ULTRASONIC APPARATUS

An ultrasonic apparatus includes a circuit substrate on which a ground electrode is formed, an ultrasonic device that is mounted on a first surface of the circuit substrate; and a shield that is electrically connected to the ground electrode and that surrounds the ultrasonic device, wherein the circuit substrate has a through hole that penetrates between the first surface and a second surface, which is at an opposite side from the first surface, the shield has a main body section that is disposed on the first surface of the circuit substrate and that surrounds the ultrasonic device and a leg section that extends from the main body section and that passes through the through hole and protrudes from the second surface, and a protruding section is provided on a portion of the leg section that protrudes from the second surface and the protruding section protrudes, when the second surface is viewed in plan view, further outward than the through hole.

The present application is based on, and claims priority from JP Application Serial Number 2023-072366, filed Apr. 26, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an ultrasonic apparatus.

2. Related Art

JP-A-2020-25242 discloses an ultrasonic apparatus that includes a circuit substrate, a base section, an ultrasonic element, and a shield section. The base section is disposed on the circuit substrate. The ultrasonic element is disposed on the base section. The base section is interposed between the circuit substrate and the ultrasonic element. The shield section, which is an example of a shield, covers the base section and the ultrasonic element. The shield section is fixed to the circuit substrate.

JP-A-2020-25242 does not describe how the shield is secured to the circuit substrate. In a previous ultrasonic apparatus, there is room for improvement in the way the shield is secured.

SUMMARY

An ultrasonic apparatus includes a circuit substrate on which a ground electrode, which is connected to a ground potential, is formed; an ultrasonic device that is mounted on a first surface of the circuit substrate; and a shield that is electrically connected to the ground electrode and that surrounds the ultrasonic device; wherein the circuit substrate has a through hole that penetrates between the first surface and a second surface, which is at an opposite side from the first surface, the shield has a main body section that is disposed on the first surface of the circuit substrate and that surrounds the ultrasonic device and a leg section that extends from the main body section and that passes through the through hole and protrudes from the second surface, and a protruding section is provided on a portion of the leg section that protrudes from the second surface and the protruding section protrudes, when the second surface is viewed in plan view, further outward than the through hole.

DESCRIPTION OF EMBODIMENTS

An embodiment will be described using an image scanner as an example. As shown inFIG.1, the image scanner1includes an outer case2and a document support3. The image scanner1is a scanning device that scans an image of a document M placed on the document support3. The document M is an example of a medium.

The outer case2constitutes an outer shell of the image scanner1. The outer case2is provided with a supply port4and a discharge port5. The document M in a cut-sheet form is placed on the document support3. The document support3is configured to have placed thereon a plurality of sheets of the document M. The document support3is disposed above the outer case2. The document support3is provided at a position that connects to the supply port4. The supply port4is an introduction port for introducing the document M placed on the document support3into the inside of the outer case2. The supply port4is connected to the document support3. The supply port4is disposed above the outer case2. The discharge port5is an exit through which the document M introduced into the outer case2from the supply port4is discharged to the outside of the outer case2. The discharge port5is provided below the outer case2.

As shown inFIG.2, the image scanner1includes a transport device7, a scanning unit8, an ultrasonic sensor9, and a control unit11inside the outer case2. The transport device7transports the document M that is introduced into the outer case2from the supply port4, in the transport direction T toward the discharge port5. The transport device7transports the document M from an upper portion of the outer case toward a lower portion of the outer case2. The document M is not limited to paper. The document M may be formed from film, fabric, or the like. The transport device7transports the document M placed on the document support3one sheet at a time. The transport device7includes a transport path12, a first transport roller pair13, a second transport roller pair14, a third transport roller pair15, and a fourth transport roller pair16.

The transport path12is the movement path of the document M from the supply port4to the discharge port5. The document M is transported from the supply port4to the discharge port5along the transport path12. The first transport roller pair13, the second transport roller pair14, the third transport roller pair15, and the fourth transport roller pair16are arranged along the transport path12. The transport path12corresponds to an example of a transport track. Each of the first transport roller pair13, the second transport roller pair14, the third transport roller pair15, and the fourth transport roller pair16is an example of a transport roller.

The first transport roller pair13transports the document M, which is supplied to the supply port4, along the transport path12. When a plurality of sheets of document M are placed on the document support3, the first transport roller pair13supplies the uppermost sheet of the document M of the plurality of sheets of document M into the transport path12. The first transport roller pair13includes a first drive roller13A and a first driven roller13B. The first drive roller13A transmits a drive force for transporting the document M. The first drive roller13A is rotationally driven by the drive force of a transport motor17(to be described later). The first drive roller13A transports the document M along the transport path12by being rotationally driven. The first driven roller13B is in contact with the first drive roller13A. The first driven roller13B is driven to rotate when the first drive roller13A is rotationally driven. The first driven roller13B and the first drive roller13A sandwich the document M therebetween and transport the document M along the transport path12.

The second transport roller pair14is disposed downstream from the first transport roller pair13in the transport direction T. The second transport roller pair14transports the document M transported by the first transport roller pair13along the transport path12. The second transport roller pair14functions as a separation mechanism that separates the document M transported by the first transport roller pair13into individual sheets. The second transport roller pair14includes a second drive roller14A and a second driven roller14B. The second drive roller14A transmits a drive force for transporting the document M. The second drive roller14A is rotationally driven by the drive force of the transport motor17. The second drive roller14A is rotationally driven to transport the document M along the transport path12. The second driven roller14B is in contact with the second drive roller14A. The second driven roller14B is driven to rotate when the second drive roller14A is rotationally driven. The second driven roller14B and the second drive roller14A sandwich the document M and transport the document M along the transport path12. A friction coefficient of the outer circumferential surface of the second driven roller14B with respect to the document M is larger than a friction coefficient of the outer circumferential surface of the second drive roller14A with respect to the document M. The document M is separated one sheet at a time by the rotation of the second transport roller pair14.

The third transport roller pair15is disposed downstream of the second transport roller pair14in the transport direction T. The third transport roller pair15transports the document M transported by the second transport roller pair14along the transport path12. The third transport roller pair15includes a third drive roller15A and a third driven roller15B. The third drive roller15A transmits a drive force for transporting the document M. The third drive roller15A is rotationally driven by the drive force of the transport motor17. The third drive roller15A is rotationally driven to transport the document M along the transport path12. The third driven roller15B is in contact with the third drive roller15A. The third driven roller15B is driven to rotate when the third drive roller15A is rotationally driven. The third driven roller15B and the third drive roller15A sandwich the document M and transport the document M along the transport path12.

The fourth transport roller pair16is disposed downstream of the third transport roller pair15in the transport direction T. The fourth transport roller pair16transports the document M transported by the third transport roller pair15along the transport path12. The fourth transport roller pair16transports the document M toward the discharge port5. The fourth transport roller pair16includes a fourth drive roller16A and a fourth driven roller16B. The fourth drive roller16A transmits a drive force for transporting the document M. The fourth drive roller16A is rotationally driven by the drive force of the transport motor17. The fourth drive roller16A is rotationally driven to transport the document M along the transport path12. The fourth driven roller16B is in contact with the fourth drive roller16A. The fourth driven roller16B is driven to rotate when the fourth drive roller16A is rotationally driven. The fourth driven roller16B and the fourth drive roller16A sandwich the document M and transport the document M along the transport path12.

The scanning unit8scans the document M transported along the transport path12. The scanning unit8is disposed along the transport path12. In this embodiment, the scanning unit8is disposed between the third transport roller pair15and the fourth transport roller pair16. In other words, the scanning unit8is located upstream from the fourth transport roller pair16in the transport path12. The scanning unit8is located downstream from the third transport roller pair15in the transport path12. The scanning unit8includes a first scanner8A and a second scanner8B. The first scanner8A and the second scanner8B are located on opposite sides of the transport path12.

The first scanner8A scans a first surface of the document M transported along the transport path12. The first scanner8A scans the first surface of the document M and generates first scanning data. The first scanner8A includes a first light source18A and a first image sensor19A. The first light source18A irradiates light onto the first surface of the document M. The first light source18A is disposed at a position facing the first surface of the document M. The first light source18A irradiates the light along the document width direction, which is orthogonal to the transport direction T of the document M.

The first image sensor19A receives the light reflected from the first surface of the document M. The first image sensor19A scans the first surface of the document M by receiving the light. The first image sensor19A is configured to extend in the document width direction. The first scanner8A irradiates the light to the first surface of the document M from the first light source18A, and receives the light reflected from the first surface of the document M by the first image sensor19A. The first image sensor19A scans the first surface of the document M by receiving the light at the first image sensor19A.

The second scanner8B scans a second surface of the document M transported along the transport path12. The second surface of the document M is a back surface of the first surface of the document M. The second scanner8B scans the second surface of the document M and generates second scanning data. The second scanner8B includes a second light source18B and a second image sensor19B. The second light source18B irradiates light onto the second surface of the document M. The second light source18B is disposed at position facing the second surface of the document M. The second light source18B irradiates the light along the document width direction, which is orthogonal to the transport direction T of the document M. The configuration of the second light source18B may be the same as or different from that of the first light source18A. The configuration of the second light source18B is desirably the same as that of the first light source18A.

The second image sensor19B receives the light reflected from the second surface of the document M. The second image sensor19B scans the second surface of the document M by receiving the light. The second image sensor19B is configured to extend in the document width direction. The configuration of the second image sensor19B may be the same as or different from the configuration of the first image sensor19A. The configuration of the second image sensor19B is desirably the same as that of the first image sensor19A. The second scanner8B irradiates the light onto the second surface of the document M from the second light source18B, and receives light reflected from the second surface of the document M by the second image sensor19B. The second image sensor19B scans the second surface of the document M by receiving the light at the second image sensor19B.

The ultrasonic sensor9detects overlapped feeding of the document M transported along the transport path12. In this embodiment, the ultrasonic sensor9is disposed between the second transport roller pair14and the third transport roller pair15. In other words, the ultrasonic sensor9is located upstream from the third transport roller pair15in the transport path12. The ultrasonic sensor9is located downstream from the second transport roller pair14in the transport path12. The ultrasonic sensor9is disposed along the transport path12. The ultrasonic sensor9is a part of the configuration of the transport device7. The ultrasonic sensor9includes a transmission unit21and a reception unit22. The transmission unit21and the reception unit22are located on opposite sides of the transport path12.

The transmission unit21transmits ultrasonic waves. The transmission unit21includes an ultrasonic transmitting element. The ultrasonic transmitting element generates ultrasonic waves. The ultrasonic waves generated by the ultrasonic transmitting element are transmitted from the transmission unit21toward the transport path12. When the ultrasonic waves are transmitted while the document M is being transported to a position facing the transmission unit21, the ultrasonic waves pass through the document M and are transmitted to the reception unit22. When the ultrasonic waves pass through the document M, the sound pressure of the ultrasonic waves attenuates.

The reception unit22receives the ultrasonic waves. The reception unit22includes an ultrasonic reception element. The ultrasonic reception element receives the ultrasonic waves. The ultrasonic waves transmitted from the transmission unit21toward the transport path12are received by the ultrasonic reception element of the reception unit22. The reception unit22receives the ultrasonic waves that are transmitted from the transmission unit21and that pass through the transport path12. If the ultrasonic waves are transmitted while the document M is being transported at the position facing the transmission unit21, the reception unit22receives the ultrasonic waves that passed through the document M. The reception unit22generates a reception signal corresponding to the sound pressure of the ultrasonic waves. The reception unit22sends the generated reception signal to the control unit11.

The transmission unit21and the reception unit22have the same configuration. The configurations of the transmission unit21and the reception unit22will be described later. The ultrasonic sensor9includes a transmission unit21and a reception unit22, but is not limited to this configuration. The transmission unit21may have the function of the reception unit22. The transmission unit21receives the ultrasonic waves reflected from the document M. The transmission unit21generates a reception signal corresponding to the sound pressure of the received ultrasonic waves. The transmission unit21sends the generated reception signal to the control unit11.

The control unit11is a controller that performs various kinds of control. The control unit11is, for example, a processor including a central processing unit (CPU). The control unit11may be composed of one or more processors. The control unit11may include a memory such as a random access memory (RAM) or a read only memory (ROM). The memory functions as a work area of the control unit11. The control unit11functions as various functional sections by executing a control program stored in a memory (not shown).

The control unit11controls the transport of the document M by the transport device7by controlling the drive of the transport motor17. The control unit11transports the document M along the transport path12by driving the transport motor17. The control unit11controls the timing of starting the document M transport, the speed of document M transport, the stopping of document M transport, and the like. The control unit11controls scanning of the document M by controlling the drive of the scanning unit8. The control unit11causes the scanning unit8to scan the document M by operating the scanning unit8. The control unit11controls scanning start timing, scanning stop timing, single-sided or double-sided scanning, and the like of the scanning unit8. The transport motor17generates the drive force for driving various drive rollers. The transport motor17transmits the generated drive force to various drive rollers via a drive transmission mechanism (not shown). The transport motor17rotationally drives the first drive roller13A, the second drive roller14A, the third drive roller15A, and the fourth drive roller16A.

The control unit11receives the reception signal output from the ultrasonic sensor9. The control unit11detects overlapped feeding of the document M based on the received reception signal. The control unit11stops the transport of the document M when overlapped feeding is detected. The control unit11causes to stop the document M transport by controlling the transport device7. Also, the control unit11controls the drive of the ultrasonic sensor9. The control unit11controls the drive of the ultrasonic transmitting element of the transmission unit21. The control unit11controls the drive of the ultrasonic reception element of the reception unit22. The ultrasonic sensor9and the control unit11are an example of an ultrasonic apparatus. The ultrasonic sensor9and the control unit11are an example of an overlapped feeding detection device.

Each of the transmission unit21and the reception unit22includes an ultrasonic element substrate31shown inFIG.3. The ultrasonic element substrate31is an example of an ultrasonic device. The ultrasonic element substrate31includes a plurality of ultrasonic elements32. The ultrasonic element32generates ultrasonic waves or receives ultrasonic waves according to the supplied drive signal. In the ultrasonic element substrate31of the transmission unit21, the ultrasonic element32is referred to as an ultrasonic transmitting element32A. In the ultrasonic element substrate31of the reception unit22, the ultrasonic element32is referred to as an ultrasonic reception element32B. The plurality of ultrasonic elements32are formed on a main surface33of the ultrasonic element substrate31. The main surface33is one of the two surfaces that have the largest area among the multiple surfaces that form the ultrasonic element substrate31.

In a plurality of drawings includingFIG.3, an X-axis, a Y-axis, and a Z-axis are marked. The Z-axis is along a direction perpendicular to the main surface33. The X-axis is an axis that is orthogonal to the Z-axis. The X-axis is an axis parallel to the longitudinal sides of the ultrasonic element substrate31. The Y-axis is an axis that is orthogonal to each of the Z-axis and the X-axis. The Y-axis is an axis parallel to the shorter sides of the ultrasonic element substrate31. Arrows are marked on the X-axis, the Y-axis, and the Z-axis, respectively. Directions indicated by the arrows are + directions. Directions opposite to the + directions are − directions. The +Z direction is a direction from the main surface33toward the back surface of the main surface33.FIG.3is a plan view of the ultrasonic element substrate31in the +Z direction.

In the ultrasonic element substrate31, the plurality of ultrasonic elements32constitute an element array35. The element array35is an array of a plurality of ultrasonic elements32. In the ultrasonic element substrate31, the plurality of ultrasonic elements32form a matrix with an array along the X-axis as rows and an array along the Y-axis as columns. As shown inFIG.4, which is a cross-sectional view cut along line A-A inFIG.3, the ultrasonic element substrate31includes a substrate main body section41, a vibrating plate42, and a piezoelectric element43. The substrate main body section41, the vibrating plate42, and the piezoelectric element43are disposed along the Z-axis. The vibrating plate42is disposed on the −Z direction side of the substrate main body section41. The piezoelectric element43is disposed on the −Z direction side of the vibrating plate42.

The substrate main body section41is made of a semiconductor substrate such as Si. A plurality of opening sections45are formed in the substrate main body section41. The opening sections45are surrounded by partition walls46. The plurality of opening sections45are formed along the X-axis and the Y-axis. The opening sections45pass through the substrate main body section41. The plurality of opening sections45are partitioned by the partition walls46. Since the vibrating plate42is provided to the −Z direction side of the substrate main body section41, an end portion of the −Z direction side of the opening sections45is closed by the vibrating plate42. The opening sections45open toward the +Z direction. In the ultrasonic element substrate31, the vibrating plate42is exposed through the opening sections45. The vibrating plate42is composed of a laminate of silicon oxide and zirconium oxide, or the like. The vibrating plate42is supported by the partition walls46of the substrate main body section41. The +Z direction side surface of the vibrating plate42comprises the vibration surface47.

One opening section45corresponds to one piezoelectric element43. An opening section45is formed for each of the piezoelectric elements43. The partition walls46are formed by forming the opening sections45in the substrate main body section41. In other words, the partition walls46are the remaining portions of the substrate main body section41where the opening sections45are formed. A portion of the vibrating plate42that overlaps one opening section45and the piezoelectric element43that overlaps one opening section45constitute one ultrasonic element32. In the transmission unit21, one ultrasonic element32corresponds to one ultrasonic transmitting element32A. In the transmission unit21, the vibrating plate42vibrates to transmit the ultrasonic waves from the vibration surface47. The ultrasonic transmitting element32A converts an electrical signal into ultrasonic waves. The ultrasonic reception element32B converts ultrasonic waves into an electrical signal. In the transmission unit21, the ultrasonic transmitting element32A converts the electrical signal into ultrasonic waves and transmits the ultrasonic waves. In the reception unit22, the ultrasonic reception element32B receive the ultrasonic waves and converts the ultrasonic waves into the electrical signal.

In the reception unit22, one ultrasonic element32corresponds to one ultrasonic reception element32B. In the reception unit22, the vibrating plate42vibrates by receiving the ultrasonic waves at the vibration surface47. An electric signal is output from the piezoelectric element43in response to the vibration of the vibrating plate42. When the vibrating plate42vibrates by receiving the ultrasonic wave, the piezoelectric element43converts the vibration into an electrical signal. The plurality of piezoelectric elements43are provided on the −Z direction side surface of the vibrating plate42. The piezoelectric element43is disposed at a position in the −Z direction side of the opening section45. The piezoelectric element43includes a first electrode49, a piezoelectric body51, and a second electrode53. The first electrode49is disposed on the −Z direction side surface of the vibrating plate42. The first electrode49, the piezoelectric body51, and the second electrode53are stacked in this order on the −Z direction side surface of the vibrating plate42. The piezoelectric body51is formed of, for example, a piezoelectric material such as lead zirconate titanate (PZT).

As shown inFIG.3, the first electrode49is an electrode commonly connected to the plurality of piezoelectric elements43in each row of the element array35. The second electrode53is a common electrode connected to the plurality of piezoelectric elements43. In the ultrasonic transmitting elements32A, the first electrode49sends an electrical signal to the piezoelectric bodies51of the plurality of piezoelectric elements43. The piezoelectric body51expands and contracts according to the electric signal. The piezoelectric body51expands and contracts when a pulse wave voltage of a predetermined frequency is applied between the first electrode49and the second electrode53. The expansion and contraction of the piezoelectric body51causes the vibration surface47shown inFIG.4to vibrate at a frequency corresponding to the opening width of the opening section45. By this, the ultrasonic transmitting element32A generates ultrasonic waves.

In the ultrasonic reception element32B, the first electrode49receives the electric signal from the piezoelectric bodies51of the plurality of piezoelectric elements43. In the ultrasonic reception element32B, when the vibration surface47shown inFIG.4receives an ultrasonic wave, the piezoelectric body51expands and contracts via the vibrating plate42. When the piezoelectric body51expands and contracts, the potential difference between the first electrode49and the second electrode53will change. The ultrasonic reception element32B outputs an electric signal corresponding to the change of the potential difference. The generated electric signal is output to the control unit11as a reception signal.

As shown inFIG.5, the image scanner1includes a transmission circuit56, a power supply circuit57, and a reception circuit58. The image scanner1may include an interface section for communicating with an external device such as a personal computer. The control unit11includes a calculation section61and a memory62. The calculation section61includes a transport control section63, a scanning control section64, a overlapped feeding detection section65, and a drive control section66. The memory62functions as a work area of the control unit11. The control unit11functions as various functional sections by executing a control program stored in the memory62.

The control unit11functions as each functional section of the transport control section63, the scanning control section64, the overlapped feeding detection section65, and the drive control section66by executing the control program stored in the memory62. The transport control section63controls the drive of the transport motor17. The transport control section63controls the transport device7by controlling the drive of the transport motor17. The scanning control section64controls the scanning unit8. The scanning control section64causes the scanning unit8to scan an image of the document M.

The transmission circuit56is electrically connected to the ultrasonic transmitting element32A of the transmission unit21. The transmission circuit56generates a drive signal to be applied to each of the ultrasonic transmitting elements32A based on a command from the control unit11. The power supply circuit57is electrically connected to the ultrasonic reception elements32B of the reception unit22. The power supply circuit57generates a DC voltage to be applied to the ultrasonic reception elements32B based on a command from the control unit11. The transmission circuit56and the power supply circuit57are each controlled by the drive control section66of the control unit11. The reception circuit58performs various kinds of processing on the reception signal output from the ultrasonic reception element32B of the reception unit22, and then outputs the reception signal to the control unit11.

The reception circuit58includes a bandpass filter67, an amplifier68, a sample and hold circuit69, and a comparator71. The reception signal output from the reception unit22is input to the bandpass filter67. Noise components and the like are removed from the reception signal by the bandpass filter67. The reception signal is amplified by the amplifier68so that the signal becomes equal to or greater than a predetermined signal intensity. Next, the reception signal is input to the sample and hold circuit69. The sample and hold circuit69samples the reception signal at a predetermined frequency. The sampled reception signal is input to the comparator71. The comparator71detects the reception signal having a signal intensity exceeding the predetermined determination intensity among the sampled reception signals. The comparator71sends the reception signal exceeding the determination intensity to the control unit11.

The overlapped feeding detection section65detects the overlapped feeding state of the sheets of the document M. The reception unit22receives the ultrasonic waves that are transmitted from the transmission unit21and that pass through the document M. The reception unit22outputs a reception signal corresponding to the received ultrasonic waves. The overlapped feeding detection section65determines the state of the document M based on the reception signal input from the reception unit22. If the voltage value of the reception signal is smaller than the determination value, the overlapped feeding detection section65determines that sheets of the document M are being fed in an overlapped state. When the overlapped feeding detection section65determines that the sheets of the document M are being fed in an overlapped state, the transport control section63stops transporting the document M.

The drive control section66instructs the transmission circuit56to generate a drive signal. Upon receiving the instruction to generate the drive signal, the transmission circuit56outputs a pulse wave voltage of a predetermined frequency as the drive signal to the transmission unit21. In this embodiment, the driving signal output to the transmission unit21is a burst waveform drive signal. Driving the ultrasonic transmitting element32A by the drive signal output from the transmission circuit56to the transmission unit21is referred to as transmission drive.

The drive control section66controls the power supply circuit57. The drive control section66controls a drive voltage to be applied to the ultrasonic reception element32B by controlling the power supply circuit57. The drive control section66applies a DC voltage to the ultrasonic reception elements32B or stops applying the DC voltage by controlling the power supply circuit57. The drive control section66changes the voltage value of the drive voltage applied to the ultrasonic reception element32B by controlling the power supply circuit57. Applying the drive voltage to the ultrasonic reception element32B by the drive control section66controlling the power supply circuit57is referred to as reception drive.

The transmission unit21, the reception unit22, the transmission circuit56, the power supply circuit57, the reception circuit58, and the drive control section66are a part of the configuration of the ultrasonic apparatus73. The drive control section66as a functional section is an example of a control section. The ultrasonic apparatus73includes the transmission unit21, the reception unit22, the transmission circuit56, the power supply circuit57, the reception circuit58, and the drive control section66. However, the components of the ultrasonic apparatus73are not limited to these, and may include other configurations. The transmission unit21, the reception unit22, the transmission circuit56, the power supply circuit57, the reception circuit58, the drive control section66, and the overlapped feeding detection section65are a part of the configuration of the overlapped feeding detection device. The overlapped feeding detection device includes the transmission unit21, the reception unit22, the transmission circuit56, the power supply circuit57, the reception circuit58, the drive control section66, and the overlapped feeding detection section65. However, the components of the overlapped feeding detection device are not limited to these, and may include other configurations.

As shown inFIG.6, each of the transmission unit21and the reception unit22includes a circuit substrate81and a shield82. The circuit substrate81has a first surface83and a second surface84. The shield82is disposed on the first surface83of the circuit substrate81. The second surface84is the opposite surface from the first surface83. The second surface84is a back surface of the first surface83. As shown inFIG.7, the ultrasonic element substrate31is mounted on the circuit substrate81. The circuit substrate81is a general term of a substrate on which the ultrasonic element substrate31is mounted. Thus, it can be said that the transmission unit21and the reception unit22have the same configuration. Therefore, each of the transmission unit21and the reception unit22can be collectively referred to as an ultrasonic unit85.

A plurality of wirings86are formed on the circuit substrate81. The ultrasonic element substrate31mounted on the circuit substrate81is electrically connected to some of the plurality of wirings86. The ultrasonic element substrate31of the transmission unit21is connected to the transmission circuit56shown inFIG.5via the wirings86of the circuit substrate81. The ultrasonic element substrate31of the reception unit22is connected to the power supply circuit57and the reception circuit58shown inFIG.5via the wirings86of the circuit substrate81. The plurality of wirings86include a ground electrode86A and a ground electrode86B. The ground electrodes86A and86B are connected to a metallic frame (not shown) of the image scanner1via the wirings86of the circuit substrate81. By this, the ground electrode86A and the ground electrode86B are maintained at the ground potential of the chassis ground.

The circuit substrate81of the transmission unit21and the circuit substrate81of the reception unit22may be the same substrate or different substrates. The transmission circuit56shown inFIG.5may be formed on the circuit substrate81of the transmission unit21. The power supply circuit57and the reception circuit58shown inFIG.5may be formed on the circuit substrate81of the reception unit22. Note that when the circuit substrate81of the transmission unit21and of the reception unit22are to be distinguished between each other, the circuit substrate81of the transmission unit21is referred to as a transmission circuit substrate81A, and the circuit substrate81of the reception unit22is referred to as a reception circuit substrate81B. The shield82is formed of a conductive material, and protects the ultrasonic element substrate31and the wirings86from electromagnetic noise. In this embodiment, the shield82is made of metal.

A first example of the shield82will be described. The first example of the shield82is referred to as a shield82A. The ultrasonic unit85having the shield82A is referred to as an ultrasonic unit85A. As shown inFIG.8, the shield82A has a main body section87, a first leg section88, and a second leg section89. The first leg section88and the second leg section89are examples of leg sections. Each of the first leg section88and the second leg section89extends from the main body section87. As shown inFIG.7, the main body section87is a portion that surrounds the ultrasonic element substrate31from the first surface83side of the circuit substrate81. The main body section87is disposed on the first surface83. Each of the first leg section88and the second leg section89extends from the main body section87toward the circuit substrate81. A first through hole91and a second through hole92are formed in the circuit substrate81. The first through hole91and the second through hole92are examples of through holes.

FIG.9is a cross-sectional view cut along line A-A inFIG.6. As shown inFIG.9, each of the first through hole91and the second through hole92penetrates between the first surface83and the second surface84of the circuit substrate81. When viewing the first surface83in plan view, the first through hole91and the second through hole92are located on opposite sides to each other with the ultrasonic element substrate31interposed therebetween. Viewing the first surface83in a plan view means looking at the circuit substrate81in a state of facing the first surface83. In other words, viewing the first surface83in plan view means looking at the circuit substrate81in a direction from the first surface83toward the second surface84.

The first leg section88protrudes from the second surface84through the first through hole91. The second leg section89protrudes from the second surface84through the second through hole92. When viewing the first surface83in plan view, the first leg section88and the second leg section89are located on opposite sides of the ultrasonic element substrate31from each other. A first claw93is provided at a portion of the first leg section88that protrudes from the second surface84of the circuit substrate81. A second claw94is provided at a portion of the second leg section89that protrudes from the second surface84of the circuit substrate81.

When viewing the second surface84in plan view, the first claw93protrudes to outside of the first through hole91. When viewing the second surface84in plan view, the second claw94protrudes further outside than is the second through hole92. The first claw93and the second claw94are examples of protruding sections. Viewing the second surface84in a plan view means looking the circuit substrate81in a state of facing the second surface84. In other words, viewing the second surface84in plan view means viewing the circuit substrate81in a direction from the second surface84toward the first surface83. The shield82A can be attached to the circuit substrate81by inserting the first leg section88into the first through hole91from the first surface83side and by inserting the second leg section89into the second through hole92from the first surface83side.

When viewing the second surface84in plan view, the first claw93of the shield82A protrudes to outside of the first through hole91and the second claw94protrudes to outside of the second through hole92. By this, the first claw93and the second claw94hook onto the second surface84. Therefore, it is easy to prevent the first leg section88from pulling out off from the first through hole91, and it is easy to prevent the second leg section89from pulling out from the second through hole92. As a result, the shield82A can be fixed to the circuit substrate81. According to this structure of the shield82A, the shield82A can be secured to the circuit substrate81by the first leg section88and second leg section89, which are located on opposite sides of the ultrasonic element substrate31from each other as viewed the first surface83in plan view. As a result, it is easy to stably fix the shield82A to the circuit substrate81.

Each of the first leg section88and the second leg section89has elasticity. The shield82A is attached to the circuit substrate81, in a state where the first leg section88and the second leg section89are bent inward, by inserting the first leg section88into the first through hole91and by inserting the second leg section89into the second through hole92. The term “inward” means that directions in which the first leg section88and the second leg section89face each other. If the first claw93and the second claw94protrude from the second surface84, a part of the deflection of each of the first leg section88and the second leg section89is released. Even when the first claw93and the second claw94protrude from the second surface84, deflection remains in the first leg section88and the second leg section89. Therefore, when the first claw93and the second claw94protrude from the second surface84, the first leg section88and the second leg section89bias the circuit substrate81outward. The term “outward” means directions opposite to directions in which the first leg section88and the second leg section89face each other.

As shown inFIG.10, the first claw93is formed by bending a portion of sheet metal of the first leg section88. The second claw94is formed by bending a portion of sheet metal of the second leg section89. The first claw93and the second claw94open outward from each other. In other words, the first claw93and the second claw94are bent outward from each other. However, it is also possible to adopt a configuration in which the first claw93and the second claw94are bent inward. Even in this configuration, the shield82A can be fixed to the circuit substrate81if the first claw93protrudes to the outside of the first through hole91and the second claw94protrudes to the outside of the second through hole92.

FIG.11is an enlarged view of a portion B inFIG.9. As shown inFIG.11, the ground electrode86A formed around the first through hole91on the first surface83extends to the second surface84through the first through hole91. A tip end portion of the first claw93contacts the ground electrode86A extending over the second surface84. Although not shown, the ground electrode86A formed around the second through hole92on the first surface83also extends to the second surface84through the second through hole92. A tip end portion of the second claw94contacts the ground electrode86A extending over the second surface84. Therefore, the shield82A is maintained at the ground potential. The shield82A can protect the ultrasonic element substrate31and the wirings86from electromagnetic noise.

As shown inFIG.7, the ground electrodes86B are provided on the first surface83of the circuit substrate81. In this embodiment, a plurality of ground electrodes86B are formed on the first surface83of the circuit substrate81. In this embodiment, four ground electrodes86B are formed on the first surface83. As shown inFIG.8, the shield82A has a plurality of contact sections96. Each of the plurality of contact sections96extends from the main body section87. In this embodiment, the shield82A has four contact sections96. As shown inFIG.7, each of the plurality of contact sections96extends from the main body section87toward the first surface83of the circuit substrate81.

The ground electrodes86B are formed at positions corresponding to the respective contact sections96. In other words, when viewing the first surface83of the circuit substrate81in plan view, the ground electrodes86B are located in regions overlapping the contact sections96. Each contact section96is in contact with the corresponding ground electrode86B. According to this configuration, the shield82A can be electrically connected to the ground electrode86B via the contact sections96. Further, by sandwiching the circuit substrate81between the plurality of the contact sections96and the first and second claws93and94, it is possible to strengthen the fixing force of the shield82A for the circuit substrate81.

A second example of the shield82will be described. The second example of the shield82is referred to as a shield82B. The ultrasonic unit85having the shield82B is referred to as an ultrasonic unit85B. As shown inFIG.12, an opening98is formed in the shield82B of the ultrasonic unit85B. The opening98is formed in the main body section87. The shield82B has the same configuration as the shield82A except that the opening98is formed in the main body section87. In the following description, the same configurations of the shield82B as those of the shield82A are denoted by the same reference numerals as those of the shield82A, and detailed description thereof will be omitted. As shown inFIG.13, when viewing the first surface83of the circuit substrate81in plan view, the opening98is formed in a region overlapping the ultrasonic element substrate31. Therefore, even when the opening98is formed in the main body section87, the shield82B surrounds the ultrasonic element substrate31. According to this configuration, it is possible for the ultrasonic waves to easily pass through the opening98.

A third example of the shield82will be described. The third example of the shield82is referred to as a shield82C. The ultrasonic unit85having the shield82C is referred to as an ultrasonic unit85C. As shown inFIG.14, in the shield82C, introduction portions101are formed in each of the first leg section88and the second leg section89. The shield82C has a configuration similar to that of the shield82A except that the shield82C has the introduction portions101. In the following description, the same configurations of the shield82C as those of the shield82A are denoted by the same reference numerals as those of the shield82A, and detailed description thereof will be omitted. The introduction portion101is formed at the distal portion of the first leg section88, which is at the opposite side from the main body section87side. The introduction portion101is formed at a distal portion of the second leg section89, which is at the opposite side from the main body section87side.

As shown inFIG.15, the introduction portion101of the first leg section88and the introduction portion101of the second leg section89are bent inward. From another viewpoint, the introduction portion101of the first leg section88and the introduction portion101of the second leg section89are inclined in directions that are line symmetrical to each other. The introduction portion101of the first leg section88and the introduction portion101of the second leg section89are bent in directions line symmetrical to each other. The introduction portion101of the first leg section88is formed by bending the distal end portion of the first leg section88, which is formed of a sheet metal. The introduction portion101of the second leg section89is formed by bending a distal end portion of the second leg section89, which is formed of a sheet metal. As shown inFIG.16, since the introduction portions101are formed in the shield82C, the first leg section88is easily introduced into the first through hole91, and the second leg section89is easily introduced into the second through hole92. Further, in the shield82C, as shown inFIG.14, the introduction portion101has a tip end section102. The tip end section102is formed at the distal end portion of the introduction portion101, which is at the opposite side from the main body section87side. The tip end section102has a width dimension H2that is smaller than the width dimension H1, which is the width dimension of the first leg section88and of the second leg section89on the main body section87side. In other words, in the shield82C, the distal end part of the first leg section88is formed thinner than the main body section87side of the first leg section88. Similarly, in the shield82C, the distal end part of the second leg section89is formed thinner than the main body section87side of the second leg section89. In the shield82C having the tip end section102, the first leg section88is more easily introduced into the first through hole91, and the second leg section89is more easily introduced into the second through hole92. Note that a configuration in which the opening98of the shield82B is applied to shield82C can also be employed.