_
`Unlted States Patent
`
`[191
`
`llllllllllllllllllllllIllllllllllllllllllllllllllllllllllllllllllllllllllll
`U5005313234A
`[11] Patent Number:
`
`5 313 234
`9
`9
`
`Edmonson et al.
`[45] Date of Patent: May 17, 1994
`
`
`[54] LIQUID CRYSTAL PROJECTOR
`
`[75]
`
`_
`Inventors Oerm Edmonson, Eagan, ano;
`Christopher Mathewson, Rochester,
`N.Y.
`"
`
`.
`Sayett Group, 1110., Rochester, NY.
`[73] Assrgnee:
`21 A LN .2 6144
`I
`1
`pp
`0
`’
`[22] Filed:
`Jan. 19,1993
`
`-
`-
`Related U'S' Apphcanon Data
`Continuation of Ser. No. 736,246, Jul. 26, 1991, aban-
`doned.
`
`[63]
`
`Int. CLS .............................................. G03B 21/16
`[51]
`[52] U.S. C1. ......................................... 353/61; 353/57
`[58] Field of Search ....................... 353/52, 54’ 55_56,
`353/60—61, 119-122, DIG. 3; 359/66, 79
`R f
`C'
`11
`e erences
`1te
`U.S. PATENT DOCUMENTS
`
`56
`
`1
`
`[
`
`y
`2,569,918 10/1951 Berggren .
`3,250,175
`5/1966 Braun .................................... 353/61
`4,088,400
`5/1978 Assouline et a1,
`...... 353/20
`
`4,154,007 5/ 1979 Judd .................
`
`340/711
`4,165,160
`8/1979 Persha et al.
`.
`..... 353/55
`
`4,167,310 9/1979 Persha et a1.
`-- 353/52
`4,222,641
`9/1980_ Stolov .......
`
`-- 353/84
`4,294.524 10/1981 Stolov
`” 353/84
`...... 353/31
`1/1983 Stolov
` 4,368,963
`355/3 R
`4,386,836
`6/1983 Aold 61 a].
`4,453,810 6/1984 Curie] .................................... 353/55
`4,536,014
`8/1985 Boutaleb et al.
`.................... 353/122
`4,563,067
`1/1986 Ozeki .................................... 353/60
`
`4,613,207 9/1986 Fergason ............................... 359/36
`4,552,101
`3/1987 Grunwald
`353/122
`..
`4,671,634 6/1987 Kizaki et a1.
`353/122
`
`4,722,593
`2/1988 Shimazaki .....
`353/122
`9/1988 Umeda etal..
`4,770,525
`353/122
`
`4,787,737 11/1988 0 awa ct al. .
`..... 353/60
`
`4,811,064
`3/1989 Olgrmura at al.
`353/122
`4,824,210 4/1989 Shimazaki .........
`353/119
`
`4,864,390 9/1989 McKeehnie et al..
`..... 358/60
`
`4,875,064 10/1989 Umeda et a1. .......... 353/78
`
`4,880,303 11/1989 Grunwald .....
`353/122
`..... 353/60
`4,882,599 11/1989 Grunwald ..
`
`8/1990 Honda ................................... 353/61
`4,950,072
`7
`FOREIGN PATENT DOCUMENTS
`
`2553552 4/1985 France ---------------------------------- 353/55
`61-24673]
`6/1987 Japan -
`0959018 9/1982 U.S.S.R. ................................ 353/55
`Primary Examiner—William A. Cuchlinski, Jr.
`Assistant Exammer—Wflliam C. Dowhng
`Attorney, Agent, or Firm—Cumpston & Shaw
`[57]
`ABSTRACT
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`A 11qu1d crystal display Panel PIOJector Including a
`housing having a thermally isolated hot compartment
`which has an illumination source and a cold compart-
`ment which retains liquid crystal display panel. The
`housing inc1udes individual cooling fluid paths for the
`hot and cold compartments. The display panel is dis-
`posed in the cold compartment where it is isolated from
`.
`.
`.
`.
`the thermal energy of the 111um1nat1on source to prov1de
`a SUbS‘am'all-‘Y Stable thermal enV‘mnmem-
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`7 Claims, 3 Drawing Sheets
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`US. Patent
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`May 17, 1994
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`3 Sheet 1 of 3
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`5,313,234
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`US. Patent
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`May 17, 1994
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`Sheet 2 of 3
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`5,313,234
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`' FIG.4
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`XLNX-1010
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`US. Patent
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`May 17, 1994
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`Sheet 3 of 3
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`5,313,234
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`u
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`nnu.um
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`FIG. 5
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`XLNX-1010
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`1
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`LIQUID CRYSTAL PROJECTOR
`
`5,313,234
`
`This is a continuation of copending application Ser.
`No. 07/736,246 filed Jul. 26, 1991 now abandoned.
`The present invention relates to liquid crystal projec-
`tors, and more particularly, to a liquid crystal projector
`having thermally isolated optically transparent com-
`partments within the projector for providing a ther-
`mally stable environment for a liquid crystal display
`panel.
`
`BACKGROUND OF THE INVENTION
`
`Liquid crystal projectors employ a liquid crystal
`display panel positionable between a projector lamp and
`a lens. An illumination beam from the lamp passes
`through the liquid crystal display panel to form an
`image beam. The image beam is enlarged by a projec-
`tion lens system and focused to cast an enlarged picture
`on a display screen.
`To provide maximum contrast of the displayed im-
`age, liquid crystal display panels must be maintained at
`a cool and uniform temperature. The exposure of the
`display panel to heat from the projection lamp substan-
`tially degrades the quality of the projected image.
`A prior projector employing a liquid crystal display
`panel is disclosed in US. Pat. No. 4,875,064 to Umeda.
`In the Umeda projector, the illumination beam passes
`through ultraviolet reflectors and absorbers to remove
`thermal energy from the beam. A reflective mirror
`redirects the illumination beam so that the beam is per-
`pendicular to the lamp. A condenser lens directs the
`illumination beam to the liquid crystal display panel.
`The display panel forms an image beam which passes
`through a fresnel lens, and is redirected by a mirror.
`The image beam then passes through a projection lens,
`off a projection mirror, and on to a projection screen.
`While the Umeda device provides a relatively compact
`projector and employs ultraviolet reflectors and absorb-
`ers, the liquid crystal display panel is located in the same
`thermal environment as the illumination source, and is
`therefore subject to substantial heat and temperature
`fluctuations which degrade the quality of the image and
`contribute to premature failure of the panel.
`A need exists for a liquid crystal display panel projec-
`tor which provides a cool, thermally stable environ-
`ment for the display panel. There is also a need for a
`compact projector having a reduced volume to permit
`integration with control equipment.
`SUMMARY OF THE INVENTION
`
`A liquid crystal display panel projector having a
`thermally isolated liquid crystal display panel and illum-
`ination source is disclosed. The thermal isolation of the
`display panel and the illumination source is achieved by
`housing each within a thermally separate compartment
`in the projector and circulating a cooling liquid through
`the compartments.
`.
`The projector of the present
`invention includes a
`housing having a hot compartment and a thermally
`isolated cold compartment, wherein the illumination
`source is disposed in the hot compartment and the liquid
`crystal display panel is disposed in the cold compart-
`ment. The cold compartment provides a relatively cool
`and substantially uniform temperature environment for
`the liquid crystal display panel. The stability of the
`environment
`in the cold compartment
`improves the
`contrast of the image produced by the display panel.
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`The hot and cold compartments are thermally iso-
`lated by removing the thermal energy from the illumi-
`nating beam while it is in the hot compartment, and
`preventing fluid communication from the hot compart-
`ment to the cold compartment.
`The present invention may be used with liquid crystal
`display panels including color filter TFT, black and
`white double twisted, STN, and TFT panels. In addi-
`tion, the present invention employs double folded optics
`to reduce the size of the projector, The compact design
`of the projector allows for the incorporation of a com-
`puter including a mother board, a disk drive and a
`backup system to provide a stand alone computer image
`projection system.
`Specifically, the present invention includes a liquid
`crystal display panel projector comprising:
`(a) a housing including a cold compartment having a
`fluid inlet and a hot compartment having a fluid outlet,
`wherein the hot compartment is at least partially ther-
`mally isolated from the cold compartment;
`(b) a display panel substantially disposed within the
`cold compartment such that the cold compartment, the
`display panel having a first side and a second side;
`(c) illumination means in the hot compartment for
`producing an illumination beam;
`(d) single pass optics means for directing the illumina-
`tion beam from the illumination means through the
`display panel in a single pass to produce an image beam;
`(e) focusing means for projecting the image beam
`upon the screen; and
`(f) fluid communication means extending between the
`inlet and the outlet for providing a fluid flow from the
`inlet into cold compartment in direct thermal contact
`with the first and the second side of the display panel
`such that the fluid flow then passes through the hot
`compartment in thermal contact with the illumination
`means and exits the housing through the outlet.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a top plan view of the projector of the
`present invention;
`FIG. 2 is a front elevational view of the projector;
`FIG. 3 is a side elevational view of the projector
`housing;
`FIG. 4 is a rear elevational view of the projector; and
`FIG. 5 is a schematic cross-sectional view taken
`along lines 5—5 of FIG. 3.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`Referring to FIGS. 1—3, the projector 10 of the pres-
`ent invention includes a housing 20. A projector lens
`120 is retained by the housing 20. As shown in FIGS. 1
`and 4, the housing 20 may include a control panel 16
`including on/off, and focusing controls.
`Referring to FIG. 5, the housing 20 includes a hot
`compartment 50 and a cold compartment 60. The hot
`compartment 50 is separated from the cold compart-
`ment 60 by a thermally insulating interior housing walls
`22 and 24. The insulating walls 22, 24 may be formed of
`a variety of materials, such as insulated aluminum. The
`cold compartment 60 includes an illumination optics
`chamber 80 and an imaging optics chamber 90. As
`shown in FIG. 5, a light path whose boundaries are
`shown by broken arrows, extends from the hot com-
`partment 50 through the illumination optics chamber 80
`and imaging optics chamber 90 to exit the housing 20
`through the projection lens 120.
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`XLNX-1010
`Page 5 of 8
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`5,313,234-
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`3
`Referring to FIG. 5, the housing 20 includes a fan 140
`between the hot compartment 50 and the cold compart-
`ment 60. As shown in FIGS. 1 and 5, the hot compart-
`ment 50 includes an exhaust port 25. Referring to FIG.
`5, the interior insulating wall 24 separates the hot com-
`partment 50 from the illumination optics chamber 80.
`The interior insulating wall 22 and fan 140 separate the
`hot compartment 50 from the imaging optics chamber
`90. Referring to FIGS. 3-5,
`the illumination optics
`chamber 80 includes inlet vents 23 along the periphery
`of the housing 20.
`As shown in FIG. 5, a fluid passageway 130 separates
`the illumination optics chamber 80 from the imaging
`optics chamber 90. The inlet vents 23 are fluidly con-
`nected to the passageway 130 by outlet vents 23a. Re-
`ferring to FIGS. 4 and 5, the imaging optics chamber 90
`includes inlet vents 27, and as shown in FIG. 5, outlet
`vents 27a. Preferably, the outlet vents 27a discharge
`into the passageway 130 proximal to the fan 140.
`The fan 140 intakes fluid from the passageway 130,
`and exhausts fluid into the hot compartment 50.
`Referring to FIG. 5, the hot compartment 50 includes
`the illumination source 62, and a hot condenser lens 72.
`As shown in FIG. 5, the illumination source 62 pro-
`duces an illumination beam which travels along the
`light path. The illumination source 62 includes a halo-
`gen or metal-halide projection lamp 63 and a reflector
`65 for directing the light emitted from the lamp 63 along
`the light path. The reflector 65 is parabolic for reflect-
`ing the light from the lamp 63 in substantially parallel
`beams along the light path.
`The illumination source 62 includes a dual lamp sys-
`tem having a pair of parallely aligned diametrically
`oriented lamps 63, 63’, which may be selectively rotated
`about a central axis 67 to orient either lamp in an opera-
`ble position with respect to the light path. The dual
`lamps provide for efficient switching of the bulbs. That
`is, as one bulb burns out, the remaining bulb may be
`immediately rotated into operable position,
`thereby
`reducing down time of the system. In addition to man»
`ual rotation of the lamps, an automatic switch (not
`shown) may be used to rotate the lamps 63, 63' based
`upon a percentage of the rated useful life of the bulb or
`upon actual failure of one bulb. The dual lamp system
`allows for alternating use of a long life-normal bright-
`ness lamp and high intensity-short life bulb.
`The hot condenser lens 72 is disposed perpendicular
`to the light path in the wall 24 to intersect the illumina-
`tion beam. The hot condenser lens 72 removes thermal
`energy from the illumination beam by reflecting infra-
`red radiation back into the hot compartment 50 while
`permitting visible light in the illumination beam to pass
`into the illumination optics chamber 80. A preferred hot
`condenser lens 72 is a Pyrex mirror coated with an
`infrared reflector as is well known in the art.
`As shown in FIG. 5, the illumination optics chamber
`80 includes the first surface mirror 82 oriented obliquely
`to both the light path and the hot condenser lens 72 and
`a fresnel lens 84. The orthogonal of the first surface
`mirror 82 may be at any angle from approximately 35°
`to 55° from the orthogonal of the hot condenser lens 72,
`with a preferred orientation of approximately 45°. The
`first surface mirror 82 reflects visible light in the illumi-
`nation beam towards the fresnel lens 84.
`Referring to FIG. 5, the fresnel lens 84 is disposed in
`the light path subsequent to the first surface mirror 82
`and oriented perpendicular to the light path. The illumi-
`nation beam passes substantially orthogonally through
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`the fresnel lens 84. As shown in FIG. 5, the fresnel lens
`84 may form a portion of the wall of the illumination
`optics chamber 80, such that the fresnel lens defines a
`portion of the fluid passageway 130.
`As shown in FIG. 5, the imaging optics chamber 90
`includes a liquid crystal display panel 100, a first surface
`mirror 110, and a projection lens 120.
`Referring to FIG. 5, the liquid crystal display panel
`100 is disposed in the cold compartment 90 and opposes
`the fresnel lens 84 across the passageway 130. The dis-
`play panel 100 is retained by peripheral mounting plate
`101. The mounting plate 101 includes the peripheral
`outlet ports 27a proximal to the fan 140 for allowing
`cooling fluid to pass therethrough.
`The display panel 100 may be of any of a variety of
`types including color filter TFT, black and white dou-
`ble twisted, STN and TFT panels. The display panel
`100 is parallel to the fresnel lens 84 and perpendicular to
`the light path. As shown in FIG. 5, the display panel
`100 and plate 101 may form a portion of the wall of the
`imaging optics chamber 90 such that the panel is in
`thermal contact with cooling fluid in the passageway
`130.
`
`Referring to FIG. 5, the first surface mirror 110 is
`obliquely oriented with respect to the light path subse-
`quent to the display panel 100. The orthogonal of the
`first surface mirror 110 may be from approximately 35°
`to 55° from both the light path and the orthogonal of the
`display panel 100, with a preferred orientation of ap-
`proximately 45°. The first surface mirror 110 may be of
`any type of visible light reflecting mirror well known in
`the art.
`
`As shown in FIG. 5, the projection lens 120 is re-
`tained in the wall of the housing 20 in the cold compart-
`ment 90 such that the optical axis of the projection lens
`120 is coincident with the light path. The light path
`from the first surface mirror 110 passes through the
`projection lens 120 and exits the projector 10. The pro-
`jection lens 120 focuses the image beam for projection
`upon an external screen. The projection lens 120 may be
`any lens system a-s well known in the art.
`
`OPERATION OF THE PROJECTOR
`
`As shown in FIG. 5, the light path in the present
`invention extends from the illumination source 62 to the
`projection lens 120 such that the illumination source
`and the projection lens are disposed towards the screen
`end of the projector 10, wherein the illumination source
`directs the illumination beam away from the screen,
`while the projection lens is pointed at the screen, not
`shown. The light path thereby defines a double folded
`optic path.
`Light from the illumination source 62 is reflected by
`the parabolic reflector 65 to form the illumination beam
`along» the light path. The illumination beam orthogo-
`nally passes through the hot condenser lens 72. The hot
`condenser lens 72 reflects a majority of the thermal
`energy, such as infrared radiation, back into the hot
`compartment 50. The illumination beam, passes into
`cold compartment 60 by way of the illumination optics
`chamber 80 and intersects the first surface mirror 82
`such that the visible light is directed along the light path
`towards the fresnel lens 84. The illumination beam then
`orthogonally passes through the fresnel lens 84 and is
`focused for passage along the light path into the imag-
`ing optics chamber 90.
`The illumination beam passes through the passage-
`way 130 and orthogonally intersects the display panel
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`XLNX-1010
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`5,313,234
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`5
`100 in the imaging optics chamber 90. As the illumina-
`tion beam passes through the display panel 100, the
`image on the display panel is transferred into the beam
`to form an image beam. The image beam travels along
`the light path and is reflected by the first surface mirror
`110 to the projection lens 120.
`The projection lens 120, as well known in the art,
`focuses the image beam for projection upon a screen not
`shown.
`.
`The cooling of the hot and cold compartments 50, 60
`is accomplished by circulating a cooling fluid, such as
`ambient air, through the individual compartments of the
`housing 20.
`The fan 140 draws in ambient air through the inlet
`vents 23 and 27, and discharges the air over the hot
`illumination source 62, which is the hottest temperature
`in the system. The air then exhausts through the exhaust
`port 25. The energy from the illumination source 62 is
`substantially retained within the hot compartment 50
`and transferred to the cooling air flow. By providing
`the hottest element of the projector, the illumination
`source 62, as the last element in the cooling fluid flow
`path,
`the cooling fluid will
`remove the maximum
`amount of heat energy from the projector.
`Specifically, ambient air is drawn into the illumina-
`tion optics chamber 80 through vents 23. The ambient
`air exits the illumination optics chamber 80 through
`outlet vents 23a, and passes into the passageway 130.
`The air in the passageway 130 is in direct
`thermal
`contact with a first side of the display panel 100. After
`contacting the first side of the display panel 100, the air
`enters the fan 140, to be discharged across the illumina-
`tion source 62 in the hot compartment 50.
`Additional fluid flow is drawn in through vents 27 in
`the imaging optics chamber 90. Fluid flow passes
`through the vents 27 and directly thermally contacts a
`second side of the display panel 100. The fluid flow
`passes through the ports 27a in the mounting plate 101,
`and is drawn into the fan 140. The fan then discharges
`the fluid flow from the first and second side of the dis—
`play panel 100 into the hot compartment 50. The fluid
`flow passesover the illumination source 62 and is dis-
`charged through port 25.
`The fluid flow path thereby provides a cooling fluid
`flow across each surface of the display panel 100, while
`providing the total cooling fluid flow rate to pass over
`the illumination source 62. The projector 10 thereby
`defines a cooling fluid flow path which includes the
`passageway 130 and the imaging optics chamber 90. As
`the display panel 100 is in thermal contact with the
`passageway 100 and the imaging optics chamber 90, the
`cooling fluid passing through the flow path removes
`heat from both sides of the display panel.
`The isolation of the hot compartment 50 and the cold
`compartment 60 by the insulating walls 22, 24 substan-
`tially retains the majority of the thermal energy pro-
`duced by the illumination source 62 within the hot com-
`partment.
`the high temperature air ex-
`that
`It
`is important
`hausted from the hot compartment 50 is not drawn into
`the housing through inlet vents 23, 27 or passageway
`130. Therefore, the inlet ports 23, 27 are distal to the
`exhaust port 25 of the hot compartment 50.
`While a preferred embodiment of the invention has
`been shown and described with particularity, it will be
`appreciated that various changes and modifications may
`suggest themselves to one having ordinary skill in the
`art upon being apprised of the present invention. It is
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`intended to encompass all such changes and modifica-
`tions as fall within the scope and spirit of the appended
`claims.
`What is claimed is:
`
`l. A liquid crystal display projector comprising:
`(a) a housing having a hot compartment including a
`fluid inlet and a fluid outlet spaced apart from the
`fluid inlet and a cold compartment including a fluid
`inlet and a fluid outlet wherein the cold compart-
`ment is at least partially thermally isolated from the
`hot compartment, and the fluid outlet of the cold
`compartment is in communication with the fluid
`inlet of the hot compartment;
`(b) an illumination source within the hot compart-
`ment between the fluid inlet and the fluid outlet so
`that fluid flow through the hot compartment from
`the fluid inlet to the fluid outlet cools the illumina-
`
`tion source, the source producing an illumination
`beam, and means in the illumination beam for re-
`moving heat from the beam before it passes from
`the hot compartment to the cold compartment;
`(c) a fluid flow path extending from the inlet in the
`cold compartment through the cold compartment
`then through the inlet in the hot compartment past
`the illumination source to the outlet in the hot
`compartment;
`((1) a liquid crystal display panel in the cold compart-
`ment the display panel having a first and a second
`side, at least one of the sides in the thermal contact
`with the flow path;
`(e) means for conducting a cooling fluid through the
`flow path from the inlet in the cold compartment to
`the outlet in the hot compartment; and
`(0 means for directing the illumination beam from the
`illumination source to the display panel to produce
`an image beam.
`2. The liquid crystal display projector of claim 1,
`further comprising focusing means for focusing the
`image beam upon a screen.
`3. A projector for a display panel, comprising:
`(a) a housing having thermally isolated first and sec-
`ond compartments;
`(b) cooling means for causing a cooling fluid to flow
`along a flow path sequentially from an inlet,
`through the second compartment,
`into the first
`compartment through the first compartment and
`exhausting the fluid from an outlet in the first com-
`partment;
`(c) an illumination source in the first compartment in
`the fluid flow path for producing an illumination
`beam and thermal energy and transferring the ther-
`mal energy to the cooling fluid;
`(d) heat retention means in a thermally conductive
`path between the first and second compartments
`for retaining a portion of the thermal energy pro-
`duced by the illumination source within the first
`compartment;
`(8) a display panel in the second compartment; and
`(t) reflection means for passing the illumination beam
`from the illumination source through the display
`panel.
`4. A projector for projecting an image on a liquid
`crystal display panel onto a screen, comprising:
`(a) a housing having substantially thermally isolated
`first and second compartments wherein a light path
`extends from the first compartment through the
`second compartment;
`(b) a cooling passageway in the second compartment;
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`XLNX-1010
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`(c) a light source in the first compartment for project-
`ing visible light along the light path;
`(d) an infrared reflector condenser lens in the first
`compartment disposed in the light path for reflect-
`ing a portion of the radiation produced by the light
`source while permitting the passage of visible light;
`(e) a first surface mirror in the second compartment
`for directing visible light in the light path towards
`the passageway;
`(f) a fresnel lens disposed in the light path for focusing
`the illumination beam;
`(g) a liquid crystal display panel in the second com-
`partment disposed in the light path such that a first
`surface of the display panel thermally contacts a 15
`portion of the cooling passageway and a portion of
`the illumination beam passes through the liquid
`crystal display to form an image beam;
`(h) a second first surface mirror in the second com- 20
`partment for reflecting the image beam; and
`(i) focusing means in the second compartment for
`focusing the image beam upon an imaging surface.
`5. The projector of claim 4, further comprising means
`for removing heat from the first compartment.
`6. A projector for projecting an image from a display
`panel onto a screen, comprising:
`(a) a housing including a cold compartment having a
`fluid inlet and a hot compartment having a fluid
`outlet, wherein the hot compartment is at
`least
`partially thermally isolated from the cold compart-
`ment;
`(b) a display panel substantially within the cold com-
`partment, the display panel having a first side and a 35
`second side;
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`(c) illumination means in the hot compartment for
`producing an illumination beam;
`(d) optics means for directing the illumination beam
`from the illumination means through the display
`panel to form an image beam;
`(e) focusing mean for projecting the image beam
`upon the screen; and
`(f) a fluid communication pathway extending be-
`tween the inlet and the outlet for providing contin-
`uous fluid flow from the inlet into the cold com-
`partment in direct thermal contact with at least one
`of the first and the second sides of the display panel
`then passing through the hot compartment in ther-
`mal contact with the illumination means and then
`exiting the housing through the fluid outlet.
`7. A method for projecting an image beam from a
`liquid crystal display panel upon a screen, comprising:
`(a) producing an illumination beam in a first compart-
`ment of a housing the first compartment having a
`cooling fluid outlet;
`(b) single passing the illumination beam through a
`liquid crystal display panel in a second compart-
`ment to form the image beam the second compart-
`ment having a cooling fluid inlet;
`(c) thermally isolating the first compartment from the
`second compartment; and
`(d) removing heat from the illumination beam as it
`passes from the first compartment to the second
`compartment;
`(e) passing a flow of cooling air sequentially from the
`inlet
`in the second compartment, by the liquid
`crystal display panel, then into the first compart-
`ment and then through the first compartment to an
`outlet in the first compartment; and
`(t) focusing the image beam upon the screen.
`*
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`XLNX-1010
`Page 8 of 8
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