Display device control method and display device

Abstract

To reduce the standby power consumption of a display device that is in a standby state.SOLUTION: A display device control method includes: when a display device is in an active state, feeding power to an image supply device connected to a power feedable first terminal of the display device in a first feed amount via the first terminal; and when the display device is standby state, feeding power to the image supply device via the first terminal in a second feed amount that is smaller than the first feed amount.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for controlling a display device and a display device.

Background Art

[0002] Patent Document 1 discloses an information processing device capable of constantly supplying power to an external device connected via a USB (Universal Serial Bus) connector.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The information processing device disclosed in Patent Document 1 supplies power to an external device at the same power supply amount as when the device itself is in the power-on state even when the device itself is in the standby state. Therefore, the power consumption of the information processing device in the standby state cannot be reduced.

Means for Solving the Problems

[0005] A method for controlling a display device according to one aspect of the present invention includes: when the display device is in the startup state, supplying power to an image supply device connected to a power supply-capable first terminal included in the display device via the first terminal at a first power supply amount; and when the display device is in the standby state, supplying power to the image supply device via the first terminal at a second power supply amount smaller than the first power supply amount.

[0006] A display device according to one aspect of the present invention includes a first terminal capable of supplying power, a power supply circuit that supplies power to an image supply device connected to the first terminal at a predetermined amount via the first terminal, and a processor that controls the power supply circuit, wherein the processor causes the power supply circuit to supply power to the image supply device at a first amount when the device is in a startup state, and causes the power supply circuit to supply power to the image supply device at a second amount smaller than the first amount when the device is in a standby state. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic block diagram showing the configuration of the display device of this embodiment. [Figure 2] This is a state transition diagram of the display device of this embodiment. [Modes for carrying out the invention]

[0008] Hereinafter, one embodiment of this disclosure will be described with reference to the drawings. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see.

[0009] Figure 1 is a schematic block diagram showing the configuration of the display device 1 of this embodiment. As shown in Figure 1, the display device 1 comprises an external power supply cable 10, a video signal cable 20, a power supply unit 30, an optical device 40, an input device 50, a speaker 60, a cooling fan 70, and a main board 80. As an example, the display device 1 of this embodiment is a projector that displays an image on a projection surface 100 by projecting image light L onto the projection surface 100. The projection surface 100 may be a dedicated projector screen or a wall, etc.

[0010] The external power supply cable 10 is a cable used to supply power from the display device 1 to an external device. The external power supply cable 10 has a power supply terminal 11 and a power supply cable 12. The power supply terminal 11 is an external connection terminal that supports a communication standard capable of supplying power to an external device. The power supply terminal 11 corresponds to a first terminal capable of supplying power. Examples of communication standards capable of supplying power to an external device include USB standards such as "USB Type-A" and "USB Type-C", or standards such as Thunderbolt®. The power supply terminal 11 is connected to the main board 80 via the power supply cable 12. The power supply cable 12 is a cable that transmits the power supply voltage for the external device and various signals output from the main board 80 to the power supply terminal 11.

[0011] The video signal cable 20 is a cable used to transmit video signals supplied from an external device to the display device 1. The video signal cable 20 has a video input terminal 21 and a signal cable 22. The video input terminal 21 is an external connection terminal that supports video transmission standards such as HDMI (High-Definition Multimedia Interface: registered trademark) or DVI (Digital Visual Interface). The video input terminal 21 is connected to the main board 80 via the signal cable 22. The signal cable 22 is a cable that transmits video signals supplied from an external device via the video input terminal 21 to the main board 80.

[0012] In this embodiment, an image supply device 2 is connected to the display device 1 as an external device via an external power supply cable 10 and a video signal cable 20. That is, the power supply terminal 11 and the video input terminal 21 are each connected to the image supply device 2. The image supply device 2 is housed inside the housing of the display device 1 while connected to the external power supply cable 10 and the video signal cable 20.

[0013] The image supply device 2 starts up by receiving power from the display device 1 via an external power supply cable 10. After starting up, the image supply device 2 accesses the internet via a wireless LAN (Local Area Network) that supports wireless communication standards such as Wi-Fi (registered trademark), and supplies video signals received from video streaming services on the internet to the display device 1 via a video signal cable 20. An image supply device 2 with such functions is sometimes called a media streaming terminal. The display device 1 generates image light L based on the video signals supplied from the image supply device 2.

[0014] The power supply unit 30 is connected to the power plug 31 via a power cord 32. The power plug 31 is inserted into, for example, an electrical outlet (not shown) installed in the user's home. When the power plug 31 is inserted into the outlet, a commercial AC voltage of, for example, 100(V) is supplied to the power supply unit 30 via the power cord 32. The power supply unit 30 converts the commercial AC voltage supplied via the power cord 32 into a DC voltage and outputs it to the main board 80.

[0015] The DC voltage output from the power supply unit 30 is used as the power supply voltage to operate the electronic components and circuits provided on the main board 80. As will be described later, the main board 80 is provided with at least a power supply circuit 81, memory 82, and processor 83. The DC voltage output from the power supply unit 30 is also supplied to the optical device 40, input device 50, speaker 60, and cooling fan 70 via the main board 80 and is used as the power supply voltage to operate these devices.

[0016] The optical device 40, controlled by the processor 83, generates image light L representing a color image and projects the generated image light L toward the projection surface 100. The optical device 40 includes a first image generation panel 41, a second image generation panel 42, a third image generation panel 43, a dichroic prism 44, and a projection optical system 45.

[0017] The first image generation panel 41 generates red image light LR representing a red image and emits it to the dichroic prism 44. The first image generation panel 41 has multiple pixels arranged in a matrix, and each of the multiple pixels emits red light. The amount of red light emitted from each pixel is controlled by the processor 83, so that red image light LR is emitted from the first image generation panel 41.

[0018] The second image generation panel 42 generates green image light LG representing a green image and emits it to the dichroic prism 44. The second image generation panel 42 has multiple pixels arranged in a matrix, and each of the multiple pixels emits green light. The amount of green light emitted from each pixel is controlled by the processor 83, so that the green image light LG is emitted from the second image generation panel 42.

[0019] The third image generation panel 43 generates blue image light LB representing a blue image and emits it to the dichroic prism 44. The third image generation panel 43 has multiple pixels arranged in a matrix, and each of the multiple pixels emits blue light. The amount of blue light emitted from each pixel is controlled by the processor 83, so that the blue image light LB is emitted from the third image generation panel 43.

[0020] For example, each of the image generation panels 41, 42, and 43 is a self-emitting electro-optical device such as an OLED (Organic Light Emitting Diode) panel or a μLED (Micro Light Emitting Diode) panel. Note that each of the image generation panels 41, 42, and 43 may be a non-self-emitting electro-optical device such as a liquid crystal panel or a DMD (Digital Micromirror Device). When each of the image generation panels 41, 42, and 43 is a non-self-emitting electro-optical device, light from a light source (not shown) such as an LED is separated into red light, green light, and blue light, respectively. The red light is incident on the first image generation panel 41. The green light is incident on the second image generation panel 42. The blue light is incident on the third image generation panel 43. Also, a single image generation panel may be used to emit light of each color in a time-sharing manner.

[0021] The dichroic prism 44 generates an image light L representing a color image by combining the red image light LR, the green image light LG, and the blue image light LB, and emits it to the projection optical system 45. The projection optical system 45 is composed of a plurality of optical elements such as lenses, and enlarges and projects the image light L emitted from the dichroic prism 44 toward the projection surface 100. Although not shown in the figure, the projection optical system 45 is provided with a mechanism for adjusting optical parameters such as the lens shift amount, the lens focus amount, and the lens zoom amount. By controlling these mechanisms by the processor 83, the optical parameters of the projection optical system 45 are adjusted.

[0022] The input device 50 includes an operation unit 51 and a light receiving unit 52. The operation unit 51 is composed of a plurality of operation keys provided on the display device 1. For example, the operation keys include a power key, a menu call key, direction keys, a determination key, and a volume adjustment key, etc. The operation keys may be hardware keys or software keys displayed on a touch panel. The operation unit 51 outputs an electrical signal generated when each operation key is operated by the user as an operation signal to the processor 83 of the main board 80.

[0023] The light receiving unit 52 includes a photoelectric conversion circuit that receives infrared light transmitted from a remote controller (not shown) of the display device 1 and converts it into an electric signal. The light receiving unit 52 outputs the electric signal obtained by the photoelectric conversion of the infrared light as a remote operation signal to the processor 83 of the main board 80. The remote controller is provided with a plurality of operation keys similar to the operation unit 51. The remote controller converts an electric signal generated when each operation key provided on the remote controller is operated by the user into infrared light and transmits it to the display device 1. That is, the remote operation signal output from the light receiving unit 52 is substantially the same as the electric signal generated when each operation key of the remote controller is operated by the user. When the remote controller transmits a radio wave signal in accordance with a short-range wireless communication standard such as Bluetooth (registered trademark), a receiving device for receiving the radio wave signal may be provided instead of the light receiving unit 52.

[0024] The speaker 60 outputs a voice having a predetermined volume by being controlled by the processor 83. The cooling fan 70 generates cooling air inside the housing of the display device 1. In the following description, the cooling air is referred to as "cooling wind". The cooling fan 70 is mainly arranged at a position where the cooling wind hits the devices that generate high heat. For example, the cooling fan 70 is arranged at a position where the cooling wind hits the power supply device 30, the optical device 40, the main board 80, and the image supply device 2 stored in the housing. The rotation speed of the cooling fan 70 is controlled by the processor 83.

[0025] The main board 80 is a control board provided with electronic components and circuits for controlling the overall operation of the display device 1. The main board 80 has at least a power supply circuit 81, a memory 82, and a processor 83.

[0026] The power supply circuit 81 is a circuit that adjusts the power supplied from the main board 80 to the image supply device 2 via the external power supply cable 10. In other words, the power supply circuit 81 supplies power to the image supply device 2 connected to the power supply terminal 11 at a predetermined amount via the power supply terminal 11. More specifically, the power supply circuit 81 supplies power to the image supply device 2 at the amount instructed by the processor 83. In this embodiment, "amount of power supplied" refers to the value of the power supplied to the image supply device 2, and its unit is watts (W).

[0027] Memory 82 includes non-volatile memory that stores programs and various setting data necessary for the processor 83 to execute various processes, and volatile memory used as a temporary storage location for data when the processor 83 executes various processes. For example, non-volatile memory may be EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory. Volatile memory may be RAM (Random Access Memory).

[0028] The processor 83 is an arithmetic processing unit that controls the overall operation of the display device 1 according to a program pre-stored in the memory 82. For example, the processor 83 is composed of one or more CPUs (Central Processing Units). Some or all of the functions of the processor 83 may be composed of circuits such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array). The processor 83 executes various processes in parallel or sequentially.

[0029] For example, the processor 83 controls the optical device 40 and the speaker 60 based on the operation signal input from the operation unit 51 and the remote operation signal input from the light receiving unit 52. Specifically, the processor 83 controls the optical device 40 so that an image light L representing an image based on the video signal supplied from the image supply device 2 via the video signal cable 20 is generated, and controls the speaker 60 so that sound based on the video signal is output.

[0030] Furthermore, the processor 83 controls the power supply circuit 81. As will be described in detail later, the processor 83 performs the following actions: when the device (i.e., the display device 1) is running, the power supply circuit 81 supplies power to the image supply device 2 with a first power supply amount; and when the device is in standby mode, the power supply circuit 81 supplies power to the image supply device 2 with a second power supply amount that is smaller than the first power supply amount.

[0031] The processor 83 executes the above processing according to the program stored in the memory 82, thereby realizing the control method for the display device 1. Specifically, the control method for the display device 1 in this embodiment includes, when the display device 1 is in an activated state, supplying power to the image supply device 2 connected to the power supply terminal 11 of the display device 1 via the power supply terminal 11 at a first power supply amount, and when the display device 1 is in a standby state, supplying power to the image supply device 2 via the power supply terminal 11 at a second power supply amount smaller than the first power supply amount.

[0032] Next, the operation of the display device 1 configured as described above will be explained. Figure 2 is a state transition diagram of the display device 1. As shown in Figure 2, the display device 1 has four states: non-power supply state ST1, ECO standby state ST2, startup state ST3, and standby state ST4. The non-power supply state ST1 is the state in which the power plug 31 is not inserted into the outlet. Therefore, when the display device 1 is in the non-power supply state ST1, the display device 1 is inoperable. The operation of the display device 1 in the following three states: ECO standby state ST2, startup state ST3, and standby state ST4 will be explained below.

[0033] [ECO Standby State ST2] ECO standby state ST2 is the state in which the power plug 31 is inserted into the outlet and the power key on the operation unit 51 of the display device 1 is not pressed. In other words, when the power plug 31 is inserted into the outlet, the display device 1 transitions from the non-power supply state ST1 to the ECO standby state ST2. When the display device 1 is in the ECO standby state ST2, for example, the standby power consumption of the display device 1 is limited to 0.5 (W) or less.

[0034] When the display device 1 is in ECO standby state ST2, the power supply unit 30 operates in a first power mode that supplies the main board 80 with the minimum power necessary to operate each device built into the display device 1. However, until the power key on the operation unit 51 is pressed, no power voltage is supplied from the power supply unit 30 to the main board 80, so the processor 83 does not start, and the power supply circuit 81 does not supply power to the image supply device 2. In other words, when the display device 1 is in ECO standby state ST2, the amount of power supplied from the display device 1 to the image supply device 2 is 0 (W). Note that when the display device 1 is in ECO standby state ST2, the cooling fan 70 is stopped.

[0035] [Startup status ST3] When the power plug 31 is inserted into the outlet and the power key on the control unit 51 is pressed, the display device 1 transitions from ECO standby state ST2 to startup state ST3. When the power key on the control unit 51 is pressed, power voltage is supplied from the power supply unit 30 to the main board 80, so the processor 83 starts up and each device, including the processor 83, becomes operational.

[0036] Thus, in this embodiment, when the display device 1 is in the startup state ST3, it means that each device, including the processor 83 built into the display device 1, is in an operational state. When the display device 1 transitions to the startup state ST3, the power supply unit 30 operates in a second power supply mode, supplying the main board 80 with the maximum power necessary to operate each device built into the display device 1 at maximum performance.

[0037] When the processor 83 receives an instruction to transition from the ECO standby state ST2 to the startup state ST3, it instructs the power supply circuit 81 to supply power to the image supply device 2 at the first power supply amount. When the processor 83 receives an instruction to transition from the ECO standby state ST2 to the startup state ST3, it means that the power key provided on the operation unit 51 is pressed when the display device 1 is in the ECO standby state ST2.

[0038] The first power supply is the maximum power required to operate the image supply device 2 at maximum performance. For example, the first power supply is 10 (W). During the period when the display device 1 is in the startup state ST3, the power supply circuit 81 supplies power to the image supply device 2 with the first power supply instructed by the processor 83.

[0039] As described above, when the device (i.e., the display device 1) is in the startup state ST3, the processor 83 instructs the power supply circuit 81 to supply power to the image supply device 2 with a first power supply amount. By the processor 83 executing this process, the process included in the control method of the display device 1 is realized, in which, when the display device 1 is in the startup state ST3, power is supplied to the image supply device 2, which is connected to the power supply terminal 11 of the display device 1, with a first power supply amount via the power supply terminal 11.

[0040] The image supply device 2 starts up by receiving power from the display device 1 via an external power supply cable 10. After starting up, the image supply device 2 accesses the internet via a wireless LAN and supplies video signals received from video streaming services on the internet to the display device 1 via a video signal cable 20. The processor 83 controls the optical device 40 so that an image light L representing an image based on the video signal supplied from the image supply device 2 is generated, and controls the speaker 60 so that sound based on the video signal is output.

[0041] During the period when the display device 1 is in the startup state ST3, the cooling fan 70 rotates, generating cooling air inside the housing of the display device 1. This cools the power supply unit 30, the optical device 40, the main board 80, and the image supply device 2 housed inside the housing. The rotation speed of the cooling fan 70 is set to a first rotation speed by the processor 83. That is, in the control method of the display device 1 of this embodiment, when the display device 1 is in the startup state ST3, the rotation speed of the cooling fan 70 provided by the display device 1 is the first rotation speed. For example, the first rotation speed is the upper limit of the rotation speed of the cooling fan 70.

[0042] [Standby State ST4] When the display device 1 is in the startup state ST3, if the power key on the operation unit 51 of the display device 1 or the power key on the remote controller is pressed, the display device 1 transitions from the startup state ST3 to the standby state ST4. When the power key is pressed while the display device 1 is in the startup state ST3, the processor 83 interrupts the work (processing) that is currently being executed, saves data indicating the state at the time of the work interruption to the memory 82, and then enters a state of waiting for a wake-up signal. When the processor 83 enters the state of waiting for a wake-up signal, it stops all functions except the function of detecting the wake-up signal.

[0043] Thus, in this embodiment, when the display device 1 is in standby state ST4, it means that the processor 83 is in a state of waiting for a wake-up signal. When the processor 83 is in a state of waiting for a wake-up signal, this can be rephrased as the processor 83 being in a sleep state or a suspend state. Therefore, standby state ST4 can be rephrased as sleep state or suspend state. Even when the display device 1 transitions to standby state ST4, the supply of power voltage from the power supply unit 30 to the main board 80 is maintained. However, when the display device 1 transitions to standby state ST4, the power supply unit 30 operates in first power mode.

[0044] When the processor 83 receives an instruction to transition from the startup state ST3 to the standby state ST4, it instructs the power supply circuit 81 to supply power to the image supply device 2 with a second power supply amount that is smaller than the first power supply amount. When the processor 83 receives an instruction to transition from the startup state ST3 to the standby state ST4, it means that the power key is pressed when the display device 1 is in the startup state ST3.

[0045] The second power supply is the minimum power required to operate the image supply device 2. For example, the second power supply is 6 watts (W). During the period when the display device 1 is in standby state ST4, the power supply circuit 81 supplies power to the image supply device 2 with the second power supply instructed by the processor 83.

[0046] As described above, when the device (i.e., the display device 1) is in standby state ST4, the processor 83 instructs the power supply circuit 81 to supply power to the image supply device 2 with a second power supply amount smaller than the first power supply amount. By the processor 83 executing this process, the process included in the control method of the display device 1 is realized, in which, when the display device 1 is in standby state ST4, power is supplied to the image supply device 2 via the power supply terminal 11 with a second power supply amount smaller than the first power supply amount. It is preferable that the processor 83 instructs the power supply circuit 81 to supply the second power supply amount during the period from when the power key is pressed until the device enters a state of waiting for the wake-up signal.

[0047] Furthermore, when the processor 83 receives an instruction to transition from the startup state ST3 to the standby state ST4, it sends a first instruction to the image supply device 2 via the external power supply cable 10 to transition the image supply device 2 from the startup state to the standby state. As described above, when the display device 1 is in the startup state ST3, the image supply device 2 is also in the startup state. The image supply device 2 being in the startup state means that each device, including the processor built into the image supply device 2, is in an operational state.

[0048] As is evident from the fact that the processor 83 transmits the first instruction as described above, the control method of the display device 1 in this embodiment further includes transmitting a first instruction to the image supply device 2 via the power supply terminal 11 to transition the image supply device 2 from the startup state to the standby state when the display device 1 receives an instruction to transition from the startup state ST3 to the standby state ST4.

[0049] When the image supply device 2 receives a first instruction from the display device 1 via the external power supply cable 10, it transitions from the startup state to the standby state. The image supply device 2 being in the standby state means that the processor built into the image supply device 2 is in a state of waiting for a wake-up signal. Thus, when the display device 1 transitions from the startup state ST3 to the standby state ST4, the image supply device 2 also transitions from the startup state to the standby state. It is preferable that the processor 83 transmits the first instruction to the image supply device 2 during the period between the power key being pressed and the device entering the state of waiting for a wake-up signal.

[0050] During the period when the display device 1 is in standby state ST4, the rotation speed of the cooling fan 70 is limited to a second rotation speed, which is lower than the first rotation speed. For example, the processor 83 sets the second rotation speed to 0 (rpm). In other words, since the cooling fan 70 does not rotate during the period when the display device 1 is in standby state ST4, no cooling air is generated inside the enclosure of the display device 1. Thus, in the control method of the display device 1 of this embodiment, when the display device 1 is in standby state ST4, the rotation speed of the cooling fan 70 provided by the display device 1 is a second rotation speed, which is lower than the first rotation speed. Note that the second rotation speed may be lower than the first rotation speed and higher than 0 (rpm). It is preferable that the processor 83 sets the rotation speed of the cooling fan 70 to the second rotation speed during the period from when the power key is pressed until the system enters a state of waiting for the wake-up signal.

[0051] [Returning from standby state ST4 to active state ST3] When the display device 1 is in standby state ST4, pressing the power key on the operation unit 51 of the display device 1 or the power key on the remote controller causes the display device 1 to transition (return) from standby state ST4 to startup state ST3. When the power key is pressed while the display device 1 is in standby state ST4, the processor 83 detects a signal indicating that the power key has been pressed as a wake-up signal. Upon detecting the wake-up signal, the processor 83 returns from the waiting state to the operational state and restores the state of the display device 1 to the state at the time of the work interruption based on the data indicating the state at the time of the work interruption stored in memory 82. When the display device 1 transitions from standby state ST4 to startup state ST3, the power supply unit 30 operates in second power mode.

[0052] When the processor 83 receives an instruction to transition from standby state ST4 to startup state ST3, it instructs the power supply circuit 81 to supply power to the image supply device 2 at the first power supply amount. The processor 83 receiving an instruction to transition from standby state ST4 to startup state ST3 means that the power key is pressed when the display device 1 is in standby state ST4. As a result, the power supply circuit 81 again supplies power to the image supply device 2 at the first power supply amount instructed by the processor 83.

[0053] Furthermore, when the processor 83 receives an instruction to transition from the standby state ST4 to the startup state ST3, it sends a second instruction to the image supply device 2 via the external power supply cable 10 to transition the image supply device 2 from the standby state to the startup state. As described above, when the display device 1 is in the standby state ST4, the image supply device 2 is also in the standby state. When the image supply device 2 receives the second instruction from the display device 1 via the external power supply cable 10, it transitions from the standby state to the startup state.

[0054] As is evident from the fact that the processor 83 transmits the second instruction as described above, the control method of the display device 1 of this embodiment further includes transmitting a second instruction to the image supply device 2 via the power supply terminal 11 to transition the image supply device 2 from the standby state to the startup state when the display device 1 receives an instruction to transition from the standby state ST4 to the startup state ST3.

[0055] When the image supply device 2 transitions from standby to startup, it accesses the internet again via wireless LAN and supplies video signals received from video streaming services on the internet to the display device 1 via the video signal cable 20. The processor 83 controls the optical device 40 so that image light L representing an image based on the video signal supplied from the image supply device 2 is generated, and controls the speaker 60 so that sound based on the video signal is output. When the display device 1 transitions from standby state ST4 to startup state ST3, the cooling fan 70 starts rotating again at the first rotation speed.

[0056] (Effects of this embodiment) As described above, the control method for the display device 1 of this embodiment includes supplying power to the image supply device 2 connected to the power supply terminal 11 of the display device 1 at a first power supply amount when the display device 1 is in the startup state ST3, and supplying power to the image supply device 2 at a second power supply amount smaller than the first power supply amount via the power supply terminal 11 when the display device 1 is in the standby state ST4. In this embodiment, when the display device 1 is in the startup state ST3, power is supplied from the display device 1 to the image supply device 2 at a first power supply amount, and when the display device 1 is in the standby state ST4, power is supplied from the display device 1 to the image supply device 2 at a second power supply amount that is smaller than the first power supply amount. Therefore, according to this embodiment, the standby power consumption of the display device 1 in standby state ST4 can be minimized. In addition, as in this embodiment, it is preferable that the second power supply amount is the minimum power required to operate the image supply device 2. The reason for this is that if the second power supply amount is simply set to 0(W) or a value close to 0(W), the power supply device 30 may break down if the image supply device 2 requests an unexpectedly large amount of power.

[0057] In the control method for the display device 1 of this embodiment, when the display device 1 is in the startup state ST3, the rotation speed of the cooling fan 70 provided by the display device 1 is a first rotation speed, and when the display device 1 is in the standby state ST4, the rotation speed of the cooling fan 70 is a second rotation speed which is lower than the first rotation speed. In this embodiment, when the display device 1 is in the startup state ST3, the cooling fan 70 rotates at a relatively high first rotation speed, generating a relatively strong cooling airflow inside the housing of the display device 1. As a result, when the display device 1 is in the startup state ST3, the power supply unit 30, the optical unit 40, the main board 80, and the image supply device 2 housed inside the housing can be effectively cooled. On the other hand, when the display device 1 is in standby state ST4, the rotation speed of the cooling fan 70 is limited to a relatively low second rotation speed. This suppresses the generation of noise caused by the rotation of the cooling fan 70 and prevents dust and other debris from being sucked into the housing, thereby extending the lifespan of the optical device 40. In this embodiment, the second rotation speed is preferably 0 (rpm), but the second rotation speed may be higher than 0 (rpm).

[0058] The control method for the display device 1 of this embodiment further includes, when the display device 1 receives an instruction to transition from the startup state ST3 to the standby state ST4, transmitting a first instruction to the image supply device 2 via the power supply terminal 11 to transition the image supply device 2 from the startup state ST3 to the standby state ST4. According to this embodiment, when the display device 1 receives an instruction to transition from the startup state ST3 to the standby state ST4, both the display device 1 and the image supply device 2 transition from the startup state ST3 to the standby state ST4, thereby minimizing the total standby power consumption of the display device 1 and the image supply device 2.

[0059] The control method for the display device 1 of this embodiment further includes, when the display device 1 receives an instruction to transition from a standby state ST4 to a startup state ST3, transmitting a second instruction to the image supply device 2 via the power supply terminal 11 to transition the image supply device 2 from a standby state to a startup state. According to this embodiment, when the display device 1 receives an instruction to transition from the standby state ST4 to the startup state ST3, the image supply device 2, which is in the standby state, quickly returns to the startup state together with the display device 1, so that the image display by the display device 1 can be quickly resumed.

[0060] The display device 1 of this embodiment includes a power supply terminal 11 capable of supplying power, a power supply circuit 81 that supplies power to an image supply device 2 connected to the power supply terminal 11 at a predetermined amount via the power supply terminal 11, and a processor 83 that controls the power supply circuit 81. The processor 83 performs the following actions: when the device is in a startup state ST3, it causes the power supply circuit 81 to supply power to the image supply device 2 at a first power supply amount; and when the device is in a standby state ST4, it causes the power supply circuit 81 to supply power to the image supply device 2 at a second power supply amount smaller than the first power supply amount. According to this embodiment, the standby power consumption of the display device 1 in standby state ST4 can be minimized.

[0061] Although one embodiment of the present disclosure has been described above, the technical scope of the present disclosure is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

[0062] For example, in the above embodiment, when the processor 83 receives an instruction to transition from the standby state ST4 to the startup state ST3, it transmits a second instruction to the image supply device 2 via the external power supply cable 10 to transition the image supply device 2 from the standby state to the startup state. The disclosure is not limited thereto, and when the image supply device 2 receives an instruction to transition from the standby state to the startup state, the display device 1 may receive a third instruction from the image supply device 2 via the external power supply cable 10 to transition the display device 1 from the standby state ST4 to the startup state ST3.

[0063] In other words, the control method for the display device 1 may further include receiving a third instruction from the image supply device 2 via the power supply terminal 11 to transition the display device 1 from the standby state ST4 to the startup state ST3 when the image supply device 2 receives an instruction to transition from the standby state to the startup state.

[0064] The image supply device 2 receives an instruction to transition from standby to startup state, for example, when the power key on the dedicated remote controller for the image supply device 2 is pressed. Alternatively, if the image supply device 2 has a voice recognition function, it may receive a predetermined pattern of voice spoken by the user as a transition instruction.

[0065] When the image supply device 2 receives an instruction to transition from standby to startup, the image supply device 2 returns from standby to startup and transmits a third instruction to the display device 1 via the external power supply cable 10. When the processor 83 detects the third instruction received from the image supply device 2 as a wake-up signal, it returns from standby to operational state and restores the state of the display device 1 to the state at the time of work interruption based on the data indicating the state at the time of work interruption stored in memory 82.

[0066] According to the above modified example, when the image supply device 2 receives an instruction to transition from standby to startup, the display device 1, which is in standby state ST4, quickly returns to startup state ST3 together with the image supply device 2, thereby enabling the display device 1 to quickly resume image display.

[0067] In the above embodiment, the case in which the display device 1 is a projector was illustrated, but the display device of this disclosure is not limited to a projector. For example, the display device of this disclosure may be other electronic devices having an image display function, such as a personal computer and a tablet terminal. Generally, electronic devices such as personal computers and tablet terminals can be said to be a form of display device because they include a first terminal capable of supplying power, a power supply circuit that supplies a predetermined amount of power to an image supply device connected to the first terminal via the first terminal, and a processor that controls the power supply circuit.

[0068] A control method for a display device according to one aspect of this disclosure may have the following configuration. A control method for a display device according to one aspect of the present disclosure includes, when the display device is in an activated state, supplying power to an image supply device connected to a power-supplyable first terminal of the display device via the first terminal at a first power supply amount, and when the display device is in a standby state, supplying power to the image supply device via the first terminal at a second power supply amount smaller than the first power supply amount.

[0069] In a control method for a display device according to one aspect of the present disclosure, when the display device is in the startup state, the rotational speed of the cooling fan provided by the display device is a first rotational speed, and when the display device is in the standby state, the rotational speed of the cooling fan may be a second rotational speed lower than the first rotational speed.

[0070] A control method for a display device according to one aspect of the present disclosure may further include transmitting a first instruction to the image supply device via the first terminal to transition the image supply device from the startup state to the standby state when the display device receives an instruction to transition from the startup state to the standby state.

[0071] A control method for a display device according to one aspect of the present disclosure may further include, when the display device receives an instruction to transition from the standby state to the startup state, transmitting a second instruction to the image supply device via the first terminal to cause the image supply device to transition from the standby state to the startup state.

[0072] A control method for a display device according to one aspect of the present disclosure may further include receiving a third instruction from the image supply device via the first terminal to transition the display device from the standby state to the startup state when the image supply device receives an instruction to transition from the standby state to the startup state.

[0073] A display device according to one aspect of this disclosure may have the following configuration: A display device according to one aspect of the present disclosure includes a first terminal capable of supplying power, a power supply circuit that supplies power to an image supply device connected to the first terminal at a predetermined amount via the first terminal, and a processor that controls the power supply circuit, wherein the processor causes the power supply circuit to supply power to the image supply device at a first amount when the device is in a startup state, and causes the power supply circuit to supply power to the image supply device at a second amount smaller than the first amount when the device is in a standby state. [Explanation of Symbols]

[0074] 1…Display device, 2…Image supply device, 10…External power supply cable, 11…Power supply terminal (terminal 1), 20…Video signal cable, 30…Power supply unit, 40…Optical device, 50…Input device, 60…Speaker, 70…Cooling fan, 80…Main board, 81…Power supply circuit, 82…Memory, 83…Processor, 100…Projection surface

Claims

1. When the display device is in an activated state, the display device is connected to a first terminal capable of supplying power. supplying power at a first power supply amount to the image supply device via the first terminal; When the display device is in a standby state, the first terminal supplying power at a second power supply amount smaller than the first power supply amount via a power supply terminal; A method for controlling a display device, comprising:

2. The number of revolutions of a cooling fan provided in the display device when the display device is in the activated state. is the first rotation speed, When the display device is in the standby state, the rotation speed of the cooling fan is a second rotation speed lower than the first rotation speed; A method for controlling the display device according to claim 1.

3. When the display device receives an instruction to transition from the activated state to the standby state, a first instruction for causing the image supply device to transition from the activated state to the standby state; to the image supply device via the first terminal; The method for controlling the display device according to claim 1 , further comprising:

4. When the display device receives an instruction to transition from the standby state to the activated state, a second instruction for causing the image supply device to transition from the standby state to the activated state; to the image supply device via the first terminal; The method for controlling a display device according to claim 3 , further comprising:

5. When the image supply device receives an instruction to transition from the standby state to the activated state, a third instruction for transitioning the display device from the standby state to the activated state in the case from the image supply device via the first terminal; The method for controlling a display device according to claim 3 , further comprising:

6. A first terminal capable of supplying power; A predetermined amount of power is supplied to an image supply device connected to the first terminal via the first terminal. A power supply circuit that supplies power by A processor for controlling the power supply circuit; Equipped with The processor, When the image supply device is in an activated state, the power supply circuit supplies a first amount of power to the image supply device. and causing the power supply to be performed; When the device itself is in a standby state, a second power supply amount smaller than the first power supply amount is supplied to the power supply circuit. supplying power to the image supply device at two power supply amounts; Execute Display device.

Images