro. It has bean found that'by angling the right-ayi and left-eys optical centerline paths slightly in towards the location o! the virtual imaQs, aye fatigue is reduced. This is because ~tha~usas is use to angling his eyes is towards.a real object a0 that is located at a distancs that is less than optical infinity.
In accordance with an important feature o!
the present invention, the optical systas~~is such as to project a virtual image in the direct ,25 lira o! sight and central field o! viw o! each o! the usar~s ayes so that the displayed information can ba the main locus of the usar~s attention, however the optical systsa and support era also such as to maintain at least a 30 ~ portion o! the peripheral view o! oach of the.
user s eyes free from obstruction. 1~s shown in Figs. 7 and 8, tha.axit surface o! the optical elements) closast~to the usar~s ayes, which in the case of Fig. Z is the pries 30, is 35 repzesantad by the line a8 whare~ll and 8~
respectively represent the locations o! the .
outer side edges of the closet optical . elamant(s). The exit surlao~ o! the closest 60713-6'21D ~ .
' ~ is '. optical element(s~ is preferably approximately .
' Z0 mm from the user~i eyes. Ths distance float .
~~ A to 8 is preferably on the order~100 ma so that "
'. a user having an IPD o! approximately =.s-inches ' . 5 or , 64~ mm need only mow , an eye to the iidi ' ' ' through an angle~a to focus ow his surroundings - ' , irr~his aide peripheral vision. The angle a will ' vary for usars'having ditlesent IpOs but i~ ~.
. ~ generally in the range of 5~ - is~. iii order to ~' maintain a subatarrtial porti~ of the uset~s , .
. lovor,peripheral~vision unobstructed, thi~lowes~, .~ .
edge ~E ~o! the closest ~ optical ~slemant preteral~~y , . does not extend significantly below the bottom . o! the uaer~s'ey~. For example, the distance d '15 from the center o! the~closest optical~~ilement to the lower edge E thereof is-oa the:ordit o1~9 ' ~ - is mm.
with the system depicted in Figs. ?-i, the , ussr has side peripheral vision and a .
considerable amount ot,lowes pesipharal vision.
The lower peripheral vision is important.ao as to allow the user to be able to-vinr the keyboasd 18 or another dwice.such as a medical .
or industrial instrument without obstruction.
Eecause at least a portion of the peripheral ' view o! each o! the-usar'a~eyes is lrse~lrom . obstruction, the user can selectively locw oti the projected virtual image or not to minimise or substantially eliminate eye fatigue. .
~FVrther, because the user is visually cognizant of his surroundings while hs is . viewiral the ' , .
virtual image, feelinga~ot anxiety and . claustrophobia are eliminated. It is also . noted, that because the user cao selectively 3s view his surroundings, thi systu 'o! the present invention does not~promote feeling~~ot "spa ~ .
sickness" as frequently encountered with other systeas. -Although the user can simultaneously view his surroundings, as well as the virtual image of the head mounted.display systeri o! the W
present invention, it has bean found that the present system creates a Pealing o! total immersion in the video imago. It has further been~Pound that because the user has at least sours vision of the real world,. as well as the virtual imago, the three-dimensional cue: in the real world cause the user to perceive that the virtual image has depth, i.~., is thras-dimensional, without requiring a stereo image source.
Tha visor 36 is preferably a semi- ' transparent reflector, being on.tha order o! 808.
rellectiw so that the user can sas the raal'~
world through the visor 36. In a preferred embodiment of the invention, the display Z8 includes a brightness control, such as a brightness control knob 65 mounted on the frame iZ o! the head mountad~display unit 10, or mounted on the keyboard housing 18. Tha brightness control 65 allows the brightness o!
the display Z8 to be varied, such that.tha display 28, wham operating nsar its brightest level, results in a virtual image that completely blocks that portion o! the usar~s Field o! view in which the imaga.is projected.
Hy dimming the brightness o! the display ZB, the virtual imago appears to ba superimposed on the real world in that portion o! the us~r~s field o! view in whic~i the image is projected so that both the image and the real world behind the imago can ba simultaneously seen by. the user.
By completely dimming the display, the virtual imago can ba extinguished lroa that portion o!
the usar~s Field o! view so that the ussr-can sea the real world, but the user does not sad the virtual image at all: It i* noted that a ' ~ window into the real world through the displayed image can also be accomplished by providing a display which can be controlled. so that light does not pass frog the display in a defined area or window thereof. When.the light blocking feature of the display is actuated, a window into the real world in the area o! the blocked display -light is provided through the displayed ' image, and when not actuated,°ths imago is seen in its entirety. -Th~ binocular optical systea shown in Figs.
2-6 automatically compensates for variations in the interpupillary distance of different uriaics, wherein those variatioru may be as gisat as one inch. More particularly, the systes automatically accommodates users havi~ an interpupillary distance that is within a Z-3 inch range. Thin ~is accomplished -by ~th~
combination of the pris~os 3= and -34 with a concave reflector shown as the visor 36. More.
particularly, the pries in each of the right-eye and left-eye optical paths bands light frog any location along the width, fit, of the prise 5 representing various positions o! the ussrs~
eyes, and thus various interpupillary distances, towards the central area, C, on the visor 36.
The prisms convert the Z-3 inch difference between the centers of ths.users~ ayes to within .2 inches-.3 inches on the face 4Z of the visor 36 in the central area C thereof. ~ The visor 36 than reconciles this small difference at the .
face of the display by focusing-parallel light incident to surface 4Z on the same point on the . 35 display Z8 so that the users left aye sees the same image that the user's right eye seas through the optical systea. .
The visor 36 may be spherical in shape so ., as to project an enlarged image of the displayed information. It is noted, howsyez, that th~~
visor 36 may also be parabolic iw shape or haw another shape so as to obtain the desired degrse of magnification with minimal distortions.of the image, as is well known. Furthsr, separate concave reflectors for each eys may be used.
Due to the compact nature of the optical systea, the visor extends out frog the user by only 70 mm or less: The prisms 3Z aid 34 may be formed .
as a single olement 30 or as two distinct elements. Further, as shown in Fig. 10, a respective lens 60-6Z may be.mounted on or .
adjacent ta~ the exit surface 61, 63 of the v ,.
respective prise 3Z, 34 in the right-eye and left-eye optical paths 50, 5Z.Each o! the lenses 60 and 6= is preferably a conv~c lens to increase the field o! view of the image. Each of the prism-lens pairs 3Z, 60 and 34, 6Z also preferably forms an achromat to correct chromatic aberrations.
The display ZS is preferably such that the _ contrast and~brightness thereof does not change . over l0~ frog the perpendicular to the display Z5 ~so that the image seen by the left eye has the same brightness and contrast as the image smsa .
by the right eye. In ordir for the image scan by the Left aye to appear at the same location 'as the image aeon by the right eye, the left-eyi optical centerline path and the right-eye optical centerline path must be equal is length.
Further, the path lengths to the right side o!
the display Z8 from one aye mustbe equal to the path length frog that same eye to the left side 35' of the display Z8. If the path ~lengtha to the right side of the display and~tha left aide o!
the display are not.squal, the image will appear distorted such that -one side of the i~oag~
.. ~ CA 02490344 1994-09-23 ' 19 appears larger than the other side ol~the image.
These latter requirements are accomplished by an optical systea wherein the chie! rays'ol each v optical path, arm equal iu length.
s ~ ~: It i-s noted that i! the contrast and' brightness of the display cannot be ;maintained ralatiwly constant over 10' lros thl~
' . perpendicular~to the display, the optical systaw ' d~pictad in Figs. Z-6 may be eonvertid to a _. ' 10v ~ monocular systea by adding a light block 58, as . , shown by the dotted.lina in Fiq..9. The light blockv58 prevents light lroa the display lroi~
reaching one o! the user s eyes. Preferably, ..
. . the light block 58 is =emovably~mountsd on the ss bottoa cover Z4 or on the side of the display Z8 so that the light block may be positioned either on the side 55 0! the display.or:on the opposite aids 57 thereol. Because most people haw a.
dominant eye,~t! the light block is positioned .
~. .
Z0 on~the side o! the display so as to block light lroa.the display Z8 lroa reaching the non~
dominant eye, it will appeas to the user that h~
is viewing the display with both eyes; although -. hs is actually only viewing the display with hip .25 dominant eye. The bottoa view o! the optical.
display aystea shown in Fig. 9 illustrate ths.
position o! the ligbt block 58 !or a right-eye dominant user. although. this systea ~is i~ot binocular, it is extremely~llexibls iu that it y, ~30 ~ can be utilized~by both~right-eys dominant and .
felt-eye dominant people by merily changing the position o! the light blocat 58~lros ons sids o!
.ths display 55, 57 to the other iid~ o! the display 57, 5S. .
35 Fig. ii depicts a true stereo embodiment o!
the present invention that utilizes the say binocular systea as described, iii Figs. Z-6 or Fig. 7,.wherein the display 28~ is controlled to ZO
provide distinct images to the left eye and the . right~eye with a block 64 separating the right-eye optical path from the left-eye optical path.
Thevembodiment of the present invention . 5 illustrated in Fig. is is similar to the embodiments depicted in Figs. Z-6. However, the position ot.tha display 28 is altered so that ' instead of facing the inner surface 4Z of the visor 36, the face 40 of the display~28 tacaa ' downward onto a reflective surface 7Z that is disposed at a 45 angla with respect to the display surface 40 in~ordsr to retlact the information depicted on the face 40 0! the .display Z8 onto the inner surlaca 4Z.ot.tha ' ~ ' 15' , visor 36. Although the reflector 7Z may' be . formed of a conventional flat mirror, a prise w element 7o with a reflective surface 7Z i~
preferred to prevent.tha reflective surface 7Z
.from being marred by lingerprinta or scratches.
Tha features of the optical system depicted ' in Figs. Z-6 can ba obtained by other binocular optical.systems. For exempla, Fiq. 13 is another embodiment o! a binocular optical~systsa in accordance with the present invantiot~.that~
2~ utilize a single displayf automatically compensates for variatioru in IPOs o! users up to one inch; directs tba usar~s eyes inward towards the location of a virtual image that is located~a distance from the user that fs lss~
than infinity= and/or that'projects an snlarg~d image of displayed information in the usar~s direct Tina of sight and central field of view,.
while maintaining at least a portion o! the ~usar~s peripheral view ol~sach o! the us~r~s eyes free from obstruction. Whereas the embodiment illustrated in Figa. Z-9 accomplishes these features with a semi-reflective visor and prisms, the embodiment of Fiq.~ 13 accomplishes ZZ
these~features utilizing a lens, mirror(s~ and a beam splitter in each of the right-sye and left-eye optical paths. One of the advantages o! the . embodiment depicted~in Fig. l3 is that.thi contrast and brightness of the display Z8 need not ba maintained constant over 10~ from the perpendicular to the display to pravsnt conflicting infor~ation from being see=r by the riSht and left eyes of the user:-More particularly, the embodiment o! the present invention shown in Fig: 13 includss a display 28 with a base splittsr 80 disposed at a 45~ angle with respect to the face 40 of the display. The base splittsr 80 splits the~lig~t .
~15 froa the display 28 along a rigbt-eye optical _ path 50~ and a left-eye optical path 5=~: The light from the display 28 directed by the beam.
splittsr 80 along the right-eye optical path 50~
is reelected by a mirror 8~ into. the user~~
right aye through a biconveu lens-84. The base splitter 8o directs light !rose the display Z8 .
along the left-eye optical path 5=~ so that the light is reflected by~a mirror 86 to a second mirror 88 into the users lstt aye through a biconvex lens 90. Each of the biconvex lenses provides focusing arnd magnification of the ~imaga. .
With this embodiment, the display may be positioned at a location 8? or alternatively at 3o a location 89. Positioning of the display 38 at location 89 so that the outer edge o! the display 9Z does not exte~ beyond the outermost edge ol~the mirrors 80 and 8Z provides a more compact head mounted display unit with the weight thereof closer to the user s face. It is desirable to keep the weight of the optical system and display as close to the user s head as~possible to reduce the downward torque of the ~_ system and eliminating the need for countsr ' ~ weights on the support lZ.
When the virtual image of the information depicted on the display Z8 is to appear at optical infinity, the focal point of each of the lenses 84 and 90 is located at the center of the display faco 40. Further, the be8a splittsr 80 is'positioned at a 45~ angle with respset to the faco 40 of the display 28 with the mirror 8Z
parallel to the beam splitter 80. The mirror 86 is perpendicular to the beam splatter 80 and the mirror 88 is parallel~to the mirror 86.
If, however,, the virtual image is to appear at a distance from the user that is less than infinity, for example two felt, the sirror 8Z- in.
the right-aye optical path and the mirror 88 in . the left-eye optical path are angled slightly inwardly ao as to direct the user~i ey~~ inward at a convergence angle that is natural for a Z0 person viewing an obiect at a distance oqual to the distance~of ths,virtual image from the user.
For example, for a virtual image that is to appear approximately two feet frog the user, a convergence angle of approximately Z~-t~ is desired. Therefore, the mirror 8= at~d the mirror 88 are positione8 at am angle a that is approximately 41~-43~ frog a line that is parallel to the face 40 of the display Z8, as opposed to being at a 45~ angle with respect thsroto. With the uaer~a eyes directed inwardly to the location o! the virtual image at a natural angle, the head mounted display systes of the present invention is more comfortable and less eye fatiguing than prios system. It ii doted that in this embodiment, the display Z8 is at a distance from each of the lenses 84~and 90 that is less than the local length~o! each o!
the lenses.
23 . . ' Regardless o! whether the virtual imaga.is to ba,focused at infinity, or at less than.
infinity, the length o! the right-eye optical ce~terlina path 50~ representad~by the length o!
the segments a, b, and c is equal to the length o! the left-eye optical.centerlina paths represented by the length o! the segmsnts a, d, .
s,', and f. Further, the distance fro: a qivan eye to the one side ol~tha display 28 is,equal .10 to the distance from that sya to the opposite .si8a of the display, 8uch~that the chin! rays o!
. the system era o! equal length.
The embodiment of the present invention ~ .
depictsd in Fig. l3.automatically compansatas~, for variations in the interpupillary distance o!
various users because each o! the focusing lenses 84, 90 is such. that light at any location along the width, i.e. diamatir, tharso!
representing various positions o! a usars~ syu ZO and thus various interpupillary. distances, is focused on the same point with the mirrors and bees splittar disposed it each of'the right sya . and loft sya optical paths to direct the path of .
light lroa the usar~s ayes through the respective lenses to the lama point. Further, the size of the beam splittar 80 and the aurora 8Z, 86, and 88 are selected so as to account for light diverging outward Eros the face 40.0! the display Z8 by an angle ~3 0! approximately Z.5~
so as to insure that the entire display is reflected by the beam splittar and mirrors into the ussr~s eyes for users having ons inch variations in their IPDa.
The system o! Fig..i3 is a very compact, lightweight system with a wide field o! view, being on the order of ZO~-45~. Tha hensss 8~, 90; mirrors 8Z, 86, 88, beam splittas 80, and the display 28 era preferably mounted on the bottom cover 24 of the frame iZ, such that the - ~ . ~ exit surface of each of the lenses 8~, 90 is approximately 20 mm froa.tha usar~a.eyss.
Hecausa each of the lenses 84 and 90 ors relatively close to the user s eyes, the image has a large field o! view. Howevsr,~tha 20 m~
spacing between each of the lenses and thi~ ' ussr~s respective eyes is typically sufficient ' to allow the user to wear a pair o! glasses with the head mounted display systaa. Tha lenses 84 and 90 may.actually~ba disposed even closer to the user's eyes, but preferably no closer than the lenses o! a typical pair of glasses worn by .
a user so as to prevent anxiety in the user when an object is extremely clogs to.hia .eyes. Thr .
Tenses may also ba positioned farther frog the ussr~s eyes; however, in order to obtaiA a given tilld of view, as the distance between the sya and the lens 8~, 90 incraases,'tha diameter o!
the lens generally increases. It 'is noted that with the lenses 84 and 90 located approximately 20 ma troy the usar~s eyes and with the display 28 at the location 89, the heed mounted display unit l0 extends only about Z-1/Z inches out in front o! the usar~s face.
The optical systes aepictsd in Fiq. 19 is mounted on the trams is so as to project the ' virtual imago in the central field ot.viaw arrd direct line of sight of each o! the ussr~s eysa.~
~ The sizs~o! the lenses 8f and 90, as well as the configuration ol.tha support is, era such as to maintain at least a portion of the peripheral view of each of the ussr~s eyes free troy obstruction so as to obtain all o! the advantages described above for the embodiment of the invention depicted in FiQ. Z. As showif in Figs. 7 and 8, the exit surface o! the optical alement(s). closest to the usar~s eyes, 60713-621D.
. which,in the case of Fig: 13 are the lenses 84 and 90, is represented by the line A8 where A
and B respectively represent the locations o! ' the outer side edges of the closest optical element(s). As described above, the exit surface of the closest optical elements, the lenses 8~ and 90, is preferably approximatily~20 mm from the user s eyes. The~diameter of the ' lenses is preferably on the. order of Z5 mm-35 nm y l0 so that a user having an IPD of. approximately .
Z.5 inches need only.mow an eye to the side through. an angle a to'focus~on his surroundings in his side peripheral vision. The angle a will vary for users. having' difteisnt ZPDs, but. ii, .
~15 .generally in the range of 5~-15~. Because the diameta= of the lenses 84 and 90 is ou the os~dsr of Z5 mm-35 mm, the optical systas ol~Flg. 13 maintains a significant amount of the~ussr~s lower peripheral vision free fros.obstruction.
20 Fig. l4~illustrates a slight modification .
of the embodiment of the present invention depicted in Fig: 13.~; In Fig. i~, tbs entire optical systea from the lenses 84 and 90 to the display Z8 is rotated 90~ from that show~t is 25 Fig. 10 so that the axis of each of the lenses ' 84 and 90 is perpendicular to the respective axes of the usar~s right eye and.left eye. .~11 . pair o! mirrors are added to the system.auch that one mirros 100 is disposed.in the right-aye 30 optical path at a 45~ angle with respect to the lens 84 so as to reflect the image from the .
display through 'the lane into the user s aye. .
r Similarly, a reflector 100 is positioned in'the left-eye optical path at a 45~ angle with 35 respect to the lens 90 so as to reflect the image from the display through the lens into the users loft eye. It is noted that the reflector 100 may be any type of mirror including s . . ~ 26 holographic mirror, a curved m,~rrQr, etc.
In the embodiment.ot FiQ. 14,'th~ ~ . .
reflectors 100 can b~ positioned in the central' -, . field of view and direct line of sight o! the .
user 's eyes whilt maintaining the usar~a~', peripheral view unobstructed. Tha reflectors l00 may also be positioned iu the upper ,' . peripheral view of ~tha usar~~~s eyu for those .
applications where the imago di~playad~~is not to 1o ba the main focus o! the uses~a attention. The reflectors 100 era also preferably sasi=. .
reflective, for exempla 80i retlactiw so as to allow the user to see the real world through .ths .
' reflector 100. ~ ~ ~ .
l1a described above, the display Via' may include a brightness control 60 to allow~tl~
brightness of the display ZS to ba varied such that the display at its brightest results.io a virtual image that completely blocks.tha uses~s Z0 view of the real imago in the portion ol.tha ~ ' usar~s field of view im which the imago is projected. ey dimming the brightness o! the display Ze, the virtual imago appears to ba superimposed on tba real wosld is that,postiom of the users field of view in which the image .
is projected. so that both the imago and the raal~
world behind the image can ba simultaneously . .
seen by the user. 8y completely dimming the ~ .
. display, the virtual image can bi a~ctinguished from that portion of the users field o! view so that the user can sea the real world, but the user does not sea tba virtual imago at all. 1,s described above, this feature o! controlling the display Z8 to provide a~window through the imago into the real world can also ba accomplished by providing a display.which can ba controlled so~
that light does not~paaa from the display im'a defined area or' window thereof. Wharf the light ~7 . blocking.featura o! such.a display is actuatsd, ~. a window into the real world is provided. through .. the displayed image in the area where light is . blocked from the display. Whew the light blocking feature is not actuated, the imago is sesn it its entirety.
The embodiment o! the binocular optical system depicted. in Fig. 15 has the various features described above !off the othat . 10 embodiments, but includes, an internal imago. y plans to allow the display 28 to ba positioned more remotely from the usar~s eyes while still obtaining a faisly large field o! view. In thii - embodiment, the display Ze is positioned such' that the lace 40 thsreo! is lacing outward from the user. 1~ mirror illustrated by the dotted line 110 is disposed at a 45~ angle with respect .to the display so as to direct the .imagi o! the . displayed information downward in front o! the user': face to a lens ii= which liar is a generally horizontal plane. The lens iiZ
focuses light onto tlia display Ze: 11 pair o!
prisms 114 and 116 disposed below the laps its bend the light that passes through the fans along respective right-eye amd felt-aye optical paths through a second pair o! lenses ii8 and iZO. The lenses 118 and'iiZ lie in the saga . horizontal plane below the prises 114 and 116. .
Mirrors 12Z and iZ4 are disposed in the respective right-eye and ls!t-eye optical paths at 45~ angles with respect to the lensu 118 and . ~ 120 so as to direct light back towards the user s eyes to respective inner surlaces.134~ot a pair ol~prisms~iz6 and iZe. Tha light is reflected in each optical path lros the respoctiva inner surfaces 134 0! the prism elements 126 and~iZ8 to respective outer surfaces 136 thereof. Tha respactiw outer 28 . w surfaces 136 of the prisms iZ6 and 128 in turtf ~. reflect the light through respective lenses 130 acrd 138 into the usar~s eyes.
. Tha optical system of FiQ. l5 results in an intermediate image plans within the prisms is6 and 128 wherein the respective lenses 130,and .
.. ~ 138 era located one focal length frog the,' intermediata~image plane in the prisms 186,.and 138. The lensaa 118 and iZ0 era such as to v 10 focus light incident thoroto lroa the display onto the respective image pla~os withi=i the' . prisms 186 and 188. This embodiment of the binocular optical display systaa is sihilas to those ambodimanta~dascribod above iu that the. .
prisms ~ 114, . 116 bend light towards a central, ~ , .
area with the lens 118 locusing the light to a ..
single point fros each of the optical paths onto a single point.on the display 88. Further, the surfaces 134 and 136 of the r~spactiw psisas Z0' is6 and is8 direst the light from the ussr~s aye fn towards the canter of the systa~. .
Figs. 16-19 illustrate one embodiment o! a w foldable keyboard bouainq 18, in accordance with the present invention, that may ba utiliaad to house tha.electronica of a computer. Tha electronics o! the computsr are those . .
conventionally used in a lap top computer, such _ as a main microprocessor and, i! desired, a coprocessor, coupled to a memory device such as a R~ and a disk or diskette drive, as is wall known. The microprocessor is responsive to .
information input on the keyboard 801 to generate video,inpu't signals that era couplsd to or communicated to the drive electronics~for the display.28 to display alphanumeric and/or .
graphic information on the display 88. eecausa the computer, in accordance with the present invention, utilizaa a head mourrtad display system, as described above, thi overall computer is much more lightweight and compact than . conventional lap top computers. However, the ' computer o! the present invention actually 5. provides a much larger~display than has ' .
heretofore~been.possible with prior lap top or notebook computers, due to the optics, o! the .
head mounted display systea. Further, because the head mounted display unit i0 maintains the users lower peripheral field o! view unobstructed, the user can easily see tlu . -keyboard if needed to~enter information to thi, user.
The keyboard housing 18; as show=s in Figi.
16-19; is.divided into two halves 200 and Z0Z
that are pivotal about a point in a hingi Z04 so as to alloy the keyboard ~o be folded. in halt.as depicted in Fig. 14. Each o! the.keyboard housing halves 200 and Z0Z includes an electrical connector 206 and Z08 which mate when . the two halves are unfolded so as to electrically connect that portion o! the computer electronics diaposed.within the housing 200 with the computer electronics disposed within the housing ZOZ.
!~s shown in Fig . 19 , ~ the hinge 2.04 includes a pair o! cylindrical members ZlO and - Z12 with centrally located apertures Z14 and a16 located therein. Each of the members Z10 and ~21Z includes an-integrally formed, generally . -arcuati flange portion Z18 and ZZ~O that extends over approximately a quarter of the member X10, Zis. When assembled, the member Z10 overlies the member Zi? so that the apertures Z14 and Z16 are aligned with an end ZZZ of the arcuate flange 2Z0 abutting an and Z=4 0! tha.arcuate flange X18. Each o! the arcuate flanges includes an aperture Z~6 and ZZ8 so a~ to 3~0 receive an end o! a respective rod Z30 and Z38 therein. when the member 21o is mountsd.on thi - member ZlZ such that the ends 2Z0 and ZZ4 ~o! the respective arcuate flanges 220 and 218 abut, the ~5 rods~230 and 23Z are longitudinally alignid.
The-cylindrical members 310 and ZiZ era held together by piru Z40, Z4Z and a bolt Z48 that extend through the apertures Z16 and Z14.
The pin 24Z has a cylindrical postion~~44 that ' 1o extends into the aperture o! the cylindrical portion Z46 0! the pin~Z40. 11 bolt Z48 has a . , head~250 that engages.a lip Z5Z o! the pin Z4,~
so-that when the bolt Z48~ie inserted thtoug~
the cylindrical portion Z44 0! the pie ~Z4~., the '15 threads o! the bolt Z50 can engage thi threaded portion Z60 or the pin Z40.. Ths pins:Z4o and ' ' 1 Z4Z, and bolt Z48, hold the circular.members si0 and Zis together in axial alignmerit,.but alloy the members ZiO and ZiZ to pivot with rupect to 20 each other so as to move the rods Z30 and Z3=.
out of longitudinal alignment in order to~told . the keyboard houoinq l8. 11s saen.ia Fiq. 38, the rods Z30 and Z3Z are secured to respective bottom portions Z70 and Z7Z o! the respective .
25 keyboard housing halves Z0Z and Z00 by assns o!
gripper members Z74 and Z76 respectively.
~n alternative hinge arrangement lor.a~.:
lo~.dable keyboard is illustrated in Figs.~2o-23 !or the foldable keyboard housing 18~. Tha 30 bottom portions 300 and 30~ o! respoctiw housing halves 304 and 306 0! the keyboard 18~
are formed wilt fairs o! longitudinally-aligned slots 308, 310 and 31Z, 314 disposed oa opposite sides o! the bottom portions 300 and 30Z.. Ths 3S longitudinally-aligned slots 308 and 310,iricluda a hinge member 316, ~bereaa the longitudinally=
aligned slots 31Z and 314 include a hinge member 318. Each o! the hinges 316, 318 include a i~ i i center bar 320 having a pair of apertures 322 through Which respective pins.324, 325 extend. The pine 324 , 325 extend through respective longitudinally-aligned slots 326, 328 disposed in adjacent ends of respective outer bare 330 and 332. The pins~324, 325 slide along in the respective slots 326, 328 to allow the bars 330 and 332 to move in towards each other or to move apart from each other. The bars 330 and 332 are pulled away from each other so as to separate the two halves 304 and 306 of the keyboard housing 18'. The bars 330.and 332 are then pivoted about the respective pine 324, 325 so that the bars extend generally parallel to one another when the two halves of the keyboard 304 and 306 are folded together, as shown in Fig. 23.
Whereas the embodiments of the foldable keyboards depicted in Figs. 16-20 illustrate a standard-size computer keyboard, the keyboard of Fig. 24 is a smaller-size computer keyboard utilizing the same hinge assembly as the embodiment ' depicted in Figs. 16-20. Further, the keyboard illustrated in Figs. 24-26 is designed so ae.to have an arcuate mounting surface 400 on one end thereof for mounting the head mounted display unit 10 thereon when it is not in use. The opposite end 402 of the keyboard 404 is also arcuate in shape so that both halves 406 and 408 of the keyboard accommodate the head mounted display unit 10. A computer keyboard with~a 25' mounting surface for the head mounted display unit 10 provides a very compact lightweight computer system that can easily be transported.
The overall size and weight of the computer system is substantially reduced over that of conventional lap top or notebook computers because the head mounted.display unit 10 is ' considerably smaller and lighter in weight than conventional display panels utilized in portable computers. AYthough more compact and lightsr in weight, the head mounted display unit 10, in accordance with the present invention, provides a high-quality display for alphanumeric information with the virtual image of the displayed information being as large or larger than a conventional full-sire display for a desk-top personal computor. Hecauae the head mounted display unit~l0 is a personal display systea, the user. can view confidential .
information in~a crowded environment without disclosing the~displayed information to others.
Further, because the binocular optical systes of the present invantion,maintains the uses~s peripheral~vision free frog obstruction and preferably maintains at least the lower ' peripheral vision of the user free, the user can ' selectively view the displayed alphanumsrio text or the keyboard as.he desires.
A number of the features o! the.prsisnt invention are not limited to a single display, binocular optical aystas that project: an image in the central field of the users view, but ars applicable to head mounted display units that are monocular or use two displays or that project the virtual image in the users 30~ peripheral field of view. Further, variow combinations of optical elements other than those described tn detail herein can be employed in accordance with~th~ present teachings as wll as many other moditications and variations o!
the present invention. Thus, it is to be understood that, within the scope of tht appended claims, the invention may be practiced otherwise than as described hereinabove.
i~ ~ i ~ i What is claimed and desired to bs secured ' . by Letters Patsnt is:
combination of the pris~os 3= and -34 with a concave reflector shown as the visor 36. More.
particularly, the pries in each of the right-eye and left-eye optical paths bands light frog any location along the width, fit, of the prise 5 representing various positions o! the ussrs~
eyes, and thus various interpupillary distances, towards the central area, C, on the visor 36.
The prisms convert the Z-3 inch difference between the centers of ths.users~ ayes to within .2 inches-.3 inches on the face 4Z of the visor 36 in the central area C thereof. ~ The visor 36 than reconciles this small difference at the .
face of the display by focusing-parallel light incident to surface 4Z on the same point on the . 35 display Z8 so that the users left aye sees the same image that the user's right eye seas through the optical systea. .
The visor 36 may be spherical in shape so ., as to project an enlarged image of the displayed information. It is noted, howsyez, that th~~
visor 36 may also be parabolic iw shape or haw another shape so as to obtain the desired degrse of magnification with minimal distortions.of the image, as is well known. Furthsr, separate concave reflectors for each eys may be used.
Due to the compact nature of the optical systea, the visor extends out frog the user by only 70 mm or less: The prisms 3Z aid 34 may be formed .
as a single olement 30 or as two distinct elements. Further, as shown in Fig. 10, a respective lens 60-6Z may be.mounted on or .
adjacent ta~ the exit surface 61, 63 of the v ,.
respective prise 3Z, 34 in the right-eye and left-eye optical paths 50, 5Z.Each o! the lenses 60 and 6= is preferably a conv~c lens to increase the field o! view of the image. Each of the prism-lens pairs 3Z, 60 and 34, 6Z also preferably forms an achromat to correct chromatic aberrations.
The display ZS is preferably such that the _ contrast and~brightness thereof does not change . over l0~ frog the perpendicular to the display Z5 ~so that the image seen by the left eye has the same brightness and contrast as the image smsa .
by the right eye. In ordir for the image scan by the Left aye to appear at the same location 'as the image aeon by the right eye, the left-eyi optical centerline path and the right-eye optical centerline path must be equal is length.
Further, the path lengths to the right side o!
the display Z8 from one aye mustbe equal to the path length frog that same eye to the left side 35' of the display Z8. If the path ~lengtha to the right side of the display and~tha left aide o!
the display are not.squal, the image will appear distorted such that -one side of the i~oag~
.. ~ CA 02490344 1994-09-23 ' 19 appears larger than the other side ol~the image.
These latter requirements are accomplished by an optical systea wherein the chie! rays'ol each v optical path, arm equal iu length.
s ~ ~: It i-s noted that i! the contrast and' brightness of the display cannot be ;maintained ralatiwly constant over 10' lros thl~
' . perpendicular~to the display, the optical systaw ' d~pictad in Figs. Z-6 may be eonvertid to a _. ' 10v ~ monocular systea by adding a light block 58, as . , shown by the dotted.lina in Fiq..9. The light blockv58 prevents light lroa the display lroi~
reaching one o! the user s eyes. Preferably, ..
. . the light block 58 is =emovably~mountsd on the ss bottoa cover Z4 or on the side of the display Z8 so that the light block may be positioned either on the side 55 0! the display.or:on the opposite aids 57 thereol. Because most people haw a.
dominant eye,~t! the light block is positioned .
~. .
Z0 on~the side o! the display so as to block light lroa.the display Z8 lroa reaching the non~
dominant eye, it will appeas to the user that h~
is viewing the display with both eyes; although -. hs is actually only viewing the display with hip .25 dominant eye. The bottoa view o! the optical.
display aystea shown in Fig. 9 illustrate ths.
position o! the ligbt block 58 !or a right-eye dominant user. although. this systea ~is i~ot binocular, it is extremely~llexibls iu that it y, ~30 ~ can be utilized~by both~right-eys dominant and .
felt-eye dominant people by merily changing the position o! the light blocat 58~lros ons sids o!
.ths display 55, 57 to the other iid~ o! the display 57, 5S. .
35 Fig. ii depicts a true stereo embodiment o!
the present invention that utilizes the say binocular systea as described, iii Figs. Z-6 or Fig. 7,.wherein the display 28~ is controlled to ZO
provide distinct images to the left eye and the . right~eye with a block 64 separating the right-eye optical path from the left-eye optical path.
Thevembodiment of the present invention . 5 illustrated in Fig. is is similar to the embodiments depicted in Figs. Z-6. However, the position ot.tha display 28 is altered so that ' instead of facing the inner surface 4Z of the visor 36, the face 40 of the display~28 tacaa ' downward onto a reflective surface 7Z that is disposed at a 45 angla with respect to the display surface 40 in~ordsr to retlact the information depicted on the face 40 0! the .display Z8 onto the inner surlaca 4Z.ot.tha ' ~ ' 15' , visor 36. Although the reflector 7Z may' be . formed of a conventional flat mirror, a prise w element 7o with a reflective surface 7Z i~
preferred to prevent.tha reflective surface 7Z
.from being marred by lingerprinta or scratches.
Tha features of the optical system depicted ' in Figs. Z-6 can ba obtained by other binocular optical.systems. For exempla, Fiq. 13 is another embodiment o! a binocular optical~systsa in accordance with the present invantiot~.that~
2~ utilize a single displayf automatically compensates for variatioru in IPOs o! users up to one inch; directs tba usar~s eyes inward towards the location of a virtual image that is located~a distance from the user that fs lss~
than infinity= and/or that'projects an snlarg~d image of displayed information in the usar~s direct Tina of sight and central field of view,.
while maintaining at least a portion o! the ~usar~s peripheral view ol~sach o! the us~r~s eyes free from obstruction. Whereas the embodiment illustrated in Figa. Z-9 accomplishes these features with a semi-reflective visor and prisms, the embodiment of Fiq.~ 13 accomplishes ZZ
these~features utilizing a lens, mirror(s~ and a beam splitter in each of the right-sye and left-eye optical paths. One of the advantages o! the . embodiment depicted~in Fig. l3 is that.thi contrast and brightness of the display Z8 need not ba maintained constant over 10~ from the perpendicular to the display to pravsnt conflicting infor~ation from being see=r by the riSht and left eyes of the user:-More particularly, the embodiment o! the present invention shown in Fig: 13 includss a display 28 with a base splittsr 80 disposed at a 45~ angle with respect to the face 40 of the display. The base splittsr 80 splits the~lig~t .
~15 froa the display 28 along a rigbt-eye optical _ path 50~ and a left-eye optical path 5=~: The light from the display 28 directed by the beam.
splittsr 80 along the right-eye optical path 50~
is reelected by a mirror 8~ into. the user~~
right aye through a biconveu lens-84. The base splitter 8o directs light !rose the display Z8 .
along the left-eye optical path 5=~ so that the light is reflected by~a mirror 86 to a second mirror 88 into the users lstt aye through a biconvex lens 90. Each of the biconvex lenses provides focusing arnd magnification of the ~imaga. .
With this embodiment, the display may be positioned at a location 8? or alternatively at 3o a location 89. Positioning of the display 38 at location 89 so that the outer edge o! the display 9Z does not exte~ beyond the outermost edge ol~the mirrors 80 and 8Z provides a more compact head mounted display unit with the weight thereof closer to the user s face. It is desirable to keep the weight of the optical system and display as close to the user s head as~possible to reduce the downward torque of the ~_ system and eliminating the need for countsr ' ~ weights on the support lZ.
When the virtual image of the information depicted on the display Z8 is to appear at optical infinity, the focal point of each of the lenses 84 and 90 is located at the center of the display faco 40. Further, the be8a splittsr 80 is'positioned at a 45~ angle with respset to the faco 40 of the display 28 with the mirror 8Z
parallel to the beam splitter 80. The mirror 86 is perpendicular to the beam splatter 80 and the mirror 88 is parallel~to the mirror 86.
If, however,, the virtual image is to appear at a distance from the user that is less than infinity, for example two felt, the sirror 8Z- in.
the right-aye optical path and the mirror 88 in . the left-eye optical path are angled slightly inwardly ao as to direct the user~i ey~~ inward at a convergence angle that is natural for a Z0 person viewing an obiect at a distance oqual to the distance~of ths,virtual image from the user.
For example, for a virtual image that is to appear approximately two feet frog the user, a convergence angle of approximately Z~-t~ is desired. Therefore, the mirror 8= at~d the mirror 88 are positione8 at am angle a that is approximately 41~-43~ frog a line that is parallel to the face 40 of the display Z8, as opposed to being at a 45~ angle with respect thsroto. With the uaer~a eyes directed inwardly to the location o! the virtual image at a natural angle, the head mounted display systes of the present invention is more comfortable and less eye fatiguing than prios system. It ii doted that in this embodiment, the display Z8 is at a distance from each of the lenses 84~and 90 that is less than the local length~o! each o!
the lenses.
23 . . ' Regardless o! whether the virtual imaga.is to ba,focused at infinity, or at less than.
infinity, the length o! the right-eye optical ce~terlina path 50~ representad~by the length o!
the segments a, b, and c is equal to the length o! the left-eye optical.centerlina paths represented by the length o! the segmsnts a, d, .
s,', and f. Further, the distance fro: a qivan eye to the one side ol~tha display 28 is,equal .10 to the distance from that sya to the opposite .si8a of the display, 8uch~that the chin! rays o!
. the system era o! equal length.
The embodiment of the present invention ~ .
depictsd in Fig. l3.automatically compansatas~, for variations in the interpupillary distance o!
various users because each o! the focusing lenses 84, 90 is such. that light at any location along the width, i.e. diamatir, tharso!
representing various positions o! a usars~ syu ZO and thus various interpupillary. distances, is focused on the same point with the mirrors and bees splittar disposed it each of'the right sya . and loft sya optical paths to direct the path of .
light lroa the usar~s ayes through the respective lenses to the lama point. Further, the size of the beam splittar 80 and the aurora 8Z, 86, and 88 are selected so as to account for light diverging outward Eros the face 40.0! the display Z8 by an angle ~3 0! approximately Z.5~
so as to insure that the entire display is reflected by the beam splittar and mirrors into the ussr~s eyes for users having ons inch variations in their IPDa.
The system o! Fig..i3 is a very compact, lightweight system with a wide field o! view, being on the order of ZO~-45~. Tha hensss 8~, 90; mirrors 8Z, 86, 88, beam splittas 80, and the display 28 era preferably mounted on the bottom cover 24 of the frame iZ, such that the - ~ . ~ exit surface of each of the lenses 8~, 90 is approximately 20 mm froa.tha usar~a.eyss.
Hecausa each of the lenses 84 and 90 ors relatively close to the user s eyes, the image has a large field o! view. Howevsr,~tha 20 m~
spacing between each of the lenses and thi~ ' ussr~s respective eyes is typically sufficient ' to allow the user to wear a pair o! glasses with the head mounted display systaa. Tha lenses 84 and 90 may.actually~ba disposed even closer to the user's eyes, but preferably no closer than the lenses o! a typical pair of glasses worn by .
a user so as to prevent anxiety in the user when an object is extremely clogs to.hia .eyes. Thr .
Tenses may also ba positioned farther frog the ussr~s eyes; however, in order to obtaiA a given tilld of view, as the distance between the sya and the lens 8~, 90 incraases,'tha diameter o!
the lens generally increases. It 'is noted that with the lenses 84 and 90 located approximately 20 ma troy the usar~s eyes and with the display 28 at the location 89, the heed mounted display unit l0 extends only about Z-1/Z inches out in front o! the usar~s face.
The optical systes aepictsd in Fiq. 19 is mounted on the trams is so as to project the ' virtual imago in the central field ot.viaw arrd direct line of sight of each o! the ussr~s eysa.~
~ The sizs~o! the lenses 8f and 90, as well as the configuration ol.tha support is, era such as to maintain at least a portion of the peripheral view of each of the ussr~s eyes free troy obstruction so as to obtain all o! the advantages described above for the embodiment of the invention depicted in FiQ. Z. As showif in Figs. 7 and 8, the exit surface o! the optical alement(s). closest to the usar~s eyes, 60713-621D.
. which,in the case of Fig: 13 are the lenses 84 and 90, is represented by the line A8 where A
and B respectively represent the locations o! ' the outer side edges of the closest optical element(s). As described above, the exit surface of the closest optical elements, the lenses 8~ and 90, is preferably approximatily~20 mm from the user s eyes. The~diameter of the ' lenses is preferably on the. order of Z5 mm-35 nm y l0 so that a user having an IPD of. approximately .
Z.5 inches need only.mow an eye to the side through. an angle a to'focus~on his surroundings in his side peripheral vision. The angle a will vary for users. having' difteisnt ZPDs, but. ii, .
~15 .generally in the range of 5~-15~. Because the diameta= of the lenses 84 and 90 is ou the os~dsr of Z5 mm-35 mm, the optical systas ol~Flg. 13 maintains a significant amount of the~ussr~s lower peripheral vision free fros.obstruction.
20 Fig. l4~illustrates a slight modification .
of the embodiment of the present invention depicted in Fig: 13.~; In Fig. i~, tbs entire optical systea from the lenses 84 and 90 to the display Z8 is rotated 90~ from that show~t is 25 Fig. 10 so that the axis of each of the lenses ' 84 and 90 is perpendicular to the respective axes of the usar~s right eye and.left eye. .~11 . pair o! mirrors are added to the system.auch that one mirros 100 is disposed.in the right-aye 30 optical path at a 45~ angle with respect to the lens 84 so as to reflect the image from the .
display through 'the lane into the user s aye. .
r Similarly, a reflector 100 is positioned in'the left-eye optical path at a 45~ angle with 35 respect to the lens 90 so as to reflect the image from the display through the lens into the users loft eye. It is noted that the reflector 100 may be any type of mirror including s . . ~ 26 holographic mirror, a curved m,~rrQr, etc.
In the embodiment.ot FiQ. 14,'th~ ~ . .
reflectors 100 can b~ positioned in the central' -, . field of view and direct line of sight o! the .
user 's eyes whilt maintaining the usar~a~', peripheral view unobstructed. Tha reflectors l00 may also be positioned iu the upper ,' . peripheral view of ~tha usar~~~s eyu for those .
applications where the imago di~playad~~is not to 1o ba the main focus o! the uses~a attention. The reflectors 100 era also preferably sasi=. .
reflective, for exempla 80i retlactiw so as to allow the user to see the real world through .ths .
' reflector 100. ~ ~ ~ .
l1a described above, the display Via' may include a brightness control 60 to allow~tl~
brightness of the display ZS to ba varied such that the display at its brightest results.io a virtual image that completely blocks.tha uses~s Z0 view of the real imago in the portion ol.tha ~ ' usar~s field of view im which the imago is projected. ey dimming the brightness o! the display Ze, the virtual imago appears to ba superimposed on tba real wosld is that,postiom of the users field of view in which the image .
is projected. so that both the imago and the raal~
world behind the image can ba simultaneously . .
seen by the user. 8y completely dimming the ~ .
. display, the virtual image can bi a~ctinguished from that portion of the users field o! view so that the user can sea the real world, but the user does not sea tba virtual imago at all. 1,s described above, this feature o! controlling the display Z8 to provide a~window through the imago into the real world can also ba accomplished by providing a display.which can ba controlled so~
that light does not~paaa from the display im'a defined area or' window thereof. Wharf the light ~7 . blocking.featura o! such.a display is actuatsd, ~. a window into the real world is provided. through .. the displayed image in the area where light is . blocked from the display. Whew the light blocking feature is not actuated, the imago is sesn it its entirety.
The embodiment o! the binocular optical system depicted. in Fig. 15 has the various features described above !off the othat . 10 embodiments, but includes, an internal imago. y plans to allow the display 28 to ba positioned more remotely from the usar~s eyes while still obtaining a faisly large field o! view. In thii - embodiment, the display Ze is positioned such' that the lace 40 thsreo! is lacing outward from the user. 1~ mirror illustrated by the dotted line 110 is disposed at a 45~ angle with respect .to the display so as to direct the .imagi o! the . displayed information downward in front o! the user': face to a lens ii= which liar is a generally horizontal plane. The lens iiZ
focuses light onto tlia display Ze: 11 pair o!
prisms 114 and 116 disposed below the laps its bend the light that passes through the fans along respective right-eye amd felt-aye optical paths through a second pair o! lenses ii8 and iZO. The lenses 118 and'iiZ lie in the saga . horizontal plane below the prises 114 and 116. .
Mirrors 12Z and iZ4 are disposed in the respective right-eye and ls!t-eye optical paths at 45~ angles with respect to the lensu 118 and . ~ 120 so as to direct light back towards the user s eyes to respective inner surlaces.134~ot a pair ol~prisms~iz6 and iZe. Tha light is reflected in each optical path lros the respoctiva inner surfaces 134 0! the prism elements 126 and~iZ8 to respective outer surfaces 136 thereof. Tha respactiw outer 28 . w surfaces 136 of the prisms iZ6 and 128 in turtf ~. reflect the light through respective lenses 130 acrd 138 into the usar~s eyes.
. Tha optical system of FiQ. l5 results in an intermediate image plans within the prisms is6 and 128 wherein the respective lenses 130,and .
.. ~ 138 era located one focal length frog the,' intermediata~image plane in the prisms 186,.and 138. The lensaa 118 and iZ0 era such as to v 10 focus light incident thoroto lroa the display onto the respective image pla~os withi=i the' . prisms 186 and 188. This embodiment of the binocular optical display systaa is sihilas to those ambodimanta~dascribod above iu that the. .
prisms ~ 114, . 116 bend light towards a central, ~ , .
area with the lens 118 locusing the light to a ..
single point fros each of the optical paths onto a single point.on the display 88. Further, the surfaces 134 and 136 of the r~spactiw psisas Z0' is6 and is8 direst the light from the ussr~s aye fn towards the canter of the systa~. .
Figs. 16-19 illustrate one embodiment o! a w foldable keyboard bouainq 18, in accordance with the present invention, that may ba utiliaad to house tha.electronica of a computer. Tha electronics o! the computsr are those . .
conventionally used in a lap top computer, such _ as a main microprocessor and, i! desired, a coprocessor, coupled to a memory device such as a R~ and a disk or diskette drive, as is wall known. The microprocessor is responsive to .
information input on the keyboard 801 to generate video,inpu't signals that era couplsd to or communicated to the drive electronics~for the display.28 to display alphanumeric and/or .
graphic information on the display 88. eecausa the computer, in accordance with the present invention, utilizaa a head mourrtad display system, as described above, thi overall computer is much more lightweight and compact than . conventional lap top computers. However, the ' computer o! the present invention actually 5. provides a much larger~display than has ' .
heretofore~been.possible with prior lap top or notebook computers, due to the optics, o! the .
head mounted display systea. Further, because the head mounted display unit i0 maintains the users lower peripheral field o! view unobstructed, the user can easily see tlu . -keyboard if needed to~enter information to thi, user.
The keyboard housing 18; as show=s in Figi.
16-19; is.divided into two halves 200 and Z0Z
that are pivotal about a point in a hingi Z04 so as to alloy the keyboard ~o be folded. in halt.as depicted in Fig. 14. Each o! the.keyboard housing halves 200 and Z0Z includes an electrical connector 206 and Z08 which mate when . the two halves are unfolded so as to electrically connect that portion o! the computer electronics diaposed.within the housing 200 with the computer electronics disposed within the housing ZOZ.
!~s shown in Fig . 19 , ~ the hinge 2.04 includes a pair o! cylindrical members ZlO and - Z12 with centrally located apertures Z14 and a16 located therein. Each of the members Z10 and ~21Z includes an-integrally formed, generally . -arcuati flange portion Z18 and ZZ~O that extends over approximately a quarter of the member X10, Zis. When assembled, the member Z10 overlies the member Zi? so that the apertures Z14 and Z16 are aligned with an end ZZZ of the arcuate flange 2Z0 abutting an and Z=4 0! tha.arcuate flange X18. Each o! the arcuate flanges includes an aperture Z~6 and ZZ8 so a~ to 3~0 receive an end o! a respective rod Z30 and Z38 therein. when the member 21o is mountsd.on thi - member ZlZ such that the ends 2Z0 and ZZ4 ~o! the respective arcuate flanges 220 and 218 abut, the ~5 rods~230 and 23Z are longitudinally alignid.
The-cylindrical members 310 and ZiZ era held together by piru Z40, Z4Z and a bolt Z48 that extend through the apertures Z16 and Z14.
The pin 24Z has a cylindrical postion~~44 that ' 1o extends into the aperture o! the cylindrical portion Z46 0! the pin~Z40. 11 bolt Z48 has a . , head~250 that engages.a lip Z5Z o! the pin Z4,~
so-that when the bolt Z48~ie inserted thtoug~
the cylindrical portion Z44 0! the pie ~Z4~., the '15 threads o! the bolt Z50 can engage thi threaded portion Z60 or the pin Z40.. Ths pins:Z4o and ' ' 1 Z4Z, and bolt Z48, hold the circular.members si0 and Zis together in axial alignmerit,.but alloy the members ZiO and ZiZ to pivot with rupect to 20 each other so as to move the rods Z30 and Z3=.
out of longitudinal alignment in order to~told . the keyboard houoinq l8. 11s saen.ia Fiq. 38, the rods Z30 and Z3Z are secured to respective bottom portions Z70 and Z7Z o! the respective .
25 keyboard housing halves Z0Z and Z00 by assns o!
gripper members Z74 and Z76 respectively.
~n alternative hinge arrangement lor.a~.:
lo~.dable keyboard is illustrated in Figs.~2o-23 !or the foldable keyboard housing 18~. Tha 30 bottom portions 300 and 30~ o! respoctiw housing halves 304 and 306 0! the keyboard 18~
are formed wilt fairs o! longitudinally-aligned slots 308, 310 and 31Z, 314 disposed oa opposite sides o! the bottom portions 300 and 30Z.. Ths 3S longitudinally-aligned slots 308 and 310,iricluda a hinge member 316, ~bereaa the longitudinally=
aligned slots 31Z and 314 include a hinge member 318. Each o! the hinges 316, 318 include a i~ i i center bar 320 having a pair of apertures 322 through Which respective pins.324, 325 extend. The pine 324 , 325 extend through respective longitudinally-aligned slots 326, 328 disposed in adjacent ends of respective outer bare 330 and 332. The pins~324, 325 slide along in the respective slots 326, 328 to allow the bars 330 and 332 to move in towards each other or to move apart from each other. The bars 330 and 332 are pulled away from each other so as to separate the two halves 304 and 306 of the keyboard housing 18'. The bars 330.and 332 are then pivoted about the respective pine 324, 325 so that the bars extend generally parallel to one another when the two halves of the keyboard 304 and 306 are folded together, as shown in Fig. 23.
Whereas the embodiments of the foldable keyboards depicted in Figs. 16-20 illustrate a standard-size computer keyboard, the keyboard of Fig. 24 is a smaller-size computer keyboard utilizing the same hinge assembly as the embodiment ' depicted in Figs. 16-20. Further, the keyboard illustrated in Figs. 24-26 is designed so ae.to have an arcuate mounting surface 400 on one end thereof for mounting the head mounted display unit 10 thereon when it is not in use. The opposite end 402 of the keyboard 404 is also arcuate in shape so that both halves 406 and 408 of the keyboard accommodate the head mounted display unit 10. A computer keyboard with~a 25' mounting surface for the head mounted display unit 10 provides a very compact lightweight computer system that can easily be transported.
The overall size and weight of the computer system is substantially reduced over that of conventional lap top or notebook computers because the head mounted.display unit 10 is ' considerably smaller and lighter in weight than conventional display panels utilized in portable computers. AYthough more compact and lightsr in weight, the head mounted display unit 10, in accordance with the present invention, provides a high-quality display for alphanumeric information with the virtual image of the displayed information being as large or larger than a conventional full-sire display for a desk-top personal computor. Hecauae the head mounted display unit~l0 is a personal display systea, the user. can view confidential .
information in~a crowded environment without disclosing the~displayed information to others.
Further, because the binocular optical systes of the present invantion,maintains the uses~s peripheral~vision free frog obstruction and preferably maintains at least the lower ' peripheral vision of the user free, the user can ' selectively view the displayed alphanumsrio text or the keyboard as.he desires.
A number of the features o! the.prsisnt invention are not limited to a single display, binocular optical aystas that project: an image in the central field of the users view, but ars applicable to head mounted display units that are monocular or use two displays or that project the virtual image in the users 30~ peripheral field of view. Further, variow combinations of optical elements other than those described tn detail herein can be employed in accordance with~th~ present teachings as wll as many other moditications and variations o!
the present invention. Thus, it is to be understood that, within the scope of tht appended claims, the invention may be practiced otherwise than as described hereinabove.
i~ ~ i ~ i What is claimed and desired to bs secured ' . by Letters Patsnt is:
Claims (7)
1. A head mounted display system comprising:
a support to mount the display system on a user's head;
a first prism mounted on said support in a right-eye optical path;
a second prism mounted on said support in a left-eye optical path;
a display mounted on said support for displaying video information; and a reflector shaped to project an enlarged image of said video at a distance from the user, said reflector being mounted on said support in each of said right-eye and left-eye optical paths, wherein said first and second prisms bend the right-eye and left-eye optical paths from a user's eye towards each other and said reflector in each path focuses light traveling along the respective optical paths onto the same point relative to said display.
a support to mount the display system on a user's head;
a first prism mounted on said support in a right-eye optical path;
a second prism mounted on said support in a left-eye optical path;
a display mounted on said support for displaying video information; and a reflector shaped to project an enlarged image of said video at a distance from the user, said reflector being mounted on said support in each of said right-eye and left-eye optical paths, wherein said first and second prisms bend the right-eye and left-eye optical paths from a user's eye towards each other and said reflector in each path focuses light traveling along the respective optical paths onto the same point relative to said display.
2. A head mounted display system as recited in claim 1 wherein said reflector is semi-reflective.
3. A head mounted display system as recited in claim 1 wherein said reflector is a single optical element intersecting both of said right-eye and left-eye optical paths.
4. A head mounted display system as recited in claim 1 wherein said first and second prisms are integrally formed into a single optical element.
5. A head mounted display system as recited in claim 1 wherein said display is mounted on said support so as to face said reflector.
6. A head mounted display system as recited in claim 5 wherein said display is a left-handed liquid crystal display.
7. A head mounted display as recited in claim 1 wherein said display is the only display of the system.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US13351893A | 1993-10-07 | 1993-10-07 | |
| US08/133,518 | 1993-10-07 | ||
| CA002173624A CA2173624C (en) | 1993-10-07 | 1994-09-23 | Binocular head mounted display system |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002173624A Division CA2173624C (en) | 1993-10-07 | 1994-09-23 | Binocular head mounted display system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2490344A1 true CA2490344A1 (en) | 1995-04-13 |
Family
ID=34137127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002490344A Abandoned CA2490344A1 (en) | 1993-10-07 | 1994-09-23 | Binocular head mounted display system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2490344A1 (en) |
-
1994
- 1994-09-23 CA CA002490344A patent/CA2490344A1/en not_active Abandoned
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