Electronic device and accessory

Abstract

To suppress interference to a communication signal caused by a change in another signal.SOLUTION: An accessory 200 is detachably attached to an electronic device 100 having a plurality of contacts electrically connected to the accessory which are arranged in a line. The plurality of contacts include: first and second signal contacts TC12, TC13 used to transmit a first signal and a second signal which are a data signal and a clock signal respectively in communication between the electronic device and the accessory; a third signal contact TC14 used to transmit a third signal; and a fourth signal contact TC11 used to transmit a fourth signal. The signal levels of the third and fourth signals do not change during communication of the first and second signals. The first and second signal contacts are disposed adjacent to each other, the third signal contact is disposed on one of both vicinities of the first and second signal contacts, and the fourth signal contact is disposed on the other side thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to electronic devices and accessories having contacts used for communication, power supply, etc. [Background technology]

[0002] An accessory such as a flash device is attached to an accessory shoe provided on an electronic device such as a camera. The accessory shoe is provided with multiple contacts (terminals) for supplying power to the accessory and communicating with the accessory. However, if a signal connected to one contact receives noise from a signal connected to an adjacent contact during communication between the electronic device and the accessory, it can cause the electronic device or the accessory to malfunction.

[0003] Patent document 1 discloses a camera and accessory in which a contact that notifies the camera that the accessory is ready to be activated is located next to one of the contacts to which a data signal as a communication signal is connected, and a contact connected to ground is located next to the other data signal contact. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-34172 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not mention a contact arrangement for avoiding interference with communication signals due to changes in other signals.

[0006] The present invention provides an electronic device and an accessory that can suppress interference with communication signals due to changes in other signals. [Means for solving the problem]

[0007] One aspect of the present invention provides an electronic device to which an accessory is detachably attached. The electronic device has a plurality of contacts arranged in a row for electrical connection with the accessory. The plurality of contacts includes a first signal contact used to transmit a first signal, which is a data signal, in communication between the electronic device and the accessory, a second signal contact used to transmit a second signal, which is a clock signal, in the communication, a third signal contact used to transmit a third signal, which is different from the first and second signals, between the electronic device and the accessory, and a fourth signal contact used to transmit a fourth signal, which is different from the first, second, and third signals, between the electronic device and the accessory. The third and fourth signals are signals whose signal levels do not change during the communication. The first and second signal contacts are arranged adjacent to each other, and the third signal contact is arranged on one side of the first and second signal contacts, and the fourth signal contact is arranged on the other side.

[0008] Another aspect of the present invention provides an accessory that is detachably attached to an electronic device. The accessory has a plurality of contacts arranged in a row to be electrically connected to the electronic device. The plurality of contacts includes a first signal contact used to transmit a first signal, which is a data signal, in communication between the electronic device and the accessory, a second signal contact used to transmit a second signal, which is a clock signal, in the communication, a third signal contact used to transmit a third signal, which is different from the first and second signals, between the electronic device and the accessory, and a fourth signal contact used to transmit a fourth signal, which is different from the first, second, and third signals, between the electronic device and the accessory. The third and fourth signals are signals whose signal levels do not change during the communication. The first and second signal contacts are arranged adjacent to each other, and the third signal contact is arranged on one side of the first and second signal contacts, and the fourth signal contact is arranged on the other side. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress interference with a communication signal due to changes in other signals. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of a camera and accessories according to an embodiment of the present invention. [Figure 2] 1A and 1B are diagrams showing a camera with accessories attached thereto and an example of the arrangement of their contact points in an embodiment. [Figure 3] 10A and 10B are diagrams showing how an external force is applied to an accessory attached to a camera in the embodiment. [Figure 4A] FIG. 4 is a diagram showing a configuration for determining the connection state of a ground contact in the embodiment. [Figure 4B] 4 is a flowchart illustrating a process performed by a camera in an embodiment. [Figure 5] 4 is a flowchart showing a process executed by the camera of the embodiment. [Figure 6] 10 is a timing chart showing signal changes when a power contact and an adjacent contact are shorted in the embodiment. [Figure 7] FIG. 10 is a diagram showing an example of assignment of function signals to types of accessories in the embodiment. [Figure 8] FIG. 2 is a diagram showing the configuration of connection destinations of function signals in the embodiment. [Figure 9] FIG. 1 is a diagram showing an example of the configuration of a camera and accessories according to an embodiment. [Figure 10] FIG. 10 is a diagram showing another example of the configuration of the camera and accessories in the embodiment. [Figure 11] FIG. 10 is a diagram showing yet another example of the configuration of the camera and accessories in the embodiment. [Figure 12] FIG. 2 is a diagram showing a configuration example of an accessory in the embodiment. [Figure 13] 1A and 1B are diagrams showing configuration examples of a camera, an accessory, and an intermediate accessory in an embodiment. [Figure 14] 10A and 10B are diagrams showing other configuration examples of the camera, the accessory, and the intermediate accessory in the embodiment. [Figure 15] 10 is a timing chart in the case where the accessory is a strobe device in the embodiment. [Figure 16] FIG. 1 is a perspective view of a camera and an external flash unit as an accessory in an embodiment. [Figure 17] 3A and 3B are an exploded view and a perspective view of an accessory shoe in the embodiment. [Figure 18] 10A and 10B are diagrams showing the structure of an engaging member of an accessory shoe and a connection terminal connector in an embodiment. [Figure 19] 1A and 1B are a perspective view and a cross-sectional view of an external flash unit according to an embodiment. [Figure 20] 3A and 3B are a perspective view and a front view showing the internal structure of a camera connection portion in the embodiment. [Figure 21] 3A and 3B are a top view and a cross-sectional view of a camera connection portion in the embodiment. [Figure 22] 10A and 10B are perspective and cross-sectional views of a modified external flash unit; [Figure 23] 10A and 10B are a perspective view and a front view showing the internal structure of a connection portion in a modified example. [Figure 24] FIG. 2 is a front view of an accessory shoe according to an embodiment. [Figure 25] FIG. 4 is an enlarged view of a portion of the connection plug in the embodiment. [Figure 26] FIG. 2 is a front cross-sectional view showing a state in which the camera connector is attached to the accessory shoe in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] 1 shows the electrical configuration of a camera 100 as an electronic device according to an embodiment of the present invention, and an accessory 200 that is detachably attached to the camera 100. The camera 100 and the accessory 200 are electrically connected by one-to-one contact between a plurality of contacts (terminals) TC01 to TC21 of a camera connection section 141 provided on the camera 100 and a plurality of contacts TA01 to TA21 of an accessory connection section 211 provided on the accessory 200.

[0013] The camera 100 is supplied with power from a battery 111. The battery 111 is detachable from the camera 100. A camera control circuit 101, which serves as a control means for the camera 100, is a circuit that controls the entire camera 100, and is configured by a microcomputer with a built-in CPU and the like.

[0014] The system power supply circuit 112 is a circuit that generates power to be supplied to each circuit of the camera 100, and is composed of a DC-DC converter circuit, an LDO (Low Drop Out), a charge pump circuit, etc. A voltage of 1.8V generated by the system power supply circuit 112 from the battery 111 is constantly supplied to the camera control circuit 101 as the camera microcomputer power supply VMCU_C. The camera control circuit 101 controls the system power supply circuit 112 to turn on and off the power supply to each circuit of the camera 100.

[0015] The optical lens 121 is detachable from the camera 100. Light from a subject incident through the optical lens 121 is focused on an imaging sensor 122, which may be a CMOS sensor, a CCD sensor, or the like. The subject image focused on the imaging sensor 122 is encoded into a digital imaging signal. The image processing circuit 123 performs image processing such as noise reduction and white balance processing on the digital imaging signal to generate image data, and converts the image data into an image file in JPEG format or the like for recording in the recording memory 126. The image processing circuit 123 also generates VRAM image data from the image data to be displayed on the display circuit 127.

[0016] The memory control circuit 124 controls the sending and receiving of image data generated by the image processing circuit 123 and other data. The volatile memory 125 is a memory capable of high-speed reading and writing, such as DDR3 SDRAM, and is used as a workspace for image processing performed by the image processing circuit 123. The recording memory 126 is a readable and writable recording medium, such as an SD card or CFexpress card, that can be attached to and detached from the camera 100 via a connector (not shown). The display circuit 127 is a display disposed on the rear surface of the camera 100, and is composed of an LCD panel, an organic EL display panel, or the like. The backlight circuit 128 adjusts the brightness of the display circuit 127 by changing the light intensity of the backlight of the display circuit 127.

[0017] The accessory power supply circuit A131 and the accessory power supply circuit B132, which serve as power supply means, are voltage conversion circuits that convert the voltage supplied from the system power supply circuit 112 into a predetermined voltage, and in this embodiment generate 3.3 V as the accessory power supply VACC.

[0018] The accessory power supply circuit A131 is a power supply circuit with low self-consumption power, composed of an LDO or the like. The accessory power supply circuit B132 is a circuit composed of a DC / DC converter circuit or the like, and is capable of passing a larger current than the accessory power supply circuit A131. The accessory power supply circuit B132 also consumes more self-consumption power than the accessory power supply circuit A131. Therefore, when the load current is small, the accessory power supply circuit A131 is more efficient than the accessory power supply circuit B132, and when the load current is large, the accessory power supply circuit B132 is more efficient than the accessory power supply circuit A131. The camera control circuit 101 controls the on / off of the voltage output of the accessory power supply circuit A131 and the accessory power supply circuit B132 depending on the operating state of the accessory 200.

[0019] The protection circuit 133 as a protection means is configured with a current fuse element, a polyswitch element, or an electronic fuse circuit that combines a resistor, an amplifier, and a switch element, and outputs an overcurrent detection signal DET_OVC when the power supply current value supplied to the accessory 200 from the accessory power supply circuit A 131 and the accessory power supply circuit B 132 exceeds a predetermined value and becomes excessive (abnormal). In this embodiment, the protection circuit 133 is an electronic fuse circuit, and notifies the camera control circuit 101 with the overcurrent detection signal DET_OVC when a current of 1 A or more flows. The overcurrent detection signal DET_OVC indicates an overcurrent by going high.

[0020] The camera connection unit 141 is a connector for electrically connecting with the accessory 200 via 21 contacts TC01 to TC21 arranged in a row. The contacts TC01 to TC21 are arranged in this order from one end to the other in the arrangement direction.

[0021] TC01 is connected to ground (GND) and serves not only as a contact for the reference potential (GND potential), but also as a contact to control the wiring impedance of the differential signals D1N and D1P, which will be explained next. TC01 corresponds to the third ground contact.

[0022] The differential signal D1N connected to TC02 and the differential signal D1P connected to TC03 are differential data communication signals that perform data communication in pairs and are connected to the camera control circuit 101. TC02, TC03, and TC07 to TC17, TC19, and TC20, which will be described later, are communication contacts.

[0023] TC04 as a first ground contact is connected to GND and serves as a reference potential contact between the camera 100 and the accessory 200. TC04 is arranged further outward in the arrangement direction of the contacts than TC05, which will be described next.

[0024] An accessory power supply VACC generated by accessory power supply circuits A131 and B132 is connected to TC05 as a power supply contact via a protection circuit 133.

[0025] An accessory attachment detection signal / ACC_DET is connected to TC06, which serves as an attachment detection contact. The accessory attachment detection signal / ACC_DET is pulled up to the camera microcomputer power supply VMCU_C via a resistor element Rp134 (10 kΩ). The camera control circuit 101 can detect whether the accessory 200 is attached by reading the signal level of the accessory attachment detection signal / ACC_DET. If the signal level (potential) of the accessory attachment detection signal / ACC_DET is a Hi level (predetermined potential), the accessory 200 is detected as not being attached, and if it is a Lo level (GND potential as described below), the accessory 200 is detected as being attached.

[0026] When the power of the camera 100 is turned on, the signal level (electric potential) of the accessory attachment detection signal / ACC_DET changes from Hi level to Lo level, which triggers various communications between the camera 100 and the accessory 200 via the contacts.

[0027] In response to detecting that the accessory 200 is in an attached state, the camera control circuit 101 supplies power to the accessory 200 via TC05, which serves as a power contact.

[0028] SCLK connected to TC07, MOSI connected to TC08, MISO connected to TC09, and CS connected to TC10 are signals for performing SPI (Serial Peripheral Interface) communication with the camera control circuit 101 as the communication master. In this embodiment, the communication clock frequency of the SPI communication is 1 MHz.

[0029] A communication request signal / WAKE, which is used by the accessory 200 to request communication from the camera control circuit 101, is connected to TC11. The communication request signal / WAKE is pulled up to the camera microcomputer power supply VMCU_C via a resistor. The camera control circuit 101 can receive a communication request from the accessory 200 by detecting the falling edge of the communication request signal / WAKE.

[0030] The SDA connected to TC12 and the SCL connected to TC13 are signals for performing I2C (Inter-Integrated Circuit) communication with the camera control circuit 101 as the communication master. The SDA and SCL are signals for open-drain communication (hereinafter referred to as open-drain communication) pulled up to the camera microcomputer power supply VMCU_C, and in this embodiment the communication frequency is 100 kbps.

[0031] In I2C communication, data is transmitted from both the camera 100 and the accessory 200 via SDA. Comparing SPI communication and I2C communication, I2C communication has a slower communication speed than SPI communication and allows communication with low power consumption. SPI communication also has a faster communication speed than I2C communication, making it suitable for communicating large amounts of information. Therefore, in communication between the camera 100 and the accessory 200 in this embodiment, information with large amounts of data is communicated using SPI communication, and information with small amounts of data is communicated using I2C communication. For example, data is first communicated using I2C communication, and if SPI communication is possible or necessary based on this data, control can be exercised to further execute SPI communication.

[0032] The FNC1 signal connected to TC14 (synchronization contact), the FNC2 signal connected to TC15, the FNC3 signal connected to TC16, and the FNC4 signal connected to TC17 are signals whose functions can be changed depending on the type of attached accessory 200. For example, if the accessory 200 is a microphone device, the signal communicated via TC15 is an audio data signal. Also, if the accessory 200 is a lighting (strobe or flash) device, the signal communicated via TC14 is a signal that controls the timing of light emission. Note that signals that realize different functions may be communicated via the same contact depending on the type of attached accessory. For example, if the accessory 200 is an accessory other than a lighting device, a synchronization signal for controlling a timing different from the light emission timing may be communicated via TC14. TC14 to TC17 correspond to function signal contacts. Communication using at least one of the function signal contacts is also referred to as function signal communication.

[0033] Functional signal communication can be performed in parallel with I2C communication and SPI communication at a timing that is independent of I2C communication and SPI communication.

[0034] The types of accessories referred to here include the microphone devices, lighting devices, etc. mentioned above. Accessories that achieve the same purpose, such as lighting devices with different performance, are the same type of accessory. Accessories that achieve different purposes, such as microphone devices and lighting devices, are different types of accessories.

[0035] Functional signal communication is performed based on information obtained through I2C or SPI communication.

[0036] TC18, which serves as a second ground contact (reference potential contact), is also connected to GND, and is a contact that serves as the reference potential for the camera 100 and the accessory 200, similar to TC04.

[0037] A differential signal D2N connected to TC19 (first differential signal contact) and a differential signal D2P connected to TC20 (second differential signal contact) are data communication signals that perform data communication in pairs and are connected to the camera control circuit 101. For example, USB communication can be performed via TC19 and TC20.

[0038] TC21 is connected to GND and serves not only as a contact for the reference potential but also as a contact for controlling the wiring impedance of the differential signals D2N and D2P. TC21 corresponds to the fourth ground contact. Contacts TC01, TC04, TC06, TC18, and TC21 are connected to the GND portion of a flexible substrate 158 shown in FIG. 17 (described later), for example, and the GND portion of the flexible substrate 158 is fixed to a metal member that serves as the GND level of the camera 100 with screws 157 or the like. The metal member that serves as the GND level is, for example, an engagement member 151 or a base plate (not shown) inside the camera 100.

[0039] In this embodiment, the attachment detection contact TC06, to which the accessory attachment detection signal / ACC_DET is connected, is located next to the contact (first clock contact) TC07 that transmits the clock signal SCLK (first clock signal). Generally, noise (clock noise) caused by potential fluctuations in the clock signal is transmitted to contacts adjacent to the clock signal contact, which can cause malfunction. This effect is particularly significant in a configuration with a large number of contacts and a short distance between the contacts, as in this embodiment. Therefore, by locating the attachment detection contact TC06 next to the SCLK contact TC07, the effect of clock noise can be suppressed.

[0040] The accessory attachment detection signal / ACC_DET is pulled up before the accessory is attached, but is set to GND potential after the accessory is attached. On the other hand, the SCLK contact TC07, which transmits the clock signal, does not transmit the clock signal before the accessory is attached, so its potential does not fluctuate, but it transmits the clock signal only after the accessory is attached, so its potential fluctuates.

[0041] When the SCLK contact TC07 transmits the clock signal, the attachment detection contact TC06 is at GND potential. Therefore, even if the attachment detection contact TC06 is subjected to clock noise, the potential of the control circuits of the camera 100 and accessory 200 is unlikely to fluctuate, preventing malfunction. In addition, the transmission of clock noise to positions farther away than the attachment detection contact TC06 can be suppressed. As a result, there is no need to provide a GND terminal, and the effects of clock noise can be suppressed without increasing the number of contacts.

[0042] In addition, SCL (second clock signal) is also transmitted as a clock signal to contact (second clock contact) TC13. However, the SCLK transmitted to SCLK contact TC07 has a higher frequency than SCL, and more clock noise is generated from the SCLK contact TC07 than from the SCL contact TC13. For this reason, placing the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the SCL contact TC13 is more effective in preventing malfunctions due to clock noise.

[0043] In addition to the difference in frequency, the SCL transmitted through the SCL contact TC13 is a clock signal conforming to the I2C communication standard, and voltage fluctuations on the signal line are driven by an open-drain connection. On the other hand, the SCLK transmitted through the SCLK contact TC07 is a clock signal conforming to the SPI communication standard, and voltage fluctuations on the signal line are driven by a CMOS output. For this reason, the voltage fluctuation edges of the SCL contact TC13 tend to be gentler than those of the SCLK contact TC07, making it less likely to generate clock noise. Therefore, placing the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the SCL contact TC13 is more effective in preventing malfunctions caused by clock noise.

[0044] Additionally, differential signals D1N and D1P may also be transmitted as a pair to the first and second differential signal contacts TC19 and TC20 to transmit clock signals. In such cases, a clock signal (third clock signal) with a higher frequency than the SCLK contact TC07 and SCL contact TC13 may be transmitted. However, because the differential signals D1N and D1P are paired signals, they emit less clock noise than the SCLK contact TC07 and SCL contact TC13, which transmit single-ended signals. For this reason, placing the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the first and second differential signal contacts TC19 and TC20 is more effective in preventing malfunctions due to clock noise.

[0045] The contact (first data contact) TC08, located next to the SCLK contact TC07 on the opposite side of the attachment detection contact TC06, transmits MOSI (first data signal). Because MOSI is a data signal, it appears to be susceptible to clock noise. However, because MOSI is a data signal that conforms to the same SPI communication standard as the clock signal transmitted by the SCLK contact TC07, the timing of its potential fluctuations is synchronized with the clock signal, making it less susceptible to clock noise. For this reason, contact TC08 does not need to be fixed to GND potential, and can be used as the MOSI contact.

[0046] The accessory 200 has a battery 205 and receives power from the battery 205, as well as power from the camera 100 via the camera connection unit 141 and the accessory connection unit 211. The accessory control circuit 201, which serves as the control means for the accessory 200, is a circuit that controls the entire accessory 200, and is a microcomputer with a built-in CPU and the like.

[0047] The accessory power supply circuit 202 is a circuit that generates power to be supplied to each circuit of the accessory 200, and is composed of a DC-DC converter circuit, an LDO, a charge pump circuit, etc. A voltage of 1.8V generated by the accessory power supply circuit 202 is constantly supplied to the accessory control circuit 201 as the accessory microcontroller power supply VMCU_A. By controlling the accessory power supply circuit 202, on / off control of the power supply to each circuit of the accessory 200 is performed.

[0048] The charging circuit 204 is a circuit for charging the battery 205 using power supplied from the camera 100. When the accessory control circuit 201 determines that sufficient power is being supplied from the camera 100 to perform the charging operation, it controls the charging circuit 204 to charge the battery 205. Note that although this embodiment describes a case where the battery 205 is attached to the accessory 200, the accessory 200 may also operate using only the power supplied from the camera 100 without the battery 205 being attached. In this case, the charging circuit 204 is not necessary.

[0049] The differential communication circuit 207 is a circuit for performing differential communication with the camera 100, and is capable of transmitting and receiving data to and from the camera 100. The external communication IF circuit 208 is an IF circuit for performing data communication with an external device (not shown), and is an Ethernet communication IF, a wireless LAN communication IF, a public network communication IF, or the like.

[0050] The accessory control circuit 201 controls the differential communication circuit 207 and the external communication IF circuit 208 to transmit data received from the camera 100 to an external device and transmit data received from an external device to the camera 100. The function circuit 206 is a circuit having different functions depending on the type of accessory 200. An example configuration of the function circuit 206 will be described later.

[0051] The external connection terminal 209 is a connector terminal for connecting to an external device, and in this embodiment is a USB TYPE-C connector. The connection detection circuit 210 is a circuit for detecting that an external device has been connected to the external connection terminal 209, and the accessory control circuit 201 can detect the connection of an external device to the external connection terminal 209 by receiving an output signal from the connection detection circuit 210.

[0052] The power switch 203 is a switch for turning on and off the operation of the accessory 200, and the accessory control circuit 201 can detect the on position or off position by reading the signal level of the terminal to which the power switch 203 is connected.

[0053] The accessory connection unit 211 is a connector for making an electrical connection with the camera 100 via 21 contacts TA01 to TA21 arranged in a row. The contacts TA01 to TA21 are arranged in this order from one end to the other in the arrangement direction.

[0054] TA01 is connected to GND and serves not only as a reference potential contact but also as a contact to control the wiring impedance of the differential signals D1N and D1P. TA01 corresponds to the third ground contact.

[0055] The differential signal D1N connected to TA02 and the differential signal D1P connected to TA03 are data communication signals that perform data communication as a pair, and are connected to a differential communication circuit 207. TA02, TA03, and TA07 to TA17, TA19, and TA20, which will be described later, are communication contacts.

[0056] TA04 as a first ground contact is connected to GND and serves as a reference potential contact between the camera 100 and the accessory 200. TA04 is arranged further outward in the arrangement direction of the contacts than TA05, which will be described next.

[0057] The accessory power supply circuit 202 and the charging circuit 204 are connected to the power contact TA05, and the accessory power supply VACC supplied from the camera 100 is connected thereto.

[0058] TA06, which serves as an attachment detection contact, is directly connected to GND, and sets the accessory attachment detection signal / ACC_DET to the GND level (Lo level) when the accessory 200 is attached to the camera 100. This serves as a contact that allows the camera 100 to detect that the accessory 200 is attached.

[0059] SCLK connected to TA07, MOSI connected to TA08, MISO connected to TA09, and CS connected to TA10 are signals for the accessory control circuit 201 to function as a communication slave and perform SPI communication.

[0060] A communication request signal / WAKE is connected to TA11, which is used by the accessory control circuit 201 to request communication from the camera 100. When the accessory control circuit 201 determines that communication with the camera 100 is necessary, it issues a communication request to the camera 100 by outputting the communication request signal / WAKE at Lo.

[0061] When the camera control circuit 101 supplies power to the accessory 200 via TC5 in response to detecting that the accessory 200 is attached, the accessory control circuit 201 notifies the camera control circuit 101 that it has received power supply by changing the signal level (potential) of the communication request signal / WAKE from Hi level to Lo level.

[0062] The accessory control circuit 201 can notify the camera 100 that a cause for the accessory 200 to communicate with the camera 100 has occurred by changing the signal level (electric potential) of the communication request signal / WAKE from Hi level to Lo level even without a request from the camera. With this configuration, the camera control circuit 101 can omit the operation of periodically checking whether a cause for the accessory 200 to communicate has occurred by polling. Furthermore, when a cause for communication has occurred, the accessory 200 can notify the camera 100 of that fact in real time.

[0063] SDA connected to TA12 and SCL connected to TA13 are signals for the accessory control circuit 201 to function as a communication slave and perform I2C communication.

[0064] The FNC1 signal connected to TA14 (synchronization contact), the FNC2 signal connected to TA15, the FNC3 signal connected to TA16, and the FNC4 signal connected to TA17 are signals whose functions can be changed according to the type of accessory 200. For example, if the accessory 200 is a microphone device, the signal serves as an audio data signal, and if the accessory 200 is a strobe device, the signal serves as a signal that controls the timing of light emission. TA14 to TA17 correspond to function signal contacts.

[0065] TA18, which serves as a second ground contact (reference potential contact), is also connected to GND, and serves as a reference potential contact for the camera 100 and the accessory 200, similar to TA04.

[0066] The differential signal D2N connected to TA19 (first differential signal contact) and the differential signal D2P connected to TA20 (second differential signal contact) are data communication signals that form a pair to perform data communication, and are connected to the external connection terminal 209.

[0067] TA21 is connected to GND and serves not only as a reference potential contact but also as a terminal to control the wiring impedance of the differential signals D2N and D2P. TA21 corresponds to the fourth ground contact.

[0068] 19, which will be described later, and the GND portion of the flexible substrate 259 is fixed with screws (not shown) or the like to a metal member that serves as the GND level of the accessory 200. Examples of the metal member that serves as the GND level include the shoe mounting leg 251 and a base plate (not shown) inside the accessory 200.

[0069] Fig. 2(a) shows a state in which an accessory connector 211, which is located on a shoe provided at the bottom of an accessory (strobe device) 200, is connected to a camera connector 141, which is located on an accessory shoe provided at the top of the camera 100. Fig. 2(b) shows an example of the arrangement of 21 contacts TC01 to TC21 on the camera connector 141. TC01 is located on the right end as viewed from the subject side, and the 21 contacts up to TC21 are arranged in a row. The accessory shoe is attached to the accessory shoe having this camera connector 141 by sliding it from the top to the bottom in Fig. 2(b).

[0070] FIG. 2(c) shows an example of the arrangement of 21 contacts TA01 to TA21 in the accessory connection unit 211. As with the camera connection unit 141, TA01 is located at the right end when viewed from the subject side, and the 21 contacts up to TA21 are arranged in a row. Normally, the contacts TA01 to TA21 and their corresponding contacts TC01 to TC21 come into contact with each other. However, if excessive static pressure or impact is applied to the accessory 200, there is a risk that the contacts will come out of contact. In particular, if a rotational force acts on the accessory 200 in the direction in which the contacts are arranged, the contacts at the ends are likely to come out of contact.

[0071] 3(a) shows in an exaggerated manner the state in which excessive static pressure is applied to the accessory 200 from the left side as viewed from the subject side. At this time, a force acts on the contacts TC21, TA21 of the camera connector 141 and the accessory connector 211 and their nearby contacts in a direction that causes them to separate, making poor contact more likely to occur. On the other hand, a force acts on the contacts TC01, TA01 and their nearby contacts in a direction that causes them to come into contact more than in a normal state.

[0072] 3(b) shows in an exaggerated manner the state in which excessive static pressure is applied to the accessory 200 from the right side as viewed from the subject side. At this time, a force acts on the contacts TC01, TA01 and nearby contacts of the camera connector 141 and the accessory connector 211 in a direction that causes them to separate, making poor contact more likely to occur. On the other hand, a force acts on the contacts TC21, TA21 and nearby contacts in a direction that causes them to come into contact more than in a normal state.

[0073] In this embodiment, the contacts TC01, TA01 and TC21, TA21 at both ends of the camera connection unit 141 and the accessory connection unit 211 are connected to GND. This ensures that even if excessive static pressure temporarily causes poor contact at the contacts at one end, the contacts at the other end are connected to GND. This reduces the risk of the reference potential of the accessory 200 becoming unstable due to poor GND connection, which can result in damage to each circuit and electrical element.

[0074] Furthermore, when an accessory 200 is attached that is missing some of its GND contacts due to a defect or other failure in the accessory connection section 211, the camera control circuit 101 cannot detect that some of its GND contacts are missing. In such a case, the operating current will be concentrated in the remaining GND contacts, which may cause malfunction of the accessory 200.

[0075] FIG. 4A shows an example of a configuration that enables camera 100 to detect the connection state of the GND contact of accessory 200, and shows an excerpt of the portion related to the ground contact from the configuration shown in FIG.

[0076] TC01, TC04, TC18, and TC21 are connected to input terminals P1, P2, P3, and P4 of the camera control circuit 101, respectively, and are pulled up to the camera microcomputer power supply VMCU_C via resistors 1011Rp_g1, 1021Rp_g2, 1031Rp_g3, and 1041Rp_g4. In addition, SW circuit 1 (1012), SW circuit 2 (1022), SW circuit 3 (1032), and SW circuit 4 (1042) are connected to TC01, TC04, TC18, and TC21, respectively.

[0077] SW circuit 1 is a switch circuit driven by a control signal from camera control circuit 101, and when turned on by the control signal, TC01 is connected to GND. SW circuit 1 is preferably configured, for example, with an FET, and is a circuit that minimizes impedance when it is turned on and maximizes impedance when it is turned off. SW circuits 2, 3, and 4 also have the same configuration as SW circuit 1, as shown in FIG. 4A.

[0078] The flowchart in Fig. 4B shows a sequence for determining the connection state of the ground terminal in the configuration shown in Fig. 4A. The camera control circuit 101 executes this process and other processes described later in accordance with a computer program. "S" indicates a step.

[0079] In S1001, the camera control circuit 101 monitors the signal level of the accessory attachment detection signal / ACC_DET and determines whether or not the accessory 200 is attached. If the signal level is Hi, the camera control circuit 101 determines that the accessory 200 is not attached and returns to S1001 to perform detection again, and if the signal level is Lo, it determines that the accessory 200 is attached and proceeds to S1002.

[0080] In S1002, the camera control circuit 101 performs control to turn on the SW circuit 1 and turn off the SW circuit 2, the SW circuit 3, and the SW circuit 4.

[0081] In S1003, the camera control circuit 101 checks the voltage level of the input terminal P1, and if it is at a Lo level, determines that TC01 is connected to the ground contact, and if it is at a Hi level, determines that it is not connected to the ground contact.

[0082] Next, in S1004, the camera control circuit 101 performs control to turn on the switch circuit 2 and turn off the switch circuits 1, 3, and 4.

[0083] In S1005, the camera control circuit 101 checks the voltage level of the input terminal P2, and if it is at a Lo level, determines that TC04 is connected to the ground contact, and if it is at a Hi level, determines that it is not connected to the ground contact.

[0084] Next, in S1006, the camera control circuit 101 performs control to turn on the SW circuit 3 and turn off the SW circuits 1, 2, and 4.

[0085] In S1007, the camera control circuit 101 checks the voltage level of the input terminal P3, and if it is at a Lo level, it determines that TC18 is connected to the ground contact, and if it is at a Hi level, it determines that it is not connected to the ground contact.

[0086] Next, in S1008, the camera control circuit 101 performs control to turn on the switch circuit 4 and turn off the switch circuits 1, 2, and 3.

[0087] In S1009, the camera control circuit 101 checks the voltage level of the input terminal P4, and if it is at a Lo level, determines that TC18 is connected to the ground contact, and if it is at a Hi level, determines that it is not connected to the ground contact.

[0088] In S1010, the camera control circuit 101 performs control to turn on each of the switch circuits 1, 2, 3, and 4.

[0089] By performing such control, it becomes possible to check the attachment status of the ground contact with the accessory 200 to which the camera control circuit 101 is attached, and to determine whether or not power can be supplied to the accessory power circuit 202 based on the ground connection status.

[0090] Incidentally, when accessory 200 is attached to camera 100, if accessory 200 is tilted relative to camera 100, it is possible that only some of the multiple contacts TC01 to TC21 and TA01 to TA21 may come into contact. As shown in Fig. 16, when the attachment direction of accessory 200 to camera 100 is the Z direction, the direction in which multiple contacts TC01 to TC21 and TA01 to TA21 are lined up is the X direction, and the direction perpendicular to the X and Z directions is the Y direction, a situation in which only some of the contacts come into contact may occur in the following cases.

[0091] 3(a) and 3(b), when the accessory 200 tilts around an axis parallel to the Z direction with respect to the camera 100, the contacts among the multiple contacts on the sides where the camera 100 and the accessory 200 are close to each other come into contact, but the contacts on the sides where the camera 100 and the accessory 200 are farther apart do not come into contact with each other. Furthermore, although not shown, when the accessory 200 tilts (twists) around an axis parallel to the Y direction with respect to the camera 100, the contacts among the multiple contacts on the opposite sides to the contacting contacts come into a state of separation.

[0092] As will be explained in detail later using FIG. 5 , the camera 100 and accessory 200 of this embodiment execute an attachment detection process prior to various communications when the accessory 200 is attached to the camera 100. At this time, the attachment detection process can be executed if the attachment detection contacts TC06 and TA06 are in contact. After the attachment detection process is executed via the contacts TC06 and TA06, a communication request signal / WAKE is output from the accessory 200 to the camera 100 via contacts (hereinafter also referred to as communication request contacts) TC11 and TA11. By detecting this communication request signal / WAKE, the camera 100 determines that the accessory 200 is in a communication-enabled state and performs various communications. However, if the camera 100 cannot detect the communication request signal / WAKE even though attachment of the accessory 200 to the camera 100 has been detected, the camera 100 determines that a communication error with the accessory 200 has occurred. If accessory 200 is tilted or twisted while being attached to camera 100, a state may occur in which only some of the multiple contacts are temporarily in contact, which may result in a communication error being determined to have occurred and error processing such as a warning being issued, which may lead the user to mistakenly believe that accessory 200 is malfunctioning.

[0093] For this reason, this embodiment employs a contact arrangement that can reduce the occurrence of a situation in which the camera 100 is unable to detect the communication request signal / WAKE even though the attachment of the accessory 200 to the camera 100 has been detected.

[0094] As described above, when the accessory 200 tilts around an axis parallel to the Z direction relative to the camera 100, either the contacts TC01, TA01 and their nearby contacts come into contact, as shown in Figure 3(a), and the contacts TC21, TA21 and their nearby contacts do not come into contact, or the contacts TC21, TA21 and their nearby contacts come into contact, and the contacts TC01, TA01 and their nearby contacts do not come into contact, as shown in Figure 3(b).

[0095] In this embodiment, contacts TC06 and TA06 are used to detect attachment of accessory 200 to camera 100. When contacts TC01 and TA01 are in contact as shown in FIG. 3A, contacts TC06 and TA06 located nearby are often also in contact. In this case, if communication request contacts TC11 and TA11 are located near distant contacts TC21 and TA21, the camera 100 is likely to be unable to detect the communication request signal / WAKE even though attachment of accessory 200 to camera 100 has been detected.

[0096] On the other hand, when contacts TC21 and TA21 are in contact and contacts TC06 and TA06 are also in contact as shown in Figure 3(b), if contacts TC11 and TA11 are located closer to contacts TC01 and TA01 than contacts TC06 and TA06, it is likely that the camera 100 will not be able to detect the communication request signal / WAKE even though it has detected that accessory 200 has been attached to the camera 100.

[0097] In contrast, this embodiment employs the following contact arrangement. As shown in FIG. 1, the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11 are arranged between the contacts TC01, TA01 at the most one end and the contacts TC21, TA21 at the most other end in the direction in which the multiple contacts TC01 to TC21, TA01 to TA21 are arranged (hereinafter referred to as the contact arrangement direction). This arrangement is referred to as the first arrangement. The attachment detection contacts TC06, TA06 are also arranged between the communication request contacts TC11, TA11 and the contacts TC01, TA01. This arrangement is referred to as the second arrangement. In the contact arrangement direction, the distance between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11 is shorter than the distance between the communication request contacts TC11, TA11 and the contacts TC21, TA21. This arrangement is referred to as the third arrangement. In this embodiment, since the contacts TC01 to TC21 and TA01 to TA21 are arranged at equal pitches, the distance between the contacts here can be rephrased as the number of other contacts arranged between the contacts, and a short (long) distance can be rephrased as a small (large) number of other contacts.

[0098] Furthermore, in this embodiment, the distance between the communication request contacts TC11, TA11 and the contacts TC01, TA01 in the contact arrangement direction is less than or equal to the distance between the communication request contacts TC11, TA11 and the contacts TC21, TA21. This arrangement is referred to as the fourth arrangement. In particular, in this embodiment, the communication request contacts TC11, TA11 are arranged in the center of the contacts TC01-TC21, TC01-TC21, so that the distance between the communication request contacts TC11, TA11 and the contacts TC01, TA01 is equal to the distance between the communication request contacts TC11, TA11 and the contacts TC21, TA21. Note that the communication request contacts TC11, TA11 do not necessarily have to be arranged in the center of the contacts TC01-TC21, TC01-TC21, but it is preferable to arrange them near the center.

[0099] Additionally, in this embodiment, the distance between the attachment detection contacts TC06, TA06 and the contacts TC01, TA01 in the contact arrangement direction is equal to or greater than the distance between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11. This arrangement is referred to as a fifth arrangement. In particular, in this embodiment, the attachment detection contacts TC06, TA06 are arranged in the center between the communication request contacts TC11, TA11 and the contacts TC01, TA01, so that the distance between the attachment detection contacts TC06, TA06 and the contacts TC01, TA01 is equal to the distance between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11. Note that the attachment detection contacts TC06, TA06 do not necessarily have to be arranged in the center between the communication request contacts TC11, TA11 and the contacts TC01, TA01, but it is preferable to arrange them near the center.

[0100] With the contact arrangement described above, if the attachment detection contacts TC06 and TA06 come into contact in the tilted state shown in Fig. 3(a), there is a high possibility that the communication request contacts TC11 and TA11 will also come into contact, and in the tilted state shown in Fig. 3(b), there is a high possibility that the attachment detection contacts TC06 and TA06 will not come into contact even if the communication request contacts TC11 and TA11 come into contact. As a result, regardless of the tilted state, it is possible to reduce the occurrence of a situation in which the camera 100 is unable to detect the communication request signal / WAKE even though attachment of the accessory 200 to the camera 100 has been detected.

[0101] Here, as a comparative example, a case will be described in which the positions of contacts TC06, TA06 and contacts TC11, TA11 are swapped. That is, a case will be described in which contacts TC11, TA11 are used for attachment detection, and contacts TC06, TA06 are used for detecting the communication request signal / WAKE. In this configuration, if accessory 200 is tilted with respect to camera 100 and contacts TC01, TA01 and their neighboring contacts are not in contact, contacts TC11, TA11 for attachment detection will be in contact but contacts TC06, TA06 for the communication request signal / WAKE will not be in contact, which may result in a communication error.

[0102] Therefore, in order to avoid communication errors, it is preferable to arrange the contact for attachment detection closer to one end in the contact arrangement direction than the contact for the communication request signal / WAKE, as in this embodiment.

[0103] 20(a) to 20(c) and 23, which will be described later, in a configuration in which the accessory 200 holds multiple contacts with a connection plug 256 serving as a holding member formed of a non-conductive material such as a resin material, the connection plug 256 may have a convex shape toward the lower side in the figure (the direction of contact with the camera connection portion 141). In such a case, it is more likely that the contacts at one end of the contact arrangement direction will be in contact, but the contacts at the other end will not be in contact. However, by adopting the contact arrangement as in this embodiment, it is possible to reduce the occurrence of communication errors even if some of the contacts are not in contact when the accessory 200 is attached to the camera 100.

[0104] Furthermore, as described above, when accessory 200 is twisted around an axis parallel to the Y direction relative to camera 100, it is possible that the contacts at one end of the contact arrangement direction among the multiple contacts are in contact, but the contacts at the other end are not in contact. If this state occurs during the process of attaching accessory 200 to camera 100, a discrepancy occurs in the timing at which the multiple contacts come into contact. If the discrepancy in the timing of contact is large, the time lag between the detection of attachment of accessory 200 to camera 100 and the detection of WAKE increases, which may result in a determination that a communication error has occurred. In this case, depending on the direction of twist of accessory 200, the contacts TC01 and TA01 will start to come into contact first, or the contacts TC21 and TA21 will start to come into contact first.

[0105] When contact begins from the contacts TC01 and TA01 side, the closer the communication request contacts TC11 and TA11 are to contacts TC21 and TA21, the longer the time lag becomes from detection of attachment of the accessory 200 to detection of the communication request signal / WAKE. The longer the time lag, the more likely it is to be determined as a communication error. On the other hand, when contact begins from the contacts TC21 and TA21 side, if the communication request contacts TC11 and TA11 are located closer to contacts TC01 and TA01 than the attachment detection contacts TC06 and TA06, a time lag occurs from detection of attachment of the accessory 200 to detection of the communication request signal / WAKE.

[0106] In contrast to these, in this embodiment, by adopting the contact arrangement described above, the time lag from the detection of attachment of the accessory 200 to the detection of the communication request signal / WAKE can be shortened regardless of which end of the contacts makes contact.

[0107] Furthermore, in this embodiment, contacts TC07, TA07 to TC10, and TA10 used for SPI communication (communication using the second communication method) between the camera 100 and the accessory 200 are arranged between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11. Also, contacts TC12, TA12, TC13, and TA13 used for I2C communication (communication using the first communication method) between the camera 100 and the accessory 200 are arranged close to the communication request contacts TC11 and TA11 on the opposite side of the attachment detection contacts TC06 and TA06.

[0108] Communication between the camera 100 and the accessory 200 is performed after the camera 100 detects a communication request signal / WAKE. For this reason, contact of the contacts used for communication is not confirmed until communication is performed between the camera 100 and the accessory 200. In contrast, in this embodiment, if the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11 are in contact, respectively, it can be assumed that the communication contacts TC07, TA07 to TC10, TA10, TC12, TA12, TC13, and TA13 arranged between and near them are also in contact.

[0109] Furthermore, since the position between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11 can be considered to be in more reliable contact, it is preferable to place the contacts used for SPI communication, which is executed after I2C communication, in a position between the attachment detection contacts TC06, TA06 and the communication request contacts TC11, TA11.

[0110] 4 and FIGS. 12 and 20, which will be described later, accessory 200 may be configured with fewer contacts than camera 100. Even in such a configuration, attachment detection contacts and communication request contacts are necessary contacts, and it is preferable to arrange the attachment detection contacts and communication request contacts in the same way as in a configuration with an equal number of contacts as camera 100. However, it is not necessary for some of the arrangement relationships 1 to 5 described above to be satisfied.

[0111] For example, in a configuration that does not have contact TA21 as shown in FIG. 4, the distance between communication request contact TA11 and contact TA01 in the contact arrangement direction is longer than the distance between communication request contact TA11 and contact TA20. In other words, the fourth arrangement relationship described above is not satisfied. Also, for example, in a configuration that does not have contacts TA01 to TA03 and TA19 to 21 as shown in FIG. 12, the distance between attachment detection contact TA06 and contact TA04 in the contact arrangement direction is shorter than the distance between attachment detection contact TA06 and communication request contact TA11. In other words, the fifth arrangement relationship described above is not satisfied.

[0112] As described above, in a configuration in which the positions of the contacts at the ends of the accessory 200 are different from the positions of the contacts at the ends of the camera 100, some of the above-described arrangement relationships 1 to 5 may not be satisfied. In such a case, the attachment detection contact and the communication request contact may be arranged so as to satisfy the above-described arrangement relationships 1 to 5, assuming that the positions facing the contacts at the ends of the camera 100 when the accessory 200 is attached are the positions of the contacts at the ends of the accessory 200. Alternatively, as with the protrusion 256a shown in FIG. 20, the attachment detection contact and the communication request contact may be arranged so as to satisfy the above-described arrangement relationships 1 to 5, taking into account the distance from the protrusion 256a instead of the distance from the end contacts. The flowchart in FIG. 5(a) shows the processing executed by the camera control circuit 101 when the accessory 200 is attached to the camera 100.

[0113] In S401, the camera control circuit 101, which serves as an attachment detection means, monitors the signal level of the accessory attachment detection signal / ACC_DET and determines whether or not the accessory 200 is attached. If the signal level is Hi, the camera control circuit 101 determines that the accessory 200 is not attached and returns to S401 to perform detection again, and if the signal level is Lo, it determines that the accessory 200 is attached and proceeds to S402.

[0114] In S402, the camera control circuit 101 sets the power supply control signal CNT_VACC1 to Hi level to turn on the output of the accessory power supply circuit A131, and proceeds to S403. The accessory power supply circuit A131 outputs the accessory power supply VACC in response to the power supply control signal CNT_VACC1 becoming Hi.

[0115] In S403, the camera control circuit 101 monitors the signal level of the overcurrent detection signal DET_OVC and determines whether or not an overcurrent is flowing. If the signal level is Lo, the camera control circuit 101 determines that an overcurrent is not flowing and proceeds to S404, and if the signal level is Hi, it determines that an overcurrent is flowing and proceeds to S405 to perform error processing.

[0116] 6(a) shows a schematic diagram of the changes in the above signals when the process in FIG. 5(a) has progressed to S404. IACC is the current of the accessory power supply VACC. Since the accessory power supply VACC started up normally after the power supply control signal CNT_VACC1 was set to Hi in S402, the overcurrent detection signal DET_OVC remains at Lo level.

[0117] 6(b) schematically shows the changes in the above signals when the processing in FIG. 5(a) progresses to S405. Because an overcurrent flows through IACC after the power supply control signal CNT_VACC1 is set to Hi in S402, the overcurrent detection signal DET_OVC changes to Hi level and notifies the camera control circuit 101. Upon receiving the notification of the overcurrent detection signal DET_OVC, the camera control circuit 101 turns off the outputs of the accessory power supply circuits A131 and B132 as error processing, thereby stopping the power supply to the accessory 200. In this way, even if an overcurrent flows through the accessory power supply VACC, the camera control circuit 101 can detect the overcurrent and safely shut down the system.

[0118] Normally, when an abnormal current flows through the accessory power supply VACC, it is assumed that the camera 100 and the accessory 200 are malfunctioning, but because the camera connection part 141 and the accessory connection part 211 are exposed to the outside, there is a possibility that foreign matter such as metal fragments may adhere to them and cause adjacent contacts to short out.

[0119] In this embodiment, the accessory power supply VACC has a voltage of 3.3V, while the camera microcontroller power supply VMCU_C and the accessory microcontroller power supply VMCU_A have a voltage of 1.8V. Therefore, if a voltage of 3.3V is applied to an electrical element operating at 1.8V, there is a concern that the electrical element may be damaged. Furthermore, because the behavior after a short circuit depends on the characteristics of the electrical element, the camera control circuit 101 may not always be able to detect a short between terminals. For example, since the I2C communication signal is at a high level when in a communication standby state, even if a short circuit occurs with a 3.3V voltage (a signal voltage of 1.8V or higher), depending on the characteristics of the connected electrical element, it may not be possible to detect an abnormality.

[0120] In contrast, in this embodiment, GND contacts TC04 and TA04 are located on one side of the accessory power supply VACC contacts TC05 and TA05, and accessory attachment detection signal / ACC_DET contacts TC06 and TA06 are located on the other side. As explained above, the accessory attachment detection signal / ACC_DET is connected to GND within the accessory 200. Therefore, even if a short circuit occurs between the contacts, an overcurrent can be detected and the system can be safely shut down without 3.3V being applied to elements operating at 1.8V.

[0121] Furthermore, as mentioned above, if the accessory power supply VACC is supplied without the GND contact being connected, the reference potential of the accessory 200 becomes unstable, which may result in damage to the circuits and electrical elements. During device operation, an external force strong enough to destabilize the contact of the connector terminals may be applied. In response to this, by placing the accessory power supply VACC contact and the GND contact adjacent to each other as in this embodiment, it is possible to make it less likely that only the accessory power supply VACC contact will be connected, compared to placing the accessory power supply VACC contact and the GND contact on terminals far apart.

[0122] In this embodiment, the accessory attachment detection signal / ACC_DET is connected to GND within the accessory 200, but it may also be connected to GND via a resistor element Rd231, as in the accessory 200 shown in Fig. 9. Connecting to GND via resistor Rd231 can reduce the short-circuit current.

[0123] In this case, it is necessary to select a resistor Rd231 with a resistance value such that the voltage (Rd / (Rp+Rd))×1.8V obtained by dividing the 1.8V voltage of the camera microcontroller power supply VMCU_C by the resistor Rp134 and the resistor Rd231 satisfies the Low-level threshold (Vil) of the camera control circuit 101. For example, if the Low-level detection threshold (Vil) of the camera control circuit 101 is 0.33 times the power supply voltage, the resistance of the resistor Rd231 must be equal to or less than half that of the resistor Rp134 (10 kΩ). In the example of FIG. 9, the resistance of the resistor Rd231 is set to 5 kΩ.

[0124] Fig. 5(b) shows the processing executed by the camera control circuit 101 when the accessory 200 having the configuration shown in Fig. 9 is attached to the camera 100. S411 to S413 are the same as S401 to S403 shown in Fig. 5(a), respectively, and therefore the description thereof will be omitted.

[0125] In S414 after S413, the camera control circuit 101 monitors the signal level of the accessory attachment detection signal / ACC_DET and determines whether or not the contacts TC06 and TA06 of the accessory attachment detection signal / ACC_DET are shorted to the contacts TC05 and TA05 of the accessory power supply VACC. If the signal level is Lo, the camera control circuit 101 determines that there is no short and proceeds to S415, and if the signal level is Hi, it determines that there is a short and proceeds to S416 to perform error processing.

[0126] 6(c) shows the state of the accessory power supply VACC and the accessory attachment detection signal / ACC_DET when they are shorted in the accessory 200 having the configuration shown in FIG. 9 with the addition of resistor element Rd231 (5 kΩ). After the power supply control signal CNT_VACC1 is set to Hi in S402, the current is limited by resistor element Rd231, so no overcurrent flows through IACC.

[0127] On the other hand, the voltage of the accessory power supply VACC is applied to the accessory attachment detection signal / ACC_DET. As soon as the signal level of the accessory attachment detection signal / ACC_DET becomes Hi due to interrupt processing or the like, the camera control circuit 101 sets the power control signal CNT_VACC1 to Lo as error processing to stop the output of the accessory power supply VACC (power supply to the accessory 200). This allows the system to be safely shut down without continuing to apply 3.3V to the terminals of elements operating at 1.8V.

[0128] 10, the accessory 200 may be configured so that the accessory attachment detection signal / ACC_DET is controlled to Lo level (GND potential) by the accessory control circuit 201 via an NPN transistor 212 serving as a switch means. In the configuration shown in Fig. 1, the camera control circuit 101 can always detect the accessory 200 when the accessory 200 is attached to the camera 100, but with the configuration of Fig. 10, the accessory control circuit 201 can notify the camera 100 that the accessory 200 has been attached at any timing.

[0129] 11, the accessory 200 may be configured such that a resistor element Rd231 is connected in series with an NPN transistor 212. In this case, similar to the configuration in FIG. 1, the resistance value needs to be equal to or less than half of the resistor element Rp134 (10 kΩ).

[0130] As described above, according to this embodiment, even if a short occurs between the power contact and the adjacent contact, the safety of the system consisting of the camera 100 and the accessory 200 can be maintained and damage to them can be suppressed.

[0131] FIG. 7 shows examples of functions of FNC1 signals to FNC4 signals as functional signals connected to contacts TC14 to TC17 and contacts TA14 to TA17 for each type of accessory 200 (here, microphone device and strobe device).

[0132] In a microphone device, the FNC2 to FNC4 signals are used as a digital audio (I2S: Inter-IC Sound standard) data bus to transfer audio data. Fig. 8(a) shows an example of the configuration of the functional circuit 206 when the accessory 200 is a microphone device.

[0133] The audio processing circuit 206A1 in the functional circuit 206 is a codec circuit that converts audio signals input from the microphone 206A2 into digital audio (I2S) data format, and is controlled by the accessory control circuit 201. The accessory control circuit 201 controls the audio processing circuit 206A1 to set the sampling frequency and resolution. In this embodiment, the sampling frequency is 48 kHz and the resolution is 32 bits. The microphone 206A2 is, for example, a MEMS-IC microphone or an electret condenser microphone.

[0134] TA14 is not used as an I2S data bus for the FNC1 signal and is connected to GND. In this embodiment, unused functional signals are connected to GND, but this is not limiting and they may be connected to a stable reference potential other than GND potential (0 V), such as the power supply potential or the L level (low potential) or H level (high potential) of a signal.

[0135] The FNC2 signal connected to TA15 (DATA contact) is an audio data signal (DATA), and is a signal output from the accessory 200 to the camera 100.

[0136] The FNC3 signal connected to TA16 (LRCLK contact) is an audio channel clock signal (LRCLK), and is a signal output from the accessory 200 to the camera 100.

[0137] The FNC4 signal connected to TA17 (BCLK contact) is an audio bit clock signal (BCLK), and is a signal output from the camera 100 to the accessory 200.

[0138] In this embodiment, as described above, the sampling frequency is 48 kHz and the resolution is 32 bits, so the LRCLK frequency is 48 kHz and the BCLK frequency is 3.072 MHz. The maximum frequency of DATA is 1.536 MHz, which is half the period of CLK.

[0139] In the contact arrangement of this embodiment, reference potential contacts TA18 and TC18, which are connected to the reference potential GND, are located next to contacts TA17 and TC17, which are connected to the FNC4 signal (BCLK), which has the highest frequency among the function signal contacts to which function signals are connected. Signal wiring to the actuator interface is generally configured using a flexible board. To reduce product costs, the flexible board may be single-sided, with the board wiring arranged in the same order as the contact arrangement. In this embodiment, the reference potential GND contact is located next to the function signal contact to which the signal with the highest frequency among the function signals is connected. This reduces radiated noise (EMI) from the function signal contacts, interference with signals connected to other contacts, and crosstalk with signals other than the I2S data bus.

[0140] In this embodiment, the contacts TA18 and TC18 adjacent to the contacts TA17 and TC17 to which the FNC4 signal (BCLK) with the highest frequency is connected are connected to the GND potential, which is the reference potential, but this is not limiting and the same effect can be obtained even if the contacts are connected to a stable reference potential other than the GND potential.

[0141] Fig. 8(b) is an example of a configuration in which the amount of audio data is increased compared to Fig. 8(a). The purpose of increasing the amount of audio data is to increase the number of channels and resolution.

[0142] The FNC4 signal connected to TA17 is an audio bit clock signal (BCLK) and is the same as in FIG. 8(a).

[0143] On the other hand, the FNC3 signal connected to the TA14 is an audio channel clock signal (LRCLK), which is output from the accessory 200 to the camera 100.

[0144] The FNC2 signal connected to TA15 is an audio data signal (DATA2), and is a signal output from the accessory 200 to the camera 100.

[0145] The FNC1 signal connected to TA16 operates as a signal to be output from the accessory 200 to the camera 100 as an audio data signal (DATA2).

[0146] In this way, when adding an audio data signal to increase the amount of audio data and configuring two signals to be used, by placing the signals with the highest frequency closer to the GND terminal, a configuration can be created that is relatively more effective at preventing crosstalk.

[0147] 8(c) shows an example of the configuration of the functional circuit 206 when the accessory 200 is a strobe device. The light-emitting circuit 206B1 in the functional circuit 206 is a strobe light-emitting circuit composed of an IGBT, a trigger coil, etc., and controls the light emission of the light-emitting unit 206B2. The light-emitting unit 206B2 is composed of a xenon tube, etc., and emits illumination light to irradiate the subject. The charging circuit 206B3 is composed of a transformer, a switching FET, a capacitor, etc., and accumulates electric charge to cause the light-emitting unit 206B2 to emit light.

[0148] The FNC1 signal connected to TA14 is a light emission synchronization signal (STARTX) for controlling the light emission timing of the light emitting unit 206B2, and is a signal output from the camera 100 to the accessory 200. The FNC2 to FNC4 signals are not used in the strobe device, and no signals are connected to these contacts.

[0149] In this embodiment, unused functional signal contacts are left unconnected (OPEN), but this is not limited to this. They may also be connected to a stable reference potential such as the power supply potential or the L or H level of a signal, in accordance with the contacts TC15 to TC17 to which the contacts TA15 to TA17 are connected.

[0150] In a strobe device, only the FNC1 signal is used among the function signals. Also, although the light emission synchronization signal (STARTX) is not a periodically generated signal, the camera 100 can assign GND to the FNC1 signal when a microphone device is connected, thereby preventing the configuration of the camera control circuit 101 from becoming complicated.

[0151] Further features of the contact arrangement of this embodiment will be described below. SDA (first signal) connected to contacts TC12 and TA12 as first signal contacts, and SCL (second signal) connected to contacts TC13 and TA13 as second signal contacts, are both signals for I2C communication. These signals are transmitted by open-drain communication. Because both SDA and SCL are pulled up to the camera microcontroller power supply VMCU_C, they are signals with relatively high impedance when communication is in standby mode, and are susceptible to crosstalk.

[0152] For this reason, in this embodiment, the communication request signal (fourth signal) / WAKE is assigned to the contacts TC11 and TA11 as fourth signal contacts adjacent to the SDA contacts TC12 and TA12. As described above, the communication request signal / WAKE is a signal that issues a communication request from the accessory 200 to the camera 100.

[0153] 15(a) shows the timing when the accessory 200 issues a communication request to the camera 100 and performs I2C communication. As shown in FIG. 15(a), the communication request signal / WAKE is Before I2C communication using SCL and SDA, the signal level changes from Hi to Lo. I2C communication occurs in response to this change. Therefore, by arranging the communication request signal / WAKE contacts TC11 and TA11 adjacent to the SDA contact and SDA contact for I2C communication, crosstalk between the communication request signal / WAKE and SDA can be prevented.

[0154] Furthermore, as shown in FIG. 15(a), by controlling the signal level of the communication request signal / WAKE to change from Lo level to Hi level after I2C communication, crosstalk of the communication request signal / WAKE with SDA can be prevented.

[0155] Furthermore, the FNC1 signal is assigned to contacts TC14 and TA14, which are third signal contacts adjacent to the SCL contacts TC13 and TA13. As mentioned above, GND is assigned to the FNC1 signal in microphone devices, so crosstalk with respect to SCL can be prevented.

[0156] Furthermore, in a strobe device, a light emission synchronization signal (STARTX: third signal) serving as an FNC1 signal is assigned to contacts TC14 and TA14 adjacent to the SCL contacts TC13 and TA13. FIG. 15(b) shows the timing when a communication request is made from the accessory 200 to the camera 100, and when I2C communication and strobe emission are performed. As shown in FIG. 15(b), during the timing (period) when the light emission synchronization signal is output, I2C communication is not performed between the camera 100 and the accessory 200, because strobe emission control is given top priority. In other words, the signal level of the light emission synchronization signal changes before (or after) I2C communication, but the signal level does not change during I2C communication. This prevents crosstalk between the light emission synchronization signal and the SCL.

[0157] In this way, in this embodiment, the STARTX contact is placed on one of the two sides of the SDA contact and the SCL contact, and the / WAKE contact is placed on the other side, thereby enabling good I2C communication.

[0158] In this embodiment, the communication request signal / WAKE connected to the contacts TC11 and TA11 adjacent to the SDA contacts TC12 and TA12 is an open-drain signal like the SDA, which can reduce crosstalk with the SDA when the signal level of the communication request signal / WAKE changes, compared to when the communication request signal / WAKE is a push-pull signal.

[0159] The SCLK connected to the SCLK contacts TC07 and TA07 is a clock signal for SPI communication, and in this embodiment operates at a drive frequency of 1 MHz. In this embodiment, the attachment detection contacts TC06 and TA06 next to the SCLK contacts TC07 and TA07 are used to transmit the accessory attachment detection signal / ACC_DET. As mentioned above, the accessory attachment detection signal / ACC_DET is a signal that becomes equivalent to GND in potential when an accessory 200 is attached to the camera 100. For this reason, this contact arrangement can prevent crosstalk between SCLK and signals other than the SPI bus.

[0160] MOSI, connected to contacts TC08 and TA08 adjacent to the SCLK contacts TC07 and TA07, is a data signal transmitted from the camera control circuit 101 to the accessory control circuit 201 via SPI communication. Generally, the timing at which the MOSI output level changes in SPI communication is synchronized with the timing at which the SCLK output level changes. Therefore, by placing MOSI contacts TC08 and TA08 adjacent to the SCLK contacts TC07 and TA07, crosstalk between SCLK and MOSI can be suppressed.

[0161] MISO, connected to the contacts TC09 and TA09 adjacent to the MOSI contacts TC08 and TA08, is a data signal transmitted from the accessory control circuit 201 to the camera control circuit 101 in SPI communication. Generally, the timing at which the MISO output level changes in SPI communication is synchronized with the timing at which the SCLK output level changes, just like MOSI. For this reason, by placing the MISO contacts TC09 and TA09 adjacent to the MOSI contacts TC08 and TA08, crosstalk between MOSI and MISO can be suppressed.

[0162] The CS connected to the contacts TC10 and TA10 next to the MISO contacts TC09 and TA09 is a communication request signal sent from the camera control circuit 101 to the accessory control circuit 201 in SPI communication. Generally, the CS in SPI communication maintains a constant output level from the time a communication request is made until the communication is completed. For this reason, by placing the CS contacts TC10 and TA10 next to the MISO contacts TC09 and TA09, crosstalk to the MISO can be suppressed.

[0163] The communication request signal / WAKE connected to the contacts TC11 and TA11 adjacent to the CS contacts TC10 and TA10 is a signal that issues a communication request from the accessory control circuit 201 to the camera control circuit 101. As explained above, the communication request signal / WAKE is an open-drain signal, and is therefore relatively susceptible to crosstalk. For this reason, in this embodiment, crosstalk to the communication request signal / WAKE can be suppressed by arranging the CS contacts TC10 and TA10, which have a relatively low frequency of signal level changes, adjacent to the communication request signal / WAKE contacts TC11 and TA11.

[0164] Furthermore, differential signals requiring impedance control are connected to contacts TC01-TC03, TA01-TA03 and contacts TC19-TC21, TA19-TA21 located at both ends and in the vicinity of the camera connection section 141 and the accessory connection section 211 (hereinafter collectively referred to as both ends). Signal wiring to the accessory interface is generally configured using a flexible board. To achieve the desired wiring impedance with a flexible board, it is necessary to maintain a constant distance between the differential signal lines and between the lines and the parallel GND wiring. Furthermore, in double-sided boards, it is common to form mesh-like GND wiring on the back side of the differential signal lines. Signal wiring requiring impedance control in this way places greater constraints on wiring design than typical single-ended signals.

[0165] In contrast to this, in this embodiment, differential signals that require impedance control are connected to contacts located on both ends of the camera connection section 141 and the accessory connection section 211, thereby reducing the interaction with other signals relatively and increasing the freedom of wiring design.

[0166] Furthermore, differential signals enable high-speed transfers of several hundred Mbps to several Gbps, like USB and PCIe, and are suitable for transferring large amounts of data between devices. However, some types of accessory 200 do not use differential signals. In accessories that do not use differential signals, the contacts allocated to differential signals are unnecessary, and therefore eliminating the contacts can reduce the cost of the accessory.

[0167] FIG. 12 shows an example of a modified configuration of accessory 200 shown in FIG. 1. Specifically, the configuration omits contacts TA01 to TA03, TA19 to TA21 and the signals and circuits connected to them. That is, accessory 200 in FIG. 12 has 15 contacts. In the configuration in FIG. 12, differential signals are assigned to contacts TC01 to TC03 and TC19 to TC21 located on both ends of camera connection section 141. On the other hand, in accessory 200 that does not require differential signals, the contacts for differential signals in accessory connection section 211 are eliminated, and a contact arrangement is adopted that includes only the contacts necessary for accessory 200.

[0168] 12, contacts TC04, TA04 and contacts TC18, TA18 near both ends of camera connection unit 141 and accessory connection unit 211 are set as GND contacts. By arranging the contacts in this manner, even in accessory 200 that is connected to some of the contacts of camera connection unit 141, contacts at both ends of accessory connection unit 211 can be set as GND contacts. This makes it possible to prevent the GND contacts from coming loose even when accessory 200 is subjected to excessive static pressure or impact.

[0169] Up to this point, we have explained the case where the accessory 200 is directly attached to the camera 100. Next, we will explain the case where an intermediate accessory 400 is attached between the camera 100 and the accessory 200 using Figure 13. The configuration of the camera 100 and the accessory 200 is as described above. Examples of the intermediate accessory 400 include an extension cable for extending the distance between the camera 100 and the accessory 200, and an adapter for simultaneously attaching multiple accessories to the camera 100. In this embodiment, we will explain the case where the intermediate accessory 400 is an extension cable. In the configuration in Figure 13, the intermediate accessory 400 corresponds to the accessory, and the accessory 200 corresponds to the other accessory.

[0170] Intermediate accessory 400 has a camera shoe and an accessory shoe that can be attached to camera 100 and accessory 200, respectively, and is provided with a camera-side intermediate connection part 311 and an accessory-side intermediate connection part 312, respectively. Camera-side intermediate connection part 311 has 21 contacts TM01 to TM21 arranged in a row, and is a connector for making an electrical connection with camera 100. Contacts TM01 to TM21 make one-to-one contact with contacts TC01 to TC21 in camera connection part 141, respectively.

[0171] On the other hand, the accessory side intermediate connection portion 312 has 21 contacts TN01 to TN21 arranged in a row, and is a connector for making an electrical connection with the accessory 200. The contacts TN01 to TN21 come into contact with the contacts TA01 to TA21 in the accessory connection portion 211 in a one-to-one correspondence, respectively.

[0172] By arranging the contacts in the intermediate accessory 400 in this manner, it is possible to supply power and perform communication in the same manner as when the accessory 200 is directly attached to the camera 100. In this case, the intermediate accessory 400 may receive power from the camera 100, or may transmit the power supply from the camera 100 directly to the accessory 200. The power supply in this embodiment also includes a case where no power is supplied to the accessory 400, such as when the power supply from the camera 100 is transmitted directly to the accessory 200.

[0173] In Figure 13, the number of contacts in the camera side intermediate connection part 311 is the same as the number of contacts in the camera connection part 141, and the number of contacts in the accessory side intermediate connection part 312 is the same as the number of contacts in the accessory connection part 211, but it is not necessarily necessary to make the numbers of contacts the same.

[0174] FIG. 14 shows an example in which the configuration of accessory 200 and intermediate accessory 400 has been modified from the configuration of FIG. 13. Differential signals are connected to contacts TC01 to TC03 and TC19 to TC21 on both ends of camera connection section 141, but differential signals may not be necessary depending on the function of accessory 200. In the configuration of FIG. 14, the contacts to which differential signals are connected from camera side intermediate connection section 311 and accessory side intermediate connection section 312 to accessory connection section 211 have been eliminated. In other words, intermediate accessory 400 and accessory 200 in FIG. 14 each have 15 contacts. This allows for a contact arrangement that includes only the contacts necessary for intermediate accessory 400 and accessory 200.

[0175] Next, a connection structure between the camera 100 and an external flash unit 120, which is an example of the accessory 200, will be described in detail.

[0176] Figure 16(a) shows the camera 100 as seen from the diagonal rear side. Figure 16(b) shows how to attach the external flash unit 120 to the accessory shoe 1123 of the camera 100. Figure 16(c) shows the state in which the external flash unit 120 is attached to the camera 100 as seen from the diagonal rear side.

[0177] The imaging optical system is provided on the front side (field side) of the camera 100, and the image display unit 107 is provided on the back side of the camera 100. A top cover 150 is provided on the top surface of the camera 100 as an exterior member, and an accessory shoe 1123 is disposed on the top cover 150. Meanwhile, in the external flash unit 120, the camera connection unit 216 is provided on the bottom of the external flash unit 120. As shown in FIG. 16(b), the external flash unit 120 is slid parallel to the front side in the Z direction (the attachment side in the first direction) relative to the camera 100 to engage the camera connector 216 with the accessory shoe 1123. This allows the external flash unit 120 to be attached to the camera 100. The front side in the Z direction is the direction from the rear side to the front side of the camera 100, that is, the direction from the image display unit 107 side to the imaging optical system side. Note that the X direction (second direction), Y direction (third direction), and Z direction (front-rear direction) shown in the drawings from FIG. 16 onwards are common. The X direction is the direction perpendicular to the Z direction in a horizontal plane when the Z direction is parallel to the horizontal direction, and is the width direction of the camera 100. The Y direction is the direction perpendicular to the Z direction and the X direction, and is the height direction of the camera 100.

[0178] Next, the accessory shoe 1123 of the camera 100 will be described in detail. Figure 17(a) shows the accessory shoe 1123 disassembled from the top cover 150. Figure 17(b) shows the assembled accessory shoe 1123. The attachment direction of the accessory shoe 1123 to the top cover 150 is the Y direction.

[0179] The accessory shoe 1123 has an engagement member 151, a connection terminal connector 152, a shoe stage 153, and an accessory shoe spring 154. The engagement member 151 is a member for holding the external flash unit 120 by engaging with the external flash unit 120. The connection terminal connector 152 has a plurality of connection terminals 152a arranged at equal pitches in the X direction on a connector base member 152e serving as a holding member formed of a resin material or the like and held by the connector base member 152e. The connection terminals 152a correspond to the contacts TC01 to TC21 of the camera connection portion 141 shown in FIG. 1.

[0180] 17(b), the connection terminal 152a of the connection terminal connector 152 is located forward in the Z direction (on the front side of the camera 100), which is the attachment direction of the external flash unit 120. An engagement hole 156 that engages with the lock pin 252 of the external flash unit 120 shown in FIG. 19(a) is provided at the rear of the connection terminal connector 152 in the Z direction (on the back side of the digital camera 100).

[0181] When the external flash unit 120 is attached to the accessory shoe 1123, the connection terminal 152a is electrically connected to the external flash unit 120. Furthermore, each of the multiple connection terminals 152a is electrically connected to a flexible board 158 located on the lower side of the top cover 150 in the Y direction. The flexible board 158 is connected to a main board (not shown) of the camera 100. Therefore, when the external flash unit 120 is attached to the accessory shoe 1123, communication between the external flash unit 120 and the camera 100 becomes possible.

[0182] The shoe stage 153 is a housing member that surrounds the engaging member 151 and the connection terminal connector 152. The accessory shoe holding member 155 is a structural body that holds the engaging member 151. As shown in FIG. 17(a), the accessory shoe holding member 155, flexible board 158, top cover 150, shoe stage 153, and connection terminal connector 152 are fastened to the engaging member 151 by four screws 157 that pass through them. This positions and fixes these components relative to one another. By arranging the four screws 157, one in each of four regions that are equally divided in the X and Z directions, the above components can be joined in a balanced manner.

[0183] Figure 18(a) shows the structure of the upper surface of the engaging member 151, and Figure 18(b) shows the structure of the lower surface of the engaging member 151. Figure 18(c) shows the structure of the upper surface of the connection terminal connector 152. Figure 24 shows the accessory shoe 1123 as seen from the insertion direction of the external flash unit 120.

[0184] The engaging member 151 is formed by bending a metal plate into a loop shape so that the end faces of both folded ends abut against each other at a seam 151a. The engaging member 151 has a pair of engaging portions 151b and a connecting portion 151c that interconnects the pair of engaging portions 151b. The engaging member 151 is formed with a pair of first screw holes 151d and a pair of second screw holes 151e that are used to fasten screws 157. The engaging member 151 also has an engaging hole 156 that engages with a lock pin 252 of the external flash unit 120.

[0185] As shown in Figures 18(a) and 12, the pair of engagement portions 151b are spaced apart in the X direction by a first width (hereinafter referred to as engagement portion spacing) 151aa. A holding member 254 of the external flash unit 120 (described later and shown in Figure 19(b)) is inserted into the engagement portion spacing 151aa. The pair of first screw hole portions 151d are spaced apart in the X direction and function as a pair of first fastening hole portions spaced apart in the X direction at the rear (back side) of the Z direction. The pair of second screw hole portions 151e are spaced apart in the X direction and function as a pair of second fastening hole portions spaced apart in the X direction at the front of the Z direction. The engagement hole portion 156 is formed in the area sandwiched between the pair of first screw hole portions 151d at a position that allows it to engage with a lock pin 252 of the external flash unit 120.

[0186] 17(b) and 18(c), a plurality of connection terminals 152a are exposed in the connection terminal connector 152. In the pitch direction (X direction) in which the plurality of connection terminals 152a are arranged, the position of the camera connection part 216 is determined by the engagement part spacing 151aa of the engagement member 151. Therefore, the holding member 254 of the external flash unit 120 is positioned relative to the connection terminal connector 152 by the engagement member 151.

[0187] Furthermore, abutment surfaces and grooves shown in FIG. 24 are formed on both sides of the multiple connection terminals 152a sandwiched in the X direction at the front side in the Z direction of the connection terminal connector 152 (connector base member 152e), which is an example of the camera connection portion 141 shown in FIG. 1. That is, abutment surfaces 152b that abut against and position the accessory shoe 1123 in the Z direction when the external flash unit 120 is attached, and grooves 152c into which the accessory shoe 1123 is inserted are formed. Each groove 152c is formed to extend from the abutment surface 152b toward the front side (attachment side) in the Z direction and is provided with sloped surfaces 152d that are formed to face inward and diagonally upward (inclined with respect to the X direction). Note that the portion of the groove 152c above the sloped surfaces 152d extends outward in the X direction from the position of the upper end of the sloped surfaces 152d. This is to prevent a depression (sink mark) from occurring in the slope 152d when the slope 152d is formed up to the upper end of the groove 152c during resin molding.

[0188] As shown in Figure 24, in the X direction, the outermost inner surface 152ccc of the groove portion 152c in the connector base member 152e of the accessory shoe 1123 is located outside the inner end surfaces (engagement portion spacing 151aa) of the pair of engagement portions 151b of the engagement member 151 and inside the outermost inner surface 151bb of the engagement member 151.

[0189] The slope start position 152cc, which is the end (lower end) of the slope portion 152d on the bottom side of the groove 152c, is located inside the engagement portion interval 151aa. This ensures an area for providing the abutment surface 152b that abuts against the abutment portion 251b (described later) of the camera connection portion 216 to position it in the Z direction. Furthermore, by providing a slope shape starting from the slope start position 152cc, the space for inserting the shoe device of the external flash unit 120 (the camera connection portion 216 (described later)) can be expanded, ensuring flexibility in the shape of the shoe device. As a result, the shoe device of the external flash unit 120 can be shaped to adequately protect its connection terminal.

[0190] Next, the external flash unit 120 will be described. Figure 19(a) shows the external flash unit 120 as seen from the camera connector 216 side (the lower side in the Y direction). Figure 19(b) shows a cross section taken along line AA in Figure 19(a), illustrating the internal structure of the camera connector 216. Figure 20(a) shows the camera connector 216. However, the base 250 and lock lever 253, which will be described later, are not shown. Figure 20(b) shows the camera connector 216 as seen from the front in the Z direction.

[0191] 19(b), the camera connection part 216 is provided on the lower side in the Y direction (upper side in FIG. 19(a)) of the base part 250 of the external flash unit 120 when attached to the accessory shoe 1123 of the camera 100. The camera connection part 216 has a shoe mounting leg (engagement member, shoe plate) 251, a lock pin 252, a lock lever 253, a holding member 254, a connection plug 256, and a Y-direction holding member 258.

[0192] The shoe mounting leg 251 is an engagement member that engages and holds the external flash unit 120 on the accessory shoe 1123 of the camera 100. In other words, the shoe mounting leg 251 is an engagement member on the external flash unit 120 side that is detachable from the engagement member 151 of the accessory shoe 1123.

[0193] The accessory shoe 1123 and the camera connection part 216 are subjected to large stresses due to pressure to maintain the attached state and external forces (such as impacts) acting on the external flash unit 120. The shoe mounting leg 251 is manufactured by processing a metal plate (sheet metal) to ensure high mechanical strength against such large stresses.

[0194] The lock pin 252 is a member for preventing the external flash unit 120 from falling off when the camera connection part 216 (shoe mounting leg 251) is attached to the accessory shoe 1123, and is held by the shoe mounting leg 251 so as to be movable in the Y direction. Specifically, the lock pin 252 is held by a Y-direction holding member 258 so as to be slidable in the Y direction. The lock lever 253 and the Y-direction holding member 258 are held by a holding member 254.

[0195] When the external flash unit 120 is attached to the accessory shoe 1123 and the lock lever 253 is rotated, a cam portion (not shown) moves the Y-direction holding member 258 downward in the Y direction in FIG. 19(b). At that time, the lock pin 252 also moves downward in the Y direction in FIG. 19(b) together with the Y-direction holding member 258. As a result, the lock pin 252 protrudes from the shoe mounting leg 251 and engages with an engagement hole portion 156 provided in the engagement member 151 of the accessory shoe 1123. The lock pin 252 and the engagement hole portion 156 function as positioning members in the Z direction to ensure electrical connection between the external flash unit 120 and the camera 100.

[0196] 1 is provided on the front side of the camera connection portion 216 in the Z direction, is made of a non-conductive material (dielectric material) such as a resin material, and is integrated with the holding member 254. The outermost width T of the connection plug 256 in the X direction is narrower than the width W of the shoe mounting leg 251 in the X direction. This ensures an area for providing the contact portion 251b on the shoe mounting leg 251. The connection plug 256 has multiple connection terminals 257 for communication by contacting multiple connection terminals 152a of the accessory shoe 1123 shown in FIG. 18(c). The connection terminals 257 correspond to the contacts TA01 to TA21 of the accessory connection portion 211 shown in FIG. 1.

[0197] The multiple connection terminals 257 are provided in one-to-one correspondence with the multiple connection terminals 152a and are held by the holding member 254 so as to extend in the Z direction and be aligned in the X direction. Each connection terminal 257 has a tip portion 257a that contacts the corresponding connection terminal 152a. Each connection terminal 257 also has an extension portion 257b that extends rearward in the Z direction from the tip portion 257a and elastically displaces the tip portion 257a upward in the Y direction in FIG. 19(b) when the tip portion 257a abuts the connection terminal 152a. An extension portion 257c that extends upward in the Y direction is formed at the rear end of the extension portion 257b in the Z direction. A flexible board connection portion 257d is provided at the upper end of the extension portion 257c and is connected to a main board (not shown) of the external flash unit 120 and is inserted into the holding member 254 from above in the Y direction.

[0198] The extension 257b has a stepped portion 257e formed in the Z direction, which has a step in the Y direction. As described above, the extension 257b is capable of elastic deformation in the Y direction. However, if the distance L of the extension 257b in the Z direction is short, a sufficient amount of deformation cannot be obtained, resulting in reduced durability. As a result, repeated attachment and detachment of the connection terminal 152a and the tip 257a may make the extension 257b more susceptible to damage. Therefore, by providing the stepped portion 257e in the extension 257b, a sufficient distance L is ensured without the extension 257b interfering with the shoe mounting leg 251.

[0199] 20(a) and 20(b), a pair of protrusions 256a is provided at both ends in the X direction of the connection plug 256, protruding downward in the Y direction (third direction) so as to sandwich the plurality of connection terminals 257 therebetween. As shown in Fig. 20(b), a lower tip 256d of each protrusion 256a protrudes below a line connecting the lower ends of the tip portions 257a of the connection terminals 257 in order to protect the connection terminals 257 from external forces such as pressure and impact. In other words, the tip portion 257a of the connection terminal 257 is provided above (inside) the line connecting the lower tip portions 256d of the pair of protrusions 256a.

[0200] Furthermore, on the outer side (outer surface) in the X direction of each protrusion 256a, a sloped portion 256b is provided as an outer surface that extends obliquely upward from a lower tip 256d and faces obliquely downward, i.e., is inclined with respect to the X direction. Since each protrusion 256a has such a shape, it is possible to insert the connection plug 256 into the groove 152c having the sloped portion 152d in the connection terminal connector 152.

[0201] The sloped surface 256b serves to prevent damage to the connection plug 256 by dissipating external forces such as pressure and impact on the connection plug 256. For example, Fig. 20(c) shows a case where an external force is applied to the connection plug 256 from the X direction. Fig. 20(c) shows the connection plug 256 as seen from the front in the Z direction.

[0202] An external force acting in the X direction is designated as F1 and is defined as a vector. When the external force F1 acting on the sloped surface 256b is resolved according to the rules of addition in vector space, it is resolved into a component force F2 in a direction along the sloped surface 256b and a component force F3 in a direction perpendicular to the sloped surface 256b. If the angle formed by the external force F1 and the sloped surface 256b is designated as θ, the component forces F2 and F3 can be calculated using the following equation (1): F2=F1cosθ F3=F1sinθ (1) When the inclined surface portion 256b is provided, θ is in the range of 0°<θ<90°. F2 <F1 F3 <F1(2) Since the component force F2 escapes in a direction along the inclined surface portion 256b, the only force that affects the connection plug 256 is the component force F3. As described above, the component force F3 is smaller than the external force F1, and therefore the connection plug 256 can be prevented from being damaged even if a relatively large external force is applied.

[0203] By forming the inclined surfaces 256b on both sides in the X direction so that the width in the X direction narrows toward the lower side in the Y direction, it is possible to dissipate a portion of the external force not only from the X direction but also from the lower side in the Y direction.

[0204] FIG. 25 shows an enlarged view of a portion of the connection plug 256 as viewed from the Z direction. In the Y direction, the height from the lower end 256d of the protrusion 256a to the upper surface of the connection plug 256 (the height of the connection plug including the protrusion) is defined as B, and the height of the slope 256b from the lower end 256d (slope starting position 256c) to the upper end of the slope 256b is defined as A. In this case, A is preferably at least 1 / 5 of B, and more preferably at least 1 / 4, 1 / 3, or even at least half as shown in FIG. 13. That is, the slope 256b is formed to have a significant dimension for the function of dissipating external forces from the X direction, and is different from the chamfered shape typically provided at the corners of protrusions. Furthermore, the inclination angle θ of the slope 256b with respect to the X direction is preferably set within the range of 45°±20° to achieve the above-described function of dissipating external forces.

[0205] In order to ensure a sufficient area for the abutment portion 251b of the shoe mounting leg 251 relative to the abutment surface 152b of the accessory shoe 1123, which is a positioning portion in the Z direction, it is desirable to make the width in the X direction between the slope start positions 256c at the lower tip ends 256d of the slope portions 256b on both sides as short as possible. In this embodiment, the width in the X direction between the slope start positions 256c is set inside the width V of the holding member 254 in the X direction, thereby ensuring a sufficient area for the abutment portion 251b.

[0206] The camera connection section 216 has a structure in which a shoe mounting leg 251 and a holding member 254 are fastened together. Details of this fastening structure will be described later.

[0207] The holding member 254 has a connecting portion 254a that can be inserted into the engaging portion spacing 151aa of the engaging member 151 of the accessory shoe 1123 shown in FIG. 18(a) and has a width V that is shorter than the width W of the shoe mounting leg 251 in the X direction. The dimensions of the widths W and V are specified in Japanese Industrial Standards (JIS) B7101-1975, "Camera Accessory Mounting Seats and Mounting Feet." The connecting portion 254a engages with the engaging member 151, thereby determining the position of the external flash unit 120 in the X direction relative to the camera 100. Furthermore, the shoe mounting leg 251 is biased upward in the Y direction by abutting against the elastic deformation portion 154a of the accessory shoe spring 154, which serves as a biasing member, as shown in FIGS. 17(a) and (b). This causes the upper surface of the shoe engaging portion 251a to abut (press against) the lower surface of the engaging member 151, thereby determining the position of the external flash unit 120 in the Y direction relative to the camera 100.

[0208] Furthermore, the position of the external flash unit 120 in the Z direction relative to the camera 100 is determined by the abutment portion 251b of the shoe mounting leg 251 abutting against the abutment surface 152b on the front side in the Z direction of the connection terminal connector 152.

[0209] The holding member 254 is also a structure for connecting the shoe mounting leg 251 and the base part 250, and the lock pin 252 and the connection terminal 257 are disposed inside the connecting part 254a.

[0210] Next, we will explain the fastening structure between the holding member 254 and the shoe mounting leg 251. Figure 21(a) shows the camera connection part 216 as seen from above in the Y direction, and Figure 21(b) shows a cross section taken along line B-B in Figure 21(a).

[0211] A pair of first screws 260a and a pair of second screws 260b, which are fastening members for fastening the shoe mounting leg 251 to the holding member 254, penetrate the holding member 254 and are fastened to the shoe mounting leg 251. At this time, by arranging the screws in a well-balanced manner, one in each of four regions that are approximately equally spaced in the X and Z directions, the shoe mounting leg 251 is structured to be stably held to the holding member 254. Also, as mentioned above, the shoe mounting leg 251 is a component that is subjected to large stress. For this reason, by fastening the metal shoe mounting leg 251 to the holding member 254 with a well-balanced pair of first screws 260a and a pair of second screws 260b, it is possible to ensure the necessary mechanical strength.

[0212] 21(b), a plurality of connection terminals 257 are arranged in an area S sandwiched between the pair of first screws 260a and the pair of second screws 260b. The width between the pair of first screws 260a and the pair of second screws 260b is narrower than the width between the lower tip ends 256d of the protrusions 256a of the connection plug 256, the width V of the holding member 254, the outermost width T of the connection plug 256, and the width W of the shoe mounting leg 251.

[0213] 26 shows a cross section seen from the Z direction when the camera connector 216 is attached to the accessory shoe 1123. This figure shows the dimensions T and V of the camera connector 216 described above and the positional relationship between each part of the camera connector 216 and each part of the accessory shoe 1123.

[0214] In FIG. 26, as described above, the upper surface of the shoe fitting portion 251a of the camera connecting portion 216 abuts against the lower surface (ceiling surface) of the engaging member 151 of the accessory shoe 1123 for positioning in the Y direction.

[0215] Meanwhile, the lower tip 256d and the sloped portion 256b of the protrusion 256a of the connection plug 256 in the camera connector 216 do not abut against the bottom surface and sloped portion 152d of the groove 152c of the accessory shoe 1123, respectively. The gap between the lower tip 256d of the protrusion 256a and the bottom surface of the groove 152c of the accessory shoe 1123 is set as small as possible. This allows the lower tip 256d of the protrusion 256a to abut against the bottom surface of the groove 152c of the accessory shoe 1123 when an external force in the X direction is applied to the external flash unit 120, thereby reducing the floating of the connection plug 256 (inclination with respect to the accessory shoe 1123).

[0216] Additionally, the gap between the slopes 256b and 152d and the gap between the inner end face 152ccc of the groove 152c and the outer end face of the connection plug 256 are each set to a certain size. This prevents a load from being applied to the connection terminals 257 and 152a when an external force is applied to the external flash unit 120 in the X direction.

[0217] In groove 152c of accessory shoe 1123, the relationship between the height of groove 152c in the Y direction (the height from the bottom surface of groove 152c to the ceiling surface of engaging member 151) and the height of slope 152d in the Y direction is the same as the relationship between height B of connection plug 256 and height A of slope 256b in camera connecting portion 216. Similarly to slope θ of slope 256b in camera connecting portion 216, the tilt angle of slope 256b with respect to the X direction is preferably set in the range of 45°±20°.

[0218] In the above embodiments, the surface shape of the inclined surface 256b provided on the protrusion 256a has been described as a flat surface, but the inclined surface 256b may be a curved surface having a curvature. In other words, the inclined surface 256b may be a surface that is inclined with respect to the X direction.

[0219] According to the above embodiment, in the small camera connection part 216 and accessory shoe 1123, it is possible to secure an area for providing a larger number of connection terminals and shapes to protect them than before, as well as an area for positioning the components.

[0220] Next, modified examples of the external flash unit 120 will be described. Fig. 22(a) shows the external flash unit 120 as seen from the camera connector 216 side (the lower side in the Y direction). Fig. 22(b) shows a cross section taken along line AA in Fig. 22(a), illustrating the internal structure of the camera connector 216. Fig. 23(a) shows the camera connector 216. However, the base 250 and lock lever 253 are not shown. Fig. 23(b) shows the camera connector 216 as seen from the front in the Z direction.

[0221] 22(b), the camera connection part 216 is provided on the lower side in the Y direction of the base part 250 of the external flash unit 120 (upper side in FIG. 22(a)) when attached to the accessory shoe 1123 of the camera 100. The camera connection part 216 has a shoe mounting leg 300a, a lock pin 252, a lock lever 253, a holding member 300, a connection plug 300b, a Y-direction holding member 258, and a shoe cover 301.

[0222] Similar to the shoe mounting leg 251 of the previously described embodiment, the shoe mounting leg 300a is an engagement member for engaging the external flash unit 120 with the accessory shoe 1123 of the camera 100. In other words, the shoe mounting leg 300a is an engagement member on the external flash unit 120 that is detachable from the engagement member 151 of the accessory shoe 1123.

[0223] In the previously described embodiment, the shoe mounting leg 251, which is a metal shoe plate, and the resin holding member 254 are formed as separate members, with mechanical strength being prioritized. In contrast, in the modified example, the shoe mounting leg 300a and the holding member 300 are formed as a single member using a resin material (a non-conductive material). This eliminates the need for the pair of first screws 260a and the pair of second screws 260b in the previous embodiment, providing more space for arranging the connection terminals 257, allowing a greater number of connection terminals 257 to be arranged. As a result, the external flash unit 120 can communicate more information with the camera 100 via the camera connection portion 216 and the accessory shoe 1123.

[0224] The connection plug 300b is located on the front side of the camera connection portion 216 in the Z direction and is formed as an integral part of the holding member 300, which is made of a non-conductive resin material in this embodiment. As in the previously described embodiment, the outermost width T of the connection plug 300b in the X direction is narrower than the width W of the shoe mounting leg 300a in the X direction, thereby ensuring an area on the shoe mounting leg 300a for providing the abutment portion 300e. The connection plug 300b has multiple connection terminals 257 that contact the multiple connection terminals 152a of the accessory shoe 1123 shown in FIG. 18(c) to communicate. The shoe cover 301 is an enclosure attached to the holding member 300 and protects the multiple connection terminals 257. The shape of the connection terminals 257 is the same as in the previous embodiment, and a step portion 257e is provided to ensure a sufficient distance L in the Z direction of the extension portion 257b without interfering with the shoe cover 301.

[0225] The shape of the connection plug 300b is also similar to that of the connection plug 256 of the previous embodiment, and a pair of protrusions 300c is provided at both ends of the connection plug 300b in the X direction, protruding downward in the Y direction so as to sandwich the plurality of connection terminals 257. As shown in Fig. 23(b) , the lower tip 300k of each protrusion 300c protrudes below a line connecting the lower ends of the tip portions 257a of the connection terminals 257 in order to protect the connection terminals 257 from external forces such as pressure and impact. In other words, the tip portion 257a of the connection terminal 257 is provided above (inside) the line connecting the lower tip portions 300k of the pair of protrusions 300c.

[0226] Also in this embodiment, each protrusion 300c has a slope 300f extending obliquely upward from the lower tip 300k and facing obliquely downward on the outer side in the X direction. Since each protrusion 300c has such a shape, it is possible to insert the connection plug 300b into the groove 152c having the slope 152d in the connection terminal connector 152 described in the previous embodiment. As described in the previous embodiment, the slope 300f serves to release external forces, such as pressure and impact, applied to the connection plug 300b, thereby preventing the connection plug from being damaged.

[0227] Furthermore, as in the previous embodiment, it is desirable to make the distance in the X direction between the slope start positions 300g at the lower tip ends 300k of the slope portions 300f on both sides as short as possible. For this reason, the slope start positions 300g on both sides are located inside the width V of the holding member 254 in the X direction, ensuring a sufficient area for the abutment portions 300e of the shoe mounting legs 300a.

[0228] The holding member 300 has a connecting portion 300h that is insertable into and engages with the engaging portion spacing 151aa of the engaging member 151 shown in FIG. 18(a) and has a width V that is shorter in the X direction than the width W of the shoe mounting leg 300a. As with the previous embodiment, the dimensions of widths W and V are specified in Japanese Industrial Standards (JIS) B7101-1975, "Camera Accessory Mounting Bases and Mounting Feet." When the connecting portion 300h engages with the engaging member 151, the position of the external flash unit 120 in the X direction relative to the camera 100 is determined. Furthermore, the shoe mounting leg 300a is biased upward in the Y direction by abutting against the elastic deformation portion 154a of the accessory shoe spring 154 shown in FIGS. 17(a) and (b), causing the upper surface of the shoe engaging portion 300d to abut against the lower surface of the engaging member 151. This determines the position of the external flash unit 120 in the Y direction relative to the camera 100.

[0229] Furthermore, the position of the external flash unit 120 in the Z direction relative to the camera 100 is determined by the abutment portion 300e of the shoe mounting leg 300a abutting against the abutment surface 152b on the front side in the Z direction of the connection terminal connector 152. The holding member 300 is also a structure for connecting the shoe mounting leg 300a and the base part 250, and the lock pin 252 and the connection terminal 257 are disposed inside the connecting part 300h.

[0230] In this embodiment, the camera 100, the accessory 200, and the intermediate accessory 400 have 21 or 15 contacts, but the number of contacts may be any other number.

[0231] In this embodiment, a microphone device and a strobe device have been described as the accessory 200, but the accessories referred to in the present invention include various devices other than microphone devices and strobe devices, such as an electronic viewfinder unit. In this embodiment, a camera has been described as the electronic device, but the electronic devices referred to in the present invention also include various electronic devices other than cameras. (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0232] The embodiments described above are merely representative examples, and various modifications and alterations are possible to each embodiment when implementing the present invention. [Explanation of symbols]

[0233] 100 cameras 101 Camera control circuit 131,132 Accessory power supply circuit 141 Camera connection part 200 Accessories 211 Accessory connection TC01~TC21, TA01~TA21 contacts

Claims

1. An electronic device to which an accessory is detachably attached, and in which a plurality of contacts electrically connected to the accessory are arranged in a line, The plurality of contacts are a first signal contact used to transmit a first signal, which is a data signal, in communication between the electronic device and the accessory; a second signal contact used for transmitting a second signal, which is a clock signal, in the communication; a third signal contact used for transmitting a third signal different from the first and second signals between the electronic device and the accessory; a fourth signal contact used for transmitting a fourth signal different from the first, second, and third signals between the electronic device and the accessory; the third and fourth signals are signals whose signal levels do not change during the communication; the first signal contact and the second signal contact are disposed adjacent to each other; An electronic device, characterized in that the third signal contact is arranged adjacent to one of the first and second signal contacts, and the fourth signal contact is arranged adjacent to the other.

2. 2. The electronic device according to claim 1, wherein the first and second signals are signals used for open-drain communication.

3. 3. The electronic device according to claim 2, wherein the first and second signals are signals used in I2C communication.

4. 4. The electronic device according to claim 1, wherein at least one of the third and fourth signals is a signal whose signal level changes at least either before or after the communication.

5. 5. The electronic device according to claim 1, wherein the third and fourth signals are different from signals indicating data and clock.

6. the accessory is a lighting device; 6. The electronic device according to claim 1, wherein the third signal is a signal for controlling light emission of the lighting device from the electronic device.

7. 7. The electronic device according to claim 1, wherein the fourth signal is a signal for requesting communication from the accessory to the electronic device.

8. An accessory that is detachably attached to an electronic device and has a plurality of contacts arranged in a row to be electrically connected to the electronic device, The plurality of contacts are a first signal contact used to transmit a first signal, which is a data signal, in communication between the electronic device and the accessory; a second signal contact used for transmitting a second signal, which is a clock signal, in the communication; a third signal contact used for transmitting a third signal different from the first and second signals between the electronic device and the accessory; a fourth signal contact used for transmitting a fourth signal different from the first, second, and third signals between the electronic device and the accessory; the third and fourth signals are signals whose signal levels do not change during the communication; the first signal contact and the second signal contact are disposed adjacent to each other; An accessory characterized in that the third signal contact is arranged adjacent to one of the first and second signal contacts, and the fourth signal contact is arranged adjacent to the other.

9. 9. The accessory according to claim 8, wherein the first and second signals are signals used for open-drain communication.

10. 10. The accessory according to claim 9, wherein the first and second signals are signals used in I2C communication.

11. 11. The accessory according to claim 8, wherein at least one of the third and fourth signals is a signal whose signal level changes at least either before or after the communication.

12. 12. The accessory according to claim 8, wherein the third and fourth signals are different from signals indicating data and clock.

13. the accessory is a lighting device; The accessory according to claim 8 , wherein the third signal is a signal for controlling light emission from the lighting device from the electronic device.

14. 14. The accessory according to claim 8, wherein the fourth signal is a signal for requesting communication from the accessory to the electronic device.

15. The accessory according to any one of claims 8 to 14, wherein the accessory is an intermediate accessory that is attached between the electronic device and another accessory.

16. An accessory comprising the accessory according to claim 15 as an intermediate accessory and a contact point used for communication with the electronic device via the intermediate accessory.

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