projector

Abstract

To provide a projector that can improve cooling performance.SOLUTION: A projector comprises: an exterior housing that sucks outside air into the housing through a filter; a light source that is arranged in the exterior housing; an image forming unit that converts light from the light source into image light; a suction fan that has a suction port to suck in the outside air; a front chamber that is communicated with the filter and the suction port; a pressure sensor that is arranged in the front chamber; and a control section that controls to drive the suction fan. The control section executes first measurement processing of starting up the suction fan and measuring the pressure in the front chamber with the pressure sensor at the number of rotations at the start-up, second measurement processing of changing the number of rotations of the suction fan to the number of rotations smaller than the number of rotations at the start-up and measuring the pressure in the front chamber with the pressure sensor, and determination processing of determining if the filter is clogged based on the difference between the value of pressure measured in the first measurement processing and the value of pressure measured in the second measurement processing.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a projector. [Background technology]

[0002] Patent Document 1 discloses a projector that includes an intake fan for taking air into the housing through an intake port, an exhaust fan for discharging the air from the housing, a dust filter attached to the intake port, and a pressure sensor for detecting the pressure inside the housing, and detects the clogging state of the dust filter based on the output of the pressure sensor. The pressure sensor is disposed between the intake fan and the exhaust fan. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-188040 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the projector described in Patent Document 1 has a problem in that it takes time for the pressure inside the housing to become constant throughout the entire housing, and therefore takes time to cool the inside of the housing if the dust filter is clogged. In other words, there is a demand for a device that can quickly detect clogging of the dust filter to improve the cooling performance inside the housing, as well as shorten the time from when the power is turned on until an image is projected. [Means for solving the problem]

[0005] The projector includes an exterior casing that draws in outside air through a filter, a light source disposed on the exterior casing, an image forming device disposed on the exterior casing that converts light from the light source into image light, a suction fan disposed on the exterior casing and having an intake port for drawing in the outside air, a front chamber disposed on the exterior casing that communicates with the filter and the intake port, a pressure sensor disposed in the front chamber, and a control unit that drives and controls the suction fan, and the control unit executes a first measurement process of starting the suction fan and measuring the pressure in the front chamber at the rotation speed at the start-up with the pressure sensor, a second measurement process of setting the rotation speed of the suction fan to a speed lower than the rotation speed at the start-up and measuring the pressure in the front chamber with the pressure sensor, and a determination process of determining whether the filter is clogged based on the difference between the pressure values ​​of the first measurement process and the pressure values ​​of the second measurement process. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing a configuration of a projector. [Diagram 2] FIG. 2 is a plan view showing a configuration from a light source unit to a projection optical unit. [Diagram 3] 3 is a cross-sectional view taken along line AA' shown in FIG. 2. [Figure 4] FIG. 2 is a plan view of the inside of the projector as seen from the top side. [Diagram 5] FIG. 2 is a plan view showing a partial internal configuration of the projector. [Figure 6] FIG. 2 is a plan view showing a configuration from a light source unit to a projection optical unit. [Figure 7] FIG. 1 is a perspective view showing a configuration of a portion of a projector. [Figure 8] A side view of the inside of the projector. [Figure 9] FIG. 1 is a block diagram showing the configuration of a projector. [Figure 10] 5 is a flowchart showing a method for driving a suction fan. [Figure 11] 5 is a timing chart showing a method of driving a suction fan. [Figure 12]5 is a timing chart showing a method of driving a suction fan. [Figure 13] 5 is a timing chart showing a method of driving a suction fan. [Figure 14] 5 is a timing chart showing a method of driving a suction fan. [Figure 15] 5 is a timing chart showing a method of driving a suction fan. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] In the following drawings, three mutually orthogonal axes are described as the X-axis, Y-axis, and Z-axis. The direction along the X-axis is the "X-direction", the direction along the Y-axis is the "Y-direction", and the direction along the Z-axis is the "Z-direction", the direction of the arrow is the + direction, and the direction opposite to the + direction is the - direction. The +Z direction is also called "up" or "upward", and the -Z direction is also called "down" or "downward", and the view from the +Z direction is also called planar view or planar. In addition, the surface on the + side of the Z direction is described as the top surface, and the surface on the opposite side of the Z direction is described as the bottom surface. In this embodiment, the direction from the front 100a to the back 100b of the exterior housing 100 described later is defined as the +Y direction of the Y axis, the direction of the exhaust port 210 of the X axis perpendicular to the Y axis is defined as the +X direction, and the direction of the projection port of the Z axis perpendicular to the Y axis and the X axis is defined as the +Z direction.

[0008] First, the configuration of a projector 1000 will be described with reference to FIGS.

[0009] 1, the projector 1000 includes an exterior housing 100, an intake port 200 disposed on a front surface 100a of the exterior housing 100, and a projection optical unit 300 that projects image light L onto a rear surface 100b of the exterior housing 100. A reflection mirror for reflecting the image light L is disposed in the projection optical unit 300.

[0010] 2, the projector 1000 includes a light source unit 400, a light guide optical unit 500, an image forming unit 600 as an image forming device, and a projection optical unit 300. The light source unit 400, the light guide optical unit 500, the image forming unit 600, and the projection optical unit 300 are arranged along a system optical axis (image light L).

[0011] The light source unit 400 includes a light source 401 having a solid-state light source such as a laser semiconductor that can provide high brightness or a wavelength conversion element made of a phosphor that converts the wavelength of a part of the laser light as excitation light, an integrator lens, and a polarization conversion element. The light source 401 may be an LED light source or a white light source such as an ultra-high pressure mercury lamp or a halogen lamp. The polarization conversion element has a function of aligning the P-polarized component and the S-polarized component emitted from the light source 401.

[0012] The light-guiding optical unit 500 includes, for example, a dichroic mirror as a light separation element, a reflecting mirror, and a relay lens.

[0013] The image forming unit 600 is a part that generates image light from the light emitted from the light source unit 400, and includes liquid crystal panels 601R, 601G, and 601B as three light modulation panels, and a cross dichroic prism 602 as a light combining element.

[0014] 3, the projection optical unit 300 is attached to the exterior housing 100. The projection optical unit 300 may be provided with a lens shift mechanism. The combined image light L is projected onto a screen by a projection lens, and the image is enlarged and displayed.

[0015] Next, the flow of the outside air G taken into the projector 1000 will be described with reference to FIGS.

[0016] 4, as described above, the projector 1000 includes the light source unit 400, the image forming unit 600, and the projection optical unit 300 inside the exterior housing 100. The speaker unit 101 is disposed on the right side of the front surface 100a of the exterior housing 100, i.e., on the +X direction side with respect to the projection optical unit 300. The power supply unit 102 is disposed on the right side of the rear surface 100b of the exterior housing 100, i.e., on the +X direction side with respect to the projection optical unit 300 and on the +Y direction side with respect to the speaker unit 101.

[0017] As described above, the air intake 200 is disposed on the left side of the front surface 100a of the exterior housing 100, i.e., on the -X direction side of the projection optical unit 300. The air intake 200 is provided with a filter 201 that captures dust and other particles contained in the outside air. A front chamber 202 having a plurality of suction fans, four suction fans 203a, 203b, 203c, and 203d in this embodiment, is disposed inside the exterior housing 100 relative to the filter 201.

[0018] The front chamber 202 is a space separating the filter 201 and the intake port 203x of the suction fan 203, and constitutes a pseudo outside air pressure forming chamber. The intake port 203x is a tip of the suction fan 203. The suction fan 203 also has an outlet port for discharging the intake outside air G. A pressure sensor 204 for measuring the pressure inside the front chamber 202 is disposed in a part of the front chamber 202.

[0019] The three suction fans 203a, 203c, and 203d blow outside air to the three liquid crystal panels 601 that constitute the image forming unit 600. The remaining suction fan 203b blows outside air to the projection lens and the polarization conversion element that constitute the projection optical unit 300. The outside air is blown using a duct.

[0020] 5, an outlet (not shown) of suction fan 203 is connected to three liquid crystal panels 601R (red), 601G (green), and 601B (blue) constituting image forming unit 600 via duct 103. Specifically, three suction fans 203a, 203c, and 203d (see FIG. 4) blow air to each liquid crystal panel 601 via an individual duct 103.

[0021] As described above, the suction fans 203a, 203b, 203c, and 203d do not have to be designed to cool specific objects. For example, a part of the suction fan 203 may be connected to one duct 103, and the duct 103 may be branched into three in the middle to blow air to each of the liquid crystal panels 601. The part 103a of the duct 103 is configured to be able to blow air to the polarization conversion element.

[0022] Also, the number of suction fans 203 is not limited to four, and only one may be used. In this case, for example, air may be sent only to the liquid crystal panel 601 that is the heat source that most needs to be cooled, for example, the blue liquid crystal panel 601B. Although the suction ports 203x of the multiple suction fans 203 are open in one front chamber 202, a front chamber 202 and a pressure sensor 204 may be provided for each suction fan 203.

[0023] 4, a part of the air K1 that has been blown from the suction fan 203 to cool the image forming unit 600 is sucked into the fan 205. The air K1 blown from the fan 205 cools the light source unit 400 and is discharged to the outside from an exhaust port of the exterior housing 100 on the left side of the exterior housing 100 in the -X direction with respect to the light source unit 400. In addition, the air K2 that has cooled the image forming unit 600, the power supply unit 102, the projection optical unit 300, and the like is discharged via the fans 206, 207, and 208 from an exhaust port 210 of the exterior housing 100 on the right side of the exterior housing 100 in the +X direction.

[0024] The pressure sensor 204 is disposed in the space between the filter 201 and the intake port 203x of the suction fan 203 (see FIG. 5).

[0025] Next, the flow of the air K in a plan view and a cross-sectional view will be described with reference to FIGS.

[0026] As shown in FIG. 6, in plan view, outside air G is taken into exterior housing 100 via filter 201 arranged in intake port 200 of projector 1000.

[0027] 7, when the projector 1000 is viewed obliquely, outside air G is taken into the interior of the exterior housing 100 through an air intake 200 disposed at the lower left of the front surface 100a of the exterior housing 100. The taken-in outside air G passes through a filter 201 and enters an antechamber 202.

[0028] The filter 201 is disposed below the suction fan 203, that is, so as to face the suction fan 203 in the -Z direction. As shown in FIG. 8, when the projector 1000 is viewed from the side, outside air G is taken into the exterior housing 100 through the intake port 200 disposed on the lower side of the front surface 100a of the exterior housing 100. The taken-in outside air G passes through the filter 201 and enters the front chamber 202. Note that the suction fan 203 only needs to be disposed so that the intake port 203x communicates with the front chamber 202, and may be disposed inside the front chamber 202 or outside the front chamber 202. Also, the intake port 203x may be located on the side of the wall of the front chamber 202 or may extend inside the front chamber 202.

[0029] Next, the configuration of the projector 1000 will be described with reference to FIG.

[0030] The projector 1000 includes a control unit 10 that controls the overall operation of the projector 1000, an image processing unit 11, a light modulation element driving unit 12, a light modulation element 13, a light source 401, and a light source driving unit 14 that drives the light source 401.

[0031] The projector 1000 also includes a suction fan 203 that takes in air from the outside through the air intake 200 described above, an exhaust fan 208 that expels air inside the exterior housing 100 to the outside through an exhaust port 210 (see FIG. 4) formed in the exterior housing 100, and a fan drive unit 15 that drives the suction fan 203 and the exhaust fan 208, respectively.

[0032] Furthermore, the projector 1000 is equipped with an operation unit 16 including switches for inputting various operation signals to the control unit 10, a display unit 17 that indicates the status of the projector 1000, an audio output unit 18, and a non-volatile memory unit 19 that holds various data and programs.

[0033] The projector 1000 also includes a detection unit 20 that detects the output of the pressure sensor 204, and a judgment unit 21 that judges whether the filter 201 is clogged or not based on the pressure value of the antechamber 202 detected by the detection unit 20 and a threshold value.

[0034] The control unit 10 is composed of a microcomputer including a CPU, ROM, RAM, and other memories, and controls the overall operation of the projector 1000, such as the operation of the image processing unit 11, light source driving unit 14, fan driving unit 15, display unit 17, operation unit 16, audio output unit 18, memory unit 19, detection unit 20, and judgment unit 21, in accordance with various programs stored in the ROM.

[0035] The light modulation element 13 is composed of a liquid crystal light valve including three liquid crystal panels 601R, 601G, and 601B that modulate the light emitted from the light source 401, and modulates each of the colors R (red), G (green), and B (blue), respectively.

[0036] The light emitted from the light source 401 is separated into each color light by the light-guiding optical unit 500, then modulated by a liquid crystal light valve (not shown) including a corresponding liquid crystal panel 601, and then combined by a cross dichroic prism 602, and then enlarged and projected by the projection optical unit 300.

[0037] The image processing unit 11, for example, supplies the generated frame video signal to the light modulation element driving unit 12. Furthermore, when the operation unit 16 is operated, the control unit 10 drives the light source driving unit 14 to turn on the light source 401, and drives the fan driving unit 15 to rotate the suction fan 203 and the exhaust fan 208.

[0038] This allows external air to be taken into exterior housing 100, while discharging air inside exterior housing 100 to the outside, cooling the inside of exterior housing 100. Furthermore, control unit 10 starts image processing unit 11, which performs various processes on the input video signal to generate a frame video signal and supplies it to light modulation element driving unit 12, whereby the light transmittance of each pixel of light modulation element 13 is controlled based on the frame video signal.

[0039] Next, a method for driving the suction fan 203 will be described with reference to Figures 10 to 13. Below, a driving method when the projector 1000 is used at low altitude will be described.

[0040] As shown in Fig. 10, in step S11, when the user turns on the power of the projector 1000, the control unit 10 causes the fan driving unit 15 to start driving the suction fan 203. Specifically, as shown in Fig. 11, the suction fan 203 is started at a start-up speed. This start-up speed is set to a higher rotation speed than normal driving in order to drive the suction fan 203 stably.

[0041] In the timing chart of the operation of suction fan 203 shown in Fig. 11, the horizontal axis indicates the passage of time, and the vertical axis corresponds to the rotation speed of suction fan 203. The rotation speed increases as you move up the vertical axis. In the timing chart of the operation of pressure sensor 204, the horizontal axis indicates the passage of time, and the vertical axis indicates pressure. Pressure decreases as you move down the vertical axis.

[0042] This rotation speed is the rotation speed required for stable operation of the suction fan 203 when the suction fan 203 is started. This rotation speed is lower than the maximum driving speed of the suction fan 203, and is set to reduce noise. If noise is not a consideration, the suction fan 203 may be driven at maximum. During the start-up period when the rotation speed of the suction fan 203 is high (driving capacity is high), outside air G is taken into the front room 202 via the filter 201. In FIG. 11, "PWRON fan rotation starts" is displayed. At this time, the movement of the pressure sensor 204 is atmospheric pressure.

[0043] In step S12, the control unit 10 causes the light source driving unit 14 to turn on a laser as the light source 401. Here, it is assumed that a laser is used as the light source 401. Specifically, as shown in FIG. 11, the suction fan 203 maintains its startup speed. The movement of the pressure sensor 204 in the front chamber 202 is a pressure value lower than the atmospheric pressure. By starting the light source 401, the light from the light source 401 causes the liquid crystal panel 601, the polarization conversion element, the phosphor, etc. to rise in temperature as heat sources. The phosphor has a function of converting the excitation light into fluorescence.

[0044] In step S13, the control unit 10 causes the detection unit 20 to perform a first pressure measurement (pressure measurement 1) as the first measurement process. Specifically, the suction fan 203 maintains the start-up speed. The pressure in the front chamber 202 at this time is measured using the pressure sensor 204 to obtain a reference value.

[0045] In step S14, the control unit 10 causes the fan drive unit 15 to set the rotation speed of the suction fan 203 to the minimum rotation speed. Specifically, as shown in FIG. 11, after pressure measurement 1, the suction fan 203 is set to the minimum drive speed. The minimum drive speed is a drive for setting the pressure in the front chamber 202 to the same level as the outside air pressure, i.e., atmospheric pressure. When the suction fan 203 is stopped, it needs to be driven again to start it up, so it is driven as slowly as possible. The pressure in the front chamber 202 at this time becomes the pseudo outside air pressure (atmospheric pressure). The period during which it rotates at the minimum rotation speed is defined as a stable drive period.

[0046] In step S15, the control unit 10 causes the detection unit 20 to perform a second pressure measurement (pressure measurement 2) as the second measurement process. As described above, the pressure in the front chamber 202 is set to the pseudo-atmospheric pressure. As a threshold value for clogging of the filter 201, a threshold value is set based on the pressure value acquired in pressure measurement 2.

[0047] In step S16, the control unit 10 causes an arithmetic processing unit (not shown) to calculate the difference between the pressure value measured in pressure measurement 2 and the pressure value measured in pressure measurement 1 (pressure difference=pressure measurement 2−pressure measurement 1).

[0048] In step S17, the control unit 10 causes the determination unit 21 to determine whether or not the pressure difference calculated in step S16 is greater than a threshold value (determination process). If it is less than the threshold value and the filter 201 is not clogged, the process proceeds to step S19. If it is greater than the threshold value and the filter 201 is clogged, the process proceeds to step S18.

[0049] As shown in Fig. 11, when the filter 201 is not clogged and the process proceeds to step S19, the control unit 10 causes the fan drive unit 15 to increase the rotation speed of the suction fan 203 from the minimum drive speed and drive it at the normal drive rotation speed. This rotation speed is the rotation speed required to maintain the cooling function of the liquid crystal panel 601, which is a heat source, the polarization conversion element, and the light source 401. The rotation speed of this normal control is lower than the rotation speed at the startup speed. The movement of the pressure sensor 204 at this time indicates a pressure value where a negative pressure is added to the atmospheric pressure.

[0050] As shown in Fig. 12, when filter 201 is clogged and the process proceeds to step S18, control unit 10 causes fan drive unit 15 to drive suction fan 203 at a higher rotation speed than the rotation speed at the startup speed for a certain period of time, a step-up time. In Fig. 12, this is indicated as step-up speed. This is because light source 401 is driven after suction fan 203 is started, and so for example, the temperature of liquid crystal panel 601 continues to rise, so that the suction fan 203 is driven to stop the temperature rise of liquid crystal panel 601 and to bring the temperature into a state where it can be controlled.

[0051] During this step-up time, the rotation speed is increased to a higher speed than the startup speed, taking priority over the increase in noise of the suction fan 203. Full rotation drive is also acceptable. At this time, the pressure value of the pressure sensor 204 disposed in the front chamber 202 further drops to negative pressure. In this way, when there is clogging, the temperature rise of the heat source can be quickly suppressed by increasing the rotation speed.

[0052] When filter 201 is clogged, the pressure value in pressure measurement 1 is lower than when filter 201 is not clogged, as shown in Fig. 12. In other words, the negative pressure is higher. As a result, the pressure difference calculated in step S16 is determined to be greater than the threshold value in step S17.

[0053] By measuring the pressure in the anterior chamber 202 using the start-up drive operation of the suction fan 203, which requires a higher rotation speed than the normal drive speed, the amount of outside air sucked in is large, so clogging can be measured prominently. Furthermore, even if there is clogging, the pressure in the anterior chamber 202 in pressure measurement 2 is measured as a pseudo outside air pressure because there is no difference from the pressure when there is no clogging, since the suction fan 203 is driven at a low speed.

[0054] 12, when the step-up time has elapsed, the rotation speed of the suction fan 203 is reduced from the step-up speed to the driving rotation speed of the suction fan 203 in a clogged state, i.e., the clogged driving rotation speed. In other words, the suction fan 203 is driven at a rotation speed (step-up speed) higher than the clogged driving rotation speed, and then reduced to the clogged driving rotation speed. At this time, the rotation speed of the suction fan 203 is driven at a higher rotation speed than the rotation speed of normal control without clogging, since the environment is one in which the heat source is likely to rise. Note that the rotation drive in a clogged state is not limited to one rotation speed, and it is preferable to provide multiple types of rotation drives according to the degree of clogging.

[0055] Although not shown in Fig. 10, when it is determined that the filter 201 is clogged, it is preferable to determine whether to continue using the projector 1000 or to stop using it. Stopping the use of the projector 1000 refers to a state in which the cooling function of the liquid crystal panel 601, which is a heat source, the polarization conversion element, and the light source 401 cannot be maintained, and is determined based on a threshold value. In other words, the diagram shown in Fig. 12 shows a case where the cooling function of the heat source can be maintained by controlling the suction fan 203. When the use of the projector 1000 is stopped, for example, the power of the projector 1000 is turned off or a warning is issued.

[0056] Furthermore, while it is possible to use the projector 1000, if there is a relatively large amount of clogging, the suction fan 203 may be driven to maintain the step-up speed rotation speed even after the step-up time has elapsed, as shown in FIG. 13.

[0057] Furthermore, pressure measurement 1 utilizes the start-up drive operation of suction fan 203, which requires a higher rotation speed than the normal drive rotation speed, while pressure measurement 2 does not stop the drive of suction fan 203, so that the time until the projection image is projected is not delayed by the clogging determination process measurement.

[0058] Next, a method of driving the suction fan 203 when the projector 1000 is used at high altitude will be described with reference to Fig. 14 and Fig. 15. The differences from the above-mentioned case where the projector 1000 is used at low altitude will be described in detail. High altitude is, for example, an environment above 2000m.

[0059] At high altitudes, the air pressure is low, so it is desirable to use a driving method for cooling the heat source that is suitable for high altitudes. Figure 14 shows a driving method when there is no clogging at high altitudes. Figure 15 shows a driving method when there is clogging at high altitudes.

[0060] As shown in Fig. 14, when the projector 1000 is started and the suction fan 203 is started, the value of the pressure sensor 204 becomes more negative than the low ground. Note that the dashed line showing the movement of the pressure sensor 204 in Fig. 14 indicates the pressure value when there is no clogging at the low ground for reference.

[0061] Therefore, the first pressure measurement (pressure measurement 1) as the first measurement process results in a pressure value that is more negative than the low ground. Similarly, the second pressure measurement (pressure measurement 2) as the second measurement process results in a pressure value that is more negative than the low ground.

[0062] Note that a high altitude mode determination threshold is set in advance to be compared with the pressure value of the pseudo atmospheric pressure in pressure measurement 2. In other words, if the pressure value in pressure measurement 2 is more negative than the high altitude mode determination threshold, the suction fan 203 is driven in the high altitude mode. Since the absolute value of atmospheric pressure changes greatly between high altitude and low altitude, it is possible to determine whether the altitude is high or low only with the pressure value in pressure measurement 2.

[0063] To determine whether or not there is clogging, the difference between pressure measurement 1 and pressure measurement 2 is compared with the threshold value, just like in the case of low altitude. In the case of Fig. 14, the difference is smaller than the threshold value, which means there is no clogging.

[0064] If there is no clogging and it is determined that the altitude is high, the suction fan 203 is driven at a first high altitude mode drive rotation speed, which is higher than the normal drive rotation speed at low altitude. This is because at high altitudes, the temperature of the heat source is likely to rise and more cooling is required. In this way, using the pressure sensor 204, it is possible to accurately determine whether the altitude is high and whether the air is clogged.

[0065] Next, a method of driving the suction fan 203 when clogging occurs will be described with reference to FIG.

[0066] 15, when clogging occurs at high altitude, the pressure value of pressure measurement 1 is lower than that at low altitude. The threshold for determining whether clogging occurs or not is set based on the pseudo atmospheric pressure value of pressure measurement 2, and when the difference between pressure measurement 1 and pressure measurement 2 is greater than the threshold, it is determined that clogging occurs.

[0067] If it is determined that there is clogging and that the projector 1000 can be used, the suction fan 203 is driven at the step-up speed during the step-up time, and then driven at the second high altitude mode drive rotation speed due to the clogging state. The second high altitude mode drive rotation speed is a rotation speed higher than the clogging drive rotation speed in the low altitude mode.

[0068] As described above, the projector 1000 of this embodiment includes the exterior housing 100 that draws in outside air G through the filter 201, the light source 401 arranged in the exterior housing 100, the image forming unit 600 arranged in the exterior housing 100 that converts light from the light source 401 into image light, the suction fan 203 arranged in the exterior housing 100 and having an intake port 203x that draws in outside air G, the front chamber 202 arranged in the exterior housing 100 and communicating with the filter 201 and the intake port 203x, and the front chamber 202 arranged in the front housing 202. The control unit 10 executes a first measurement process in which the suction fan 203 is started and the pressure in the anterior chamber 202 is measured by the pressure sensor 204 at the rotation speed at the start-up, a second measurement process in which the rotation speed of the suction fan 203 is set to a lower rotation speed than the rotation speed at the start-up and the pressure in the anterior chamber 202 is measured by the pressure sensor 204, and a determination process in which the filter 201 is clogged based on the difference between the pressure value of the first measurement process and the pressure value of the second measurement process.

[0069] According to this configuration, the first measurement process can measure a pressure value reflecting the clogging state of the filter 201, the second measurement process can measure a pressure value close to the pressure of the outside air G, and the determination process can determine whether the filter 201 is clogged based on the difference between the two pressure values. Furthermore, since the pressure sensor 204 is disposed in the front chamber 202 and measures the pressure value of the front chamber 202, which is a limited area, it takes less time for the pressure to become constant and the pressure value can be measured earlier than when the pressure value of the entire exterior housing 100 is measured. This makes it possible to accurately determine clogging in a short time after the suction fan 203 is started, and for example, a cooling process based on the determination can be performed. Furthermore, since the cooling process can be performed quickly, image light can be projected in a short time after the suction fan 203 is started.

[0070] Furthermore, in the projector 1000 of this embodiment, if the control unit 10 determines in the determination process that the condition does not correspond to clogging, it is preferable that the control unit 10 drives the suction fan 203 in normal drive and drives the suction fan 203 at a normal drive rotation speed higher than the rotation speed in the second measurement process, and if the control unit 10 determines in the determination process that the condition corresponds to clogging, it drives the suction fan 203 in clogging drive and drives the suction fan 203 at a clogging drive rotation speed higher than the normal drive rotation speed. With this configuration, when clogging is determined, it is possible to maintain the cooling performance by driving the suction fan 203 at a clogging drive rotation speed higher than the normal drive rotation speed, and the projector 1000 can be used.

[0071] Furthermore, in the projector 1000 of this embodiment, when the control unit 10 determines that clogging has occurred in the determination process, it is preferable that the control unit 10 drives the suction fan 203 at a rotation speed higher than the clogging drive rotation speed, and then reduces the rotation speed to the clogging drive rotation speed. With this configuration, when clogging has been determined, the temperature rise of the heat source can be quickly suppressed by setting the rotation speed higher than the clogging drive rotation speed.

[0072] Furthermore, in the projector 1000 of this embodiment, it is preferable that the control unit 10 turns on light from the light source 401 during the period from when the suction fan 203 is started to when the first measurement process is performed, and executes the second measurement process during the stable drive period of the light source 401. According to this configuration, the light source 401 is turned on after the suction fan 203 is started, and the second measurement process is executed during the stable drive period, so that it is possible to perform the first measurement process and the second measurement process quickly, and the projector 1000 can be put into a usable state quickly.

[0073] Furthermore, in projector 1000 of this embodiment, it is preferable that control unit 10 has a threshold value for determining whether the altitude is high or low, and when it is determined that the altitude is high by comparing the pressure value of the second measurement process with the threshold value, drives suction fan 203 at a higher rotation speed than the rotation speed at low altitude. With this configuration, the pressure value of the second measurement process, which is a pseudo atmospheric pressure, is compared with the threshold value, and if the altitude is high, suction fan 203 is driven at a high rotation speed, so that it is possible to maintain the cooling performance and use projector 1000.

[0074] Moreover, in projector 1000 of this embodiment, it is preferable that image forming unit 600 has liquid crystal panel 601, suction fan 203 has an outlet, and the outlet and liquid crystal panel 601 are connected by duct 103. According to this configuration, since duct 103 is provided, liquid crystal panel 601 can be cooled in response to clogging of filter 201.

[0075] Moreover, in the projector 1000 of the present embodiment, it is preferable that another suction fan 203 different from the suction fan 203 is provided, the other suction fan 203 has another intake port 203x, and the other intake port 203x communicates with the front chamber 202. According to this configuration, the other suction fan 203 also communicates with the common front chamber 202 and draws in outside air G via the common filter 201, so that even when the other suction fan 203 is used, clogging of the filter 201 can be measured.

[0076] Modifications of the above embodiment will now be described.

[0077] As described above, when clogging is detected, the method is not limited to changing the driving method of the suction fan 203, and for example, a notification process may be performed to prompt the user to replace or clean the filter 201. Examples of the notification process include notifying the user using the display unit 17 of the projector 1000, or notifying a connected device via wireless means. Note that the notification may be displayed using an LED or the like, or may be given by voice via the audio output unit 18. [Explanation of symbols]

[0078] 10...control unit, 11...image processing unit, 12...light modulation element driving unit, 13...light modulation element, 14...light source driving unit, 15...fan driving unit, 16...operation unit, 17...display unit, 18...audio output unit, 19...storage unit, 20...detection unit, 21...determination unit, 100...exterior housing, 100a...front, 100b...rear, 101...speaker unit, 102...power supply unit, 103...duct, 103a...part, 200...air intake, 201...filter, 202...front chamber, 203...suction fan, 203a,2 03b, 203c, 203d...suction fan, 203x...intake port, 204...pressure sensor, 205, 206, 207...fan, 208...exhaust fan, 210...exhaust port, 300...projection optical unit, 400...light source unit, 401...light source, 500...light-guiding optical unit, 600...image forming unit as image forming device, 601, 601B, 601G, 601R...liquid crystal panel as light modulation panel, 602...cross dichroic prism, 1000...projector.

Claims

1. An exterior housing that draws in outside air through a filter; A light source disposed in the exterior housing; an image forming device disposed in the exterior housing and configured to convert light from the light source into image light; a suction fan disposed in the exterior housing and having an intake port for drawing in the outside air; a front chamber disposed in the exterior housing and communicating with the filter and the intake port; A pressure sensor disposed in the anterior chamber; A control unit that drives and controls the suction fan; Equipped with The control unit is a first measurement process of starting the suction fan and measuring the pressure in the front chamber at the rotation speed at the start with the pressure sensor; a second measurement process of setting a rotation speed of the suction fan to a rotation speed lower than the rotation speed at the start-up, and measuring the pressure in the front chamber with the pressure sensor; a determination process for determining whether the filter is clogged based on a difference between a pressure value in the first measurement process and a pressure value in the second measurement process; Run the projector.

2. The projector according to claim 1 , The control unit is When it is determined in the determination process that the clogging does not occur, the suction fan is driven in a normal driving manner so as to be driven at a normal driving rotation speed that is higher than the rotation speed in the second measurement process. When it is determined in the determination process that the condition corresponds to a clogging, the suction fan is driven in a clogging drive state, and the suction fan is driven at a clogging drive rotation speed that is higher than the normal drive rotation speed.

3. The projector according to claim 2 , When the control unit determines that a clogging occurs in the determination process, the control unit drives the suction fan at a rotation speed higher than the clogging drive rotation speed, and then reduces the rotation speed to the clogging drive rotation speed.

4. The projector according to any one of claims 1 to 3, The control unit turns on light from the light source during the period from when the suction fan is started until the first measurement process, and executes the second measurement process during a stable drive period of the light source.

5. The projector according to any one of claims 1 to 4, The control unit is A threshold value is provided for determining whether the land is high or low; the pressure value of the second measurement process is compared with the threshold value, and when it is determined that the altitude is high, the suction fan is driven at a rotation speed higher than the rotation speed at the low altitude.

6. The projector according to any one of claims 1 to 5, the image forming apparatus has a light modulation panel, The suction fan has an outlet, The discharge port and the light modulation panel are connected by a duct.

7. The projector according to any one of claims 1 to 6, A suction fan other than the suction fan is provided, The other suction fan has another suction port, The other intake port is in communication with the front chamber.

Images