JP2000051213A - Ultrasonic probe and ultrasonic diagnosing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of an electronic switch circuit in the connector of an ultrasonic probe by detecting the falling-off of the connector of the ultrasonic probe and the connector of an ultrasonic diagnosing device main body just before the falling-off and inhibiting a high voltage pulse. SOLUTION: The ultrasonic probe in the state of being freely attachable and detachable to/from the device main body is composed of a probe head 3 mounting plural oscillator 2, a probe connector 5 incorporating an electronic switch circuit 4 for switching electrical connection between the plural oscillators and the device main body and a cable 10 electrically connecting the plural oscillators 2 and the circuit 4. The connector 5 is provided with a power source pin 6 for fetching the driving power of the circuit 4, a signal pin 7 for fetching the driving signal of an oscillator, and short pins 8 and 9 for detecting the falling-off of a connector shorter than the pin 6 and the pin 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe and an ultrasonic diagnostic apparatus in which switching of a vibrator to be driven is realized by an electronic switch circuit built in a probe connector.

[0002]

2. Description of the Related Art There are various medical applications of ultrasonic waves, and the mainstream is an ultrasonic diagnostic apparatus for tomographic images of soft tissues of a living body using an ultrasonic pulse reflection method. This ultrasonic diagnostic apparatus displays a tomographic image of a tissue by a non-invasive examination method, and includes an X-ray diagnostic apparatus, an X-ray computed tomography apparatus (CT scan), and a magnetic resonance imaging apparatus (MRI).
Compared with other imaging devices such as nuclear medicine diagnostic devices, real-time display is possible, the device is small and inexpensive, there is no exposure to X-rays, etc., and the blood flow imaging is possible by ultrasonic Doppler method. It has unique features such as

[0003] For this reason, its utilization range is wide in heart, abdomen, mammary gland, urology, obstetrics and gynecology, and the like. In particular, heartbeats and fetal movements can be obtained on a real-time display with a simple operation simply by assigning an ultrasonic probe from the body surface, and it is highly safe, so repeated examinations can be performed and moving to the bedside The inspection is simple and easy.

[0004] In many of such ultrasonic diagnostic apparatuses, various types of probes can be replaced with the main body of the apparatus depending on the object to be diagnosed. For example, a probe for a body cavity formed in a rod shape so as to be easily inserted into a body cavity such as a transrectal or a vagina, a transesophageal probe observable on a biplane, and suitable for peeping a heart or the like from between ribs. Pencil-type heart probes, puncture probes with puncture needle guides, small children's probes, probes ideal for abdominal diagnosis that secure a wide field of view from shallow to deep, etc. It can be said that the specialization and diversification are more and more advanced.

In such a tendency, for example, in a linear electronic scanning type ultrasonic probe, as shown in FIG. 8, an electronic switch circuit 52 is provided in a probe connector 51, and connector pins, especially transmission pulses ( A device has been introduced in which the required number of signal pins 53 for taking in high-voltage pulses from the device main body 59 and transferring the echo signal to the device main body 59 is reduced as much as possible. As is well known, for example, the linear electronic scanning is performed by driving, for example, ten vibrators among the vibrators 55 arranged in a line in the probe head 54 at a time, and transmitting the ten vibrators every transmission and reception. Electronic switching is sequentially performed, and an electronic switch circuit 52 is in charge of electronically switching the vibrator. The electronic switch circuit 52 includes a C-MOS
The transistor is configured as a switch element, and this power supply voltage is supplied to the device main body 59 via a pin (power supply pin) 6.
Received from.

In the type in which the electronic switch circuit 52 is provided in the probe connector 51, means for detecting whether or not the power supply voltage is normally applied to the electronic switch circuit 52 by the apparatus body is indispensable. . This is the destruction of the electronic switch circuit 52, many of which are C-MO
This is to prevent the destruction of the S transistor.

Specifically, the power supply pins 56 fall off or break,
Further, when the power supply voltage is not normally applied to the electronic switch circuit 52 due to various causes such as a contact failure or the like, the C-MOS transistor does not normally function normally. For example, a situation may occur in which a C-MOS transistor to be turned on is actually in an off state. In such a situation, when a very high voltage pulse of several tens times the power supply voltage is applied to the C-MOS transistor, the C-MOS transistor is instantaneously destroyed. In order to prevent this, the apparatus main body detects whether or not the power supply voltage is normally applied to the electronic switch circuit 52.
When the power supply voltage is not normally applied, the application of the high voltage pulse is inhibited (inhibited).

The most general structure of this detecting means is to multiply the voltage of the power supply pin 56 in the probe connector 51 by a logical product circuit 57 and, when both voltages are normal, the logical product circuit 57 Device body 5 through 58
9, the power supply presence / absence signal is supplied at the “H” level.
When at least one of the two voltages is abnormal, that is, when the voltage has not reached the predetermined level, the power supply presence / absence signal switches to the “L” level. On the other hand, in the device main body 59, according to the signal level of the power supply presence / absence signal, the transmission pulse control unit outputs an enable signal (permission signal) to the pulser at the "H" level, and conversely, the transmission pulse control unit at the "L" level. Outputs an inhibit signal (prohibition signal) to the pulser to prohibit the output of the high-voltage pulse.

However, such a detecting means may have the following problems. As shown in FIG. 9, it takes a very short time from when the power supply pin is pulled out of the pinhole of the connector on the apparatus body side to when the pulsar enters the inhibit state and the high-voltage pulse is actually stopped. There is a time lag Δt1, during which application of the high voltage pulse is continued. If the signal pins are connected at this time, the C-MOS transistor will probably be destroyed.

[0010] Such a situation, that is, a situation where the power supply pin is disconnected but the signal pin is not disconnected is not considered to actually occur so frequently, but usually the detection pin 58 is not provided. Since the probe connector is provided at the end of the pin array, it may occur in a situation where the probe connector is obliquely detached or dropped obliquely from the connector on the device main body side, and the power supply pin comes out before the signal pin.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to detect a disconnection between a connector of an ultrasonic probe and a connector of a main body of an ultrasonic diagnostic apparatus immediately before that, and apply an inhibit to a high voltage pulse to thereby realize an ultra-high voltage pulse. An object of the present invention is to prevent destruction of an electronic switch circuit in a connector of a sound wave probe.

[0012]

According to the present invention, a probe connector detects a connector drop more than a power supply pin for taking in drive power of an electronic switch circuit incorporated therein and a signal pin for taking in a drive signal of a vibrator. Short pin is configured to be short. When the probe connector falls off from the connector on the apparatus main body side, the short pins for detecting connector disconnection always come off before the power supply pins and the signal pins. Therefore, the generation of the high voltage pulse can be inhibited (prohibited) before the power supply pin and the signal pin are actually disconnected, so that the power supply pin is disconnected but the signal pin is not disconnected, and the high voltage pulse is generated. A situation in which a pulse is applied and the electronic switch circuit is destroyed can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a connection portion between a connector of an ultrasonic probe and a connector of an apparatus main body, which is a main portion of the present embodiment.
The ultrasonic probe 1 includes a probe head 3 provided with a plurality of transducers 2 and an electronic switch circuit 4 for switching electrical connection between the plurality of transducers 2 and the connector 11 of the apparatus main body. A probe connector 5 and a cable 10 for electrically connecting the plurality of transducers 2 and the electronic switch circuit 4 are provided, and are detachably attached to the ultrasonic diagnostic apparatus main body and the connector 5.
For example, in the case of linear electronic scanning, for example, ten vibrators in the vibrators 2 of the probe head 3 are collectively driven, and these ten vibrators are electronically switched for each transmission and reception. The electronic switching circuit 4 is responsible for electronically switching the vibrator.

The probe connector 5 has a power supply pin (first contact) 6 for taking in the drive power of the electronic switch circuit 4 and a signal pin (second contact) 7 for taking in the drive signal of the vibrator (not shown). Electronic switch circuit 4
And pins necessary for a clock signal, a control signal, and the like are arranged in one or more rows, and short pins (third contacts) 8, 3 9 are arranged separately. The pair of short pins 8 and 9 are electrically connected inside the connector 5.

The power pins 6, the signal pins 7, and other pins are formed with a fixed length. On the other hand, short pins 8, 9
Are shorter than the power supply pins 6, the signal pins 7, and the other pins, and are formed to be half the length of the pins 6 and 7 or shorter than half the length of the pins 6 and 7. Accordingly, when the probe connector 1 falls off from the connector 11 on the apparatus main body side due to an unexpected situation during the scanning operation, at least one of the short pins 8 and 9 for detecting the connector falling off is connected to the power supply pin 6 and the signal pin 7. Before the power pin 6 and the signal pin 7 are actually released, the generation of the high-voltage pulse from the pulser can be inhibited (prohibited), so that the power pin 6 is disconnected. In a state where the signal pin 7 is not disconnected, it is possible to prevent a situation in which the high voltage pulse is applied and the electronic switch circuit 4 is destroyed. Details of this operation will be described later.

The connector pinholes 16 on the device body side
17, 18, and 19 respectively have pins 6 and 6 on the probe side.
7, 8, 9 are respectively inserted so as to make contact with each other. A pinhole 16 corresponding to the power supply pin 6 is connected to a power supply output terminal for the electronic switch circuit 4. Pinhole 17 corresponding to signal pin 7
Is connected to an output terminal of a pulser that generates a high-voltage pulse (transmission pulse) and an input terminal of a preamplifier in a receiving circuit.

A pinhole 18 corresponding to one short pin 8
Is connected to a power supply for detecting connector disconnection which generates a power supply voltage of Vcc in the apparatus main body. A pinhole 19 corresponding to the other short pin 9 is grounded (GND) in the apparatus main body. Accordingly, if the short pins 8 and 9 are not removed from the respective pin holes 18 and 19 and the contact is normal, the potential of the pin hole 18 drops, and either or both of the short pins 8 and 9 are not generated. If the contact is not normal due to disconnection from the respective pinholes 18 and 19, the potential of the pinhole 18 does not drop.
The discrimination between the two can be realized, for example, by comparing the potential of the pinhole 18 with the reference voltage Vref set to approximately 略 of the power supply voltage Vcc by the comparator 20. The output level of the comparator 20 is, for example, the short pins 8, 9
Is maintained at the "L (low)" level when the contact is normal without disconnecting from the respective pinholes 18 and 19, while both or one of the short pins 8, 9 is in the respective pinholes 18 and 19. , 19, the contact is not normal and changes to the "H (high)" level.

When the output level of the comparator 20 is L, the transmission pulse control section sends an enable signal (permission signal) to the pulser.
To allow generation of a high-frequency high-voltage pulse for driving the vibrator. On the other hand, when the output level of the comparator 20 changes from L to H, the transmission pulse control unit outputs an inhibit signal (prohibition signal) to the pulser to generate a high-frequency high-voltage pulse for driving the vibrator. Ban.

FIG. 2 shows the movement of the inhibit when the probe connector 1 drops off from the connector 11 of the apparatus main body due to an unexpected situation during the scanning operation according to the present embodiment. In a situation in which the probe connector 5 is coming off from the connector 11 on the apparatus main body side, the short pins 8 and 9 are shorter than the power supply pin 6, and therefore both or one of the short pins 8 and 9 is connected to the power supply pin 6. Also exits first. In other words, there is a time lag Δt2 from when one or both of the short pins 8 and 9 are disconnected to when the power pin 6 is disconnected.

When one or both of the short pins 8 and 9 are removed, the potential of the pinhole 18 on the apparatus main body side drops. As a result, the output level of the comparator 20 changes from L to H. In response to this change, an inhibit signal is output from the transmission pulse control unit to the pulser, and the generation of a high-frequency high-voltage pulse for driving the vibrator is prohibited.

Here, the time lag from when one or both of the short pins 8 and 9 are actually pulled out until the pulser enters the inhibit state is Δt1. When the electronic switch circuit 4 is broken, the power supply pin 6 is disconnected, but the signal pin 7 is disconnected.
This is caused by the application of a high-voltage pulse in a situation where the electronic switch circuit 4 has not been disconnected. Therefore, if the pulsar is inhibited before the power supply pin 6 is disconnected, the electronic switch circuit 4 can be prevented from being destroyed. That is, the electronic switch circuit 4
Can be achieved under the condition of Δt1 <Δt2. Conversely, if the power supply pin 6 is disconnected before the inhibit is applied to the pulsar, the electronic switch circuit 4
Could be destroyed. In order to reduce such a situation as much as possible, the time lag Δt1 from when one or both of the short pins 8 and 9 are actually removed to when the pulser enters the inhibit state is basically fixed. The time lag Δt2 from when one or both of the pins 8 and 9 are removed to when the power supply pin 6 is removed is made as long as possible, but on the other hand, the removal of both or one of the short pins 8 and 9 is too sensitive. Considering these conflicting specifications, according to the test of the inventor, as described above, the short pins 8 and 9 are connected to the power supply pin 6, the signal pin 7, and a half of the length of the other pins. Thus, in most cases, the condition of Δt1 <Δt2 is achieved, and the destruction of the electronic switch circuit 4 can be prevented.

In the above description, the potential change of the pinhole 18 on the power supply side corresponding to the short pin 8 is detected by the comparator 20 to detect the omission of one or both of the short pins 8 and 9. As shown in FIG. 3, the potential change of the pinhole 19 on the ground side corresponding to the short pin 9 is captured by the comparator 20, and both or one of the short pins 8 and 9 is omitted. You may make it detect.

The present embodiment can also be extended to a connector of a type in which the pins 28 are arranged in a two-dimensional rectangular (or circular) shape as shown in FIG. In such a type, in most cases where the probe connector 22 falls off from the connector 21 on the apparatus main body side, the probe connector 22 starts from one of the four corners. Short pins 23, 24, 25, 26 are arranged. If any one of the four short pins 23, 24, 25, 26 comes out of the pinholes 33, 34, 35, 36, the four short pins 23, 24, 25, 26 can be detected. , 26, three short pins 23, 24, 25 have pin holes 33,
The short pins 23, 24, 25 are individually connected to the power supply Vcc via 34, 35, and connected to the remaining short pins 26 via an AND circuit 27 inside the connector 22. Then, a change in the potential of the pinhole 36 corresponding to the short pin 26 is captured by the comparator 20. With this configuration, even if the probe connector 22 starts dropping from any of the four corners from the connector 21 on the apparatus main body side, it can be detected quickly.

This embodiment can also be applied to a lever lock type connector as shown in FIGS. When the probe connector (plug) 63 is inserted into the connector (receptacle) 62 on the device main body side, the contact 65 of the probe connector 63 is inserted into the contact hole 64 of the connector 62 on the device main body side.
Is inserted into the actuator hole 68 of the connector 62 on the apparatus main body side. In this state (FIG. 6B), the contacts 65 of the probe connector 63 are not electrically coupled to the contacts 67 in the contact holes 64 of the connector 62 on the apparatus main body side. Next, the actuator 66 is moved by half-turning the lever 61, whereby the probe connector 6 is moved.
The third contact 65 is pushed down, and is finally electrically connected to the contact 67 in the contact hole 64 of the connector 62 on the apparatus main body side.

The probe connector 63 includes a power contact for taking in drive power of an electronic switch circuit in the probe connector 63, a contact for controlling an electronic switch circuit, a signal contact for taking in a drive signal of an oscillator, and the like. A contact for drop-out detection is provided. Accordingly, the connector 62 on the apparatus main body side is also provided with a contact for detecting connector detachment in addition to the power supply contact and the like.

FIG. 7A shows a contact 71 for detecting a connector dropout of the probe connector 63 and a corresponding contact 81 of the connector 62 on the apparatus main body side.
FIG. 7B shows a power supply contact 72 of the probe connector 63 and a corresponding connector 62 on the apparatus main body side.
Are shown. The contact for controlling the electronic switch circuit, the signal contact for taking in the drive signal of the vibrator, etc.
2 and the contact 82.

The connector 6 on the apparatus main body side corresponding to the contact 71 for detecting connector detachment of the probe connector 63.
The tip of the second contact 81 is bent. On the other hand, the contacts 82 of the connector 62 on the apparatus main body corresponding to the power contacts 72 of the probe connector 63 are not bent but formed straight. Due to such a structural difference, the contact 7
When the probe connector 63 drops off from the connector 62 on the apparatus main body side due to an unexpected situation from a state where the contacts 71 and 72 are electrically connected to the contacts 81 and 82, respectively, the contact 71 for detecting connector dropout and the apparatus The electrical connection with the main body side contact 81
2 is cut earlier than the electrical connection between the contact 2 and the contact 82 on the apparatus main body side.

With this configuration, even if the probe connector 63 falls off from the connector 62 on the apparatus main body side, it is detected as soon as possible, and the high voltage for driving the vibrator is detected before the drive power of the electronic switch circuit is cut off. The pulse can be inhibited, thereby preventing the electronic switch circuit in the connector of the ultrasonic probe from being destroyed. It is needless to say that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

[0029]

According to the present invention, the probe connector comprises:
Since the short pin for detecting the connector dropout is shorter than the power supply pin for capturing the driving power of the electronic switch circuit incorporated therein and the signal pin for capturing the driving signal of the vibrator,
When the probe connector falls off from the connector on the apparatus main body side, the short pins for detecting connector disconnection always come off before the power supply pins and the signal pins. Therefore, the generation of the high voltage pulse can be inhibited (prohibited) before the power supply pin and the signal pin are actually disconnected, so that the power supply pin is disconnected but the signal pin is not disconnected, and the high voltage pulse is generated. A situation in which a pulse is applied and the electronic switch circuit is destroyed can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a connector portion between an ultrasonic diagnostic apparatus main body and a probe section according to an embodiment of the present invention.

FIG. 2 is a timing chart of an inhibit operation at the time of disconnection of a connector according to the configuration of FIG. 1;

FIG. 3 is a configuration diagram of a connector part between an ultrasonic diagnostic apparatus main body and a probe unit according to a first modified example.

FIG. 4 is a configuration diagram of a connector part between an ultrasonic diagnostic apparatus main body and a probe unit according to a second modified example.

FIG. 5 is an external view of a connector on the ultrasonic diagnostic apparatus main body side according to a third modified example.

FIG. 6 is an exemplary sectional view showing a procedure of electrical connection between the probe connector of FIG. 5 and a connector on the ultrasonic diagnostic apparatus main body side;

FIG. 7 is a diagram illustrating a comparison between a contact for detecting connector detachment and a power supply contact according to a third modified example.

FIG. 8 is a configuration diagram of a connector part between a conventional ultrasonic diagnostic apparatus main body and a probe part.

FIG. 9 is a timing chart of an inhibit operation at the time of disconnection of the connector according to the configuration of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Probe, 2 ... Vibrator, 3 ... Probe head, 4 ... Electronic switch circuit, 5 ... Probe connector (plug), 6 ... Power supply pin, 7 ... Signal pin, 8 ... Short pin for detecting connector detachment, 9 ... Short pin for detecting connector detachment, 10: Cable, 11: Connector (receptacle) on the device body side, 16: Power pin hole, 17: Signal pin hole, 18: Short pin hole, 19: Short pin hole, 20: Comparator .

Claims (12)

[Claims] 1. An ultrasonic probe detachably mounted on an ultrasonic diagnostic apparatus main body, comprising: a probe head provided with a plurality of transducers; and a plurality of transducers and the ultrasonic diagnostic apparatus main body. A probe connector having a built-in electronic switch circuit for switching electrical connection; and a cable for electrically connecting the plurality of vibrators and the electronic switch circuit. A power supply pin for capturing drive power of an electronic switch circuit, a signal pin for capturing a drive signal of the vibrator, and a short pin for detecting connector disconnection shorter than the power supply pin and the signal pin are provided. Ultrasonic probe. 2. The ultrasonic probe according to claim 1, wherein the short pins are provided in pairs, and the short pins of the pair are electrically connected in the probe connector. 3. The method according to claim 1, wherein a plurality of the short pins are provided, and one of the plurality of short pins is electrically connected to a remaining short pin via an AND circuit in the probe connector. The ultrasonic probe according to claim 1, wherein: 4. An ultrasonic probe configured to be detachable from an ultrasonic diagnostic apparatus main body, comprising: a probe head provided with a plurality of transducers; and a plurality of transducers and the ultrasonic diagnostic apparatus main body. A probe connector having a built-in electronic switch circuit for switching electrical connection; and a cable for electrically connecting the plurality of vibrators and the electronic switch circuit. A first contact for capturing drive power of an electronic switch circuit, a second contact for capturing drive signal of the vibrator, and the first contact and the second contact before the ultrasonic diagnostic apparatus main body side. An ultrasonic probe provided with a third contact for detecting disconnection of a connector, which is configured to disconnect the electrical connection. Over drive. 5. The third contact is provided as a pair,
The ultrasonic probe according to claim 4, wherein the third contacts of the pair are electrically connected within the probe connector. 6. A plurality of the third contacts are provided, and one of the plurality of third contacts is electrically connected to a remaining third contact via an AND circuit in the probe connector. The ultrasonic probe according to claim 4, wherein: 7. An ultrasonic diagnostic apparatus comprising an ultrasonic diagnostic apparatus main body and an ultrasonic probe detachably mounted on the ultrasonic diagnostic apparatus main body, wherein the ultrasonic probe is equipped with a plurality of transducers. Probe head, a probe connector having a built-in electronic switch circuit for switching electrical connection between the plurality of transducers and the ultrasonic diagnostic apparatus main body, and the plurality of transducers and the electronic switch. A cable for electrically connecting a circuit, and the probe connector has a power pin for capturing driving power of the electronic switch circuit, a signal pin for capturing driving signal of the vibrator, the power pin and the power pin. A short pin for detecting connector disconnection that is shorter than the signal pin; and the ultrasonic diagnostic apparatus main body is provided with a short pin due to a voltage change of the short pin. An ultrasonic diagnostic apparatus, further comprising a detecting means for detecting a drop of the probe connector. 8. The short pins of the pair are provided in pairs, and the short pins of the pair are electrically connected in the probe connector, and the detecting means of the ultrasonic diagnostic apparatus main body includes the short pins of the pair. 8. The ultrasonic diagnostic apparatus according to claim 7, further comprising: means for applying a voltage to one of the pair, and means for comparing the other voltage of the short pins of the pair with a reference voltage. 9. A plurality of short pins are provided, and one of the plurality of short pins is electrically connected to a remaining short pin via an AND circuit in the probe connector, 8. The ultrasonic diagnostic apparatus body according to claim 7, wherein the detecting means includes means for applying a voltage to each of the remaining short pins, and means for inputting an output of the AND circuit. An ultrasonic diagnostic apparatus as described in the above. 10. An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic apparatus main body; and an ultrasonic probe detachably mounted on the ultrasonic diagnostic apparatus main body, wherein the ultrasonic probe is provided with a plurality of transducers. Probe head, a probe connector having a built-in electronic switch circuit for switching electrical connection between the plurality of transducers and the ultrasonic diagnostic apparatus main body, and the plurality of transducers and the electronic switch. A cable for electrically connecting a circuit, a first contact for capturing drive power of the electronic switch circuit, a second contact for capturing drive signal of the vibrator, A connector configured to disconnect the electrical connection with the ultrasonic diagnostic apparatus main body before the first contact and the second contact. A third contact for detecting dropout of the probe connector; and a means for detecting dropping of the probe connector by a voltage change of the short pin in the ultrasonic diagnostic apparatus main body. Diagnostic device. 11. The third contact is provided in a pair, the third contact of the pair is electrically connected in the probe connector, and the detecting means of the ultrasonic diagnostic apparatus main body includes the third contact of the pair. Means for applying a voltage to one of the third contacts;
Means for comparing the other voltage of the third contact of the pair with a reference voltage.
0. The ultrasonic diagnostic apparatus according to item 0. 12. A plurality of third contacts are provided,
One of the plurality of third contacts has a remaining third contact.
Means for applying a voltage to each of the remaining third contacts to the detection means of the ultrasonic diagnostic apparatus main body, wherein the contacts are electrically connected via a logical product circuit in the probe connector; 11. An ultrasonic diagnostic apparatus according to claim 10, further comprising means for inputting an output of said AND circuit.