US006862188B2
(12) United States Patent
(10) Patent N0.:
Calh00n
(45) Date of Patent:
(54) COMPUTER WITH COVER REMOVAL
DETECTION
(Us)
retrieved from http://WWWeZekOn.com/show pr0ducts.asp
(73) Assignee? Microsoft Corporation, Redmond, WA
(Us)
_
Mar. 1, 2005
Elekon Industries, “Re?ector Sensor”, ERT—3270 (1 page)
retrieved from http://WWWeZekOn.com/show pr0ducts.asp
?cat=Re?ective+Sens0rs on Apr. 9, 2004.
Elekon Industries, “Re?ector Sensor”, ERT 3280 (2 pages)
(75) IIlVeIliOrI JOhIl C- CalhOOIl, WOOdiIlVille, WA
?cat=Re?ective+Sens0rs on Apr. 9, 2004.
Intel®SR2100 2U Rack Server Chassis, For Highly Reliable
e—Business Solutions, Copyright 2001, retrieved from http://
_
( * ) Nonce:
US 6,862,188 B2
_
_
_
SubJeCt_tO any dlsclalmeri the term of thls
WWW. adst0refr/d0Wnl0ad/SR21 00.pa'f.
MicroATX Electrical Design Suggestions, Version 1.0, pp.
Patent 15 extended or adlusted under 35
1—24, Copyright 1998, http://WWWf0rmfact0rs.org/devel
U.S.C. 154(b) by 33 days.
oper
5specsCATXELE1 1.pdf.
(21) Appl- NO-I 10/355,854
.
_
Super SMM1 System Management Module, User’Guide,
Revision 1.0 Co
(22) Flled'
Jan' 31’ 2003
(65)
Prior Publication Data
ri ht 1997, 14
. retrieved from htt .'//
WWW2.Im—sens0;?s§./nug/~Im78mdfs/fnlim lpdf.
Us 2004/0150958 A1 Aug‘ 5’ 2004
http://WWWriOWOrkS.com/Download/Manual?vurca
(51)
(52)
Int. c1.7 ................................................ .. H05K 5/00
US. Cl. .................. .. 361/752; 340/571; 340/568.1;
Pdf
* Cited by examiner
(58)
Field of Search ............................... .. 361/724, 725,
361/752, 753, 760, 796, 797; 340/554,
340/555; 340/825.71
555, 5681, 571, 82571, 82531
(56)
References Cited
5,229,749 A *
7/1993 Yenghn _________________ __ 340/5688
5,760,690 A
6/1998
French
___________
*
6/1999
Schmidt - - - - - -
_
_
_
Primary Ex“ml'?e’—DaV1d Mam“
Assistant Exammer—Thanh S Phan .
~
(74) Attorney, Agent, or Fzrm—Leyd1g, Volt & Mayer, Ltd.
(57)
ABSTRACT
re?ective optical sensor includes a light emitter and a light
_ _ _ __ 340/571
detector, and is mounted adjacent a re?ective surface on the
361/724
inner side of the cover When the cover is in place such that
- - - -- 340/571
the light emitter is re?ected by the re?ective surface and
5,825,626 A * 10/1998 Hulick et a1.
5,912,621 A
_
man
Acomputer uses an optical re?ective optical sensor to detect
the removal of a cover of the computer housing. The
U'S' PATENT DOCUMENTS
*
P
PURCA User’s Guide, Rio Works, The Reliable Building
Block, Revision 1.0, Jul. 2002, 76 pp., retrieved from
6,191,503 B1 *
2/2001 Kitten et a1
307/112
received by the light detector. When the cover is removed,
6,388,574 B1 *
5/2002 Davis et al. ........... .. 340/5681
the intensity of the re?ected light received by the light
detector drops. The change in the output of the light detector
triggers the operating system of the computer to poWer doWn
the computer.
OTHER PUBLICATIONS
Elekon Industries, “Re?ector Sensor”, ERT—3102 (1 Page)
retrieved from http://WWWeZekOn.com/show pr0ducts.asp
19 Claims, 3 Drawing Sheets
?cat=Re?ective+Sens0rs on Apr. 9, 2004.
Computer System 100
SOFTWARE
HARDWARE
Application
Processor Unit
130
Plogrem
‘I42
Application
Progr'am
142
Input Devices
134
Operating
System
Output Devices
136
140
Power Supply
138
Power
Management
.
-
HardwarelFirmware
Puwemff Prooessirg
Circuit
145
Re?ective Surface
152
u
144
U.S. Patent
Mar. 1,2005
Sheet 1 of3
US 6,862,188 B2
mm?
\
wzlk
vmw
i
KHU1 8i
NNP
QNP
vmw
U.S. Patent
Mar. 1,2005
Sheet 2 of3
US 6,862,188 B2
FIG. 2
Computer System 100
HARDWARE
SOFTWARE
_
Application
130
142
M81212”
Application
Program
Input Devices
142
134
r—_————\
Output Devices
Operating
136
System
IIU
140
Power Supply
138
Re?ect|1v5eoSensor
-
Power
Management
I
Hardware/Firmware
Power-off Processing
Circuit
146
\
Re?ective Surface
1 52
J
'
144
U.S. Patent
Mar. 1,2005
Sheet 3 of3
US 6,862,188 B2
/—~104
150
Power
\
Supply
162/
|138
(
‘----112
160
i
<
&
Operating
VCCL
System (F :
140<
168 N
'\
170"'—\J
L_
/%
/
\ ~_/164
\166
FIG. 3
154
US 6,862,188 B2
1
2
COMPUTER WITH COVER REMOVAL
DETECTION
removed While the computer is in a full-on or sleep state,
removal of the cover causes the intensity of the light
re?ected by the cover to the light sensor to drop. As a result,
the output of the light detector is changed. The change in the
light detector output is used as a signal to trigger the
operating system of the computer to start a shut doWn
process. Because the re?ective optical sensor uses light
FIELD OF THE INVENTION
The present invention relates generally to computer hard
Ware and, more particularly, to a feature incorporated into a
emitting and receiving devices, it has no mechanical parts
computer system to prevent access to components inside the
computer While the computer system is not poWered off.
10
BACKGROUND OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
Adding neW hardWare to or performing maintenance on a
FIG. 1 is a perspective vieW of a computer system
computer often requires accessing hardWare components
inside the housing of the computer. Typically, gaining access
to the inside of the computer housing requires the removal
con?gured for implementing the present invention;
15
of a cover, access panels, or lid of the housing. To protect the
the components in the computer from being damaged, it is
important that the electrical poWer to the components be
DETAILED DESCRIPTION OF THE
INVENTION
turned off When the cover is removed.
In many applications, hoWever, a computer is not com
NoW referring to the draWings, Wherein like reference
25
Interface (ACPI) speci?cation. In the sleep mode, the
higher-level applications and peripheral devices of the com
puter system are not in operation, but the rest of the
computer system remains on. To a user or service technician,
the computer may appear to have been turned off. If the user
102 includes a removable cover or panel 112.
in the computer Without completely poWering off the
The computer 100 also includes various peripheral com
computer, injury or device damage may occur, and the state
data of the computer may be lost.
puter When the computer is still on, mechanical sWitches
have traditionally been used for detecting the removal of the
cover (or access panel or lid) of the computer housing. In
such an application, the mechanical sWitch is pressed doWn
by the cover When the cover is mounted in its normal closed
position. Removing the cover causes the closing (or
opening) of the sWitch contact, Which triggers the computer
operating system to shut doWn the computer.
The mechanical sWitches, hoWever, are not satisfactory.
The mechanical sWitches have to be accurately positioned
and aligned to correctly register removal of the covers and,
just as importantly, to avoid falsely registering removal
numerals refer to like elements, FIG. 1 shoWs an embodi
ment of a computer that implements the present invention.
The computer includes a case or housing 102 that encloses
many of the hardWare components of the computer, such as
the motherboard 104 and the disk drives 106. The case 102
is structured around a chassis 110 to Which the various
enclosed components can be mounted. To gain access to the
enclosed components for maintenance and/or repair, the case
or technician removes the cover and touches the components
To prevent access to the internal components of a com
FIG. 2 is a block diagram illustrating the components of
the computer system of FIG. 1; and
FIG. 3 is schematic diagram of a re?ective optical sensor
and a re?ective panel.
safety of the person Working on the computer and to prevent
pletely poWered doWn even When it is not being used. For
instance, a computer may implement a Sleep mode, such as
the S3 state of the Advanced Con?guration and PoWer
that are susceptible to Wear or damage from repeated use or
corrosion over time.
ponents that are not enclosed Within the case 102. For
35
eXample, the computer system may include output devices
for interacting With users, such as a monitor 118 that can
display a visual image. The computer system 100 may also
40
include various input devices, such as a keyboard 120 and a
mouse 122 that permit the inputting of information and data.
The input and output devices can communicate With the
components enclosed inside the case 102 by, for eXample,
communication cables 124, such as a Universal Serial Bus
(USB), or an infrared or radio frequency transceiver 126 for
Wireless communications.
45
The hardWare and softWare components commonly
included in a computer 100 are illustrated as functional
blocks in FIG. 2. The computer 100 includes a processor unit
130 for executing instructions and a memory 132 for data
When the covers are in fact in place. Moreover, they are
storage, and input devices 134 and output devices 136. The
subject to corrosion. Being mechanical devices, the sWitches
poWer supply 138 converts utility-supplied poWer to a
are also subject to physical Wear over repeated uses and may
voltage usable by components of the computer system. The
computer softWare typically comprises an operating system
be damaged upon incorrect removal of the cover.
140 and one or more application programs 142.
SUMMARY OF THE INVENTION
re?ective optical sensor. As used hereinafter and in the
One of the many functions and subsystems of the oper
ating system 140 is a poWer management module 144 that
functions to conserve the energy required by the computer
system by sWitching betWeen a run mode and a sleep mode.
The poWer management system 144 may sWitch the com
claims, the term “cover” is used broadly to mean a cover,
puter to the sleep mode When, for instance, the computer
In vieW of the foregoing, the present invention provides a
55
mechanism for detecting the removal of a cover from the
case or housing of a computer system that makes use of a
system 100 has not received any input from a user for a
access panel, door, hatch, or lid, etc., that can be opened or
removed from the computer housing to alloW access to the
predetermined amount of time. Additionally, the user may
explicitly selects to sWitch the computer to the sleep mode.
In the sleep mode, the computer shuts doWn some of the
internal components of the computer. The re?ective optical
sensor includes a light source and a light detector. The
re?ective optical sensor is positioned such that When the
cover is in place the light emitted by the light source is
re?ected by a re?ective surface on the inner side of the cover
and received by the light detector. When the cover is
higher-level applications and peripheral devices, hoWever,
65
poWer is still very much supplied to the critical hardWare
components such as the processor unit 130 and the memory
132, and state data may not have been saved.
US 6,862,188 B2
3
4
Referring to FIGS. 1 and 2, because the computer system
100 may appear to be off When it is actually in a sleep mode,
phototransistor 164 is supplied from the poWer supply 138
of the computer system. Normally, When the cover is in
place, the light from the LED 160 is re?ected by the
a user or technician servicing the computer may think the
computer is off and may attempt to remove the cover 112
re?ective surface of the cover onto the phototransistor 164.
The phototransistor 164 is saturated by the light, and its
output signal is a logical “0”. Upon removal of the cover, the
phototransistor 164 ceases to be saturated, and its output
signal changes to a logical “1”. This transition from “0” to
While the components are still operating under poWer. To
prevent harm to the both the person and the computer 100,
one or more re?ective optical sensors 150 are incorporated
into the computer housing to detect removal of the cover 112
from the case 110 While the computer system 100 is still
under poWer. The re?ective optical sensors 150 are inter
faced With the operating system 140 to initiate a poWer
“1” is a signal that the cover has been removed. In response,
10
system. The poWer-doWn may include storing the state data
doWn operation. Interfacing the re?ective optical sensors
With the operating system can be accomplished by any
of the system on the hard drive or another non-volatile
memory.
suitable method knoWn to those of skill in the art. In one
implementation, the signal generated by a sensor 150 upon
Preferably, the poWer-doWn operation is carried out to
15
detection of the cover removal is received as a general
In some cases, the computer may be put into a “soft-off”
performing the poWer-doWn operation, the computer may
also generate an audio or visual alarm signal to indicate to
the person that the computer system is still operating.
Referring to FIG. 1, to ensure that the re?ective optical
sensors 150 and the re?ective surfaces 154 interact properly,
each re?ective surface should preferably be located in close
25
is turned off in response to the trigger signal generated by the
re?ective optical sensor 150 When the cover is removed.
produce the re?ective surface 154. Mylar tape With an
adhesive backing is, for instance, a suitable re?ective mate
35
rial for this purpose.
It should be noted that While the preceding embodiment
has been described With the re?ective optical sensor located
inside the computer case and the re?ective surface located
on the cover, the arrangement of those components can be
readily sWitched. Accordingly, embodiments of such alter
computer.
40
native arrangements are contemplated.
It should be noted that in the foregoing description, the
cover removal detection method has been describe as func
tioning While the computer system is in sleep mode. This is
sensor 150 is positioned such that the light generated by its
light emitter is re?ected by a re?ective surface 154 on the
inner side of the cover and received by its light detector. The
re?ective optical sensor may be mounted, for example, on a
sensor. In an embodiment, the metallic material that often
coats the interior of the cover 112 to control electro
magnetic interference emissions can function as the re?ec
re?ective material can be attached to the cover 112 to
cannot process the trigger signal, the trigger signal is pro
Referring to FIG. 1, to monitor the presence of the cover
112, the re?ective optical sensors 150 are located Within the
case 102 adjacent the cover. Each of the re?ective optical
sensors 150 includes a light emitter and a light detector. The
proXimity to and opposite of the respective re?ective optical
tive surface. In other embodiments, an additional piece of
Since the operating system 140 has been unloaded and thus
cessed by system hardWare and/or ?rmWare. To that end, as
illustrated in FIG. 2, the re?ective optical sensor 150 is also
interfaced to a hardWare/?rmWare poWer-off processing
circuit 146. When the computer system 100 is in the soft-off
state, if the poWer-off processing circuit 146 receives a
trigger signal from the re?ective optical sensor 150, it shuts
off the poWer applied to the hardWare portions of the
completion soon enough after the removal of the cover is
detected so that the user or technician Will not have su?icient
time to access the components in the case. In addition to
purpose event (GPE) by the operating system.
state that corresponds to the S4 state of the ACPI speci?
cation. In that state, the operating system 140 has been
unloaded from the random access memory of the computer,
but some hardWare portions of the computer system may
still have poWer applied to them. Those hardWare portions
With poWer applied may still pose a risk of electrical shock
and device damages if the cover of the computer is removed.
To prevent such a risk, the poWer to the hardWare portions
the system’s poWer management circuitry and softWare
completes an orderly poWer-doWn operation of the computer
45
because it is during sleep mode that the cover Will most
likely be accessed inadvertently. HoWever, it is not neces
sary that the cover removal detection method only functions
during sleep mode. For instance, the detection of the cover
circuit board contained in the case 102. In one
removal When the computer is in the ON state can also cause
implementation, the re?ective optical sensor is mounted on
the computer to poWer doWn.
Thus, there is provided a novel mechanism and method
for optically detecting the removal of a cover from the case
of a computer system. By using a re?ective optical sensor,
the motherboard 104. Alternatively, the re?ective optical
sensor may be mounted on the chassis 110. For those
embodiments in Which the re?ective optical sensor 150 is
mounted to the chassis, the interface With the operating
system can occur via Wires 128 connecting the re?ective
optical sensor to the appropriate locations on the mother
board 104.
In one implementation as illustrated in FIG. 3, the light
source of the re?ective optical sensor 150 is a light-emitting
there are no mechanical parts that are subject to
misalignment, Wear, or corrosion.
55
In vieW of the many possible embodiments to Which the
principles of this invention may be applied, it should be
recogniZed that the embodiments described herein With
respect to the draWing ?gures are meant to be illustrative
only and should not be taken as limiting the scope of the
diode (LED) 160, and the light detector is a phototransistor
164. The LED 160 and the phototransistor 164 are both
mounted on a supporting member 162. The phototransistor
164 is a light sensitive semiconductor device that schemati
cally includes a photovoltaic base 166 that is located
betWeen a collector 168 and an emitter 170. When light
invention. Therefore, the invention as described herein con
templates all such embodiments as may come Within the
strikes the photo-voltaic base 166, the base alloWs electric
a housing having a removable cover, the cover having a
re?ective surface on an inner side of the cover;
current to ?oW betWeen the collector 168 and emitter 170
Which can be interpreted by the operating system 140 as a
signal. The poWer needed to operate the LED 160 and the
scope of the folloWing claims and equivalents thereof.
I claim:
1. A computer comprising:
65
components contained in the housing and accessible by
removing the cover; and
US 6,862,188 B2
6
5
monitoring an intensity of light generated by the light
a re?ective optical sensor disposed in the housing adja
cent the re?ective surface of the cover and interfaced to
emitter and re?ected from the re?ective surface; and
generating a signal for triggering the computer to poWer
doWn When the intensity of light re?ected from the
an operating system of the computer for detecting
removal of the cover, the re?ective optical sensor
having a light emitter generating light directed to the
re?ective surface is reduced.
12. A method as in claim 11, further comprising the step
re?ective surface of the cover and a light detector
disposed to receive light re?ected by the re?ective
surface, the re?ective optical sensor being connected to
send a signal for triggering the operating system to
initiate a poWer-doWn operation When removal of the
of attaching a re?ective sheet to the removable cover to
10
cover is detected.
2. Acomputer as in claim 1, Wherein the re?ective optical
sensor is mounted on a circuit board contained in the
housing.
3. A computer as in claim 2, Wherein the circuit board is 15
a motherboard of the computer.
4. Acomputer as in claim 1, Wherein the re?ective optical
sensor is mounted on a chassis of the computer inside the
provide the re?ective surface.
13. A method as in claim 11, further comprising the step
of generating an audio alarm signal.
14. A method as in claim 11, further comprising the step
of generating a visual alert signal.
15. A computer comprising:
a housing having a removable cover;
components contained in the housing and accessible by
removing the cover; and
a re?ective optical sensor disposed in the housing, the
re?ective optical sensor having a light emitter gener
ating light directed to an inner surface of the cover and
a light detector disposed to receive light re?ected by the
inner surface and interfaced to an operating system of
the computer for detecting removal of the cover, the
housing and connected to a motherboard of the computer.
5. A computer as in claim 1, Wherein the light emitter is
a light emitting diode (LED).
6. A computer as in claim 5, Wherein the light detector is
a phototransistor.
7. Acomputer as in claim 1, Wherein the re?ective surface
re?ective optical sensor being connected to send a
is a re?ective sheet adhered to the inner side of the cover. 25
ponents of the computer When the computer is in a state in
signal for triggering the operating system to initiate a
poWer-doWn operation When removal of the cover is
detected.
16. A computer as in claim 15, Wherein the inner surface
Which the operating system of the computer has been
of the cover includes a re?ective sheet disposed to re?ect
unloaded.
9. A computer as in claim 1, further including an audio
light from the light emitter to the light detector.
17. A computer as in claim 15, Wherein optical sensing
8. Acomputer as in claim 1, further including a poWer-off
processing circuit responsive to the signal from the re?ective
optical sensor to turn off poWer applied to hardWare com
alert device, and Wherein the operating system controls the
means is mounted on a motherboard contained in the hous
audio alert device to generate an audio alert signal in
ing.
response to receiving the signal from the re?ective optical
35
sensor.
10. A computer as in claim 1, further including an visual
housing and connected to a motherboard of the computer.
19. A computer as in claim 15, further including a
alert device, and Wherein the operating system controls the
visual alert device to generate a visual alert signal in
response to receiving the signal from the re?ective optical
sensor.
11. A method of detecting removal of a removable cover
on a housing of a computer, comprising:
directing light generated by a light emitter onto a re?ec
tive surface on an inner side of the cover;
18. Acomputer as in claim 15, Wherein the optical sensing
means is mounted on a chassis of the computer inside the
poWer-off processing circuit responsive to the signal from
40
the optical sensing means to turn off poWer applied to
hardWare components of the computer When the computer is
in a state in Which the operating system of the computer has
been unloaded.