JP7146405B2 - Electronic device and its control method, communication system - Google Patents

Description

The present invention relates to an electronic device having a USB Type-C function, a control method thereof, and a communication system.

A USB Type-C connector has been proposed in the USB 3.1 standard. The USB 3.1 standard defines an alternate mode as an optional function. By using the alternate mode, it is possible to transfer image data and the like conforming to the DisplayPort (DP) standard, HDMI (registered trademark) (High-Definition Multimedia Interface) standard, and the like to a display or the like. In alternate mode image data transfer, image data transfer is performed using a high-speed transmission line defined in the USB 3.1 standard that supports a transmission speed of 10 Gbps or higher.

Various standards such as the USB Type-C Power Delivery (PD) standard and the USB Battery Charging standard are also defined in the USB 3.1 standard. Japanese Patent Application Laid-Open No. 2002-200001 discloses a technique of connecting a device having a Type-C port and a device having a USB port that is not a Type-C port using an extension means to perform image communication.

Further, according to the USB 3.1 standard, the roles of a DFP (Downstream Facing Port) functioning as a host and a role of a UFP (Upstream Facing Port) functioning as a device are assigned between connected devices. When communicating between connected devices, a query is sent from the device on the DFP side (DFP device) to the device on the UFP side (UFP device), and in response to receiving the query, the UFP device sends information. do.

For example, it is possible to connect a camera equipped with a monitor and an electronic viewfinder using an interface conforming to such standards. In order to reduce the circuit scale, it is desirable that the circuit for generating images for the monitor provided in the camera and the circuit for generating images for the electronic viewfinder be common. Therefore, the display on the monitor of the camera and the display on the electronic viewfinder may be exclusively controlled. In order to trigger exclusive control, for example, the camera may be notified when the user approaches or leaves the electronic viewfinder.

U.S. Patent Application Publication No. 2016/0127671

However, when the electronic viewfinder is connected to the digital camera as a UFP using the USB Type-C connector, it may not be possible to promptly notify the digital camera of the detection result of the electronic viewfinder. According to the above technology, the electronic viewfinder, which is a UFP device, can transmit information in response to receiving a query from a digital camera, which is a DFP device. You cannot send information with

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic device capable of rapidly transmitting information indicating the state of the connected electronic device to an external device that performs control according to the state of the electronic device, a control method thereof, and a communication system. It is in.

One form of the electric device of the present invention is an electronic device connected to an external device, comprising: a communication terminal connected to the external device; control means for controlling a DC voltage level of the communication terminal; communication means for superimposing and modulating a waveform on the DC voltage level of the controlled communication terminal to perform communication with the external device; detection means for detecting the state of the electronic device; determination means for determining whether or not the electronic device is connected to an external device, wherein the determination means detects that the electronic device is connected to the external device when the DC voltage level of the communication terminal is within a predetermined range for a predetermined detection period. When the detection means detects that the state of the electronic device has changed, the control means reduces the DC voltage level of the communication terminal to a period shorter than the predetermined detection period. It is characterized by changing only for a predetermined period.

One form of a communication system according to the present invention is a communication system comprising a display device for displaying an image and an output device for outputting image data to the display device, comprising: a first communication terminal; Control means for controlling the DC voltage level of the communication terminal; and first communication control for performing communication with the external device by modulating the voltage of the first communication terminal by superimposing a waveform on the controlled DC voltage level. means, detection means for detecting the state of the display device, and determination means, when the DC voltage level of the communication terminal is within a predetermined range for a predetermined detection period, the electronic device is detected as the external device. and a first display means for displaying an image based on the image data, a second communication terminal for connecting to the first communication terminal, and the second communication terminal. second communication control means for communicating with the electronic device via a second communication terminal; determining means for determining the state of the electronic device based on the DC voltage level of the second communication terminal; and displaying an image based on the image data. 2 display means; and output means for outputting the image data to at least one of the display device and the second display means based on the state of the display device, wherein the control means comprises , when the detection means detects that the state of the electronic device has changed, the DC voltage level of the communication terminal is changed for a predetermined period shorter than the predetermined detection period, and the output means is When the DC voltage level of the second communication terminal changes for a period shorter than the predetermined detection period, it is determined that the state of the display device has changed, and the output destination of the image data is changed. communication system.

According to the electronic device, the control method thereof, and the communication system of the present invention, it is possible to quickly transmit information indicating the state to an external device that performs control according to the state of the connected electronic device.

It is a perspective view which shows an electronic device and an external device. FIG. 3 is a diagram showing the pin arrangement of a USB Type-C connector; 1 is a block diagram showing an electronic device and an external device; FIG. FIG. 4 is a schematic diagram showing an example of data transmission between an external device and an electronic device; 4 is a first flow chart showing the operation of the electronic device; 4 is a second flow chart showing the operation of the external device; 4 is a first time chart showing an example of data transmission between an external device and an electronic device; 9 is a third flow chart showing the operation of the electronic device; 4 is a second time chart showing an example of data transmission between an external device and an electronic device;

<Example 1>
Preferred embodiments to which the present invention is applied will now be described in detail with reference to the accompanying drawings.

An electronic apparatus and its control method and an electronic device and its control method will be described with reference to the drawings. FIG. 1 is a perspective view showing an electronic device and an external device according to this embodiment. Here, an example in which the external device 100 is a digital camera will be described, but the present invention is not limited to this. Also, here, a case where the electronic device 200, that is, the electronic device (electronic device) is an external viewfinder attached to a digital camera will be described as an example, but it is not limited to this. In addition, the external device 100 and the electronic device 200 constitute a communication system that performs communication using the DC voltage level of the communication terminal, as will be described later.

The external device 100 is provided with a connector 101 for connecting the electronic device 200 . The connector 101 is, for example, a receptacle conforming to the USB Type-C standard. Connector 101 can be connected to electronic device 200 and can supply power to electronic device 200 . The electronic device 200 is provided with a connector 201 for connecting to the external device 100 . The connector 201 is, for example, a plug conforming to the USB Type-C standard. Connector 201 can be connected to external device 100 and can receive power from external device 100 . The connector 101 and the connector 201 have pin assignments as shown in FIG. 2 defined in the USB Type-C standard.

FIG. 2 is a diagram showing the pin arrangement of the USB Type-C connector, that is, the pin arrangement of the connectors 101 and 201. As shown in FIG. The connectors 101 and 201 are provided with CC (Configuration Channel) terminals 101b and 201b (see FIG. 3) used for connection detection, negotiation, and the like, respectively. That is, the connector 101 is provided with CC terminals (CC1, CC2) 101b. The connector 201 is provided with CC terminals (CC1, CC2) 201b.

When the connector 101 and the connector 201 are connected, the CC terminal 101b provided on the connector 101 and the CC terminal 201b provided on the connector 201 are connected to each other. The potential Vs of the CC terminal 101b is monitored using the connection detector 108 (see FIG. 3A). The potential of the CC terminal 201b is monitored using the connection detector 208 (see FIG. 3B). As will be described later, when the external device 100 and the electronic device 200 are connected, information can be transmitted and received via the CC terminal. That is, the CC terminal is a communication terminal for communication.

The connector 101 is provided with a VBUS terminal (power supply terminal) 101a and a GND terminal (ground terminal). The connector 201 is provided with a VBUS terminal 201a and a GND terminal. A predetermined voltage, that is, VBUS, can be supplied from the external device 100 to the electronic device 200 via the VBUS terminals 101a and 201a.

TX* terminals (TX1+, TX1-, TX2+, TX2-) are terminals for signal transmission, and RX* terminals (RX1+, RX1-, RX2+, RX2-) are terminals for signal reception. transmission. The SBU terminals (SBU1, SBU2) are sideband signal terminals and can be appropriately used for various purposes. The D+ and D- terminals are used to support USB 2.0.

The external device 100 is provided with an accessory shoe adapter (accessory shoe connector). The accessory shoe adapter serves to physically fix the electronic device 200 . The external device 100 is provided with a display section 114 . The electronic device 200 is provided with a display section 214 different from the display section 114 provided in the external device 100 . Electronic device 200 includes sensor 216 . A sensor 216 is a sensor for detecting eye contact and eye separation of the user. For example, sensor 216 is a ranging sensor that detects the distance to an object that is close to electronic device 200 . The external device 100 is provided with an imaging optical system 120 including a lens (not shown), that is, a lens unit. The imaging optical system 120 may be non-detachable with respect to the external device 100 or may be detachable with respect to the external device 100 .

FIG. 3 is a block diagram showing the external device 100 and the electronic device 200 according to this embodiment. 3A shows the external device 100, and FIG. 3B shows the electronic device 200. As shown in FIG.

The external device 100 has a port conforming to the USB Type-C standard. A port of the external device 100 is provided with a connector 101 .

The port of the external device 100 can be a DFP (Downstream Facing Port) or a UFP (Upstream Facing Port). In other words, assume that the port of the external device 100 is a DRP (Dual Role Port) which is a Type-C port capable of switching the roles of DFP and UFP. Here, the DFP is a port that functions as a host and supplies power, that is, a Type-C port that serves as a source. A UFP is a port that functions as a device and also receives power, that is, a Type-C port that serves as a sink.

An electronic device equipped with a DRP, that is, a DRP device can be a DFP device that supplies power to an external device, or a UFP device that receives power from an external device. can also A CC (Configuration Channel) terminal 101b is used to determine the role of each device. Note that the port of the electronic device 200 is, for example, a UFP (Upstream Facing Port).

For example, the external device 100 is assumed to be an imaging device that operates with power supplied from a battery (not shown) provided in the external device 100 . The external device 100 can transmit a video signal to the electronic device 200 via a TX terminal, which will be described later. Electronic device 200 is assumed to be a display (display device) that displays an image based on a video signal received from external device 100 or the like. Note that the external device 100 and the electronic device 200 are not limited to such devices.

The external device 100 is provided with the connector 101, specifically the receptacle, as described above. The electronic device 200 is provided with the connector 201, specifically the plug, as described above. Connector 101 of external device 100 and connector 201 of electronic device 200 are connected to each other. Communication and power supply can be performed between the port of the external device 100 and the port of the electronic device 200 via the connectors 101 and 201 .

The external device 100 has a connector 101 , a switch 102 , a pull-up resistor 103 , a pull-down resistor 104 , a switch control section 105 , a communication section 106 , a determination section 107 , a connection detection section 108 and a system control section 109 . The external device 100 further includes a power supply section 111 , an imaging section 112 , a memory 113 , a display section 114 and a device determination section 115 .

One end of the pull-up resistor 103 is connected to the power supply line. The power line is connected to a constant-voltage power supply with a predetermined voltage, and the potential of the power line is VCC. The other end of pull-up resistor 103 is connected to switch 102 . A pull-up resistor 103 can be connected to the CC terminal 101b via a switch 102. FIG. A resistance value of the pull-up resistor 103 is specified in the USB Type-C standard, and is 22 kΩ, for example. The voltage value of VCC is specified in the USB Type-C standard and is 5V, for example. VCC is generated separately from the power supplied to electronic device 200 via VBUS terminal 101a, that is, VBUS.

One end of pull-down resistor 104 is connected to the ground line. The potential of the ground line is the ground potential GND, that is, 0V. The other end of pull-down resistor 104 is connected to switch 102 . The pull-down resistor 104 can be connected through the switch 102 to a predetermined terminal, namely the CC terminal 101b. A resistance value of the pull-down resistor 104 is specified in the USB Type-C standard, and is 5.1 kΩ, for example.

The switch 102 switches connections. Switch 102 connects CC terminal 101b and pull-up resistor 103 in a certain state (pull-up state). In other states, switch 102 connects CC terminal 101b and pull-down resistor 104 (pull-down state). In yet another state, switch 102 does not connect CC terminal 101b to pull-up resistor 103 or pull-down resistor 104 (open state). The switch 102 is controlled by a switch control section 105 .

A switch control unit (SW control unit) 105 controls the switch 102 based on an instruction from the system control unit 109 . Switch control section 105 can control switch 102 such that CC terminal 101 b is connected to pull-up resistor 103 . By connecting CC terminal 101b to pull-up resistor 103, it is possible to indicate to electronic device 200 that external device 100 is a host device, ie, a DFP device.

Also, the switch control section 105 can control the switch 102 so that the CC terminal 101 b is connected to the pull-down resistor 104 . By connecting the CC terminal 101b to the pull-down resistor 104, it is possible to indicate to the electronic device 200 that the external device 100 is a device device, that is, a UFP device. The switch control unit 105 can switch the switch 102 periodically. By periodically switching switch 102, it is possible to indicate to electronic device 200 that external device 100 is a DRP device that can be both a host device and a device device.

Furthermore, switch control section 105 can set switch 102 to an open state. In other words, the switch control unit 105 can connect the CC terminal 101b to neither the pull-up resistor 103 nor the pull-down resistor 104. FIG. Switch control section 105 alternately connects CC terminal 101b to pull-up resistor 103 and pull-down resistor 104 until connection detection section 108 determines that external device 100 and electronic device 200 are connected. to control. Alternately and periodically connecting the CC terminal 101b to the pull-up resistor 103 and the pull-down resistor 104 is called toggling.

The communication unit 106 performs communication conforming to the USB Type-C Power Delivery (PD) standard, that is, PD communication, via the CC terminal 101b. The communication unit 106 performs communication between connected devices by modulating the voltage of the CC terminal. The communication unit 106 modulates the DC voltage level of the CC terminal by superimposing a waveform. Specifically, the communication unit 106 controls the DC voltage level of the CC terminal 101b so that the voltage value of the CC terminal 101b transitions between the High and Low states in a pulse-like manner. It is a communication control circuit that communicates with Note that the waveform used by the communication unit 106 to modulate the voltage of the CC terminal is not limited to the pulse waveform described above.

When communicating between connected devices in the USB standard alternate mode, the device-side device (electronic device 200) receives a query from the host-side device (external device 100). Send information.

FIG. 4 is a time chart showing an example of data transmission between the external device 100 and the electronic device 200. FIG. A query (DP Status) requesting status information is periodically transmitted from the external device 100 . The external device 100 transmits a query to the electronic device 200 at predetermined intervals. For example, external device 100 transmits a query to electronic device 200 every 50 ms.

Electronic device 200 returns an ACK in response to receiving the query, and then transmits status information of electronic device 200 . That is, it can be said that the electronic device 200 transmits information to the external device 100 in response to the received query.

Therefore, when it is detected that the user is away from the electronic device 200 (out-of-sight state) at the timing indicated by the star mark in FIG. 200 transmits distance information. In this case, there may be a time lag between when the electronic device 200 detects the eye separation state and when the external device 100 detects the eye separation state. A similar time difference also occurs when the eye contact state is detected.
For example, in compliance with the Display Port standard, the host-side external device 100 transmits DP Status every 50 msec. In this case, the electronic device 200 on the device side notifies the external device 100 of the detection of the eye contact state 50 ms at maximum after detecting the eye contact state.

In some cases, the external device 100 controls to display the live view image only on either the display unit 114 of the external device 100 or the display unit 214 of the electronic device 200 depending on the eye contact state of the electronic device 200 . In such a case, if the above-described time lag occurs, the time lag in switching the display of the live view image increases, and the user may feel uncomfortable. Specifically, it is necessary to display a live view image on the display unit 214 while the user is looking into the display unit 214 of the EVF (electronic device 200 ) (eyepiece state). On the other hand, when the user is away from the display unit 214 of the EVF (out-of-sight state), it is necessary to display a live view image on the display unit 114 of the digital camera (external device 100). If the display of the live view image does not switch quickly when the user transitions from the eye-on state to the eye-out state, the user cannot check the live view immediately after the transition. The same is true when the state transition is reversed.

The determination unit 107 detects the voltage value of the CC terminal 101b, and determines whether or not the electronic device 200 is in the eye contact state according to the voltage value of the CC terminal 101b. The determination section 107 outputs the determination result to the system control section 109 . For example, suppose that the DC voltage level of the CC terminal 101b is controlled to one of two voltage values depending on whether the electronic device 200 is in the eye-focused state. In this case, the determining unit 107 sets the intermediate value between the two voltage values controlled by the electronic device 200 as the threshold, and determines whether the detected DC voltage level of the CC terminal 101b is higher than the threshold or not. is in the eye contact state. A change in the voltage value of the CC terminal 101b depending on whether or not the electronic device 200 is in the eye-focused state will be described later.

A connection detection unit (connection detection circuit) 108 determines whether or not the external device 100 and the electronic device 200 are connected. The connection detection unit 108 outputs to the system control unit 109 the determination result as to whether or not the external device 100 and the electronic device 200 are connected. That is, when the external device 100 and the electronic device 200 are connected, the connection detection unit 108 outputs to the system control unit 109 information indicating that the external device 100 and the electronic device 200 are connected. The connection detection unit 108 determines that the external device 100 and the electronic device 200 are connected when the potential Vs of the CC terminal 101b is within a predetermined range represented by the following formula (1). The voltage Vmin is, for example, 0.2V, and the voltage Vmax is, for example, 2.04V. Voltages Vmin and Vmax are specified in, for example, the USB Type-C standard.
Vmin≦Vs<Vmax (1)

The upper limit voltage Vmax of the predetermined range shown by equation (1) is lower than the potential of the power line connected to the pull-up resistor 103, that is, VCC. Also, the lower limit voltage Vmin of the predetermined range represented by the formula (1) is higher than the potential of the ground line connected to the pull-down resistor 104, that is, GND. For example, assume that Vmin is 0.2V and Vmax is 2.04V. The voltage range of formula (1) may be any voltage range defined in the USB Type-C standard.

For example, when the CC terminal 101b is connected to the pull-up resistor 103 via the switch 102 and the external device 100 and the electronic device 200 are not connected, the potential Vs of the CC terminal 101b is VCC. VCC is a potential that is not within the predetermined range shown in equation (1). In this case, the connection detection unit 108 does not determine that the external device 100 and the electronic device 200 are connected.

When the CC terminal 101b is connected to the pull-down resistor 104 via the switch 102 and the external device 100 and the electronic device 200 are not connected, the potential Vs of the CC terminal 101b is GND (0 V). . GND is a potential that is not within the predetermined range shown in equation (1). In this case, the connection detection unit 108 does not determine that the external device 100 and the electronic device 200 are connected. Thus, when the potential Vs of the CC terminal 101b is not within the predetermined range, the connection detection unit 108 does not determine that the external device 100 and the electronic device 200 are connected.

Even if CC terminal 101b and CC terminal 201b are electrically connected, if CC terminal 101b is connected to pull-down resistor 104, potential Vs of CC terminal 101b is ground potential GND. . Ground potential GND is a potential that is not within the predetermined range shown in equation (1). In this case, the connection detection unit 108 does not determine that the external device 100 and the electronic device 200 are connected.

In order to prevent erroneous determination due to noise, it is necessary that the period during which the voltage of the CC terminal 101b satisfies Equation (1) continues for a determination threshold value or more in order to detect connection. Further, when detecting disconnection (disconnection), it is necessary to maintain a state in which the voltage of the CC terminal 101b does not satisfy the expression (1) above the determination threshold.

When the connection detection unit 108 determines that the external device 100 and the electronic device 200 are connected, the system control unit 109 controls the switch control unit 105 to end toggling. The resistor connected to the CC terminal 101b when toggling ends is the resistor selected by the switch control unit 105 as the resistor connected to the CC terminal 101b.

In this embodiment, the external device 100 is assumed to be connected to the electronic device 200 as a DFP device. That is, in this case, the port of the external device 100 becomes the source, and the port of the electronic device 200 becomes the sink. When the connection with the electronic device 200 is established with the pull-up resistor 103 connected to the CC terminal 101b, the external device 100 enters a connected state in which power can be supplied to the electronic device 200 through the port.

The system control unit 109 controls the entire external device 100 . The system control unit 109 controls each functional block provided in the external device 100, that is, the switch control unit 105, the communication unit 106, the determination unit 107, the connection detection unit 108, the display control unit 110, and the power supply unit 111. . As the system control unit 109, for example, a CPU (Central Processing Unit) or the like is used.

The system control unit 109 acquires information output from each functional block provided in the external device 100 and outputs a signal for controlling the operation of each functional block. The system control unit 109 transmits information indicating whether to continue toggling to the switch control unit 105 based on the determination result of the connection detection unit 108 as to whether the external device 100 and the electronic device 200 are connected. Output for When the connection detection unit 108 determines that the external device 100 and the electronic device 200 are connected, the system control unit 109 controls the switch control unit 105 to end toggling. Thereby, the resistor connected to the CC terminal 101b is fixed.

Further, the system control unit 109 controls the display control unit 110 to output video data to the electronic device 200 when the determination unit 107 determines that the electronic device 200 is in the eye-focused state. Further, system control unit 109 controls display control unit 110 to output video data to display unit 114 when determination unit 107 determines that electronic device 200 is in the eye-out state.

When the voltage of the CC terminal 101b changes for a first period or a second period described later in a state in which the electronic device 200 and the external device 100 are connected, the system control unit 109 determines that the eye contact state of the electronic device 200 has changed. judge.

When displaying an image or the like on the display section 114 , the display control section 110 controls the display section 114 and transmits image data or the like to the display section 114 . When the display control unit 110 causes the electronic device 200 to perform display in the alternate mode, the display control unit 110 transmits video data and the like to the electronic device 200 via the TX terminal 101c of the connector 101 and the RX terminal 201c of the connector 201, for example. Send. The destination to which the display control unit 110 outputs the video data is determined by an instruction from the system control unit 109 .

A power supply unit (power control circuit) 111 includes a voltage conversion unit (not shown). The voltage converter generates a predetermined voltage such as VCC or VBUS using power supplied from a battery (not shown) or the like. The power supply unit 111 controls power supply to electronic circuits, drive components, and the like provided inside the external device 100 .

Also, the power supply unit 111 can charge the battery with power received from the electronic device 200 . VBUS_Source indicates VBUS supplied from the external device 100 to the electronic device 200, and is supplied to the electronic device 200 via the switch 111a and the VBUS terminal 101a. VBUS_Sink indicates VBUS supplied from the electronic device 200 to the external device 100 and is supplied to a battery or the like provided in the external device 100 .

When the port of the external device 100 is used as the source, the system control unit 109 turns on the switch 111a and turns off the switch 111b. As a result, VBUS is supplied from the external device 100 to the electronic device 200 via the VBUS terminal 101a. When the port of the external device 100 is used as a sink, the system control unit 109 turns off the switch 111a and turns on the switch 111b. As a result, the VBUS from the electronic device 200 is supplied to the external device 100 via the VBUS terminal 101a.

The imaging unit 112 is provided with an imaging element (image sensor) not shown. An optical image formed by the imaging optical system 120 is incident on an imaging surface (not shown) of the imaging element. The imaging device photoelectrically converts the optical image to generate an analog image signal, and analog-to-digital converts the analog image signal to generate a digital image signal, that is, image data. The imaging unit 112 outputs the image data thus acquired to the system control unit 109 .

The memory 113 is a storage medium that stores programs and parameters executed by the system control unit 109 to control each functional block.

The display unit 114 displays still images, moving images (video), and the like based on the image data output from the display control unit 110 . As the display unit 114, for example, a small liquid crystal panel or the like is used. The display unit 114 is provided, for example, so that the display screen is exposed outside the main body of the external device 100 .

FIG. 3B is a block diagram showing functional blocks of the electronic device 200. As shown in FIG. Electronic device 200 includes connector 201 , switch 202 , pull-up resistor 203 , pull-down resistor 204 , switch control section 205 , communication section 206 , connection detection section 208 , and system control section 209 . The electronic device 200 further includes a display control section 210 , a power supply section 211 , a memory 113 , a display section 214 , a sensor 216 and an eye proximity determination section 217 .

Connector 201 , pull-up resistor 203 , pull-down resistor 204 , communication unit 206 , connection detection unit 208 , power supply unit 211 , memory 113 , and display unit 214 should exhibit the same functions as the same functional blocks of external device 100 . Therefore, detailed description is omitted.

A switch control unit 205 is a control circuit for controlling the connection state of the switch 202 according to an instruction from the system control unit 209 . As described above, since the DC voltage level of the CC terminal 201b is determined according to the connection state of the switch 202, the switch control section 205 is a control circuit for controlling the DC voltage level of the CC terminal 201b. It can be said. The switch control unit 205 performs toggling control of the switch 202 in the same manner as the switch control unit 105 .

The switch control unit 205 also connects the pull-up resistor 203 and the pull-down resistor 204 in order to output to the external device 100 a signal indicating whether or not there is a transition in the eyepiece state, which will be described later, in accordance with an instruction from the system control unit 209 . Execute the switch.

The sensor 216, as described above, is a sensor for detecting eye contact and eye separation of the user. For example, sensor 216 is a ranging sensor that detects the distance to an object that is close to electronic device 200 . The sensor 216 outputs a High signal when an object exists within a range equal to or less than a preset distance, and outputs a Low signal otherwise. The sensor 216 includes, for example, a light-emitting portion that emits infrared light and a light-receiving portion that receives infrared light reflected by a reflector or the like.

The sensor 216 determines the eye contact state and the eye detachment state based on whether or not the amount of reflected light received by the light receiving unit is equal to or greater than a preset threshold value. When a reflecting object such as the user's face approaches the sensor 216 and the amount of reflected light received by the light receiving unit becomes equal to or greater than the threshold value, the sensor 216 determines that the eye is in the eye contact state. do. When the sensor 216 determines that it is in the eye contact state, the sensor 216 outputs, for example, a High level signal, that is, an eye contact signal. On the other hand, when a reflective object such as the user's face is not close to the eye contact detection unit 125 and the amount of reflected light received by the light receiving unit is less than the threshold value, the sensor 216 is in the eye distance state. Determine that there is. When it is determined that the eye is in the eye separation state, the sensor 216 outputs, for example, a Low level signal, that is, the eye separation signal.

The eye contact determination unit 217 determines whether or not the eye is in the eye contact state according to the signal output from the sensor 216 . The state in which the eye is not in the eye contact state is the eye detached state. The eye proximity determination unit 217 outputs the determination result to the system control unit 209 . Also, the eye proximity determination unit 217 determines whether or not there is a transition in the eye proximity state, and outputs the determination result to the system control unit 209 . Specifically, the eye proximity determination unit 217 outputs information indicating transition from the eye contact state to the eye contact state and information indicating transition from the eye contact state to the eye contact state.

The system control unit 209 controls the operation of the switch control unit 205 according to the determination result acquired from the eye proximity determination unit 217 . When the eye contact determination unit 217 determines that the eye contact state has changed to the eye detachment state, the switch control unit 205 switches the resistor connected to the CC terminal 201b from the pull-down resistor 204 to the pull-up resistor 203 for the first period. Control switch 202 . Further, when the eye proximity determination unit 217 transitions from the eye distance state to the eye proximity state, the switch control unit 205 switches the resistor connected to the CC terminal 201b from the pull-down resistor 204 to the pull-up resistor 203 for the second period. 202. The first period and the second period may have the same length or different lengths.

Also, the system control unit 209 may control the operation of the display control unit 210 according to the determination result acquired from the eye proximity determination unit 217 . For example, when the eye contact determination unit 217 determines that the eye is not in the eye contact state, the system control unit 209 may control the display control unit 210 so that the power consumption of the display unit 214 is reduced. Specifically, the display control unit 210 may control the power supply to the display unit 214 to be stopped, or the power consumption may be reduced by stopping a part of the functions of the display unit 214. It may be controlled. For example, if the display unit 214 is a liquid crystal display module including a liquid crystal panel and a backlight, the display control unit 210 stops driving the backlight. For example, if the display unit 214 is an organic EL module including an organic EL panel, the display control unit 210 may control the operation of the drive power supply for the organic EL to stop. Alternatively, the display control unit 210 may control the display unit 214 to display a black image.

Further, when the eye position determination unit 217 determines that the eye position is in the eye position state, the system control unit 209 performs display control so that the display unit 214 can immediately display an image based on the image data input from the external device 100. control unit 210; Specifically, the system control unit 209 controls the display control unit 210 so that the display control unit 210 controls the display unit 214 to the standby state. The standby state is a state in which the display unit 214 can display an image based on image data. irradiate with light. By controlling the display unit 214 as described above, the power consumption of the display unit 214 can be reduced.

When the connector 201 of the electronic device 200 and the connector 101 of the external device 100 are connected directly or via a cable, and the voltage of the CC terminal satisfies the formula (1), the external device 100 and the electronic device 200 performs PD negotiation. The PD negotiation is communication for adjusting roles of power supply between the external device 100 and the electronic device 200, and adjusting permission/inhibition of transition to the alternate mode. The communication units of external device 100 and electronic device 200 perform PD negotiation via signal lines connected via CC terminals.

In this embodiment, after the PD negotiation between the external device 100 and the electronic device 200, the mode is shifted to the alternate mode, and an operating state in which the live view image can be transmitted from the external device 100 to the electronic device 200 via the data line. Suppose it becomes

FIG. 5 is a flowchart showing image display control and eyepiece state notification control of electronic device 200 . When the electronic device 200 is connected to the external device 100, the control of this flowchart is started. Further, in a state where the electronic device 200 and the external device 100 are connected, the control of this flowchart may be started in response to the external device 100 being powered on.

In step S<b>1001 , the system control unit 209 determines whether or not the eye is in the eye contact state based on the determination result acquired from the eye contact determination unit 217 . If it is in the eye contact state (S1001, Yes), the system control unit 209 outputs information indicating that the eye contact state is in the PD communication to the external device 100 via the communication unit 206, and proceeds to S1002. If the eye is not in the eye contact state (eye contact state), the system control unit 209 outputs information indicating that the eye is not in the eye contact state (eye contact state) via the communication unit 206 to the external device 100 via the PD communication. and proceed to S1008.

In S<b>1002 , the system control unit 209 controls the display unit 214 to display an image using the video signal acquired from the external device 100 .

In S1003, the system control unit 209 determines whether or not the eye contact state has changed. Here, the system control unit 209 determines whether or not there has been a transition from the on-eye state to the off-eye state. If it is determined that the eye contact state has changed, the process proceeds to S1004. Otherwise, the process proceeds to S1013.

In S1004, according to an instruction from the system control unit 209, the switch control unit 205 controls the switch 202 to change the resistor connected to the CC terminal 201b from the pull-down resistor 204 to the pull-up resistor 203. FIG.

In S1005, the system control unit 209 determines whether or not the first period has passed since the resistor connected to the CC terminal 201b was changed from the pull-down resistor 204 to the pull-up resistor 203. If the first period has not elapsed, S1005 is repeated. If the first period has passed, the process proceeds to S1006.

In S1006, according to an instruction from the system control unit 209, the switch control unit 205 controls the switch 202 to change the resistor connected to the CC terminal 201b from the pull-up resistor 203 to the pull-down resistor 204. FIG.

In S<b>1007 , the system control unit 209 ends image display processing based on the video signal acquired from the external device 100 .

In S1013, the system control unit 209 determines whether the electronic device 200 and the external device 100 are connected. If the electronic device 200 and the external device 100 are not connected, the display control process ends. If the electronic device 200 and the external device 100 are connected, the process returns to S1001.

On the other hand, if the system control unit 209 determines in S1001 that the eye is not in the eye-focused state, the process advances to S1008. In S1008, the system control unit 209 determines whether or not the eyepiece state has changed. Here, the system control unit 209 determines whether or not there has been a transition from the distanced state to the focused state. If it is determined that the eye contact state has changed, the process proceeds to S1009. Otherwise, the process proceeds to S1013.

In S1009, according to an instruction from the system control unit 209, the switch control unit 205 controls the switch 202 to change the resistor connected to the CC terminal 201b from the pull-down resistor 204 to the pull-up resistor 203. FIG.

In S1010, the system control unit 209 determines whether or not the second period has passed since the resistor connected to the CC terminal 201b was changed from the pull-down resistor 204 to the pull-up resistor 203. If the second period has not elapsed, S1010 is repeated. If the second period has passed, the process proceeds to S1011.

In S1011, according to an instruction from the system control unit 209, the switch control unit 205 controls the switch 202 to change the resistor connected to the CC terminal 201b from the pull-up resistor 203 to the pull-down resistor 204. FIG.

In S<b>1012 , the system control unit 209 controls the display unit 214 to display an image using the video signal acquired from the external device 100 . The process proceeds to S1013.

By controlling as described above, the electronic device 200 can output to the external device 100 the eye contact state or the transition of the eye contact state as a pulse of a predetermined period on the voltage of the CC terminal.

FIG. 6 is a flow chart showing display control processing of the external device 100 . Assume that this flowchart starts when the external device 100 is powered on.

In S2001, the system control unit 109 controls the display unit 114 to display an image based on the video signal.

In S<b>2002 , the system control unit 109 determines whether or not the external device 100 is connected to the electronic device 200 .

In step S<b>2003 , the system control unit 109 determines whether or not the electronic device 200 is in the eye-focused state based on information acquired through PD communication via the communication unit 106 . If it is in the eye-focused state, the process proceeds to S2004. If the eye is not in the eye-focused state (the eye is in the detached state), the process proceeds to S2010.

In step S<b>2010 , the system control unit 109 determines that the electronic device 200 is in the eyeless state, and continues to display an image on the display unit 114 of the external device 100 . Then, in S2010, the system control unit 109 determines whether or not the voltage of the CC terminal 101b has changed over the second period. It can be said that the system control unit 109 determines whether or not the pulse of the second period is output from the electronic device 200 to the CC terminal 101b. If it is detected that the voltage of CC terminal 101b has changed over the second period (S2010, Yes), the process proceeds to S2004. Otherwise, the process of S2010 is repeated.

In step S<b>2004 , the system control unit 109 determines that the electronic device 200 is in the eye-focused state, and executes processing for outputting an image signal to the electronic device 100 .

In S2005, the system control unit 109 determines whether the voltage of the CC terminal 101b has changed over the first period. It can be said that the system control unit 109 determines whether or not the pulse of the first period is output from the electronic device 200 to the CC terminal 101b. If it is detected that the voltage of the CC terminal 101b has changed over the first period (S2005, Yes), the process proceeds to S2006. Otherwise, the process of S2005 is repeated.

In step S<b>2006 , the system control unit 109 determines that the electronic device 200 is out of sight, and stops the image signal output processing. Furthermore, in S2007, the system control unit 109 controls the display unit 114 to display an image on the display unit 114 based on the image signal.

In S<b>2008 , the system control unit 109 determines whether or not the external device 100 is connected to the electronic device 200 . If the external device 100 is connected to the electronic device 200, the process proceeds to S2009. Otherwise, the process proceeds to S2001.

In S2009, the system control unit 209 determines whether or not a power-off instruction has been given. It is assumed that the power off instruction is input through operation of an operation button (not shown) or the like. Further, the power off instruction may be generated by the system control unit 209 in response to the fact that scanning has not been performed for a predetermined period of time. If the power off instruction is given, the display control process ends. If the power off instruction is not issued, the process returns to S2001.

By executing the processing as described above, the external device 100 can quickly control the image signal output processing according to the state transition of the electronic device 200 .

FIG. 7 is a schematic diagram showing the timing of eye contact state notification and image display processing based on an image signal between the external device 100 and the electronic device 200. As shown in FIG. FIG. 7A shows a comparative example without the control of this embodiment. FIG. 7(b) shows the case where the control of this embodiment is executed.

The horizontal axis of FIG. 7 indicates time. Since the external device 100 and the electronic device 200 are not connected at the time t1, the respective CC terminals change the voltage periodically by toggling control. Also, at this time, the electronic device 200 is in the distanced state, and the determination result output by the eye proximity determination unit 217 is low. Also, an image based on the image signal is displayed on the display unit 114 of the external device 100 .

At time t2, external device 100 and electronic device 200 are connected. In response to specifying that the voltage of the CC terminal is within the predetermined voltage range from t2 until the detection period elapses, the external device 100 determines that the connection between the external device 100 and the electronic device 200 has been established. .

In response to determining that the connection between the external device 100 and the electronic device 200 has been established, negotiation by PD communication is started (t3).

After completion of connection negotiation, PD communication is performed again at t4. This communication is communication for exchanging information indicating the state of the devices between the devices. In FIG. 7, PD communication is performed at t4, t7, t9, and t12. That is, it means that transmission and reception of information via PD communication can be performed only at a predetermined timing.

Assume that the electronic device 200 is in the eye-distance state and an image is being displayed on the display unit 114 of the external device 100 during the series of processes described above.

At t5, the electronic device 200 is brought into the eye contact state, and the determination result output by the eye contact determination unit 217 is high.

At t6, the system control unit 209 determines that there has been a transition from the distanced state to the focused state based on the determination result of the focused state determination unit 217, and controls to output a signal indicating the focused state to the communication unit 206. Output a signal.

However, since the PD communication is not performed at t6, the communication unit 206 waits until t7, and outputs information indicating that the eye is in the eye contact state to the external device 100 in the PD communication executed at t7.

The external device 100 outputs an image signal to the electronic device 200 based on information acquired through PD communication. An image based on the image signal is displayed on the display unit 214 of the electronic device 200 at t8. A period from t7 to t8 is a control period for the external device 100 to switch the output destination of the image signal. It takes time t8-t5 from time t5 when the eye is changed from the eye-distance state to the eye-eye state until the device displaying the image is controlled.

Further, at t10, the electronic device 200 is placed in the distanced state, and the determination result output by the eye proximity determination unit 217 is low.

At t11, the system control unit 209 determines that there has been a transition from the eye contact state to the eye contact state based on the determination result of the eye contact determination unit 217, and outputs a signal indicating the eye contact state to the communication unit 206. Output a control signal.

However, since the PD communication is not performed at t11, the communication unit 206 waits until t12, and outputs information indicating the eye separation state to the external device 100 in the PD communication executed at t12.

The external device 100 ends the process of outputting the image signal to the electronic device 200 based on the information acquired through the PD communication, and displays an image on the display unit 114 based on the image signal. An image based on the image signal is displayed on the display unit 114 of the external device 100 at t13. A period from t12 to t13 is a control period for the external device 100 to switch the output destination of the image signal. It takes time t13-t10 from time t9 at which the eye state changes to the eye detached state until the device displaying the image is controlled.

Therefore, when the cycle of PD communication is several tens of ms or longer, even if the processing speed of each device is increased, a delay in display switching corresponding to the cycle of PD communication occurs at maximum. If the external device 100 is a digital camera and the electronic device 200 is an EVF, the delay in switching the live view image display means that the user cannot check the live view image for an extended period of time. Therefore, there is a problem that the longer the delay, the more the user misses the photo opportunity.

On the other hand, when the processing shown in the present embodiment is executed, the voltage of the CC terminal changes for the first period or the second period according to the transition of the eyepiece state, as shown in FIG. 7B. As a result, the external device 100 can recognize the change in the eye-position state of the electronic device 200 without waiting for the PD communication timing.

Specifically, the display device is switched at time t8' by applying the pulse Pa to the CC terminal as a result of the system control unit 209 determining at t6 that the eye has changed from the eye-distance state to the eye-eye state. be. At t11, the system control unit 209 determines that the eye state has changed from the eye-on state to the eye-out state, so that the pulse Pb is applied to the CC terminal, thereby switching the display device at time t13'.

The timing of each switching is earlier than the timing in the comparative example. Therefore, when the state of eye contact with the electronic device 200 is changed, it is possible to quickly change the process of displaying an image. Therefore, it is possible to shorten the period during which the user cannot confirm the live view image.

In addition, since it is possible to stop the display of one of the external device 100 and the electronic device 200 according to the eye-eye state, it is also possible to reduce power consumption.

<Example 2>
The electronic device 200 of the first embodiment notifies the external device 100 of the state change of the electronic device 200 by superimposing a predetermined pulse on the CC terminal. When the electronic device 200 of the second embodiment cannot detect the pulse superimposed on the CC terminal, it makes it possible to notify the external device 100 of the state change by setting the CC terminal to the unconnected potential state.

The configuration of the external device 100 and the electronic device 200 of the second embodiment is the same as the configuration shown in the first embodiment, so detailed description thereof will be omitted.

In the second embodiment, the electronic device 200 determines whether or not the external device 100 is a predetermined type of electronic device by the device determination unit 218, and switches the mode for notifying the state change.

The device determination unit 218 is a determination unit that determines whether or not the external device connected via the connector 201 is compatible with the electronic device 200 . A compatible external device is, for example, an electronic device in which the electronic device 200 and the electronic device 100 are manufactured by the same vendor. Affinity can be determined. Information about affinity is VID (A Vendor ID), for example. Also, information about affinity is acquired in PD communication when the external device 100 and the electronic device 200 are connected.

When the device determination unit 218 determines that the connected external device 100 is compatible with the external device 100, the system control unit 209 of the second embodiment performs the eyepiece state transition by the control described in the first embodiment. It operates in the first operation mode of notifying. Further, when the device determination unit 218 determines that the connected external device 100 is compatible with the external device 100, the system control unit 209 performs control different from that of the first embodiment to notify the transition of the eyepiece state. It operates in two modes of operation. An external device with affinity is assumed to be a type of external device that can detect state transitions by the notification method described in the first embodiment.

In the following, a detailed description will be given of the control in the case of notifying the transition of the eyepiece state in the second operation mode.

FIG. 8 is a flowchart showing display control and connection state notification control of electronic device 200 in the second operation mode. Among the processes shown in the flowchart of FIG. 8, S3001 to S3003, S3007, S3008, S3012, and S3013 are the same processes as S1001 to S1003, S1007, S1008, S1012, and S1013, so description thereof will be omitted.

If the system control unit 209 determines in S3003 that the eye contact state has changed to the eye detached state, the process advances to S3004. In S<b>3004 , switch control section 205 controls switch 202 so that CC terminal 201 b is connected to neither pull-up resistor 203 nor pull-down resistor 204 . Thereby, the CC terminal 101b of the external device 100 is connected to the power supply through the pull-up resistor 103. FIG.

In S3005, the system control unit 209 determines whether or not the third period has elapsed since the connection of the CC terminal 201b was changed. Here, the third period is longer than the detection period, and is assumed to be 25 ms, for example. Similar to S1005, the determination process is repeated until the third period elapses.

In response to the elapse of the third period, in S3006, the switch control unit 205 starts toggling control of the CC terminal 201b. Note that in S<b>3006 , the switch control unit 205 may control the switch 202 to connect the CC terminal 201 b to the pull-down resistor 204 .

Also, if the system control unit 209 determines in S3008 that the state has changed from the distanced state to the focused state, in S3009 the system control unit 209 notifies the external device 100 that the state has changed to the focused state via PD communication. . As described above, in this case, there is a waiting time from when the eye contact state is detected until the PD communication is executed.

FIG. 9 is a time chart for notification in the second operation mode. The events from t1 to t10 are the same as in FIG. 7(a), so the description is omitted.

At t11, in response to the system control unit 209 determining that the eye-on state has changed to the eye-out state, the switch control unit 205 connects the CC terminal 201b to the pull-up resistor 203 and the CC terminal 201b for a third period longer than the detection period. It is set to a state in which it is not connected to any of the pull-down resistors 204 . Accordingly, the connection detection unit 108 of the external device 100 determines that the connection between the external device 100 and the electronic device 200 is lost (disconnection). Based on the detection result indicating that the external device 100 and the electronic device 200 are disconnected, the system control unit 109 controls to display the live view image on the display unit 114 (t13'').

By controlling as described above, it is possible to shorten the time difference (t13-t10) until display switching occurs when the electronic device 200 notifies the transition from the eye contact state to the eye separation state at PD communication timing. becomes.

Therefore, when the electronic device 200 changes from the eye-distance state to the eye-eye state, it is possible to quickly change the processing for displaying an image. Therefore, it is possible to shorten the period during which the user cannot confirm the live view image.

In addition, since it is possible to stop the display of one of the external device 100 and the electronic device 200 according to the eye-eye state, it is also possible to reduce power consumption.

100 external device 200 electronic device 201 connector 201b CC terminal 206 communication unit 208 connection detection unit 209 system control unit 214 display unit 217 eye proximity determination unit

Claims (17)

An electronic device that connects to an external device,
a communication terminal connected to the external device;
control means for controlling the DC voltage level of the communication terminal;
communication means for superimposing and modulating a waveform on the DC voltage level of the communication terminal controlled by the control means to perform communication with the external device;
detection means for detecting the state of the electronic device;
with
the external device determines that the electronic device is connected to the external device when the DC voltage level of the communication terminal is within a predetermined range for a predetermined detection period;
The control means changes the DC voltage level of the communication terminal for a predetermined period shorter than the predetermined detection period when the detection means detects that the state of the electronic device has changed. An electronic device characterized by: Display means for displaying an image based on the image data received from the external device,
2. The electronic device according to claim 1, wherein the detection means detects whether or not the distance between the user and the electronic device is a predetermined distance or less. 3. The electronic device according to claim 2, further comprising a terminal for receiving said image data. When the detection means detects that the state of the electronic device has changed, the control means reduces the DC voltage level of the communication terminal to the predetermined range for a predetermined period shorter than the predetermined detection period. 4. The electronic device according to any one of claims 1 to 3, wherein the voltage level is changed to a voltage level not included in the . a first resistor with one end grounded;
a second resistor having one end connected to a power supply outputting a predetermined voltage level;
furthermore,
The control means switches connection between the communication terminal and either the other end of the first resistor or the other end of the second resistor to control the DC voltage level of the communication terminal. 5. The electronic device according to any one of claims 1 to 4. 6. The electronic device according to claim 1, wherein said electronic device is a viewfinder. 7. The electronic device according to claim 6, wherein said external device is a digital camera. 8. The electronic device according to any one of claims 1 to 7, wherein the communication terminal is a CC terminal defined in the USB Type-C standard conforming to the USB 3.1 standard. A communication system comprising a display device for displaying an image and an output device for outputting image data to the display device,
a first communication terminal;
control means for controlling the DC voltage level of the first communication terminal;
first communication control means for performing communication with the output device by superimposing a waveform on the voltage of the first communication terminal to the controlled DC voltage level and modulating the voltage;
detection means for detecting the state of the display device;
a first display means for displaying an image based on the image data;
a display device comprising
a second communication terminal for connecting with the first communication terminal;
a second communication control means for communicating with the display device via the second communication terminal;
detection means for detecting that the display device is connected to the output device when the DC voltage level of the second communication terminal is within a predetermined range for a predetermined detection period;
determining means for determining the state of the display device based on the DC voltage level of the second communication terminal;
a second display means for displaying an image based on the image data;
output means for outputting the image data to at least one of the display device and the second display means based on the state of the display device;
an output device comprising
with
The control means changes the DC voltage level of the first communication terminal for a predetermined period shorter than the predetermined detection period when the detection means detects that the state of the display device has changed. ,
The determination means determines that the state of the display device has changed when the DC voltage level of the second communication terminal changes for the predetermined period shorter than the predetermined detection period,
The communication system, wherein the output means changes the output destination of the image data according to the judgment of the state change by the judgment means. A control method for an electronic device having a communication terminal for connecting to an external device,
a control step of controlling the DC voltage level of the communication terminal;
a communication step of superimposing and modulating a waveform on the DC voltage level of the controlled communication terminal to perform communication with the external device;
a detection step of detecting the state of the electronic device;
with
the external device determines that the electronic device is connected to the external device when the DC voltage level of the communication terminal is within a predetermined range for a predetermined detection period;
The control step changes the DC voltage level of the communication terminal for a predetermined period shorter than the predetermined detection period when the detection step detects that the state of the electronic device has changed. A method of controlling an electronic device characterized by: The electronic device comprises display means for displaying an image based on the image data received from the external device,
11. The method of controlling an electronic device according to claim 10, wherein the detecting step detects whether or not the distance between the user and the electronic device is a predetermined distance or less. 12. The method of controlling an electronic device according to claim 11, further comprising a receiving step of receiving said image data. In the control step, when the detection step detects that the state of the electronic device has changed, the control step reduces the DC voltage level of the communication terminal to the predetermined period for the predetermined period shorter than the predetermined detection period. 13. The method of controlling an electronic device according to claim 10, wherein the voltage level is changed to a voltage level that is not included in the range. The electronic device comprises a first resistor whose one end is grounded and a second resistor whose one end is connected to a power supply that outputs a predetermined voltage level,
The control step includes switching connection between the communication terminal and either the other end of the first resistor or the other end of the second resistor to control the DC voltage level of the communication terminal. 14. The method of controlling an electronic device according to any one of claims 10 to 13. 15. The method of controlling an electronic device according to claim 10, wherein the electronic device is a viewfinder. 16. The method of controlling an electronic device according to claim 15, wherein the external device is a digital camera. 17. The method of controlling an electronic device according to claim 10, wherein the communication terminal is a CC terminal defined in USB Type-C standard conforming to USB 3.1 standard.

Images