Description
Title of Invention: PROJECTOR
Technical Field
[0001] The present invention relates to a projector.
Background Art
[0002] In the past, there has been known a projector, which modulates a light beam emitted
from a light source to thereby form an image corresponding to image information, and
project the image on a projection target surface such as a screen in an enlarged manner.
As such a light source, there is often used a light source lamp (a light emitting tube)
such as a super-high pressure mercury lamp provided with a light emitting tube having
a discharge space inside with a pair of electrodes and a light emitting substance en
capsulated.
[0003] Here, in the rated lighting state in which the light source lamp is lighted at the rated
power, the mercury in the discharge space exists in the form of vapor. It can be said
that this state is a state exceeding a saturation threshold level. In contrast, in the case
of, for example, displaying a dark image, if the lamp electric power is reduced to
thereby decrease the luminance of the light source lamp, the temperature in the
discharge space drops to be lower than in the rated lighting state and becomes lower
than the saturation threshold level, and thus the mercury vapor is compressed to
thereby cause the state in which the pressure in the discharge space is lowered. In such
a state, it becomes difficult for the halogen cycle, in which the tungsten evaporated
from the electrode returns to the electrode, to appropriately function, and thus it
becomes easy for the blackening, in which the tungsten is attached to the inner wall of
the light emitting tube, to occur. Such blackening lowers the luminance of the light
source lamp to thereby shorten the product life of the light source lamp.
[0004] Therefore, there has been known a projector (a projector system) capable of
preventing the blackening from occurring (see, e.g., PTL 1).
[0005] In the projector described in PTL 1, when the period of a dimming operation mode
for lighting the light source lamp with low lamp electric power exceeds a prede
termined time, there occurs transition to a restoring period in which the lamp electric
power is increased to be higher than the saturation threshold level. Thus, the tem
perature in the discharge space rises to thereby eliminate the blackening accumulated,
and therefore, a further operation of the light source lamp in the dimming operation
mode becomes possible.
Citation List
Patent Literature
[0006] PTL 1: JP-T-2010-500730
Summary of Invention
Technical Problem
[0007] However, in the projector described in PTL 1, since the light source lamp is lighted
in an operation mode (an operation mode with high lamp electric power) not intended
by the user during the restoring period, there arises a problem that the luminance of the
image displayed is raised without intent of the user.
[0008] In order to eliminate such a problem, it is possible to provide a dimming device for
reducing the light intensity used for forming the image. However, since there arises a
necessity of performing the light intensity control in accordance with the operation
mode, the internal configuration and the process of the projector become complicated.
[0009] Further, in the restoring period, there arises a necessity of increasing the rotational
speed (the number of revolutions per unit time) of a fan for feeding cooling air to the
light source lamp compared to that in the time of the dimming operation made so that
the temperature of the light source lamp does not rise beyond necessity. However, in
this case, there arises a problem that the noise such as wind noise of the fan increases.
[0010] In view of these problems, there have been demanded other efficient measures for
preventing the accumulation of the blackening.
Solution to Problem
[001 1] An advantage of some aspects of the invention is to provide a projector capable of e f
ficiently preventing the accumulation of the blackening.
[0012] An aspect of the invention is directed to a projector including a light source lamp
adapted to emit light in accordance with a lamp electric power supplied, a light
modulation device adapted to modulate the light emitted from the light source lamp, a
projection optical device adapted to project the light modulated, a cooling device
adapted to feed a cooling fluid to the light source lamp to thereby cool the light source
lamp, a lighting control section adapted to supply the light source lamp with the lamp
electric power having either one of a first electric power value and a second electric
power value higher than the first electric power value to thereby light the light source
lamp, and a cooling control section adapted to control the cooling device, and the
cooling control section controls the cooling device so that the cooling fluid at a flow
rate lower than a set flow rate set in accordance with the second electric power value is
fed to the light source lamp during a predetermined period after the lamp electric
power supplied to the light source lamp is switched from the first electric power value
to the second electric power value.
[0013] According to the aspect of the invention, in the case in which the electric power
value of the lamp electric power supplied to the light source lamp is switched from the
first electric power value to the second electric power value, the cooling fluid at a flow
rate lower than the set flow rate set in accordance with the second electric power value
is fed to the light source lamp during the predetermined period after the transition to
the second electric power value. According to this process, the rise in temperature of
the light source lamp can promptly be performed compared to the case in which the
cooling fluid corresponding to the set flow rate is fed to the light source lamp.
Therefore, it is possible to make it easy to eliminate the blackening inside the light
source lamp caused by the first electric power value, and the accumulation of the
blackening can efficiently be prevented.
[0014] In the aspect of the invention, it is preferable that the cooling device is controlled to
feed the cooling fluid at a flow rate corresponding to the set flow rate to the light
source lamp after the predetermined period elapses.
[0015] According to the above configuration, since the cooling fluid at the set flow rate cor
responding to the second electric power value is fed to the light source lamp after the
predetermined period elapses, the excessive rise in temperature of the light source
lamp can be prevented, and thus it is possible to stably light the light source lamp.
[0016] In the aspect of the invention, it is preferable that the cooling control section includes
a period setting section adapted to set the predetermined period based on the set flow
rate. It is also possible that the cooling control section includes a period setting section
adapted to set the predetermined period based on a difference between the first electric
power value and the second electric power value. It is also possible that the cooling
control section includes a period setting section adapted to set the predetermined
period based on a time period during which the lamp electric power of the first electric
power value is supplied. It is also possible that the cooling control section includes a
period setting section adapted to set the predetermined period based on a voltage level
of the lamp electric power of the second electric power value.
[0017] Here, if the state in which the temperature of the light source lamp is excessively
high continues, loss of clarity is incurred, and thus the operation life of the light source
lamp is shortened.
[0018] In contrast, although it is possible to cool the light source lamp to the appropriate
temperature corresponding to the second electric power value in a short period of time
after the predetermined period described above elapses if the set flow rate corre
sponding to the second electric power value is high, if the set flow rate is low, the time
period becomes longer.
[0019] Further, although it is possible to cool it to the appropriate temperature described
above in a short period of time if the difference between the first electric power value
and the second electric power value is small, if the difference in electric power is large,
the time period becomes longer.
[0020] Further, although it is required only a short period of time (elimination time) for
maintaining the high temperature state to thereby eliminate the blackening if the
duration time during which the lamp electric power of the first electric power value is
supplied is short, if the duration time is longer, the amount of accumulation of the
blackening increases, and therefore, the elimination time becomes longer.
[0021] In addition, when supplying the lamp electric power of the same electric power
value, if the voltage level applied to the light source lamp is high, the elimination time
described above can be short since it is not a condition of easily causing the
blackening. However, if the voltage level is low, the elimination time becomes longer
since it is the condition of easily causing the blackening of the light source lamp.
[0022] In contrast, according to the above configuration, the period setting section sets the
predetermined period described above based on at least either one of the set flow rate
corresponding to the second electric power value, the difference between the first
electric power value and the second electric power value, the supply time period of the
lamp electric power of the first electric power value, and the voltage level of the lamp
electric power of the second electric power value. According to this process, since the
predetermined period in which the light source lamp becomes in the high temperature
state for eliminating the blackening can appropriately be set, it is possible to prevent
the high temperature state from continuing excessively. Therefore, the accumulation of
the blackening can efficiently be prevented, and in addition, it is possible to stabilize
the lighting of the light source lamp, and thus the longer operating life of the light
source lamp can be achieved.
[0023] In the aspect of the invention, it is preferable that the cooling control section sets a
period during which the cooling device is halted in the predetermined period.
[0024] According to the above configuration, it results that the cooling fluid does not feed to
the light source lamp, and the light source lamp is not cooled during the period in
which the cooling device is halted. According to this process, the rise in temperature of
the light source lamp can more promptly be performed. Therefore, the blackening can
promptly be eliminated. Further, since the cooling device is halted in the period, the
generation of the noise due to the drive of the cooling device can be prevented.
[0025] In the aspect of the invention, it is preferable that the cooling device includes a fan
adapted to feed the cooling fluid, and the cooling control section controls the fan to
gradually increase the flow rate of the cooling fluid fed to the light source lamp within
a range failing to reach the set flow rate during the predetermined period.
[0026] It should be noted that gradually increasing the flow rate of the cooling fluid includes
increasing the flow rate in a stepwise manner and increasing the flow rate as the time
elapses linearly or in a curved manner based on a predetermined function.
[0027] Here, if the rotational speed (the number of revolutions per unit time) of the fan
rapidly increases, the wind noise due to the drive of the fan becomes large to thereby
make the noise thus generated larger.
[0028] In contrast, according to the above configuration, since the drive of the fan is
controlled so that the flow rate of the cooling fluid gradually increases, it results that
the rotational speed of the fan is gradually increased. According to this process, the
noise due to the drive of the fan can be reduced compared to the case in which the ro
tational speed of the fan rapidly increases.
Brief Description of Drawings
[0029] [fig. l]Fig. 1 is a block diagram showing a configuration of a projector according to a
first embodiment of the invention.
[fig.2]Fig. 2 is a diagram showing variations in a lamp electric power value and a fan
voltage value in the first embodiment.
[fig.3]Fig. 3 is a diagram showing variations in the lamp electric power value and the
fan voltage value in the first embodiment.
[fig.4]Fig. 4 is a diagram showing variations in the lamp electric power value and the
fan voltage value in the first embodiment.
[fig.5]Fig. 5 is a diagram showing a relationship between duration time and delay
period in the first embodiment.
[fig.6]Fig. 6 is a diagram showing rise in temperature of the light source lamp in the
first embodiment.
[fig.7]Fig. 7 is a flowchart showing a cooling control process in the first embodiment.
[fig.8]Fig. 8 is a diagram showing variations in the lamp electric power value and the
fan voltage value in a projector according to a second embodiment of the invention.
Description of Embodiments
[0030] First Embodiment
A first embodiment of the invention will hereinafter be explained with reference to
the accompanying drawings.
[0031] Fig. 1 is a block diagram showing a configuration of a projector 1 according to the
present embodiment.
[0032] The projector 1 according to the present embodiment modulates the light beam
emitted from a light source lamp 4 1 to thereby from an image corresponding to image
information, and then projects the image on the projection target surface such as a
screen in an enlarged manner. When the electric power value (hereinafter abbreviated
as a "lamp electric power value" in some cases) of the lamp electric power supplied to
the light source lamp 4 1 is raised, the projector 1 feeds cooling air at a flow rate lower
than a set flow rate set in advance in accordance with a high electric power value to the
light source lamp 4 1 for a predetermined period of time after the electric power value
has been switched to thereby promptly perform rise in temperature of the light source
lamp 4 1 and thus prevent accumulation of blackening inside the light source lamp 41.
[0033] As shown in Fig. 1, such a projector 1 is provided with an operation device 2, a
power supply device 3, an image forming device 4, a detection device 5, a cooling
device 6, and a control device 7.
[0034] The operation device 2 is formed of an operation panel disposed on, for example, a
top surface of the projector 1. The operation panel is provided with a plurality of keys,
and outputs an operation signal corresponding to the key input to the control device 7.
As such keys, there can be cited a power key for switching ON/OFF the power of the
projector 1, a switching key for switching a color mode, a mute key for displaying a
predetermined image (e.g., a black image) instead of the display of the image corre
sponding to the image information input thereto, and so on.
[0035] The power supply device 3 supplies each of the electronic components constituting
the projector 1 with electric power. Specifically, the power supply device 3 supplies
the control device 7 with the electric power, and further supplies each of the electronic
components (e.g., a light source lamp 4 1 described later) with the electric power under
the control of the control device 7.
[0036] The image forming device 4 modulates the light in accordance with the drive signal
input from the control device 7, and then projects the light on the projection target
surface in an enlarged manner. The image forming device 4 is provided with a light
source lamp 41, a light modulation device 42, and a projection optical device 43.
[0037] Although the detailed illustration is omitted, the light source lamp 4 1 is provided
with a light emitting tube having a discharge space with a pair of electrodes and a light
emitting substance encapsulated therein, and a reflector attached to the light emitting
tube. Among these constituents, the light emitting tube lights at a luminance corre
sponding to the lamp electric power supplied from the power supply device 3.
[0038] The light modulation device 42 modulates the light beam, which is emitted from the
light source lamp 41, in accordance with the drive signal described above. As such a
light modulation device 42, a liquid crystal panel can be adopted, and in addition
thereto, a device using a micromirror can also be adopted, for example.
[0039] The projection optical device 43 is for projecting the light modulated in an enlarged
manner, and is configured as a combination lens provided with a body tube and a
plurality of lenses housed in the body tube.
[0040] The detection device 5 is connected to the power supply device 3, and detects the
voltage level of the lamp electric power supplied by the power supply device 3.
Further, the detection device 5 outputs the voltage level thus detected to the control
device 7.
[0041] The cooling device 6 feeds the cooling air as a cooling fluid introduced from the
outside of the projector 1 to the various types of heat-generating components con
stituting the projector 1 to thereby cool these components. For example, the cooling
device 6 feeds the cooling air to the light source lamp 4 1 to thereby cool the light
source lamp 41. Such a cooling device 6 has a fan 6 1 for discharging the cooling air.
[0042] Configuration of Control Device
The control device 7 is formed of a circuit board having a central processing unit
(CPU), a random access memory (RAM), a flash memory, and so on mounted thereon,
and controls the operation of the projector 1 in accordance with the input operation by
the user to the operation device 2 or in an autonomous manner. Such a control device 7
has a storage section 71, a main control section 72 realized by the CPU processing a
program and data stored in the storage section 71, an image processing section 73, a
lighting control section 74, a timing section 75, and a cooling control section 76.
[0043] Configuration of Storage Section
The storage section 7 1 is formed of the flash memory described above, and stores
various programs and data necessary for the operation of the projector 1. For example,
as such data, the storage section 7 1 stores a drive parameter of the cooling device 6
corresponding to the lamp electric power value. The drive parameter is set based on the
flow rate (set flow rate) of the cooling air to be fed to the light source lamp 41, and is
stored as a fan voltage corresponding to each of the lamp electric power values in the
case of controlling the drive of the fan 6 1 of the cooling device 6 with the applied
voltage level, or as a duty ratio corresponding to each of the lamp electric power values
in the case of controlling the drive of the fan 6 1 using pulse width modulation (PWM).
[0044] It should be noted that the explanation will be described below assuming that the
drive of the fan 6 1 is controlled using the applied voltage level.
[0045] Further, in the case in which the lamp electric power value supplied to the light
source lamp 4 1 is switched from a low level to a high level, the storage section 7 1
stores reference time corresponding to the difference between these electric power
values. The reference time is the time used as the reference of a delay period
(corresponding to a predetermined period according to the invention) for which the
operation of the cooling device 6 corresponding to the drive parameter corresponding
to the high lamp electric power value thus switched to is delayed by the cooling control
section 76 described later. The larger the difference between the electric power values
is, the longer such a reference time is set, and the smaller the difference is, the shorter
the reference time is set.
[0046] Besides the above, the storage section 7 1 stores a lamp voltage (a reference lamp
voltage) obtained when the light source lamp 4 1 is supplied with the lamp electric
power with a certain electric power value in the condition in which the light source
lamp 4 1 is not deteriorated. The reference lamp voltage is stored for each of the lamp
electric power values with which the light source lamp 4 1 can be lighted, and is stored
to the storage section 7 1 in a shipping stage of the projector 1.
[0047] Further, although the details will be described later, the storage section 7 1 stores the
time (duration time) timed by the timing section 75.
[0048] Configuration of Main Control Section
The main control section 72 controls the operation of the control device 7, and con
sequently controls the overall operation of the projector 1. For example, the main
control section 72 controls the lighting control section 74 so that the light source lamp
4 1 is supplied with the lamp electric power of the electric power value set in ac
cordance with the execution state of the mute function, the average picture level (APL)
of the image generated by the image processing section 73 described later, and the
color mode set by the user.
[0049] Further when changing the lamp electric power value, the main control section 72
obtains the time (the duration time) timed by the timing section 75 described later and
then stores the time to the storage section 71, and then resets the time counted by the
timing section 75 to thereby make the timing section 75 start timing from "0."
[0050] Configuration of Image Processing Section
The image processing section 73 develops an image, which corresponds to the image
information (including the image signal and the image data) received from external
equipment such as a PC, in a video memory not shown to thereby generate the image.
On this occasion, the image processing section 73 performs a predetermined correction
process on the image. Further, the image processing section 73 outputs the drive signal
corresponding to the image thus generated to the image forming device 4 described
above.
[005 1] Configuration of Lighting Control Section
The lighting control section 74 controls the operation of the power supply device 3
based on the control signal input from the main control section 72 to make the power
supply device 3 supply the light source lamp 4 1 with the lamp electric power to
thereby light the light source lamp 41. In other words, the lighting control section 74
controls the operation of the power supply device 3 so that the light source lamp 4 1 is
supplied with the lamp electric power of the electric power value based on the control
signal. Such a lamp electric power value is set in a range of 70 through 230W (watts)
in the present embodiment, but can arbitrarily be changed in accordance with, for
example, the type of the light source lamp 41.
[0052] Configuration of Timing Section
The timing section 75 measures the time elapsed from when the lamp electric power
value has been changed under the control of the main control section 72. Specifically,
when a start signal is input from the main control section 72 (i.e., when the change in
the target power value described later is performed), the timing section 75 starts timing
from "0," and further, when a stop signal is input from the main control section 72, the
timing section 75 stops the timing. Further, the time measured by the timing section 75
is stored in the storage section 7 1 by the main control section 72 as a duration time of
the lamp electric power value before the change, and the measurement by the timing
section 75 is started from "0" again in accordance with the subsequent input of the start
signal.
[0053] Configuration of Cooling Control Section
The cooling control section 76 controls the cooling device 6 to feed the cooling air
for cooling the constituents (e.g., the light source lamp 4 1 and the power supply device
3) of the projector 1. In particular, the cooling control section 76 feeds the cooling air
for cooling the light source lamp 4 1 based on the control signal input from the main
control section 72.
[0054] In the case in which the lamp electric power value is switched by the main control
section 72, and the lamp electric power value (the target power value) after the
switching is higher than the lamp electric power value (the previous power value)
before the switching, such a cooling control section 76 delays the operation of the
cooling device 6 based on the drive parameter corresponding to the target power value.
In other words, the cooling control section 76 controls the cooling device 6 to feed the
cooling air at a flow rate lower than the set flow rate corresponding to the target power
value for a predetermined period (the delay period) after the target power value has
become higher than the previous power value. Thus, the rise in temperature in the
discharge space of the light source lamp 4 1 is promoted to thereby eliminate the
blackening caused in the discharge space.
[0055] In order to realize such a function, the cooling control section 76 has a power value
obtaining section 761, a power value determination section 762, a difference cal
culation section 763, a duration time obtaining section 764, a lamp voltage obtaining
section 765, a parameter obtaining section 766, a period setting section 767, and a
drive control section 768.
[0056] The power value obtaining section 761 obtains the lamp electric power value
supplied to the light source lamp 4 1 based on the control signal (the same as the
control signal input to the lighting control section 74) input from the main control
section 72. Then, the power value obtaining section 761 stores the lamp electric power
values thus obtained in the storage section 7 1 in chronological order.
[0057] The power value determination section 762 refers to the storage section 7 1 to de
termines whether or not the lamp electric power value obtained by the power value
obtaining section 761 changes with respect to the previous lamp electric power value.
Then, if it is determined that the lamp electric power value has changed, the power
value determination section 762 determines whether or not the lamp electric power
value (the target power value) thus obtained is higher than the lamp electric power
value (the previous power value) before the change.
[0058] The difference calculation section 763, the duration time obtaining section 764, the
lamp voltage obtaining section 765, the parameter obtaining section 766, and the
period setting section 767 operate if the power value determination section 762 de
termines that the target power value is higher than the previous power value. In other
words, these functional sections 763 through 767 operate in the case of switching from
the state of supplying the lamp electric power with the low power value (corresponding
to a first power value according to the invention) to the state of supplying the lamp
electric power with the high power value (corresponding to a second power value
according to the invention).
[0059] The difference calculation section 763 calculates the difference between the target
power value and the previous power value.
[0060] The duration time obtaining section 764 obtains the duration time of the previous
power value, which has been measured by the timing section 75 and then stored to the
storage section 71 by the main control section 72.
[0061] The lamp voltage obtaining section 765 obtains the lamp voltage detected by the
detection device 5.
[0062] The parameter obtaining section 766 obtains the drive parameter corresponding to
the target power value from the storage section 71.
[0063] Figs. 2 through 4 are diagrams showing the variation in the fan voltage value in the
case in which the lamp electric power value is changed from 70W to 160W, from
160W to 230W, and from 70W to 230W, respectively. It should be noted that in Figs.
2 through 4, the transition of the fan voltage corresponding to the target power value is
indicated by a dotted line as a comparative example, and the transition of the fan
voltage applied to the fan 6 1 due to the control by the cooling control section 76 is
indicated by a solid line as an executed example.
[0064] The period setting section 767 sets the delay period based on the duration time, the
lamp voltage, and the drive parameter thus obtained, and the difference thus calculated.
The delay period is a time period for which the operation of the cooling device 6 with
the drive parameter corresponding to the lamp electric power value after the change is
delayed.
[0065] Specifically, the period setting section 767 obtains the reference time corresponding
to the difference between the target power value and the previous power value from the
storage section 71, then reduces or extends the reference time based on the duration
time, the lamp voltage, and the drive parameter described above to thereby set the
delay period (the period indicated by A in Figs. 2 through 4).
[0066] For example, as shown in Fig. 2, if the target power value is changed to 160W higher
than 70W as the previous power value, the period setting section 767 sets the delay
period A as a period starting at the change in the target power value for which the fan
voltage (the fan voltage of 4.0V indicated by the solid line in Fig. 2) corresponding to
the previous power value is continued instead of the fan voltage (the fan voltage of
8.3V indicated by the dotted line in Fig. 2) for feeding the cooling air at the set flow
rate corresponding to the target power value.
[0067] Similarly, as shown in Fig. 3, if the target power value is changed to 230W higher
than 160W as the previous power value, the period setting section 767 sets the delay
period A as a period for which the fan voltage (the fan voltage of 8.3V indicated by the
solid line in Fig. 3) corresponding to the previous power value is continued instead of
the fan voltage (the fan voltage of 10.9V indicated by the dotted line in Fig. 3) for
feeding the cooling air at the set flow rate corresponding to the target power value.
[0068] Further, as shown in Fig. 4, if the target power value is changed to 230W higher than
70W as the previous power value, the period setting section 767 sets the delay period
A as a period for which the fan voltage (the fan voltage of 4.0V indicated by the solid
line in Fig. 4) corresponding to the previous power value is continued instead of the
fan voltage (the fan voltage of 10.9V indicated by the dotted line in Fig. 4) corre
sponding to the target power value.
[0069] As shown in Figs. 2 through 4, the period setting section 767 sets the delay period A
to be longer if the power difference between the previous power value and the target
power value changed is larger, and shorter if it is smaller. Further, the delay period A
is set to be longer if the previous power value is lower, and shorter if it is higher.
[0070] Fig. 5 is a diagram showing the length of the delay period with respect to the length
of the duration time. It should be noted that in Fig. 5, it is assumed that the target
power value is 230W, and the case with the previous power value of 70W is illustrated
by the solid line while the case with the previous power value of 160W is illustrated by
the dotted line.
[0071] Further, for example, the period setting section 767 reduces or extends the reference
time in accordance with the proportion of the duration time to a predetermined time
period to thereby set the delay period. The predetermined time period is set in ac
cordance with, for example, the type of the light source lamp 41.
[0072] Thus, as shown in Fig. 5, in the case in which the target power value is 230W and the
previous power value is 70W, if the duration time during which the lamp electric
power of the previous power value is supplied is 2 minutes (min), the delay period is
set to 50 seconds (sec), and if the duration time is 6 minutes, the delay period is set to
120 seconds. Further, in the case in which the target power value is 230W and the
previous power value is 160W, if the duration time during which the lamp electric
power of the previous power value is supplied is 8 minutes, the delay period is set to
25 seconds (sec).
[0073] It should be noted that if the duration time becomes equal to or longer than 10
minutes, the delay period is set to substantially the same value as in the case in which
the duration time is 10 minutes. Further, as shown in Fig. 5, if the duration time is
shorter than 1 minute, reduction or extension of the reference time corresponding to the
duration time is not performed.
[0074] Returning to Fig. 1, the period setting section 767 extends the reference time in ac
cordance with the proportion of the lamp voltage obtained by the lamp voltage
obtaining section 765 to the reference lamp voltage, which is stored in the storage
section 7 1 and corresponds to the target power value, to thereby set the delay period.
[0075] Here, the variation in the lamp voltage in the case of supplying the lamp electric
power of a certain electric power value can be used as indicator of the arc length
formed between the electrodes of the light source lamp 41. Specifically, a high lamp
voltage represents a long arc length, and denotes that there arises a condition in which
the blackening is hard to occur. In contrast, drop of the lamp voltage represents
decrease in the arc length, and denotes that there arises a condition in which the
blackening is easy to occur.
[0076] Therefore, in the case in which, for example, the reference lamp voltage corre
sponding to the target power value of 230W is 100V, the period setting section 767
sets the delay period to the time obtained by multiplying the reference time by 1.5 if
the lamp voltage obtained is 70V, or to the time obtained by doubling the reference
time if the lamp voltage obtained is 60V.
[0077] It should be noted that in the case in which the reference lamp voltage corresponding
to the target power value of 230W is 100V, and the lamp voltage thus obtained is in a
range of 80 through 100V, the period setting section 767 sets the delay period without
extending the reference time.
[0078] Further, the period setting section 767 sets the delay period by reducing or extending
the reference time in accordance with the drive parameter thus obtained. Since the
drive parameter corresponds to the flow rate of the cooling air fed from the cooling
device 6 to the light source lamp 4 1 as described above, the period setting section 767
sets the delay period by reducing or extending the reference time in accordance with
the flow rate of the cooling air indicated by the drive parameter.
[0079] In other words, the period setting section 767 sets the delay period by reducing or
extending the reference time in accordance with the proportion of the flow rate of the
cooling air indicated by the drive parameter thus obtained to a predetermined flow rate.
Therefore, if the flow rate indicated by the drive parameter is lower than the prede
termined flow rate, the delay period reduced in accordance with the proportion of the
flow rate to the predetermined flow rate is set.
[0080] As described above, the period setting section 767 sets the time period obtained by
reducing or extending the reference time in accordance with the duration time, the
lamp voltage, and the drive parameter as the delay period.
[0081] The drive control section 768 controls the cooling device 6 so that the cooling air at
the set flow rate corresponding to the lamp electric power value is fed to the light
source lamp 41.
[0082] Specifically, if the target power value is lower than the previous power value, the
drive control section 768 obtains the drive parameter corresponding to the target power
value from the storage section 71, and then controls the operation of the cooling device
6 based on the drive parameter from the time point of the transition to the target power
value.
[0083] Rise in Temperature of Light Source Lamp
Fig. 6 is a diagram showing the rise in temperature of the light source lamp 4 1 in the
case in which the operation mode of the light source lamp 4 1 is changed from a low
luminance mode to a high luminance mode.
[0084] In contrast, if the target power value is higher than the previous power value, the
drive control section 768 controls the operation of the cooling device 6 based on the
drive parameter corresponding to the previous power value from the time point of the
transition to the target power value until the delay period thus set elapses. Therefore, in
the case of supplying the lamp electric power of the target power value higher than the
previous power value, by temporarily preventing cooling of the light source lamp 41,
the rise in temperature in the discharge space is performed promptly compared to the
case of providing no delay period (the case indicated by the dotted line in Fig. 6) as
indicated by the solid line in Fig. 6. Thus, the blackening having occurred when
supplying the lamp electric power of the previous power value is eliminated.
[0085] Subsequently, after the delay period has elapsed, the drive control section 768
controls the operation of the cooling device 6 based on the drive parameter corre
sponding to the target power value. Thus, it results that the cooling air at the set flow
rate corresponding to the target power value is fed to the light source lamp 41, and the
light source lamp 4 1 is cooled to the temperature suitable for the target power value.
Therefore, the lighting of the light source lamp 4 1 can be stabilized, and in addition,
longer operating life thereof can be achieved. Further, since the rise in temperature of
the light source lamp 4 1 is performed promptly, the lighting response of the light
source lamp 4 1 can be improved.
[0086] Cooling Control Process
Fig. 7 is a flowchart showing a cooling control process executed by the control
device 7.
[0087] The control device 7 processes the program stored in the storage section 7 1 during
the period in which the power of the projector 1 is kept ON to thereby execute the
cooling control process described below, and thus controls the operation of the cooling
device 6 to thereby cool the light source lamp 41.
[0088] As shown in Fig. 7, in the cooling control process, firstly, the power value obtaining
section 761 obtains (step S01) the lamp electric power value (the target power value)
supplied to the light source lamp 4 1 based on the control signal input from the main
control section 72.
[0089] Then, the power value determination section 762 determines (step S02) whether or
not the target power value changes from the previous lamp electric power value (the
previous power value) stored in the storage section 71, namely whether or not the
target power value is different from the previous power value.
[0090] If it is determined in the determination process of the step S02 that the target power
value does not change, the control device 7 returns the process to the step SOL
[0091] In contrast, if it is determined in the determination process of the step S02 that the
target power value has changed, the power value obtaining section 761 stores (step
S03) the target power value in the storage section 71.
[0092] In conjunction with the execution of the step S03, the main control section 72 outputs
a halt signal to the timing section 75 to thereby stop (step S04) timing by the timing
section 75.
[0093] Subsequently, the main control section 72 obtains the measured time of the timing
section 75 thus stopped, and then stores (step S05) the measured time in the storage
section 71 as the duration time.
[0094] Further, the main control section 72 outputs a start signal to the timing section 75 to
make (step S06) the timing section 75 start timing from "0." Thus, the elapsed time
from when the change in the target power value is performed is measured by the
timing section 75. It should be noted that it is also possible to configure that the step
S06 is executed when the control by the drive control section 768 in the step S15
described later is started, and the elapsed time from the start of the control is measured.
[0095] Subsequently, the power value determination section 762 determines (step S07)
whether or not the target power value is higher than the previous power value.
[0096] Here, if it is determined that the target power value is not higher than the previous
power value (if it is determined that the target power value is lower than the previous
power value), setting of the delay period by the period setting section 767 is not
performed, and the drive control section 768 obtains (step S08) the drive parameter
corresponding to the target power value from the storage section 71.
[0097] Then, the drive control section 768 controls (step S09) the operation of the cooling
device 6 based on the drive parameter, and then the control device 7 returns the process
to the step SOI.
[0098] On the other hand, if it is determined in the determination process of the step S07
that the target power value is higher than the previous power value, the difference cal
culation section 763 calculates (step S10) the difference between the target power
value and the previous power value.
[0099] Further, the duration time obtaining section 764 obtains the duration time stored in
the storage section 7 1 in the step S05, the lamp voltage obtaining section 765 obtains
the lamp voltage detected by the detection device 5, and further the parameter
obtaining section 766 obtains the drive parameter corresponding to the target power
value from the storage section 7 1 (steps Sll through S13).
[0100] Subsequently, the period setting section 767 sets (step S14) the delay period based on
the difference thus calculated, the duration time, the lamp voltage, and the drive
parameter thus obtained in the steps S10 through S13 as described above.
[0101] Then, the drive control section 768 continues (step S15) the control of the operation
of the cooling device 6 based on the drive parameter corresponding to the previous
power value, and at the same time, determines (step SI6) whether or not the delay
period thus calculated in the step Sll has elapsed after the transition to the target
power value.
[0102] If the drive control section 768 determines in the determination process of the step
S16 that the delay period has not yet elapsed, the determination process of the step S13
is repeated. Therefore, the drive control section 768 continues to execute the control of
the operation of the cooling device 6 in the step S15, namely the control with the drive
parameter corresponding to the previous power value. Thus, the flow rate of the
cooling air fed to the light source lamp 4 1 is reduced compared to the set flow rate of
the cooling air fed in accordance with the target power value, and therefore, the rise in
temperature of the light source lamp 4 1 is promptly performed.
[0103] In contrast, if the drive control section 768 determines in the determination process
of the step S16 that the delay period has elapsed, the drive control section 768
performs (step S17) the control of the operation of the cooling device 6 based on the
drive parameter corresponding to the target power value. Then, while executing the
step S17, the control device 7 returns the process to the step SOL
[0104] By executing the step S17 to thereby feed the cooling air at the set flow rate corre
sponding to the target power value to the light source lamp 41, the excessive rise in
temperature of the light source lamp 4 1 can be prevented.
[0105] According to the projector 1 of the present embodiment explained hereinabove, the
following advantages can be obtained.
[0106] In the case in which the lamp electric power value supplied to the light source lamp
4 1 is switched to a higher electric power value, the cooling air at the flow rate lower
than the set flow rate corresponding to the lamp electric power value is fed to the light
source lamp 4 1 in the period from when the lamp electric power value is switched to
the present lamp electric power value to when the delay time elapses. According to this
configuration, the rise in temperature of the light source lamp 4 1 can be performed
promptly compared to the case in which the cooling air at the set flow rate corre
sponding to the lamp electric power value is fed to the light source lamp 4 1 from the
time point of the transition of the lamp electric power value. Therefore, it is possible to
make it easy to eliminate the blackening inside the light source lamp caused by con
tinuously supplying the lamp electric power of the low lamp electric power value, and
the accumulation of the blackening can efficiently be prevented.
[0107] Further, since the cooling air at the set flow rate corresponding to the target power
value is fed to the light source lamp 4 1 after the delay period has elapsed, the light
source lamp 4 1 can be cooled to the appropriate temperature. Therefore, loss of clarity
can be prevented from occurring in the light source lamp 41, and the light source lamp
4 1 can be lighted stably. Further, since the operation of the cooling device 6 can tem
porarily be prevented, the power consumption of the projector 1 can be reduced during
the delay period.
[0108] The period setting section 767, which functions in the case in which the target power
value is higher than the previous power value, sets the delay period based on the drive
parameter corresponding to the set flow rate corresponding to the target power value,
the difference between the previous power value and the target power value, the
duration time of the previous power value, and the voltage level when the lamp electric
power of the target power value is actually supplied. According to this configuration,
the delay period during which the discharge space becomes in the high temperature
state for eliminating the blackening can appropriately be set. Therefore, the accu
mulation of the blackening can efficiently be prevented.
[0109] Besides the above, since the delay period can be prevented from becoming ex
cessively long, the condition in which the temperature of the light source lamp 4 1 is
excessively high can be prevented from continuing. Therefore, the lighting of the light
source lamp 4 1 can further be stabilized, and the longer operating life of the light
source lamp 4 1 can be achieved.
[0110] Second Embodiment
Hereinafter, a second embodiment of the invention will be explained.
[0111] The projector according to the present embodiment is provided with substantially the
same configuration as that of the projector 1 described above. Here, in the projector 1,
the drive control section 768 controls the operation of the cooling device 6 based on
the drive parameter corresponding to the previous power value for the delay period. In
contrast, the projector according to the present embodiment is provided with a halt
period for halting the operation of the cooling device 6 in the delay period, and in
addition, controls the operation of the cooling device 6 so that the cooling air fed to the
light source lamp 4 1 gradually increases. The projector according to the present em
bodiment and the projector 1 are different from each other in this point. It should be
noted that in the explanation below, the part the same or substantially the same as the
part having already been explained is denoted with the same reference symbol, and the
explanation therefor will be omitted.
[0112] Fig. 8 is a diagram showing a variation in the fan voltage value output by the cooling
control section 76 of the projector according to the present embodiment.
[0113] The projector according to the present embodiment has substantially the same con
figuration as that of the projector 1, but is different from the projector 1 in some of the
operation of the cooling control section 76 constituting the control device 7.
[01 14] In other words, as shown in Fig. 8, in the projector according to the present em
bodiment, the drive control section 768 halts the operation of the cooling device 6 for a
predetermined time period in the delay period after the lamp electric power is switched
to the target power value higher than the previous power value. The predetermined
time period corresponds to the halt period described above.
[0115] Further, the drive control section 768 controls the operation of the cooling device 6
so that the flow rate of the cooling air fed therefrom increases in a stepwise manner
within a range not reaching the set flow rate corresponding to the target power value
after the halt period has elapsed in the delay period. Specifically, the drive control
section 768 controls the fan voltage so that the fan voltage applied to the fan 6 1 of the
cooling device 6 increases in a stepwise manner, and the fan voltage indicated by the
drive parameter corresponding to the target power value is applied to the fan 6 1 at the
end of the delay period.
[0116] Meanwhile, since a period during which no cooling air is fed to the light source lamp
4 1 is provided by halting the cooling device 6 in the halt period, and in addition, the
flow rate of the cooling air fed to the light source lamp 4 1 increases in a stepwise
manner after the halt period has elapsed as described above, the period setting section
767 further reduces the delay period set in the manner described above to thereby
newly set the delay period.
[01 17] According to the projector related to the present embodiment explained hereinabove,
in addition to the advantages substantially the same as those of the projector 1
described above, the following advantages can be obtained.
[0118] That is, the drive of the fan 6 1 of the cooling device 6 is halted in the transition from
the low lamp electric power value to the high lamp electric power value. According to
this operation, since it results that no cooling air is fed to the light source lamp 41, the
rise in temperature in the discharge space of the light source lamp 4 1 can more
promptly be performed, and thus the delay period set by the period setting section 767
can be reduced. Therefore, the blackening formed inside the discharge space can more
promptly be eliminated, and thus the accumulation of the blackening can more e f
ficiently be prevented. Further, since the drive of the fan 6 1 is halted, generation of the
noise due to the drive of the fan 6 1 can be prevented.
[01 19] Further, in the delay period, the drive control section 768 controls the cooling device
6 so that the flow rate of the cooling air fed to the light source lamp 4 1 increases in a
stepwise manner after the halt period of the cooling device 6 has elapsed. In other
words, the fan voltage supplied to the fan 6 1 is controlled to increase in a stepwise
manner after the halt period has elapsed. Then, the drive control section 768 controls
the cooling device 6 (the fan 61) based on the drive parameter corresponding to the
target power value so that the cooling air at the set flow rate corresponding to the target
power value is fed to the light source lamp 4 1 after the delay period elapses.
[0120] According to this operation, since it results that the rotational speed (the number of
revolutions per unit time) of the fan 6 1 increases in a stepwise manner, the noise
generated due to the drive of the fan 6 1 can be reduced compared to the case in which
the rotational speed increases rapidly. Therefore, the noise during the operation of the
projector can be reduced.
[0121] Modifications of Embodiments
The invention is not limited to the embodiments described above, but includes modi
fications and improvements in a range where the advantages of the invention can be
achieved.
[0122] Although in each of the embodiments it is assumed that the period setting section 767
sets the delay period based on the difference between the target power value and the
previous power value, the duration time of the previous power value, the voltage level
of the lamp electric power of the target power value, and the drive parameter corre
sponding to the set flow rate of the cooling fluid fed from the cooling device 6 when
the lamp electric power of the target power value is supplied, the invention is not
limited thereto. That is, it is sufficient to set the delay period based on either one of
these items, or it is possible to set the delay period and the fan voltage further taking
any of other parameters (e.g., environmental temperature) into consideration.
[0123] Although in each of the embodiments it is assumed that the cooling device 6 has the
fan 6 1 for feeding the cooling air for cooling the light source lamp 41, and the cooling
control section 76 makes the power supply device 3 apply the fan voltage for driving
the fan 61, the invention is not limited thereto. It is also possible to adopt the con
figuration in which, for example, the cooling device is provided with a control
member, such as a louver, for controlling the flow rate of the cooling air fed to the
light source lamp 41, and the cooling control section controls the operation of the
control member. On this occasion, the drive of the fan can be performed at a constant
fan voltage, or performed in conjunction with the drive control of the fan described
above. In this case, further detailed control of the feeding flow rate to the light source
lamp 4 1 can be performed.
[0124] Although in each of the embodiments the cooling device 6 feeds the cooling air as a
cooling fluid, the invention is not limited thereto. For example, if the insulation of the
light source lamp 4 1 is appropriately performed, it is also possible to cool the light
source lamp 4 1 using a cooling medium such as ethylene glycol as the cooling fluid.
[0125] Although in each of the embodiments one target power value is set, and the delay
period is set based on the target power value and so on, the invention is not limited
thereto. It is also possible to adopt the configuration of, for example, setting a plurality
of target power values, and increasing the electric power value of the lamp electric
power in a stepwise manner. In this case, it is also possible to adopt the configuration
of setting the delay period based on the final target power value and so on.
[0126] Although in the second embodiment it is arranged that the operation of the cooling
device 6 is temporarily halted to thereby prevent the cooling air from being fed to the
light source lamp 4 1 during the delay period, the invention is not limited thereto. That
is, it is also possible to arrange that the operation of the cooling device 6 is stopped
during the delay period providing the delay period can be set to an appropriate time
period.
[0127] Although in the second embodiment it is arranged that the fan voltage applied to the
fan 6 1 is increased in a stepwise manner so that the flow rate of the cooling air fed to
the light source lamp 4 1 increases in a stepwise manner after the halt period elapses in
the delay period, the invention is not limited thereto. That is, it is also possible to drive
the fan so that the fan voltage gradually increases from the fan voltage based on the
drive parameter corresponding to the previous power value without providing the halt
period in the delay period. Further, it is also possible to drive the fan while increasing
the fan voltage linearly or in a curved manner as the time elapses based on a prede
termined function so that the flow rate of the cooling air increases gradually.
[0128] Further, although in each of the embodiments it is arranged that the drive of the fan
6 1 is controlled using the applied voltage level, it is also possible to arrange that the
fan 6 1 is controlled using PWM as described above.
Industrial Applicability
[0129] The invention can preferably be applied to a projector equipped with a light source
lamp.
Reference Signs List
[0130] 1 Projector
Cooling device
Light source lamp
Light modulation device
Projection optical device
Fan
Lighting control section
Cooling control section
7 Period setting section
PCT/JP2011/007074
Claims
A projector comprising:
a light source lamp adapted to emit light in accordance with a lamp
electric power supplied to the light source lamp;
a light modulation device adapted to modulate the light emitted from
the light source lamp;
a projection optical device adapted to project the light modulated;
a cooling device adapted to feed a cooling fluid to the light source lamp
to thereby cool the light source lamp;
a lighting control section adapted to supply the light source lamp with
the lamp electric power having either one of a first electric power value
and a second electric power value higher than the first electric power
value to thereby light the light source lamp; and
a cooling control section adapted to control the cooling device, the
cooling control section controls the cooling device so that the cooling
fluid at a flow rate lower than a set flow rate set in accordance with the
second electric power value is fed to the light source lamp during a pre
determined period after the lamp electric power supplied to the light
source lamp is switched from the first electric power value to the
second electric power value.
The projector according to Claim 1, wherein the cooling control section
controls the cooling device to feed the cooling fluid at a flow rate corre
sponding to the set flow rate to the light source lamp after the prede
termined period elapses.
The projector according to Claim 1 or 2, wherein the cooling control
section includes a period setting section adapted to set the prede
termined period based on the set flow rate.
The projector according to any one of Claims 1 to 3, wherein the
cooling control section includes a period setting section adapted to set
the predetermined period based on a difference between the first
electric power value and the second electric power value.
The projector according to any one of Claims 1 to 4, wherein the
cooling control section includes a period setting section adapted to set
the predetermined period based on a time period during which the lamp
electric power of the first electric power value is supplied.
The projector according to any one of Claims 1 to 5, wherein the
cooling control section includes a period setting section adapted to set
WO 2012/095925 PCT/JP2011/007074
the predetermined period based on a voltage level of the lamp electric
power of the second electric power value.
[Claim 7] The projector according to any one of Claims 1 to 6, wherein the
cooling control section sets a period during which the cooling device is
halted in the predetermined period.
[Claim 8] The projector according to any one of Claims 1 to 7, wherein the
cooling device includes a fan adapted to feed the cooling fluid, and
the cooling control section controls the fan to gradually increase the
flow rate of the cooling fluid fed to the light source lamp within a range
failing to reach the set flow rate during the predetermined period.