Projection type video display device, control method therefor, and program

Abstract

This projection type video display device comprises: an optical unit including a housing in which an optical element is disposed and which has a sealed structure; a supply unit capable of supplying a predetermined gas into the housing; a pressure sensor for measuring atmospheric pressure in the housing; and a control unit that causes the supply unit to supply the predetermined gas into the housing according to the atmospheric pressure in the housing measured by the pressure sensor.

Description

Projection-type video display device, its control method, and program

[0001] The present disclosure relates to a projection-type video display device, its control method, and a program.

[0002] In recent years, the brightness of projectors, which are projection-type video display devices, has been increasing. Along with this, the amount of heat generated by the phosphor wheel in the phosphor unit has been increasing. When the heat generation of the phosphor wheel becomes large, it directly leads to a decrease in reliability such as a decrease in light quantity and material burnout. Therefore, an improvement in the cooling efficiency of the phosphor wheel is required.

[0003] For example, Patent Document 1 discloses a configuration in which a phosphor wheel is sealed and has a cylindrical fin structure. Further, in Patent Document 1, a configuration in which the inside of the sealed structure is filled with a gas or liquid having high thermal conductivity is disclosed.

[0004] International Publication No. 2018 / 116689

[0005] The present disclosure has been devised in view of the above-described conventional situation, and aims to improve the cooling function of a projection-type video display device.

[0006] The present disclosure provides a projection-type video display device including an optical unit including a housing having a sealed structure with an optical element disposed therein, a supply unit capable of supplying a predetermined gas into the housing, a pressure sensor for measuring the air pressure inside the housing, and a control unit for supplying the predetermined gas into the housing through the supply unit according to the air pressure inside the housing measured by the pressure sensor.

[0007] Further, the present disclosure provides a control method for a projection-type video display device including an optical unit including a housing having a sealed structure with an optical element disposed therein, a supply unit capable of supplying a predetermined gas into the housing, and a pressure sensor for measuring the air pressure inside the housing, the control method including a control step of supplying the predetermined gas into the housing through the supply unit according to the air pressure inside the housing measured by the pressure sensor.

[0008] Furthermore, this disclosure provides a program for causing a computer of a projection-type image display device, which comprises an optical unit comprising an optical unit having an optical element disposed inside and a sealed housing, a supply unit capable of supplying a predetermined gas into the housing, and a pressure sensor for measuring the air pressure inside the housing, to execute a control step of supplying the predetermined gas into the housing via the supply unit in accordance with the air pressure inside the housing measured by the pressure sensor.

[0009] According to this disclosure, it is possible to improve the cooling function of projection-type image display devices.

[0010] A schematic diagram showing an example of the configuration of a projector according to one embodiment of this disclosure. A flowchart of the control process according to one embodiment of this disclosure. A graph diagram illustrating the effects of the configuration example according to one embodiment of this disclosure. A graph diagram illustrating the effects of the configuration example according to one embodiment of this disclosure. A graph diagram illustrating the effects of the configuration example according to one embodiment of this disclosure.

[0011] (Background to the details of each embodiment) In recent years, projectors, which are projection-type image display devices, have become brighter, and the amount of heat generated by the phosphor wheel in the phosphor unit that makes up the projector has increased. When the heat generated by the phosphor wheel increases, it causes a decrease in the reliability of the entire device, so there is a need to improve the cooling efficiency of such components. For example, in the cooling mechanism, heat is dissipated from the phosphor wheel by heat conduction through the air. In addition, a fin structure is provided to make it easier to generate turbulence.

[0012] Furthermore, in cooling structures, there are configurations that improve heat dissipation levels by using a gas with a higher thermal conductivity than air as the atmosphere around the phosphor wheel. However, such gases have a small molecular weight and are very prone to leakage. Therefore, it has been extremely difficult to ensure the reliability of gases with such characteristics in a sealed state over long periods of time.

[0013] Based on the above circumstances, as one embodiment of this disclosure, a projector, which is a projection-type image display device equipped with a component that may generate heat and which is provided with a cooling mechanism, will be described. It should be noted that the configuration and control method according to the present invention are applicable not only to projectors but also to any device that can be equipped with the cooling mechanism described below.

[0014] Hereinafter, with reference to the drawings as appropriate, each embodiment specifically disclosing the projection-type image display device, its control method, and program according to this disclosure will be described in detail. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0015] <Embodiment> [System Configuration] Figure 1 is a schematic diagram showing an example of the configuration of a projector 100 according to an embodiment of the present disclosure. The description will focus on the parts related to the characteristic parts of this embodiment, and other parts will be omitted. Therefore, the projector 100 may further include configurations other than those shown in Figure 1. In this embodiment, a phosphor unit will be used as an example to describe an optical unit having a sealed structure and a cooling mechanism. However, the description is not limited to this, and the configuration according to the present disclosure may be applied to other units as long as the functions described later can be applied.

[0016] The control unit 101 may be configured using, for example, a Central Processing Unit (CPU), a Micro Processing Unit (MPU), a Digital Signal Processor (DSP), a Field-Programmable Gate Array (FPGA), or a dedicated circuit. The control unit 101 realizes the functions described later by, for example, reading and executing various data and programs stored in a memory unit (not shown). The control unit 101 may be configured as an integral part of a control unit that performs control related to the image projection operation of the projector 100, or it may be configured as a control circuit that performs only the control described below.

[0017] The notification unit 102 is a user interface for providing predetermined notifications to the user, such as a display or lamp. Notifications performed based on instructions from the control unit 101 will be described later.

[0018] The phosphor unit 110 of the projector 100 is configured to include a phosphor wheel, which is an optical element, inside the housing 111. The phosphor wheel according to this embodiment has a wheel-shaped structure and is configured to be rotatable by a motor (not shown) or the like. The housing 111 has a sealed structure. The housing 111 is configured with an IR-transmitting window 112 and a lens 113, through which light is irradiated onto the phosphor wheel from a light source (not shown). The phosphor unit 110 may experience temperature changes inside due to the operation of the motor, light irradiation, etc.

[0019] A vacuum connector 114 is provided on the housing 111. The vacuum connector 114 hermetically seals the inside and outside of the housing 111, which will be filled with the gas described later, thereby suppressing gas leakage. A pressure sensor 115 is also provided on the housing 111, and is configured to measure the internal pressure, i.e., atmospheric pressure. The pressure sensor 115 notifies the control unit 101 of the measured pressure information. The fins 116 are heat dissipation members that dissipate the heat generated in the housing 111 to the outside. The gas injection duct 117 is configured as a path for injecting the gas sealed in the gas cartridge 121 into the housing 111. The vacuum duct 118 is connected to the gas injection duct 117 and can be used as an exhaust port for the duct.

[0020] The gas injection duct 117 is equipped with a solenoid valve 119 and a pressure reducing valve 120. The solenoid valve 119 opens and closes the gas injection duct 117 based on ON / OFF control instructions from the control unit 101. When the solenoid valve 119 is open, gas is injected from the gas cartridge 121 into the housing 111. On the other hand, when the solenoid valve 119 is closed, the injection of gas from the gas cartridge 121 into the housing 111 is stopped.

[0021] The gas cartridge 121 is filled with a gas having predetermined characteristics and is configured to be removable. In this embodiment, it is assumed that the gas cartridge 121 is filled with helium gas. In this embodiment, the helium gas supply unit to the inside of the housing 111 is realized by the gas injection duct 117, solenoid valve 119, pressure reducing valve 120, gas cartridge 121, etc. Note that the configuration and supply path of the gas supply unit are not limited to this, and other parts may also be included. Also, although only one gas cartridge 121 is shown in Figure 1, multiple gas cartridges 121 may be configured to be removable.

[0022] [Gas for filling] In this embodiment, the phosphor unit 110 is filled with a gas having predetermined physical properties. In this embodiment, a gas is used that is suitable for the operation of the phosphor wheel inside the phosphor unit 110, with the aim of reducing noise by reducing gas density, dissipating heat by improving thermal conductivity, and transmitting excitation light irradiated from the outside and fluorescence emitted by the phosphor.

[0023] This embodiment shows an example using helium (He). However, it is not limited to this. Any other gas may be used as long as it has the properties described below. Helium is known to have the following properties.

[0024]

[0025] By filling the enclosure 111 with helium that possesses the characteristics described above, it is possible to improve cooling performance compared to air. On the other hand, as mentioned above, helium has a small molecular weight and is prone to leakage even when sealed in the enclosure 111. Therefore, it is difficult to maintain a sealed state for a long period of time.

[0026] Therefore, in this embodiment, the atmospheric pressure inside the phosphor unit 110 is monitored by controlling it according to the flowchart shown below, and the degree of helium filling inside the housing 111 is controlled to be stable.

[0027] [Processing Flow] Figure 2 is a flowchart showing the control processing by the control unit 101 provided in the projector 100 according to this embodiment. This processing flow may be executed, for example, in response to the start of the projector 100. Alternatively, the processing may be executed at predetermined time intervals.

[0028] The control unit 101 acquires pressure information inside the housing 111 of the phosphor unit 110 via the pressure sensor 115 (step S201). The acquired pressure information may be appropriately recorded in a storage unit (not shown).

[0029] The control unit 101 determines whether the pressure value indicated by the pressure information acquired in step S201 is below a predetermined threshold (step S202). That is, it determines whether helium is leaking from inside the housing 111 and causing a decrease in air pressure. The threshold here is assumed to be set in advance. If the pressure value is below the predetermined threshold (step S202: YES), the control unit 101 proceeds to step S203. On the other hand, if the pressure value is greater than the predetermined threshold (step S202: NO), this processing flow ends. In this case, the operation of the projector 100 continues, and this processing flow may be executed at a predetermined timing.

[0030] The control unit 101 issues an ON command to the solenoid valve 119, causing it to switch to the open state (step S203). This initiates the supply of helium from the gas cartridge 121 to the inside of the housing 111.

[0031] The control unit 101 acquires pressure information inside the housing 111 via the pressure sensor 115 after a certain period of time has elapsed since the start of helium supply from the gas cartridge 121. The control unit 101 then determines whether the acquired pressure value has risen to or above a predetermined threshold (step S204). The threshold here is assumed to be a preset value. The threshold used in this step and the threshold used in step S202 may be the same or different. The waiting time from the start of helium supply until the pressure value rises may be determined based on the size of the housing 111, etc. If the pressure value rises to or above the predetermined threshold (step S204: YES), the control unit 101 proceeds to step S207. On the other hand, if the pressure value has not risen to or above the predetermined threshold (step S204: NO), the control unit 101 proceeds to step S205.

[0032] The control unit 101 notifies via the notification unit 102 that the internal pressure of the phosphor unit 110 has decreased (step S205). For example, possible causes for a decrease in the internal pressure of the phosphor unit 110 include a decrease in helium in the gas cartridge 121, and gas leakage due to deterioration of the vacuum connector 114 or O-rings (not shown) provided in the housing 111.

[0033] The control unit 101 notifies the user via the notification unit 102 that the gas cartridge 121 should be replaced due to a decrease in internal pressure (step S206). The control unit 101 then proceeds to step S207. The notifications in steps S205 and S206 may continue even after this processing flow is completed.

[0034] The control unit 101 issues an off command to the solenoid valve 119, thereby transitioning the solenoid valve 119 to the closed state (step S207). Then, this processing flow is terminated.

[0035] In this embodiment, a configuration example is shown in which the remaining amount of gas cartridge 121 is not monitored. However, a configuration in which this is monitored using a sensor or the like is also possible. For example, the remaining amount of gas cartridge 121 may be monitored in conjunction with the pressure reducing valve 120, or the remaining amount of gas cartridge 121 may be monitored based on the operation history of the solenoid valve 119.

[0036] [Evaluation Example] An example of evaluating the cooling function according to this embodiment will be explained using Figures 3 to 5.

[0037] Figure 3 is a graph illustrating the reduction rate of temperature rise of the phosphor unit 110 according to the configuration of this embodiment. In Figure 3, the horizontal axis represents atmospheric pressure [atm], and the vertical axis represents the reduction rate [%] of temperature rise of the phosphor unit 110. Here, an example is shown where the rotation speed of the rotating wheel is 8000 rpm and the excitation light intensity is 564 W.

[0038] The case where the housing 111 of the projector 100 is filled with air, as in the conventional configuration, is set to 100%. In comparison, an example is shown where the housing 111 is filled with helium, as in this embodiment, and the atmospheric pressure is changed. As shown in Figure 3, under any atmospheric pressure, helium can reduce the temperature rise of the phosphor unit 110 more effectively than air. Furthermore, in the configuration according to this embodiment, it is possible to relatively decrease the rate of temperature rise reduction as the atmospheric pressure inside the housing 111 increases. For example, when the atmospheric pressure is 2.0 atm, it is possible to reduce the temperature information reduction rate by 77%. Also, when the atmospheric pressure is 4.0 atm, it is possible to reduce the temperature information reduction rate by 69%.

[0039] Figure 4 is a graph illustrating the relationship between the temperature of the phosphor unit 110 and the excitation light intensity according to the configuration of this embodiment. In Figure 4, the horizontal axis represents the excitation light intensity, and the vertical axis represents the temperature of the phosphor unit 110. Here, the ambient temperature is assumed to be 36 degrees Celsius, and the environment is normal atmospheric pressure.

[0040] In Figure 4, the temperature threshold Th is an example of the upper limit temperature of the projector 100's operation. Graph 401 shows the values ​​when the housing 111 is filled with air and the internal pressure is 1.0 atm. Graphs 402, 403, 404, and 405 show the values ​​when the housing 111 is filled with helium and the internal pressure is 1.0 atm, 2.0 atm, 3.0 atm, and 4.0 atm, respectively. As shown in Figure 4, compared to air, when the housing 111 is filled with helium, the temperature with respect to excitation light intensity can be suppressed. Furthermore, the temperature of the phosphor unit 110 with respect to excitation light intensity can be suppressed by increasing the atmospheric pressure. For example, as shown in graphs 403 to 405, by setting the atmospheric pressure to 2.0 atm or higher, even when the excitation light intensity is increased, the temperature rise of the phosphor unit 110 can be suppressed so that it remains below the desired threshold, making the cooling function useful.

[0041] Figure 5 is a graph illustrating the relationship between rotational speed and current value when the phosphor wheel is operated in the phosphor unit 110 according to the configuration of this embodiment. In Figure 5, the horizontal axis represents the rotational speed [rpm] of the phosphor wheel, and the vertical axis represents the current value [A] for the motor used to rotate the phosphor wheel. Graph 501 shows the values ​​when the housing 111 is filled with air and the internal pressure is 1.0 atm. Graphs 502, 503, 504, 505, and 506 show the values ​​when the housing 111 is filled with helium and the internal pressure is 1.0 atm, 1.5 atm, 2.0 atm, 2.5 atm, and 3.0 atm, respectively. Furthermore, graph 507 shows the values ​​when the housing 111 is evacuated.

[0042] As shown in Figure 5, when the housing 111 is filled with helium compared to air, the current required to operate the phosphor wheel can be reduced. Furthermore, by increasing the air pressure, it is possible to reduce the current required to operate the phosphor wheel, thereby improving operating efficiency. In other words, it is possible to set the air pressure inside the housing 111 while considering the operating efficiency of the motor. As a result, the motor load on the phosphor unit 110 can be reduced, and the reliability of the motor can be improved.

[0043] As shown in Figures 3 to 5, in addition to using a gas with predetermined physical properties (helium gas in this example), the effects on temperature and motor load fluctuate due to changes in air pressure inside the housing 111. Taking this into consideration, the thresholds used in steps S202 and S204 in Figure 2 may be set accordingly. The thresholds may be fixed values, or they may be changed according to the mode and function of the projector 100 and phosphor unit 110, the remaining amount of gas cartridge 121, etc. For example, considering the temperature for excitation light shown in Figure 4 and the motor load shown in Figure 5, the threshold for air pressure may be switched based on which has higher priority.

[0044] As described above, the projection-type video display device (e.g., 100) according to this embodiment includes an optical unit (e.g., 110) composed of a housing (e.g., 111) with an optical element (e.g., a phosphor wheel) disposed therein and having a sealed structure, a supply unit (e.g., 117, 118, 119, 120, 121) capable of supplying a predetermined gas (e.g., helium gas) into the housing, a pressure sensor (e.g., 115) for measuring the air pressure inside the housing, and a control unit (e.g., 101) for supplying a predetermined gas into the housing via the supply unit in response to the air pressure inside the housing measured by the pressure sensor falling below a predetermined threshold value. According to this configuration, it is possible to improve the cooling function of the projection-type video display device. In particular, even when the gas with a small molecular weight leaks in the configuration using such a gas, it is possible to maintain the cooling function. The control unit has shown an example of performing control to supply a predetermined gas into the housing in response to the air pressure inside the housing measured by the pressure sensor falling below a predetermined threshold value, but is not limited to such a control method. The control unit may perform control to supply a predetermined gas into the housing according to the air pressure measured by the pressure sensor, and various control methods may be adopted.

[0045] Also, in the projection-type video display device according to this embodiment, the predetermined gas has a physical property with a higher thermal conductivity than air. According to this configuration, it is possible to suppress the temperature rise of the optical element due to higher thermal conductivity than air.

[0046] Also, in the projection-type video display device according to this embodiment, the predetermined gas has a physical property with a higher specific heat than air. According to this configuration, it is possible to suppress the temperature rise of the optical element due to excitation light or the like due to higher specific heat than air.

[0047] Also, in the projection-type video display device according to this embodiment, the predetermined gas is helium gas. According to this configuration, it is possible to suppress the temperature rise of the optical unit more than when air is used as the atmosphere.

[0048] Furthermore, in the projection-type image display device according to this embodiment, the supply unit is configured to be able to attach and detach a gas cartridge (for example, 121) filled with a predetermined gas. This configuration makes it possible to fill the gas using the gas cartridge.

[0049] Furthermore, in the projection-type image display device according to this embodiment, the optical unit is configured to include a phosphor wheel as an optical element. This configuration makes it possible to provide a cooling function for the phosphor unit including the phosphor wheel.

[0050] Furthermore, in the projection-type image display device according to this embodiment, the optical elements in the optical unit are driven and controlled by a motor. This configuration makes it possible to provide a cooling function that takes into account the temperature changes that occur in the motor when driving the optical unit. For example, it becomes possible to suppress the current value required to drive the motor.

[0051] <Other Embodiments> Furthermore, this disclosure also applies to programs and storage media that supply programs that realize the functions of the apparatus of the above-described embodiments to the apparatus via a network or various storage media, and which are read and executed by a computer within the apparatus. Such programs may be computer programs stored on non-temporary recording media.

[0052] Although various embodiments have been described above with reference to the drawings, it goes without saying that this disclosure is not limited to these examples. It will be clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents can occur within the scope of the claims, and these will naturally fall within the technical scope of this disclosure. Furthermore, the components of the various embodiments described above can be combined arbitrarily without departing from the spirit of the invention.

[0053] (Note) The above description of embodiments discloses the following technologies. (Technology 1) A projection-type image display device comprising: an optical unit comprising a housing having a sealed structure and an optical element disposed inside; a supply unit capable of supplying a predetermined gas into the housing; a pressure sensor for measuring the air pressure inside the housing; and a control unit that supplies the predetermined gas into the housing via the supply unit according to the air pressure inside the housing measured by the pressure sensor. This configuration makes it possible to improve the cooling function of the projection-type image display device. In particular, in a configuration using a gas with a small molecular weight, it is possible to maintain the cooling function even if a gas leak occurs.

[0054] (Technology 2) The projection-type image display device according to Technology 1, wherein the predetermined gas has a higher thermal conductivity than air. With this configuration, it is possible to suppress the temperature rise of the optical elements due to the higher thermal conductivity than air.

[0055] (Technology 3) The projection-type image display device according to Technology 1 or Technology 2, wherein the predetermined gas has a higher specific heat than air. With this configuration, the higher specific heat than air makes it possible to suppress the temperature rise of optical elements due to excitation light, etc.

[0056] (Technology 4) The projection-type image display device according to any one of Technology 1 to 3, wherein the predetermined gas is helium gas. With this configuration, it is possible to suppress the temperature rise of the optical unit more effectively than when air is used as the atmosphere.

[0057] (Technical 5) The supply unit is configured to be able to attach and detach a gas cartridge filled with the predetermined gas, as described in any one of Technical 1 to 4. With this configuration, it is possible to fill the gas using the gas cartridge.

[0058] (Technical 6) The projection-type image display device according to any one of Technical 1 to Technical 5, wherein the optical unit is configured to include a phosphor wheel as the optical element. This configuration makes it possible to provide a cooling function for the phosphor unit including the phosphor wheel.

[0059] (Technical 7) The projection-type image display device according to any one of Technical 1 to Technical 6, wherein the optical element in the optical unit is driven and controlled by a motor. With this configuration, it is possible to provide a cooling function that takes into account the temperature changes that occur in the motor when driving the optical unit. For example, it is possible to suppress the current value required to drive the motor.

[0060] (Technical 8) A control method for a projection-type image display device comprising: an optical unit comprising a housing having a sealed structure and an optical element arranged inside; a supply unit capable of supplying a predetermined gas into the housing; and a pressure sensor for measuring the air pressure inside the housing, the control step comprising supplying the predetermined gas into the housing via the supply unit in response to the air pressure inside the housing measured by the pressure sensor falling below a predetermined threshold. This configuration makes it possible to improve the cooling function of the projection-type image display device. In particular, in a configuration using a gas with a small molecular weight, it is possible to maintain the cooling function even if a gas leak occurs.

[0061] (Technical 9) A program for causing a computer of a projection-type image display device to execute a control step in which the computer of the optical unit, which has an optical element arranged inside and is made up of a housing having a sealed structure, a supply unit capable of supplying a predetermined gas into the housing, and a pressure sensor for measuring the air pressure inside the housing, to supply the predetermined gas into the housing via the supply unit in response to the air pressure inside the housing measured by the pressure sensor falling below a predetermined threshold. This configuration makes it possible to improve the cooling function of the projection-type image display device. In particular, in a configuration using a gas with a small molecular weight, it is possible to maintain the cooling function even if a gas leak occurs.

[0062] This disclosure is useful as a precision instrument, a projection-type image display device, a control method therefor, and a program.

[0063] 100...Projector 101...Control unit 102...Notification unit 110...Phosphor unit 111...Housing 112...IR transparent window 113...Lens 114...Vacuum connector 115...Pressure sensor 116...Fin 117...Gas injection duct 118...Vacuum duct 119...Solenoid valve 120...Pressure reducing valve 121...Gas cartridge

Claims

1. A projection-type image display device comprising: an optical unit comprising a housing having a sealed structure and an optical element arranged inside; a supply unit capable of supplying a predetermined gas into the housing; a pressure sensor for measuring the air pressure inside the housing; and a control unit that supplies the predetermined gas into the housing via the supply unit according to the air pressure inside the housing measured by the pressure sensor.

2. The projection-type image display device according to claim 1, wherein the predetermined gas has a physical property of having a higher thermal conductivity than air.

3. The projection-type image display device according to claim 1, wherein the predetermined gas has a physical property of having a higher specific heat than air.

4. The projection-type image display device according to claim 1, wherein the predetermined gas is helium gas.

5. The projection-type image display device according to claim 1, wherein the supply unit is configured to be able to attach and detach a gas cartridge filled with the predetermined gas.

6. The projection-type image display device according to claim 1, wherein the optical unit is configured to include a phosphor wheel as the optical element.

7. The projection-type image display device according to claim 1, wherein the optical element in the optical unit is driven and controlled by a motor.

8. A control method for a projection-type image display device comprising: an optical unit comprising a housing having a sealed structure and an optical element arranged inside; a supply unit capable of supplying a predetermined gas into the housing; and a pressure sensor for measuring the air pressure inside the housing, the control method comprising: a control step of supplying the predetermined gas into the housing via the supply unit in accordance with the air pressure inside the housing measured by the pressure sensor.

9. A program for causing a computer of a projection-type image display device to execute a control process to supply the predetermined gas into the housing via the supply unit in accordance with the air pressure inside the housing measured by the pressure sensor, the optical unit comprising an optical element arranged inside and a housing having a sealed structure, a supply unit capable of supplying a predetermined gas into the housing, and a pressure sensor for measuring the air pressure inside the housing.

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