WO2009144816A1

WO2009144816A1 - Object detector, method for detecting object, and program for detecting object

Info

Publication number: WO2009144816A1
Application number: PCT/JP2008/060038
Authority: WO
Inventors: 修富家
Original assignee: Ｎｅｃディスプレイソリューションズ株式会社
Priority date: 2008-05-30
Filing date: 2008-05-30
Publication date: 2009-12-03
Also published as: JP4977924B2; JPWO2009144816A1

Abstract

A projector device (1) includes a first duct (12) and a second duct (13) in an optical path which are arranged in opposition with a portion (30) exposed to the outside of a chassis (2) interposed in between, an exhaust fan (14) for discharging air inside the chassis and air inhaled into the chassis from the outside through the second duct to the outside of the chassis, a rotation speed detection section (18), and a control section (20). The rotation speed detection section outputs a rotation speed detection signal indicating a rotation speed of the exhaust fan. The control section outputs a control signal for controlling the rotation speed of the exhaust fan. Further, the control section outputs an object detection signal indicating intrusion of a foreign material (40) into the exposed portion in the event of no change in the control signal but change in the detection signal.

Description

Object detection apparatus, object detection method, and program

The present invention relates to an object detection device, an object detection method, and a program.

In recent years, various projector devices for projecting images and videos on a large screen have been developed.

In general projector devices, a light source that emits high-luminance light such as an ultra-high pressure mercury lamp for projecting an image or video is often used.

Further, among projector apparatuses, there is a projector apparatus having a structure in which an optical system (that is, an optical path) is exposed to the outside of the casing. In such a mirror reflection type projector device in which the optical system is exposed to the outside, light reflected by several mirrors is projected onto a screen.

In the projector apparatus having the above-described structure, the following devices are devised according to the structure.

In the case of a projector device that uses a light source that emits high-luminance light, such a light source also generates a large amount of heat with the emission of light. Therefore, various cooling techniques as described below have been considered in order to discharge generated heat to the outside of the projector apparatus.

Japanese Patent Laid-Open Publication No. 2001-042952 discloses that if a value obtained by adding a target temperature value stored in advance and an allowable error value and a measured operating temperature value do not match, It is disclosed to increase or decrease the driving voltage of a fan that discharges gas to the outside by a preset fixed value.

Japanese Laid-Open Patent Publication No. 2003-005289 discloses a cooling device that controls the rotational speeds of a gas suction fan and a discharge fan for the projector device in accordance with the temperature outside the casing of the projector device.

In the mirror reflection type projector device, when a foreign object is inserted in the optical path, the foreign object may be reflected in the image or video. In order to avoid such a state, it is conceivable to provide a projector device having a detection mechanism for detecting a foreign object existing on the optical path.

In the case of providing the detection mechanism as described above, for example, a light emitting unit that emits infrared light is disposed on one side of an optical path that guides light for projecting an image or video, and is opposed to the position where the light emitting unit is provided. A light receiving portion for receiving infrared light is arranged on the other side. And when the level of the infrared light which injects into a light-receiving part becomes below a predetermined value, it discriminate | determines that a foreign material exists in an optical path.

In the technology for detecting foreign matter using infrared light, a foreign matter is detected when the light receiving portion receives infrared light emitted from the light emitting portion, but a mirror reflection type projector in which the optical system is exposed to the outside. The apparatus has a problem in that ambient infrared light becomes disturbance noise and affects the detection accuracy of foreign matter.

Furthermore, according to the technology for detecting foreign matter using infrared light, a detection mechanism including an infrared light emitting unit and a light receiving unit is further added to the configuration of the projector device, so that the configuration of the projector device is complicated. There is a problem of becoming. Further, since the detection mechanism is added to the projector device, there is a problem that the cost of the projector device becomes expensive.

It is an object of the present invention to provide an object detection device, an object detection method, and a program that solve the above-described problems by detecting a foreign object using a configuration provided in a projector device.

In order to solve the above-described problem, an object detection device of the present invention includes a cooling object disposed in a casing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and the first duct. An object detection device that is provided in a device including a discharge fan that discharges fluid that has passed through at least one of a duct and a second duct to the outside of the housing and detects an object in the vicinity of the object to be cooled, the discharge fan A rotational speed detection unit that detects a rotational speed of the exhaust fan and outputs a rotational speed detection signal indicating the detected rotational speed; a fan rotational speed control unit that outputs a rotational speed control signal that controls the rotational speed of the exhaust fan; An object indicating that an object in the vicinity of the object to be cooled is detected when the rotation speed detection signal is changed when the rotation speed detection signal and the rotation speed control signal are input and the rotation speed control signal is not changed. Inspection And a object detecting section for outputting a signal.

In order to solve the above-described problem, an object detection method of the present invention includes a cooling object disposed in a housing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and the first object. An object detection method in an object detection device provided in an apparatus including an exhaust fan that discharges fluid that has passed through at least one of a duct and a second duct to the outside of the housing, and detects an object in the vicinity of the object to be cooled. A process for detecting the rotational speed of the exhaust fan and outputting a rotational speed detection signal indicating the detected rotational speed; a process for outputting a rotational speed control signal for controlling the rotational speed of the exhaust fan; and the rotational speed An object detection indicating that an object in the vicinity of the object to be cooled is detected when the detection signal and the rotation speed control signal are input and the rotation speed detection signal is changed when the rotation speed control signal is not changed. And a process of outputting No..

In addition, a program to be executed by a computer, a cooling object disposed in a housing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and the first duct and the second duct. And a discharge fan that discharges the fluid that has passed through at least one of the casings to the outside of the casing, and an object detection device that detects an object in the vicinity of the object to be cooled, detects the rotation speed of the discharge fan, A procedure for outputting a rotation speed detection signal indicating the detected rotation speed; a procedure for outputting a rotation speed control signal for controlling the rotation speed of the exhaust fan; and the rotation speed detection signal and the rotation speed control signal. A step of outputting an object detection signal indicating that an object in the vicinity of the object to be cooled is detected when the rotation speed detection signal is changed when the rotation speed control signal is not changed; To.

According to the present invention, the number of rotations of the exhaust fan that discharges the fluid that has passed through at least one of the first duct and the second duct that are arranged to face each other with the object to be cooled is detected, and the number of rotations control signal does not change An object is detected when the number of rotations detected at the time changes. Thus, since it was set as the structure which detects an object using the structure for cooling, an object can be detected, without complicating an apparatus structure.

It is a figure which shows the structure of the projector apparatus according to embodiment of this invention. It is a figure which shows an example of a structure of the optical path shown in FIG. It is a figure which shows the positional relationship of the part exposed to the exterior of a housing | casing in an optical path, and a duct. (A) It is a figure which shows an example of the data structure of the threshold value rotation speed information shown in FIG. (B) It is a figure which shows an example of the data structure of the rotation speed control information shown in FIG. (A) It is a figure which shows an example of the relationship between external temperature and the rotation speed of the fan for obtaining fixed cooling efficiency with respect to external temperature. (B) It is a figure which shows an example of the relationship between the rotation speed of a fan and a duty ratio for obtaining fixed cooling efficiency with respect to external temperature. It is a figure which shows the structure of the control part shown in FIG. It is a flowchart which shows the operation | movement which the projector apparatus of this invention detects the foreign material on an optical path based on a temperature detection signal and a rotation speed detection signal. It is a figure which shows the state by which the foreign material was inserted on the optical path.

Hereinafter, an object detection device (including an object detection method and a program) according to an embodiment of the present invention will be described. Hereinafter, a case where the object detection device of the present embodiment is provided in the mirror reflection type projector device 1 will be described as an example.

First, the configuration of the projector device 1 will be described.

As shown in FIG. 1, the projector device 1 includes a housing 2, a fan 11, a duct 12, a duct 13, a fan 14, a temperature measurement unit 15, a lamp 16, and rotation

speed detection units

17 and 18. And a storage unit 19 and a control unit 20.

In addition, each broken line in FIG. 1 is a line indicating the flow of “fluid”. Here, the “fluid” may be either liquid or gas, but in the following explanation example, the case where the fluid is gas will be described as an example.

The housing 2 includes constituent elements (for example, the

fans

11 and 14, the

ducts

12 and 13, the temperature measuring unit 15, the lamp 16, the rotation

number detecting units

17 and 18, the storage unit 19, and the control unit included in the projector device 1. Part 20). It should be noted that a large amount of heat is generated when the lamp 16 (“cooling object”) emits high-luminance light. Therefore, the gas contained in the housing 2 is warmed.

Further, a part of the optical path 30 for guiding the light emitted from the lamp 16 to the screen (not shown) is exposed outside the housing 2. Here, the optical path 30 will be described in detail with reference to FIG. 2 is a path through which the light from the lamp 16 passes through the optical path 30.

When the light from the lamp 16 passes through the optical path 30, the light from the lamp 16 is reflected by the ellipsoidal mirror 161 and collected by the rod integrator 162. Thereafter, the condensed light is incident on a DMD (Digital Micromirror Device) 167 that is a display element through a relay lens 163, a reflection mirror 164, a reflection prism 165, and a color prism 166. Further, the light reflected by the DMD 167 passes through the color prism 166 again, is magnified by the projection lens 168, and then projected onto a screen (not shown).

In this explanation example, it is assumed that the reflection mirror 164 is exposed outside the housing 2 among the constituent elements forming the optical path 30. The number of reflection mirrors 164 is not limited to “2” and may be arbitrary.

The fan 11 shown in FIG. 1 is constituted by a predetermined motor, for example, and sucks the gas outside the housing 2 into the housing 2. Note that the motor included in the fan 11 may be, for example, a general DC motor.

Further, the fan 11 cools the lamp 16, the DMD 167, a transmissive liquid crystal element (not shown) or the like by sending the gas sucked from the outside of the housing 2 to the lamp 16 or the DMD 167 shown in FIG.

The duct 12 is a “first duct” and is an opening for discharging a part of the gas blown by the fan 11 to the outside of the housing 2.

The duct 13 is a “second duct” in which the suction side of the duct 13 and the side of the duct 12 that discharges the gas in the housing 2 face each other. The duct 13 is an opening for sucking the gas discharged from the duct 12 into the housing 2 again or sucking the gas outside the housing 2.

Here, the positional relationship of the portion of the optical path 30 exposed to the outside of the housing 2 and the

ducts

12 and 13 outside the housing 2 will be described.

As shown in FIG. 3, when the housing 2 is viewed from above, the end portions on the surface side of the housing 2 of each of the ducts 12 and 13 (dotted lines shown in FIG. 3) are the optical paths 30 exposed to the outside of the housing 2. (In the example of FIG. 3, it is installed near the reflection mirror 164).

In this example, the direction in which the discharge side of the duct 12 and the suction side of the duct 13 face each other, and the direction in which the portion of the optical path 30 exposed to the outside of the housing 2 guides light from the lamp 16 (see FIG. 3). It is substantially parallel to the one-dot chain line arrow). In addition, the dotted-line arrow shown in FIG. 3 represents the gas flow.

The fan 14 shown in FIG. 1 is an “exhaust fan” that discharges gas in the housing 2 (for example, gas blown from the fan 11 or gas sucked from the duct 13) to the outside of the housing 2. is there.

Note that the fan 14 is provided so that the gas sucked into the housing 2 by the fan 11 or the duct 13 and warmed by the lamp 16 does not stay in the housing 2.

The temperature measuring unit 15 is constituted by a temperature sensor, for example.

The temperature measurement unit 15 measures the outside air temperature To (“external temperature”) that is the temperature of the gas existing outside the housing 2, and outputs a temperature detection signal TM indicating the measured outside air temperature To to the control unit 20. .

The temperature measurement unit 15 measures the outside air temperature To and outputs the temperature detection signal TM to the control unit 20 every “predetermined period”. Here, the length of the predetermined period is not particularly limited, but in the following explanation example, a case where the temperature measurement unit 15 outputs the temperature detection signal TM at every constant period will be described as an example.

The lamp 16 is composed of, for example, an ultra-high pressure mercury lamp or the like and is a light source that emits high-luminance light. The light emitted from the lamp 16 is used to project an image or video on a screen (not shown).

Each

rotation speed detector

17 or 18 is constituted by an encoder, for example. The rotation

speed detection unit

17 or 18 detects the rotation speed of the fan 11 or the rotation speed of the fan 14 per unit time, and outputs a rotation speed detection signal RV1 or RV2 indicating the detected rotation speed to the control unit 20, respectively. To do.

The storage unit 19 is constituted by a memory, for example, and stores arbitrary data.

For example, the storage unit 19 stores threshold rotation number information 191 and rotation number control information 192.

As shown in FIG. 4A, the threshold rotation speed information 191 is information that associates the outside air temperature To with a threshold rotation speed TH corresponding to a preset outside air temperature To.

Here, the “threshold rotation speed TH” is, for example, the rotation speed of the

fan

11 or 14 such that a substantially constant cooling efficiency can be obtained even when the outside air temperature To changes.

Note that the threshold rotation speed information 191 is obtained by setting a relationship between the threshold rotation speed TH and the outside air temperature To represented by the characteristic line C1 illustrated in FIG. 5A as a preset value.

Further, as shown in FIG. 4B, the rotation speed control information 192 is information that associates the threshold rotation speed TH with the duty ratio DR1 or DR2.

The rotation speed control information 192 uses the relationship between the duty ratio DR1 and the threshold rotation speed TH of the fan 11 illustrated in FIG. 5B or the relationship between the duty ratio DR2 and the threshold rotation speed TH of the fan 14 as a preset value. It is set. Details of the duty ratios DR1 and DR2 will be described later.

Based on the temperature detection signal TM from the temperature measurement unit 15, the rotation number detection signal RV1 from the rotation number detection unit 17, and the rotation number detection signal RV2 from the rotation number detection unit 18, the control unit 20 controls the

fan

11 or 14. Control each speed.

Note that the efficiency of cooling the lamp 16 differs depending on whether the outside temperature To outside the casing 2 is high or low. Therefore, the control unit 20 changes the rotation number of the

fan

11 or 14 according to the outside air temperature To measured by the temperature measurement unit 15 based on the threshold rotation number information 191 and the rotation number control information 192. Thereby, the control part 20 controls the

fan

11 or 14 so that substantially constant cooling efficiency can be obtained even when the outside air temperature To changes.

Next, the configuration of the control unit 20 will be described in detail.

As shown in FIG. 6, the control unit 20 includes a rotation speed determination unit 21, a PWM (Pulse Width Modulation) control unit 22,

PWM generation units

23 and 24, drive

voltage supply units

25 and 26, and a foreign matter detection unit. 27, a notification unit 28, and a light amount control unit 29.

The rotational speed determination unit 21 determines whether the rotational speed of the fan 11 indicated by the rotational speed detection signal RV1 or the rotational speed of the fan 14 indicated by the rotational speed detection signal RV2 corresponds to the threshold rotational speed TH corresponding to the outside air temperature To indicated by the temperature detection signal TM. It is determined whether or not.

In this determination, the rotational speed determination unit 21 stores the rotational speed of the

fan

11 or 14 indicated by the rotational speed detection signal RV1 or RV2 in association with the outside air temperature To indicated by the temperature detection signal TM in the threshold rotational speed information 191. It is determined whether or not the threshold rotational speed TH is larger.

In this determination, the rotation speed determination unit 21 determines that the rotation speed of the

fan

11 or 14 indicated by the rotation speed detection signal RV1 or RV2 is within the appropriate range corresponding to the outside air temperature To indicated by the temperature detection signal TM. To determine whether it is too small.

Further, the rotational speed determination unit 21 also corresponds to the outside air temperature To when the rotational speed indicated by the rotational speed detection signal RV2 from the rotational speed detection unit 18 changes even when the duty ratio DR2 changes in the comparison performed by the foreign matter detection unit 27. It is determined whether or not the rotation speed is greater than the threshold rotation speed TH.

Further, the rotation speed determination unit 21 outputs the threshold temperature rotation TH associated with the outside air temperature To indicated by the temperature detection signal TM and the threshold rotation speed information 191 to the PWM control unit 22.

The PWM control unit 22 is a “fan rotation speed control unit” that outputs a “rotation speed detection signal” by executing a “fan rotation speed control process” in cooperation with the PWM generation unit 24.

The PWM control unit 22 drives the drive voltage V1 to be supplied to the fan 11 in order to rotate the

fan

11 or 14 at the threshold rotation number TH corresponding to the current outside air temperature To according to the determination result of the rotation number determination unit 21. , And a duty ratio DR2 of the drive voltage V2 to be supplied to the fan 14 are calculated.

The PWM control unit 22 outputs the calculated duty ratio DR1 or DR2 to the

PWM generation unit

23 or 24, respectively. Further, the PWM control unit 22 outputs the duty ratio DR <b> 2 to the foreign object detection unit 27.

Note that the method by which the PWM control unit 22 calculates the duty ratio DR1 or DR2 is not particularly limited.

In the present embodiment, the PWM control unit 22 specifies the duty ratio DR1 or DR2 stored in the rotation speed control information 192 in association with the threshold rotation speed TH output from the rotation speed determination unit 21. The duty ratio DR1 or DR2 is calculated.

The above-described duty ratios DR1 and DR2 are ratios of a period during which the PWM pulse PL1 or PL2 is on level to the supply cycle of the PWM pulse PL1 or PL2.

When the PWM pulse PL1 or PL2 is on level, each of the switches described later provided in the drive

voltage supply unit

25 or 26 for supplying the drive voltage V1 or V2 to the

fan

11 or 14 is turned on.

Therefore, as the duty ratios DR1 and DR2 change, the conduction time of the switch of the drive

voltage supply unit

25 or 26 that supplies the drive voltages V1 and V2 changes. That is, since the voltage value obtained by averaging the drive voltage V1 or V2 in the supply cycle changes, the rotational speed of the

fan

11 or 14 changes.

The

PWM generators

23 and 24 are composed of, for example, a PWM generator circuit.

The

PWM generator

23 or 24 generates a PWM pulse PL1 having a duty ratio DR1 or a PWM pulse PL2 having a duty ratio DR2 in accordance with the duty ratio DR1 or DR2 output from the PWM controller 22.

Here, the PWM pulse PL1 is a pulse for causing a motor provided in the fan 11 to conduct a switch that supplies a drive voltage V1 for driving (rotating) the motor.

Further, the PWM pulse PL2 (“rotational speed control signal”) is a pulse for conducting a switch for supplying the drive voltage V2 to the motor included in the fan 14.

Each of the drive

voltage supply units

25 and 26 is composed of, for example, a switch and a DC power source.

The switch included in the drive voltage supply unit 25 is turned on while the PWM pulse PL1 generated by the PWM generation unit 23 is on level, and connects the power supply included in the drive voltage supply unit 25 and the motor included in the fan 11. To do.

That is, the drive voltage supply unit 25 outputs the drive voltage V1 to the fan 11 while the PWM pulse PL1 is on level. Therefore, the rotation speed of the fan 11 changes according to the value of the duty ratio DR1 of the PWM pulse PL1.

The switch included in the drive voltage supply unit 26 is turned on while the PWM pulse PL2 generated by the PWM generation unit 24 is on level, and the power supply included in the drive voltage supply unit 26 and the motor included in the fan 14 are provided. Connect. That is, the drive voltage supply unit 26 outputs the drive voltage V2 to the fan 14 while the PWM pulse PL2 is on level. Therefore, the rotational speed of the fan 14 changes according to the value of the duty ratio DR2 that the PWM pulse PL2 has.

The foreign object detection unit 27 is an “object detection unit”.

The foreign object detection unit 27 compares the latest duty ratio DR2 input by the PWM control unit 22 with the duty ratio DR2 input immediately before the latest duty ratio DR2.

As a result of the comparison, when the latest duty ratio DR2 coincides with the latest immediately preceding duty ratio DR2 and the rotational speed of the fan 14 changes, the foreign matter detection unit 27 will be described later on the optical path 30. An object detection signal DT indicating that the foreign object 40 (“object in the vicinity of the object to be cooled”) has been detected is output to the notification unit 28 and the light amount control unit 29.

When the foreign object detection unit 27 outputs the object detection signal DT, the notification unit 28 notifies the user of the projector device 1 of a “predetermined message” regarding the detection of the foreign object 40. Here, the “predetermined message” is, for example, a message indicating that the foreign object 40 has been detected, a message for prompting the projector device 1 to be turned off, or the like.

In addition, when the notification part 28 is comprised with a LCD (liquid crystal display) panel, the data which show the above-mentioned predetermined message are displayed on the said LCD panel. Moreover, when the notification part 28 is comprised with a speaker, the sound which shows the above-mentioned predetermined message is emitted by the said speaker.

The light quantity control unit 29 functions to supply a light emission voltage for causing the lamp 16 to perform a light emission operation.

The light quantity control unit 29 functions as a “generated heat amount control unit” that controls the amount of heat generated by the lamp 16. That is, when the foreign object detection unit 27 outputs the object detection signal DT, the light amount control unit 29 reduces the light emission voltage so as to reduce the light amount of light emitted from the lamp 16, for example. As the light emission voltage decreases, the amount of heat generated by the lamp 16 also decreases.

Here, the amount of light from the lamp 16 is reduced in order to prevent the foreign matter 40 from becoming high temperature due to the light.

The light amount control unit 29 may perform an operation of turning off the lamp 16 by stopping the supply of the light emission voltage to the lamp 16 instead of the operation of reducing the light emission voltage.

Next, an operation in which the projector apparatus 1 having the above configuration detects a foreign object 40 (object) existing on the optical path 30 based on the duty ratio DR2 and the rotation speed detection signal RV2 will be described.

The duct 12 provided in the vicinity of the optical path 30 discharges the outside air sucked by the fan 11 to the outside of the housing 2. Thereafter, the gas discharged from the duct 12 is sucked into the housing 2 through the duct 13 and further discharged to the outside of the housing 2 by the fan 14.

In this state, as shown in FIG. 7, in step 501, the foreign object detection unit 27 inputs the duty ratio DR2 output from the PWM control unit 22.

Subsequently, in step 502, the foreign object detection unit 27 compares the latest duty ratio DR2 from the PWM control unit 22 with the duty ratio DR2 input immediately before the latest duty ratio DR2.

If the duty ratio DR2 changes as a result of the comparison, the rotational speed determination unit 21 determines that the rotational speed of the fan 14 is not the threshold rotational speed TH corresponding to the outside air temperature To, and the PWM control unit 22 This corresponds to controlling the rotation speed. Therefore, the control unit 20 ends the operation for detecting the foreign object 40 (object).

On the other hand, as a result of the comparison in step 502, the latest duty ratio DR2 from the PWM control unit 22 and the latest immediately preceding duty ratio DR2 coincide, that is, the PWM pulse PL2 that is the rotation speed control signal has not changed. And

In this state, as shown in FIG. 8, when the foreign matter 40 is inserted in the optical path 30 exposed to the outside of the housing 2, a part of the gas discharged from the duct 12 is blocked by the foreign matter 40.

Therefore, the number of gases sucked from the duct 13 and blown to the fan 14 decreases, that is, the pressure exerted on the fan 14 by the gas from the duct 13 to the fan 14 decreases.

When the pressure exerted on the fan 14 decreases, the flow path resistance in the projector device 1 decreases, so that the rotational speed of the fan 14 changes (rises). The rotation speed detection unit 18 outputs a rotation speed detection signal RV2 indicating the rotation speed of the fan 14 that has changed (increased) to the control unit 20.

In step 503, the rotational speed determination unit 21 receives the rotational speed detection signal RV2 output from the rotational speed detection unit 18 after the comparison of the duty ratio DR2 by the foreign matter detection unit 27.

In step 504, the rotational speed determination unit 21 determines that the rotational speed of the fan 14 indicated by the latest rotational speed detection signal RV2 from the rotational speed detection unit 18 is greater than the threshold rotational speed TH corresponding to the outside air temperature To. Determine whether or not. When the determination in step 504 is performed, the rotation speed determination unit 21 outputs the threshold rotation speed TH corresponding to the current outside air temperature To to the PWM control unit 22.

In addition, when the rotation speed determination unit 21 determines that the rotation speed of the fan 14 is larger than the threshold rotation speed TH, the rotation speed of the fan 14 is not a change in the outside air temperature To but a foreign object 40 existing on the optical path 30. It is assumed that it has changed.

Therefore, in step 505, the foreign object detection unit 27 outputs an object detection signal DT indicating that the foreign object 40 existing on the optical path 30 has been detected.

That is, on the optical path 30 based on the change in the rotation speed of the fan 14 indicated by the rotation speed detection signal RV2 from the rotation speed detection unit 18 even though the duty ratio DR2 of the PWL pulse PL2 does not change. It is possible to detect the foreign matter 40 present in the.

When the foreign object detection unit 27 outputs the object detection signal DT, in step 506, the notification unit 28 sends a predetermined message (for example, a message indicating the detection of the foreign object 40) regarding the detection of the foreign object 40 to the user. Notice.

In step 507, when the foreign object detection unit 27 outputs the object detection signal DT, the light amount control unit 29 decreases the light emission voltage supplied to the lamp 16 so as to reduce the light amount of light emitted from the lamp 16. Let

Furthermore, when the rotational speed of the fan 14 has changed due to the presence of the foreign material 40 in the optical path 30, it is necessary to rotate the fan 14 again at the threshold rotational speed TH corresponding to the outside air temperature To.

In step 508, the PWM control unit 22 responds to the current outside air temperature To based on the threshold rotational speed TH and the rotational speed control information 192 output from the rotational speed determination unit 21 during the determination processing in step 504. A duty ratio DR2 for rotating the fan 14 at the threshold rotational speed TH is newly calculated.

The PWM generator 24 generates a PWM pulse PL2 having a new duty ratio DR2 calculated in step 508. The drive voltage supply unit 26 outputs the drive voltage V2 to the fan 14 while the duty ratio DR2 of the PWM pulse PL2 is on. As a result, the fan 14 is driven again at the threshold rotational speed TH corresponding to the outside air temperature To.

Note that the control unit 20 repeatedly executes the operation shown in FIG. 7 every predetermined period.

Thus, the operation of the projector device 1 detecting the foreign matter 40 on the optical path 30 based on the duty ratio DR2 and the rotation speed detection signal RV2 is completed.

As described above, according to the present invention, it is possible to detect the foreign object 40 (object) only by adding the function performed by the foreign object detection unit 27 to the configuration of a general mirror reflection type projector device. It becomes. In other words, the foreign object 40 can be detected while avoiding a complicated configuration of the apparatus (projector apparatus).

Further, according to the present invention, it is possible to detect the foreign object 40 existing in the optical path 30 while avoiding the cost of the projector device becoming expensive.

In addition, according to the present invention, foreign matter is detected without using infrared light. Thereby, the influence with respect to the detection precision of the foreign material resulting from the infrared light around the projector apparatus 1 can be suppressed.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention without departing from the gist of the present invention.

The rotational speed determination unit 21 compares the rotational speed detection signal RV1 or RV2 with the rotational speed command signal indicating the threshold rotational speed TH corresponding to the characteristic line C1 shown in FIG. A corresponding rotation speed error signal ER may be calculated. Then, when the error value indicated by the rotational speed error signal ER is larger than a predetermined value, it is determined that each rotational speed of the

fan

11 or 14 is larger than the threshold rotational speed TH corresponding to the outside air temperature To. Good.

In the present invention, the processing in the projector apparatus 1 is recorded on a recording medium readable by the projector apparatus 1 in addition to the above-described dedicated hardware. The program recorded on the recording medium may be read by the projector device 1 and executed. The recording medium that can be read by the projector apparatus 1 refers to an HDD or the like built in the projector apparatus 1 as well as a transferable recording medium such as a floppy disk (registered trademark), a magneto-optical disk, a DVD, or a CD. For example, the program recorded on the recording medium is read by the control unit 20 included in the projector apparatus 1, and the same processing as described above is performed under the control of the control unit 20.

Here, the control unit 20 of the projector device 1 operates as a computer that executes a program read from a recording medium on which the program is recorded.

Claims

A cooling object disposed in the casing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and a fluid that has passed through at least one of the first duct and the second duct. An object detection device that is provided in a device including an exhaust fan that discharges to the outside and detects an object in the vicinity of the cooling target;
A rotational speed detection unit that detects the rotational speed of the exhaust fan and outputs a rotational speed detection signal indicating the detected rotational speed;
A fan rotation speed control unit for outputting a rotation speed control signal for controlling the rotation speed of the exhaust fan;
An object indicating that an object in the vicinity of the object to be cooled is detected when the rotation speed detection signal changes when the rotation speed detection signal and the rotation speed control signal are input and the rotation speed control signal does not change. An object detection apparatus having an object detection unit that outputs a detection signal.
The object detection apparatus according to claim 1,
A temperature measuring unit that measures the external temperature of the housing every predetermined period and outputs a temperature detection signal indicating the measured external temperature;
A storage unit for storing a predetermined threshold rotation speed corresponding to each of the external temperatures,
When the rotation speed indicated by the rotation speed detection signal is greater than a threshold rotation speed determined corresponding to the external temperature indicated by the temperature detection signal, the fan rotation speed control unit is configured to output the exhaust fan according to the rotation speed control signal. An object detection device characterized by reducing a period during which a driving voltage is supplied to the object.
In the object detection device according to claim 1 or 2,
An object detection apparatus comprising: a notification unit configured to notify a user of a predetermined message related to detection of an object in the vicinity of the cooling target when the object detection unit outputs the object detection signal.
The object detection device according to any one of claims 1 to 3,
An object detection apparatus comprising: a generated heat amount control unit that reduces the amount of heat generated by the object to be cooled when the object detection unit outputs the object detection signal.
A cooling object disposed in the casing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and a fluid that has passed through at least one of the first duct and the second duct. An object detection method in an object detection device that is provided in an apparatus including an exhaust fan that discharges to the outside and detects an object in the vicinity of the object to be cooled;
Processing for detecting the rotational speed of the exhaust fan and outputting a rotational speed detection signal indicating the detected rotational speed;
Fan rotation speed control processing for outputting a rotation speed control signal for controlling the rotation speed of the exhaust fan;
An object indicating that an object in the vicinity of the object to be cooled is detected when the rotation speed detection signal changes when the rotation speed detection signal and the rotation speed control signal are input and the rotation speed control signal does not change. An object detection method comprising: processing for outputting a detection signal.
The object detection method according to claim 5,
A process of measuring the external temperature of the housing every predetermined period and outputting a temperature detection signal indicating the measured external temperature;
Performing a process of storing a predetermined threshold rotational speed corresponding to each of the external temperatures,
In the fan rotation speed control process, when the rotation speed indicated by the rotation speed detection signal is larger than a threshold rotation speed determined corresponding to the external temperature indicated by the temperature detection signal, the exhaust fan is controlled by the rotation speed control signal. A method for detecting an object, comprising: reducing a period during which a drive voltage is supplied to the object.
The object detection method according to claim 5 or 6,
When the object detection signal is output, a process for notifying a user of a predetermined message relating to detection of an object in the vicinity of the object to be cooled is executed.
The object detection method according to any one of claims 5 to 7,
When the object detection signal is output, a process for reducing the amount of heat generated by the cooling target is executed.
A cooling object disposed in the casing, a first duct and a second duct disposed to face each other with the cooling object interposed therebetween, and a fluid that has passed through at least one of the first duct and the second duct. An object detection device provided in a device including a discharge fan for discharging to the outside and detecting an object in the vicinity of the cooling target,
Detecting the rotation speed of the exhaust fan and outputting a rotation speed detection signal indicating the detected rotation speed;
A fan rotation speed control procedure for outputting a rotation speed control signal for controlling the rotation speed of the exhaust fan;
An object indicating that an object in the vicinity of the object to be cooled is detected when the rotation speed detection signal changes when the rotation speed detection signal and the rotation speed control signal are input and the rotation speed control signal does not change. A program for executing a procedure for outputting a detection signal.
The program according to claim 9,
Measuring the external temperature of the housing every predetermined period, and outputting a temperature detection signal indicating the measured external temperature;
Causing the object detection device to execute a procedure of storing a predetermined threshold rotation speed corresponding to each of the external temperatures,
In the fan rotation speed control procedure, when the rotation speed indicated by the rotation speed detection signal is larger than a threshold rotation speed determined corresponding to the external temperature indicated by the temperature detection signal, the exhaust fan is controlled by the rotation speed control signal. A program for reducing a period during which a driving voltage is supplied to a computer.
The program according to claim 9 or 10,
A program for causing the object detection apparatus to execute a procedure for notifying a user of a predetermined message related to detection of an object in the vicinity of the cooling target when the object detection signal is output.
The program according to any one of claims 9 to 11,
When the object detection signal is output, a program for causing the object detection apparatus to execute a procedure for reducing the amount of heat generated by the cooling target.