(12) United States Patent
`Burke et al.
`
`USOO6825828B2
`(10) Patent No.:
`US 6,825,828 B2
`(45) Date of Patent:
`Nov.30, 2004
`
`(54) BACKLIT LCD MONITOR
`(75) Inventors: Thomas J. Burke, Ellington, CT (US);
`Gary Elco, Ellington, CT (US); Bryan
`Gudrian, South Windsor, CT (US)
`
`(73) ASSignee: General Digital Corporation, South
`Windsor, CT (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 139 days.
`
`(58) Field of Search ............................ 34.5/102, 87, 77,
`34.5/589-605,101
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`5,844,540 A 12/1998 Terasaki ..................... 34.5/102
`5,854,617. A 12/1998 Lee et al. ................... 34.5/102
`6,188,378 B1
`2/2001 Yamamoto et al. ......... 34.5/101
`6.255,784 B1
`7/2001 Weindorf .................... 315/291
`Primary Examiner Dennis-Doon Chow
`ASSistant Examiner Aaron S. Ward
`(74) Attorney, Agent, or Firm-Cantor Colburn LLP
`
`(22) Filed:
`(65)
`
`Feb. 21, 2002
`Prior Publication Data
`US 2002/0167637 A1 Nov. 14, 2002
`Related U.S. Application Data
`(60) Provisional a fication No. 60/270.848, filed on Feb. 23
`2001.
`pp
`2Y- Y-2
`• 4-2
`(51) Int. Cl." .................................................. G09G 3/36
`(52) U.S. Cl. ........................................ 345/101; 34.5/102
`
`An exemplary embodiment of the invention is a backlit
`liquid crystal display (LCD) monitor comprising a backlight
`assembly, a cooling assembly, a rear cover assembly and a
`controller. The controller monitors temperature and controls
`cooling accordingly. The controller also monitors bulb lumi
`nance and adjusts bulb current accordingly. Faults are moni
`tored and logged So that predictive repair before failure
`analysis may be performed.
`
`13 Claims, 16 Drawing Sheets
`
`O O O OOO O O OO O
`Z 101
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`SEC et al. v. MRI
`SEC Exhibit 1013.001
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`NOW. 30, 2004
`
`Sheet 1 of 16
`
`
`
`SEC et al. v. MRI
`SEC Exhibit 1013.002
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 2 of 16
`
`US 6,825,828 B2
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`2O2
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`
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`
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.003
`IPR 2023-00199
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`

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`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 3 of 16
`
`US 6,825,828 B2
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`
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`SEC et al. v. MRI
`SEC Exhibit 1013.004
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 4 of 16
`
`US 6,825,828 B2
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`
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`SEC et al. v. MRI
`SEC Exhibit 1013.005
`IPR 2023-00199
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`

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`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 5 of 16
`
`US 6,825,828 B2
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`
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`SEC et al. v. MRI
`SEC Exhibit 1013.006
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 6 of 16
`
`US 6,825,828 B2
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.007
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 7 of 16
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`US 6,825,828 B2
`
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`SEC et al. v. MRI
`SEC Exhibit 1013.008
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`Sheet 8 of 16
`US 6,825,828 B2
`Top Level system Process Flow Chart
`Power. On Systern
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`SEC et al. v. MRI
`SEC Exhibit 1013.009
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 9 of 16
`
`US 6,825,828 B2
`
`Entry.
`Brightness Correl
`
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.010
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 10 of 16
`
`US 6,825,828 B2
`
`
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`Recognitior
`
`SEC et al. v. MRI
`SEC Exhibit 1013.011
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 11 of 16
`
`US 6,825,828 B2
`
`Entry
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`Break Point
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`Bulb Decay Recognition
`Fe, 2
`
`SEC et al. v. MRI
`SEC Exhibit 1013.012
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 12 of 16
`
`US 6,825,828 B2
`
`
`
`Entry
`Bulb Decay Compensation
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.013
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 13 of 16
`
`US 6,825,828 B2
`
`This process is asisdtwice per program loop
`for as for inverter, Dinas for inverter 2)
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`inverter Monitoring FoW Chart
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.014
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 14 of 16
`
`US 6,825,828 B2
`
`This gradass tasis for bath tacklight
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`
`SEC et al. v. MRI
`SEC Exhibit 1013.015
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 15 of 16
`
`US 6,825,828 B2
`
`
`
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`SEC et al. v. MRI
`SEC Exhibit 1013.016
`IPR 2023-00199
`
`

`

`U.S. Patent
`
`Nov.30, 2004
`
`Sheet 16 of 16
`
`US 6,825,828 B2
`
`
`
`40B
`
`DATARASE
`
`FIG.
`
`SEC et al. v. MRI
`SEC Exhibit 1013.017
`IPR 2023-00199
`
`

`

`1
`BACKLIT LCD MONITOR
`
`US 6,825,828 B2
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`This application claims the benefit of U.S. provisional
`patent application Ser. No. 60/270.848, filed Feb. 23, 2001,
`the entire contents of which are incorporated herein by
`reference.
`
`1O
`
`15
`
`25
`
`35
`
`40
`
`BACKGROUND OF THE INVENTION
`The invention relates to backlit liquid crystal display
`(LCD) monitors. Backlit LCD monitors are often used in
`applications where ambient conditions Such as Sunlight can
`negatively affect the ability to View the display. Such appli
`cations include air traffic control displayS Viewed by air
`traffic controllerS Sitting at computer Screens located in an
`airport control tower. Backlit LCD monitors are also useful
`in maritime applications (barges, aircraft carriers and tugs),
`making it possible to execute and interpret output from
`Shipboard instrumentation Such as navigation, targeting, IFF
`and weapons control from a monitor mounted on the vessel,
`even if the monitor is Subject to extreme lighting conditions
`Such as bright Sunlight or total darkness. Further applica
`tions can include automatic teller machines (ATMs), kiosks
`and any other applications where the ability to view the
`computer Screen could be adversely affected by ambient
`conditions. Backlit LCD monitors can provide increased
`brightness in order to compensate for adverse conditions
`Such as bright Sunlight and total darkness and high glare.
`SUMMARY OF THE INVENTION
`An exemplary embodiment of the invention is a backlit
`liquid crystal display (LCD) monitor comprising a backlight
`assembly, a cooling assembly, a rear cover assembly and a
`controller. The backlight assembly has opposing top and
`bottom Surfaces and the bottom Surface includes a plurality
`of fluorescent bulbs with parallel bulb axes and two or more
`inverters to drive the bulbs. The cooling assembly has
`opposing top and bottom Surfaces and the top Surface of the
`cooling assembly is mounted on the bottom Surface of the
`backlight assembly to form a closed air space around the
`bulbs. The cooling assembly includes: a light Sensor on the
`top Surface of the cooling assembly and the light Sensor has
`an axis that is perpendicular to the bulb axes of the fluo
`rescent bulbs, a temperature Sensor, a heat Sink on the
`bottom Surface of the cooling assembly, and an air inlet and
`an air outlet in fluid communication with the closed airspace
`and positioned for causing air to flow acroSS the bulbs. The
`rear cover assembly is placed over the bottom Surface of the
`cooling assembly and includes: an exhaust fan in fluid
`communication with the air outlet, a cover inlet in fluid
`communication with the air inlet, a filter placed over the
`cover inlet and a fan positioned to draw air towards the heat
`Sink. The controller is electrically connected to the Sensor,
`inverters and fans.
`Another embodiment of the invention is a method of
`controlling a backlit liquid crystal display monitor. The
`method comprises receiving target data including target heat
`Sink temperature, target backlight chamber temperature and
`target bulb luminance. The method also compriseS receiving
`actual data including actual heat Sink temperature, actual
`backlight chamber temperature, actual bulb luminance, heat
`Sink fan Status and current, exhaust fan Status and current,
`and inverter status and current. The method further com
`65
`prises adjusting the monitor Settings in response to the target
`data and the actual data. The adjusting includes Setting input
`
`45
`
`50
`
`55
`
`60
`
`2
`current to the inverter, Setting the heat Sink fan Speed, and
`Setting the exhaust fan Speed. The method further comprises
`Sending a notification in response to the target data, the
`actual data and Said adjusting.
`The above described and other features are exemplified by
`the following figures and detailed description.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`Referring now to the figures, which are exemplary
`embodiments, and wherein the like elements are numbered
`alike:
`FIG. 1 is a perspective view of the backlight assembly
`portion of a backlit LCD monitor;
`FIG. 2 depicts interlaced bulbs and inverters in an
`embodiment of the invention;
`FIG. 3 is an exploded, perspective view of the cooling
`assembly and LCD screen;
`FIG. 4A is an exploded, perspective view of the rear cover
`assembly of the backlit LCD monitor;
`FIG. 4B is cross-sectional view of backlight assembly,
`cooling assembly and rear cover assembly;
`FIG. 5 is a block diagram of an exemplary backlit LCD
`monitor control System;
`FIG. 6 is a block diagram of the data flow in an exemplary
`backlit LCD monitor control system;
`FIG. 7A is a flowchart of a process performed by an
`exemplary backlit LCD monitor control system;
`FIG. 7B is a flowchart of an exemplary brightness control
`proceSS,
`FIG. 7C is a flowchart of an exemplary brightness sensor
`failure recognition process,
`FIG. 7D is a flowchart of an exemplary bulb decay
`recognition process,
`FIG. 7E is a flowchart of an exemplary bulb decay
`compensation process;
`FIG. 7F is a flowchart of an exemplary inverter monitor
`ing process,
`FIG. 7G is a flowchart of an exemplary thermal control
`proceSS,
`FIG. 8 is a flowchart of a bulb control process performed
`by a backlit LCD monitor controller; and
`FIG. 9 is a system diagram of an exemplary embodiment
`of the invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`An exemplary embodiment of the invention is a backlit
`liquid crystal display (LCD) monitor having an enhanced
`cooling System that can allow the monitor to operate at
`higher ambient temperatures and can promote bulb life.
`Another embodiment of the invention includes a backlight
`controller that controls operation of the backlit LCD
`monitor, monitorS faults and performs replace before fail
`analysis. FIG. 1 is a perspective View of an exemplary
`embodiment of the backlight assembly 100 of a backlit LCD
`monitor. Shown in FIG. 1 is a backlight assembly 100 that
`includes a series of fluorescent bulbs 102 having parallel
`longitudinal axes. The bulbs 102 provide the backlight
`Source used in the backlit LCD monitor. In as exemplary
`embodiment of the present invention, the bulbs 102 are
`driven by two inverters to generate a backlight luminance of
`1000 nits and the backlights have a maximum capability of
`providing over 1400 nits of luminance. In an exemplary
`
`SEC et al. v. MRI
`SEC Exhibit 1013.018
`IPR 2023-00199
`
`

`

`3
`embodiment, 31 cold cathode flourescent tubes (CCFT) are
`aligned horizontally in parallel, running from the left to the
`right of the LCD. The CCFTs are housed in a rugged
`aluminum enclosure that is lined with a highly reflective,
`flame retardant material that is designed to harneSS all of the
`light that is generated by the CCFTs and focus it towards the
`LCD.
`FIG. 2 illustrates an exemplary embodiment of how the
`bulbs 102 are driven electrically. The backlit LCD monitor
`includes two inverters 202/204 for driving the bulbs 102. In
`a preferred embodiment, thirty-one bulbs 102 are used and
`the bulbs are interlaced between the two inverters 202/204.
`Every other bulb 102 is connected to the same inverter
`202/204 so that, in the example shown in FIG. 2, odd
`numbered bulbs 102 are coupled to inverter 202 and even
`numbered bulbs 102 are coupled to inverter 204. If one
`inverter 202/204 fails, sufficient backlight is generated
`across the entire display area by the bulbs 102 coupled to the
`working inverter 202/204.
`FIG. 3 is an exploded, perspective view of the cooling
`assembly 300 coupled to the backlight assembly 100 and an
`LCD screen 10. Shown in FIG. 3 is a cooling assembly 300
`which is mounted on the backside of the backlight assembly
`100 and comprises a combination of passive and active
`cooling techniques. Light from the backlight assembly 100
`is emitted to an LCD Screen 10 opposite the cooling assem
`bly 300. The cooling assembly 300 includes a heat sink302,
`which in an exemplary embodiment comprises a finned
`aluminum plate, for conducting heat away from bulbs 102.
`The heat sink 302 lies on the side of the cooling assembly
`300 that faces away from the backlight assembly 100. In an
`exemplary embodiment, the heat Sink is constructed from a
`milled block of aluminum or aluminum extrusion to opti
`mize the thermal coefficient. Heat that is generated by the
`backlightS is dissipated through the heat Sink fins that
`provide optimized Surface area.
`In an exemplary embodiment, the cooling assembly 300
`also includes an air inlet 304 and two air outlets 306. Bulbs
`102 are positioned in a closed air Space, also referred to as
`the backlight chamber, provided between backlight assem
`bly 100 and cooling assembly 300. A gasket could be used
`to connect the backlight assembly 100 and the cooling
`assembly 300 in order to create the closed air space. The air
`inlet 304 and air outlets 306 are in fluid communication with
`this internal closed air space. Also shown in FIG. 3 is a
`light/temperature sensor assembly 308 which includes a
`number of light Sensors to monitor the light output acroSS
`bulbs 102 and a temperature Sensor to measure the tempera
`ture of the backlight chamber. The light Sensor axes are
`positioned perpendicular to the axes of the bulbs 102.
`Signals from the light Sensors are provided to a controller for
`monitoring as described in further detail herein. Also shown
`in FIG. 3 is a temperature sensor 310 on the back of the
`cooling assembly 300 that faces away from the backlight
`assembly 100. This temperature sensor measures the tem
`perature of the air near the heat sink 302 in the electronics
`chamber.
`FIG. 4A is an exploded, perspective view of an exemplary
`embodiment of the rear cover portion of the backlit LCD
`monitor. Shown in FIG. 4A is a rear cover assembly 400
`which is placed over the cooling assembly 300. The rear
`cover assembly 400 includes exhaust fans 402 in fluid
`communication with the air outlets 306. Exhaust fans 402
`direct air away from the rear cover assembly 400 as indi
`cated by the arrows in FIG. 4A. A filter (e.g. a HEPA filter)
`404 is placed over a cover inlet 406. In another embodiment,
`Some other dust reducing device Such as a gas purging
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`US 6,825,828 B2
`
`4
`System or another form of dust free air Supply may be used
`in place of the filter. The cover inlet 406 is in fluid com
`munication with the air inlet 304 on the cooling assembly
`300. During operation, the exhaust fans 402 draw air
`through the filter 404, through the air inlet 304, over the
`bulbs 102 and out through the air outlets 306. This reduces
`the interior temperature of the backlit LCD monitor and
`allows the bulbs 102 to operate at a higher current and/or in
`higher ambient temperature conditions. Another fan 408 in
`the rear cover assembly 400 directs air into the space
`between the rear cover assembly 400 and the cooling
`assembly 300, hereafter referred to as the “electronics
`chamber”, as indicated by the arrow in FIG. 4A. This air is
`directed through an opening in the rear cover assembly 400
`and onto the heat sink 302. This further reduces the interior
`temperature of the electronics chamber of the backlit LCD
`monitor.
`FIG. 4B is a cross-sectional view depicting the backlight
`assembly 100, the cooling assembly 300 and the rear cover
`assembly 400. The front of the backlight assembly 100 may
`include a diffuser 101 so that light emitted to the LCD screen
`10 is uniform. As noted above, a gasket 90 may be used to
`form an airtight chamber encompassing bulbs 102 between
`the backlight assembly 100 and the cooling assembly 300.
`Fan 402 draws air over bulbs 102 through filter 404. In
`addition, fan 408 directs air at the heat sink 302. AS
`described in further detail herein, the fans are controlled by
`a controller in response to Sensed temperature.
`FIG. 5 is a high level block diagram of an exemplary
`backlit LCD monitor control system. In an exemplary
`embodiment, the System includes a microprocessor based
`controller 500 or application specific integrated circuit
`(ASIC) that is designed to optimize the performance of an
`LCD monitor by monitoring, controlling and recording the
`performance of each of the monitor Subsystems. One func
`tion of the controller 500 is to control the brightness of the
`bulbs 102 through the inverters 202/204. Light sensors 506,
`part of the sensor assembly 308 mounted on the side of the
`cooling assembly 300 facing the backlight assembly 100,
`monitor the brightness of the bulbs 102 and provide bright
`ness signals to the controller 500. Multiple light sensors 506
`may be used, and the Signals may be averaged to provide an
`average brightness. Based on the Sensed brightness, the
`controller 500 can increase or decrease the current to the
`inverters 202/204 in order to increase or decrease the output
`of the bulbs 102.
`In an exemplary embodiment, the bulbs 102 are driven to
`produce 1000 nits of luminance but have a capability of
`generating 1400 nits of luminance. As the bulbs 102 age, it
`takes more current to generate the 1000 nits of luminance.
`Once the maximum current is applied to the bulbs 102 and
`the luminance drops below some threshold (e.g., 950 nits),
`warnings to the user may be generated through the light
`emitting diode (LED) 504. Such warnings may be repeated
`at regular intervals (e.g., a warning at every 50 nits
`decrease). Fault data associated with the drop in luminance
`may be stored in memory associated with the controller
`(e.g., RAM, NVRAM). In addition, fault data may be
`communicated to a local or remote operator by Sending data
`through a network or other data communications connection
`that can be provided by the I/O device 510. Event data, fault
`data and alert messages may be sent and instructions may be
`received by the controller 500 through the I/O device 510.
`In a preferred embodiment, operators are permitted to
`vary the brightness of the LCD monitor via a locally
`mounted potentiometer or though an external remote bright
`ness control box 508 and/or via I/O device 510 as depicted
`
`SEC et al. v. MRI
`SEC Exhibit 1013.019
`IPR 2023-00199
`
`

`

`US 6,825,828 B2
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`in FIG. 5. The brightness control device may in communi
`cation with the controller in an electrical fashion and it may
`in communication via a wireleSS connection Such as infra
`red. The controller 500 monitors a remote brightness control
`interface to determine if a remote brightness control box 508
`is present. If the remote brightness control box 508 is
`detected, dimming control (priority) is passed to the remote
`brightness control box 508 thereby disabling the local poten
`tiometer controls. The local potentiometer is the System's
`default dimming control. In an exemplary embodiment, the
`remote brightness control box 508 comprises a multi
`position Switch and a potentiometer. The Switch allows the
`Selection of a Series of pre-defined brightness ranges as well
`as manual Override. Examples of Some ranges, where the
`nits are measured at the Surface of the LCD, include:
`nighttime mode (e.g. 0.5 to 200 nits); normal mode (e.g. 201
`to 700 nits); Sunlight mode (e.g. 701 to 1000 nits); and
`manual mode (e.g. full dimming control). The potentiometer
`in the remote brightness control box 508 varies brightness
`within the Selected range.
`The remote brightness control box 508 is used as part of
`a closed loop control method including the brightness Sen
`sors 506, the controller 500 and the remote brightness
`control box 508. The remote brightness control box 508
`provides a signal (e.g., voltage) to the controller 500. The
`controller then converts this signal to a brightness level
`using known techniques (e.g., mathematical equation, look
`up table, etc.). The controller 500 then monitors the bulb
`brightness through brightness sensors 506 and adjusts bulb
`current to maintain the brightness at the user-defined level.
`By using a look-up table to define brightness Settings, the
`controller 500 can be updated to accommodate age of the
`display or application of the display. For example, if the
`display is moved from bridge of ship to the engine room, the
`tables defining brightness levels in controller 500 may be
`updated (e.g., through I/O device 510) to set new brightness
`levels for this environment.
`The controller 500 continuously monitors the inverters
`202/204 for over-current, under-current and open circuit
`conditions. AS described above, in reference to FIG. 2, an
`exemplary embodiment includes two inverters 202/204 and
`each inverter 202/204 drives one half of the backlight bulbs
`102, in an interleaved or alternating pattern. In the event that
`a single inverter 202/204 experiences a critical failure, only
`that portion of the bulbs 102 will be disabled, rendering the
`display at partial brightness, but completely operational.
`This is regarded as a Soft failure. Since the remaining bulbs
`102 will remain unaffected by a singular failure, the LCD
`display will maintain a uniform brightness acroSS its entire
`Surface. If an over-current, undercurrent or open circuit
`condition is detected, the controller 500 records these faults
`into non-volatile memory and Visually alerts operators via
`the status LED 504. In the event of an over-current or
`under-current condition, the controller 500 will automati
`cally shut down the affected inverter 202/204. In an exem
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`plary embodiment with two inverters 202/204, the target
`brightness is cut in half if an inverter 202/204 is shut down.
`The controller 500 can also send an alert message to a
`remote or local operator using a network connection pro
`vided by the I/O device 510. In addition, the controller 500
`can receive instructions from an operator through the I/O
`device 510.
`The output (or brightness) of the bulbs 102 can be affected
`by temperature and bulb decay. In an exemplary
`embodiment, the controller 500 can limit the maximum
`operator-controlled brightness to a programmed value well
`below the maximum bulb brightness. This can aid in extend
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`ing the life of the bulbs 102 and can allow the controller 500
`to maintain the programmed maximum brightness for
`extended periods of time. The light sensors 506 are con
`tinuously monitored for proper function, and in the event of
`a single or multi-modal failure(s), the failure is recorded to
`non-volatile memory and future readings from the failed
`sensor 506 are disregarded until the sensor 506 is repaired.
`Bulb condition may be determined based on present bulb
`current and/or present bulb temperature. Also, cumulative
`bulb current may be monitored to determine bulb condition
`and whether a failure is imminent. For example, if the
`cumulative bulb current for a bulb has exceeded a threshold,
`this indicates that a bulb failure is imminent.
`Failure data and operator alerts can be sent to a remote or
`local operator through a network connection provided by the
`I/O device 510. When the bulbs 102 are no longer able to
`Sustain the maximum brightness established by the control
`ler 500, the controller 500 records the maximum brightness
`into non-volatile memory. This maximum brightness data
`recorded can be recorded at programmable intervals. This
`information can assist in determining the need to replace the
`backlight bulbs 102 before a critical failure has been expe
`rienced.
`As shown in the exemplary embodiment depicted in FIG.
`5, the controller 500 also monitors the temperature in the
`backlit LCD monitor through temperature sensors 502.
`Multiple temperature sensors 502 may be used in the backlit
`LCD monitor. For example, one temperature sensor 502 may
`monitor the temperature in the electronicS chamber and
`another temperature sensor 502 may monitor ambient tem
`perature in the closed air space, or backlight chamber,
`between the backlight assembly 100 and the cooling assem
`bly 300. Exceeded temperature limits can be detected and
`warnings issued to the user through the LED 504. A fault
`may be stored in memory associated with the controller
`(e.g., RAM, NVRAM) or may be connected to a real-time
`monitoring or data gathering System or computer.
`The controller 500 activates the fans 402/408 when the
`reported temperature from the temperature sensors 502
`exceeds a minimum temperature (e.g., 20 C.) programmed
`into the controller 500. This allows the bulbs to attain
`optimum minimum bulb wall temperature (MBWT). Once
`activated by the controller 500, the fan speed is determined
`by the internal temperature Sensed by the temperature Sen
`SorS 502. A programmable maximum operating temperature
`can be set in the controller 500. In an exemplary
`embodiment, if either of the temperature readings is within
`five degrees of the maximum operating temperature, the
`event is recorded and date/time Stamped into non-volatile
`memory and a visual indicator is provided on the LED 504.
`If the temperature achieves, or exceeds, the maximum
`recommended operating temperature, an event is recorded
`and date/time Stamped, and a different visual indicator is
`provided on the LED 504. The duration of the over
`temperature condition can be recorded for warranty and
`troubleshooting purposes. An identical process can be per
`formed for an under-temperature condition where the mini
`mum operating temperature is programmable and can be Set
`by an operator. This allows the bulb temperature to remain
`in a preferred temperature range often referred to as a “Sweet
`spot.” It is known that certain bulbs operate more efficiently
`at an optimum MBWT. The control techniques used in the
`invention allow the bulb temperature to remain in this range.
`If the over-temperature condition persists, the controller
`500 executes a soft failure that begins by reducing the
`inverter output in steps (e.g. by 50%, then by another 50%)
`and it may result in one of the inverters 202/204 being shut
`
`SEC et al. v. MRI
`SEC Exhibit 1013.020
`IPR 2023-00199
`
`

`

`7
`off completely if reducing inverter output does not cure the
`over-temperature condition. When the temperature returns
`to a safe operating range, the controller 500 will return the
`inverters 202/204 to normal operation. If the temperature
`does not return to a Safe operating range then the monitor
`will be shut-down completely while still allowing log data to
`be downloaded through the I/O device 510. In addition, the
`controller 500 records the maximum and minimum tempera
`ture extremes, experienced while under power on the non
`Volatile memory or monitoring computer. Alert messages
`can be sent from the controller 500 and instructions can be
`received by the controller 500 through a network connection
`implemented by the I/O device 510.
`As depicted in FIG. 5, the fans 402/408 are monitored by
`the controller 500. Fan failure can be detected by the
`controller 500 and a warning issued to the user through the
`LED 504. An anomaly in the current waveform of a fan
`402/408 may indicate a fan failure or fault and the fault may
`be Stored in the memory associated with the controller.
`In an exemplary embodiment, a personal computer is used
`to execute Software that predicts failures and determines the
`need for preventive maintenance using fault and event data
`that has been logged in the memory associated with the
`controller 500. In addition, a personal computer can be used
`to control the backlit LCD monitor through a diagnostic
`mode in which backlit LCD monitor parameters (e.g., bulb
`brightness, temperature) can be monitored and controlled
`from a personal computer.
`The I/O device 510 allows the controller 500 to send data
`to an external device, Such as a personal computer, for
`analysis and to receive commands from the external device.
`In addition to receiving commands from an external device,
`Software upgrades to the controller can also be received
`from an external device. An embodiment of the present
`invention provides a Secure, password protected method of
`performing Software upgrades. In an exemplary
`embodiment, the external device is a personal computer that
`can use the I/O device or communication controller 510 to
`access fault and event data in the log Stored in the memory
`associated with the controller 500. A video controller 512 is
`also connected to the controller 500. In addition to a
`personal computer, any external device known in the art that
`can execute computer Software can be used with the present
`invention. The personal computer can execute Software to
`perform predictive fault analysis using the log data and
`historical statistical data to determine if failure of the backlit
`LCD monitor is imminent and recommend appropriate Ser
`Vice. For example, bulb current and brightness can be
`recorded at pre-Selected intervals. This data, or an aggregate
`of this data for Several monitors, can be used to predict
`failures and replacement timeframes. Also, the personal
`computer can issue commands to the controller 500 through
`I/O device 510 to perform a variety of actions such as a
`command to modify brightness. The I/O device 510 may be
`a serial port (e.g., RS232 port), an infrared data association
`(IrDA) port, a communications controller or any other
`communications interface known in the art. In an exemplary
`embodiment, the I/O device 510 allows the controller to
`Send and receive data over a communications network.
`In an exemplary