JP2008161427A - Electronic endoscope and electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress voltage drop of a power source line by allowing overcurrent to be detected without providing a resistance for overcurrent detection. <P>SOLUTION: The electronic endoscope is provided with: an imaging device; a power source part for supplying the imaging device with power; a power source line for connecting the power source part and the imaging device; a noise removing part for removing noises in the power source line; a voltage drop measuring means for measuring voltage drop by the noise removing part; and a power source supply control means for controlling power source supply for the imaging device by the power source part in accordance with the measurement result by the voltage drop measuring means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic endoscope provided with an image sensor. The present invention also relates to an electronic endoscope system including such an electronic endoscope and a signal processing device that is connected to the electronic endoscope and that processes an image picked up by an image pickup device so that the image can be displayed on a monitor.

  2. Description of the Related Art An electronic endoscope system including an electronic endoscope having an image pickup device at a distal end portion and a processor that processes a signal acquired by the image pickup device and outputs the processed signal to a monitor is widely known and put into practical use. .

  The tip portion of such an electronic endoscope is designed in consideration of the burden on the patient, and has a structure that is reduced in size and diameter. For example, a drive circuit for driving the imaging device is mounted not on the distal end portion but on the proximal end portion of the electronic endoscope in order to reduce the size and diameter of the distal end portion. The drive circuit and the image sensor are connected by a signal cable wired inside the flexible tube of the electronic endoscope. The signal cable and the image sensor (and the drive circuit) are connected by, for example, solder.

  Here, for example, when the flexible tube is bent by a user operation, the signal cable inside thereof is bent accordingly. When such an operation is repeated, stress repeatedly acts on the soldered connection between the image sensor and the signal cable. When such repeated stress is excessively applied, there is a concern about disconnection of the signal cable at the connection portion. Further, when an impact is applied to the flexible tube from the outside, the signal cable may collide with or rub against other parts. Furthermore, every time the signal cable is subjected to such a collision or rubbing, it is considered that the covering portion gradually wears and the inside (that is, the electric wire) is exposed.

  The disconnection of the signal cable and the exposure inside the signal cable can short-circuit a circuit in the electronic endoscope system including the image sensor and the drive circuit. When such a short circuit occurs, for example, an overcurrent may flow through the imaging element or the like, causing abnormal heating.

As a configuration for preventing an overcurrent due to a short circuit as described above, for example, Patent Document 1 below discloses a power supply device in which a power cutoff circuit is mounted around a power supply circuit. According to the power supply device described in Patent Document 1 below, when an overcurrent flows through a power supply line of a circuit in the device, a fuse installed on the input side of the power supply circuit, or an overcurrent installed on the output side thereof The detection circuit is activated and the current is cut off. In an electronic endoscope system, it is conceivable to employ such a power shut-off circuit so as to prevent an overcurrent caused by a short circuit as described above.
JP 2005-38281 A

  In the overcurrent detection circuit of Patent Document 1, overcurrent is detected by monitoring a potential difference between both ends of a resistor provided in the circuit. Here, this resistor (hereinafter referred to as “overcurrent detection resistor”) is an element that does not contribute to signal shaping or the like and is not required unless an overcurrent is assumed. This means that the power supply device exhibits its original function even without an overcurrent detection resistor. It can be said that the power supply device described in Patent Document 1 is not desirable because there is a voltage drop in the power supply line due to an overcurrent detection resistor that may be unnecessary in this way.

  In view of the above circumstances, the present invention provides an electronic endoscope and an electronic endoscope that can detect an overcurrent without providing an overcurrent detection resistor and suppress a voltage drop in a power supply line. The problem is to provide a mirror system.

  According to an aspect of the present invention for solving the above problems, an electronic endoscope including an imaging device includes a power supply unit that supplies power to the imaging device, a power supply line that connects the power supply unit and the imaging device, and a power supply A noise removing unit for removing noise in the line, a voltage drop measuring unit for measuring a voltage drop by the noise removing unit, and controlling power supply to the image sensor by the power source unit according to a measurement result by the voltage drop measuring unit. And a power supply control means.

  In this way, by configuring the electronic endoscope so as to control the power supply by measuring the voltage drop of the noise removing unit originally provided in the electronic endoscope for the purpose of removing noise in the power line. The overcurrent can be detected and dealt with without providing an overcurrent detection resistor as an additional element. Since there is no voltage drop due to the overcurrent detection resistor, the voltage drop of the power supply line can be suppressed.

  The noise removing unit may be a ferrite bead for removing unnecessary radiation noise from a power line, for example. Further, for example, a noise removal filter that removes noise flowing through the power supply line may be used.

  The power supply control means continues to supply power when the voltage drop value measured by the voltage drop measuring means falls below a predetermined value, for example, and the measured voltage drop value is the predetermined voltage drop value. If the value is greater than or equal to the value, the power supply may be cut off.

  The electronic endoscope includes, for example, a drive control unit that outputs a drive control signal for driving and controlling the image pickup device based on a signal input from an external device, and the power supply control unit. Drive control stop means for stopping output of the drive control signal from the drive control unit when supply is interrupted may be further provided.

  Further, an electronic endoscope system according to another aspect of the present invention that solves the above-described problems is capable of monitoring and displaying the electronic endoscope and an image captured by an imaging device connected to the electronic endoscope. And a signal processing device for processing. In this electronic endoscope system, when the power supply is cut off by the power supply control means, the drive control stop means outputs a notification signal for notifying the interruption of the power supply to the signal processing device. Then, in response to the received notification signal, the signal processing device displays a predetermined character superimposed on the video on the monitor.

  According to the electronic endoscope and the electronic endoscope system according to the present invention, for the purpose of removing noise in the power supply line, the voltage drop of the noise removing unit originally provided in the electronic endoscope is measured to supply power. Therefore, overcurrent can be detected and dealt with without providing an overcurrent detection resistor as an additional element. As a result, the voltage drop of the power supply line can be suppressed, and for example, power saving of the electronic endoscope is realized. Further, since the number of parts is reduced, it is possible to reduce the cost and size of the electronic endoscope.

  Hereinafter, the configuration and operation of an electronic endoscope system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically showing the appearance of an electronic endoscope system 10 according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of the electronic endoscope system 10 according to the embodiment of the present invention. The electronic endoscope system 10 according to the present embodiment is a system for observing and diagnosing the inside of a body cavity of a patient, and includes an electronic endoscope 100, a processor 200, and a monitor 300.

  A connector unit 110 is provided at the proximal end portion of the electronic endoscope 100 of the present embodiment. The connector unit 110 is provided with two plugs p1 and p2. Further, a processor side connector section 210 is provided on the front surface of the processor 200. The processor-side connector section 210 is provided with two jacks j1 and j2. By connecting the pin plug p1 and the jack j1, the electronic endoscope 100 and the processor 200 are optically connected. Moreover, the electronic endoscope 100 and the processor 200 are electrically connected by connecting the pin plug p2 and the jack j2.

  One end of a universal cord 120 is coupled to the connector unit 110. The universal cord 120 has flexibility, and the other end is coupled to the operation unit 130. That is, the connector unit 110 and the operation unit 130 are configured to be connected via the universal cord 120.

  The operation unit 130 is an input interface for causing the operator to operate the electronic endoscope 100. By operating the operation button of the operation unit 130, for example, air can be supplied into the body cavity or the cleaning liquid can be ejected. One end of the insertion portion flexible tube 140 is coupled to the operation portion 130.

  The insertion portion flexible tube 140 is a tube that is inserted into a body cavity of a patient and has flexibility. A distal end portion 150 is provided at the distal end of the insertion portion flexible tube 140. When the surgeon operates the angle knob of the operation portion 130, the insertion portion flexible tube 140 near the base of the distal end portion 150 is bent according to the operation. Thereby, the angle of the front-end | tip part 150 changes. Due to this change in angle, the direction in which the front surface of the distal end portion 150 faces directly also changes, and accordingly, the observation region visible to the operator also changes.

  The tip portion 150 is made of a hard material (for example, resin). The tip portion 150 is provided with each element required for the imaging process. The elements in this embodiment are a light distribution lens 152, an objective lens 154, and a CCD (Charge Coupled Device) 156. The light distribution lens 152 and the objective lens 154 are lenses installed on the front surface of the distal end portion 150. The CCD 156 is, for example, a Bayer type color CCD. A large number of pixels (light receiving elements) are arranged in a matrix on the light receiving surface. An on-chip color filter is mounted on the front surface of the light receiving surface. The color filter is a filter in which any one of R (Red), G (Green), and B (Blue) color chips is arranged in a matrix corresponding to each pixel. Note that the CCD 156 used here is not limited to the one equipped with the primary color filter, and may be one equipped with a complementary color filter, for example.

  Inside the electronic endoscope 100, a light guide 160 is installed along its longitudinal direction. The light guide 160 is an optical fiber bundle. One end of the light guide 160 is connected to a pin plug of the connector unit 110. The other end is disposed in the vicinity of the light distribution lens 152.

  A circuit board is provided inside the connector unit 110. On this circuit board, a DSP (Digital Signal Processor) board 170 for controlling the driving of the CCD 156 and processing for a CCD output signal (described later) is mounted.

  The processor 200 is provided with a power supply circuit 270 for converting commercial power into DC power. When a power switch (not shown) is turned on while the processor 200 is connected to a commercial power supply, the DC power converted by the power supply circuit 270 is supplied to each component of the processor 200 and the processor 200 can operate. It becomes. For simplification of the drawing, the connection between the power supply circuit 270 and each component is omitted in FIG.

  The processor 200 includes a system control unit 220 that performs overall control of the entire apparatus. Under the control of the system control unit 220, processing in each component is executed. The processor 200 includes a lamp 230, a lamp control circuit 232, and a condenser lens 234 as a light source device.

  The lamp 230 is a white light source for irradiating the body cavity. As the lamp 230, for example, a metal halide lamp, a xenon lamp, a halogen lamp, or the like is assumed. The lamp 230 emits white light under the control of the lamp control circuit 232. The emitted light from the lamp 230 is collected by a condenser lens 234 installed in front of the lamp 230. The condensed light is incident on the inside of the electronic endoscope 100 (more precisely, the core of the optical fiber bundle forming the light guide 160) via the processor-side connector unit 210.

  The light incident on the light guide 160 is transmitted through the light guide 160 and is emitted from the end on the distal end 150 side. The emitted light is emitted to the outside through the light distribution lens 152 to illuminate the body cavity of the patient. This brightly illuminates the inside of the body cavity where light does not reach from the outside.

  The illumination light emitted from the light distribution lens 152 is reflected by a wall portion or the like in the body cavity and enters the objective lens 154. Here, the CCD 156 is arranged such that its light receiving surface is substantially at the same position as the image forming surface of the objective lens 154. Therefore, the light incident on the objective lens 154 is formed as an optical image in the body cavity on the light receiving surface of the CCD 156 by the power of the objective lens 154.

  Here, FIG. 3 shows a block diagram in which the configurations of the CCD 156 and the DSP substrate 170 are extracted. As shown in FIG. 3, the DSP substrate 170 has a CCD power supply circuit 171, a chip ferrite bead 172, an FPGA (Field Programmable Gate Array) 173, a CCD drive circuit 174, a CCD signal processing circuit 175, and a voltage detection circuit 176. is doing.

A DC power supply voltage is supplied from the power supply circuit 270 of the processor 200 to the CCD power supply circuit 171. When a power switch (not shown) of the electronic endoscope 100 is turned on, the CCD power supply circuit 171 performs DC / DC conversion on this power supply and supplies a DC power supply voltage to the _CCD 156 via the _CCD power supply line L _CCD. . Note that the DC power supply voltage is also supplied from the power supply circuit 270 to components other than the CCD power supply circuit 171 included in the DSP substrate 170. Thereby, the electronic endoscope 100 can be operated.

In an electronic endoscope, the CCD and the CCD driving substrate are installed apart from each other, so unnecessary radiation noise from the power supply line for the CCD connecting them is caused by components, processors, monitors, etc. in the electronic endoscope. May be affected. It is also necessary to satisfy a predetermined noise standard. Therefore, in general, an electronic endoscope is provided with a component for removing unnecessary radiation noise. In the present embodiment, a chip ferrite bead 172 is provided as a component for removing such unnecessary radiation noise. The chip ferrite beads 172 are well-known elements (for example, refer to the Internet <http://www.murata.co.jp/articles/ta0451.html>, etc., where the URL is searched in October 2006). CCD power line L _Removes unwanted radiation noise from the _CCD . The chip ferrite bead 172 has a DC resistance component of about 0.1 to several Ω, for example. Therefore, the DC power supply voltage from the CCD power supply circuit 171 is dropped by the chip ferrite beads 172 and supplied to the CCD 156.

  The voltage detection circuit 176 is connected to both ends of the chip ferrite bead 172 on the input and output sides, and measures a potential difference between both connection portions. Then, the measured potential difference is compared with a reference value held in advance, and a signal corresponding to the comparison result is output to the FPGA 173 at every predetermined timing. The potential difference measured by the voltage detection circuit 176 is proportional to the current value supplied from the CCD power supply circuit 171 to the CCD 156.

  When the measured potential difference falls below a predetermined reference value, the voltage detection circuit 176 determines that the DC power supply voltage from the CCD power supply circuit 171 is lower than the rated voltage of the CCD 156, for example, and is “L”. The signal is output to the FPGA 173. When the measured potential difference is equal to or greater than a predetermined reference value, the DC power supply voltage from the CCD power supply circuit 171 is, for example, equal to or higher than the rated voltage of the CCD 156 and is an abnormal value. Output to. The voltage detection circuit 176 outputs an “L” signal to the FPGA 173 as long as there is no malfunction in the electronic endoscope 100.

  A synchronization pulse (described later) output from the system control unit 220 of the processor 200 is input to the FPGA 173. When the signal from the voltage detection circuit 176 is the “L” signal, the FPGA 173 determines that the DC power supply voltage supplied from the CCD power supply circuit 171 is at a normal level. Next, a control signal for controlling the drive of the CCD 156 is generated based on the synchronization pulse from the system control unit 220. Then, the generated control signal is output to the CCD drive circuit 174. The CCD drive circuit 174 outputs a drive signal to the CCD 156 according to this control signal.

  The CCD 156 is driven in accordance with a drive signal from the CCD drive circuit 174, accumulates an optical image formed in each pixel as a charge corresponding to the amount of light, and converts it into a CCD output signal. Next, the converted CCD output signal is output to the DSP substrate 170.

  The CCD output signal output from the CCD 156 is input to the CCD signal processing circuit 175. The CCD signal processing circuit 175 performs well-known signal processing, sequentially calculates the CCD output signals of the input pixels one by one, and outputs color components (R component, G component, or B component). Signal (hereinafter referred to as “color component signal”) and a luminance signal are generated. Next, the generated signal is output to the processor 200. For convenience of explanation, when the color component signal and the luminance signal are expressed collectively, it is referred to as “image signal”.

  Next, signal processing executed by the processor 200 will be described. As shown in FIG. 2, the processor 200 includes an insulation circuit 240, a pre-stage processing circuit 242, an image memory 244, a video signal processing circuit 246, a character superimposing circuit 248, and an output circuit 250 as means related to processing of the CCD output signal. Have.

  The image signal output from the electronic endoscope 100 is input to the pre-processing circuit 242 via the processor-side connector unit 210 and the insulating circuit 240. The insulating circuit 240 temporarily converts a signal transmitted between the electronic endoscope 100 and the processor 200 into another medium (here, light) using, for example, a photocoupler, so that the electronic endoscope 100 and the processor 200 are electrically insulated.

  The pre-processing circuit 242 performs processing such as amplification and A / D conversion on the input image signal and outputs the processed image signal to the image memory 244. This image memory 244 stores image signals in units of frames. The stored frame-unit image signal is output to the video signal processing circuit 246 at every predetermined timing. This output timing is determined according to a synchronization pulse from the system control unit 220. As described above, this synchronization pulse is also output to the FPGA 173 at substantially the same timing. That is, the timing of signal processing on the processor 200 side and the drive timing of the CCD 156 are synchronized by this synchronization pulse.

  The video signal processing circuit 246 converts the image signal from the image memory 244 into a form (color signal and luminance signal) that can be displayed on the monitor 300. Then, the color signal and the luminance signal obtained by the conversion are output to the output circuit 250.

  The character superimposing circuit 248 is a circuit for superimposing and displaying a predetermined character on the image in the body cavity imaged by the electronic endoscope 100. The character superimposing circuit 248 operates in cooperation with the video signal processing circuit 246 so that a predetermined character is superimposed and displayed on the video under the control of the system control unit 220.

  The output circuit 250 converts the color signal and the luminance signal into video signals of various formats (for example, a composite video signal, an S video signal, or an RGB video signal) and outputs them to the monitor 300. As a result, an image in the body cavity of the patient (or an image in which a predetermined character is superimposed on the image) is displayed on the monitor 300.

Here, for example, it is assumed that the signal cable connecting the CCD 156 and the DSP board 170 is disconnected or the inside thereof is exposed, and the signal line included in the cable and forming the _CCD power line L _CCD is short-circuited to the ground. In this case, an overcurrent flows from the CCD power supply circuit 171 to the CCD 156. When an overcurrent flows through the _CCD power supply line L _CCD , the potential difference measured by the voltage detection circuit 176 becomes equal to or greater than the reference value. The voltage detection circuit 176 outputs an “H” signal to the FPGA 173 in accordance with such a measurement result.

When the FPGA 173 receives the “H” signal from the voltage detection circuit 176, the FPGA 173 determines that an overcurrent has flowed into the _CCD power supply line L _CCD . Then, a control signal for cutting off the supply of the DC power supply voltage is output to the CCD power supply circuit 171. When the CCD power supply circuit 171 receives the control signal from the FPGA 173, the CCD power supply circuit 171 cuts off the supply of the DC power supply voltage. As a result, no current flows through the _CCD power supply line L _CCD, and a failure of the CCD 156 due to overcurrent is prevented.

That is, according to the present embodiment, a voltage drop due to an element having a DC resistance component originally provided in an electronic endoscope (here, a chip ferrite bead 172 that is a component for EMI (Electromagnetic Interference) countermeasures) is measured. As a result, overcurrent detection for the CCD power line L _CCD is realized. Therefore, for example, it is not necessary to separately mount an overcurrent detection element (for example, a resistor). In the present embodiment, since a voltage drop due to an additional element such as the overcurrent detection resistor of Patent Document 1 is eliminated, it is possible to minimize the voltage drop of the _CCD power supply line L _CCD . Thereby, for example, power saving of the electronic endoscope 100 can be realized. Further, since the number of parts is reduced, it is possible to reduce the cost and size of the electronic endoscope 100.

  Further, when receiving an “H” signal from the voltage detection circuit 176, the FPGA 173 outputs a control signal to the CCD drive circuit 174 together with a control signal to the CCD power supply circuit 171. The control signal for the CCD drive circuit 174 is a signal for instructing the output stop of the drive signal for the CCD 156. When the CCD drive circuit 174 receives the control signal from the FPGA 173, the CCD drive circuit 174 stops outputting the drive signal to the CCD 156. That is, in the present embodiment, the drive signal is not input to the CCD 156 in conjunction with the power supply cutoff to the CCD 156.

  By stopping the power supply to the CCD 156 and stopping the output of the drive signal, a voltage significantly higher than the DC power supply voltage (here, meaning 0 volt when the power supply is cut off) is not applied to the CCD 156. The latch-up of the CCD 156 is prevented. Therefore, according to the present embodiment, the CCD 156 is not excessively heated by the latch-up, and an effect that the failure of the CCD 156 due to thermal damage can be prevented can be obtained.

  The FPGA 173 outputs a control signal to the CCD power supply circuit 171 and the CCD drive circuit 174, and then outputs a signal notifying that the supply of the DC power supply voltage is cut off to the system control unit 220 due to an overcurrent flowing through the CCD 156. To do.

  The system control unit 220 controls the character superimposing circuit 248 in response to the notification signal from the FPGA 173. At this time, the character superimposing circuit 248 operates in cooperation with the video signal processing circuit 246 so that a character for notifying that a failure such as a short circuit has occurred in the electronic endoscope 100 is superimposed on the video. The surgeon can know that a defect has occurred in the electronic endoscope 100 by visually recognizing the character projected on the monitor 300, and can request repair from a manufacturer, for example.

  The above is the embodiment of the present invention. The present invention is not limited to these embodiments and can be modified in various ranges. For example, in this embodiment, the CCD signal processing circuit 175 is provided in the DSP board 170, but in another embodiment, it may be provided on the processor 200 side. In this case, the CCD signal processing circuit 175 is mounted so as to be positioned, for example, between the insulation circuit 240 and the pre-processing circuit 242.

In another embodiment, the safety factor of the _CCD power line L _CCD may be set higher. For example, when the potential difference measured by the voltage detection circuit 176 is a reference value, the DC power supply voltage from the CCD power supply circuit 171 is at a level that matches the rated voltage of the CCD 156 in this embodiment. In this form, the level may be, for example, 50% of the rated voltage. Thus, by setting the safety factor high, it becomes possible to improve the accuracy of overcurrent detection.

In still another embodiment, an overcurrent may be detected using a low-pass filter. The low pass filter here is a circuit mounted between the CCD power supply circuit 171 and the CCD 156 and has a function of removing noise generated in the CCD power supply circuit 171. For example, the voltage detection circuit 176 is connected to both ends of the inductor constituting such a low-pass filter, and the potential difference is measured to determine whether or not an overcurrent has flowed through the _CCD power supply line L _CCD as in the present embodiment. Can be detected. In addition, the elements and circuits that can be used to detect overcurrent are assumed to be various elements that are originally provided in electronic endoscopes and have a DC resistance component that lowers the DC power supply voltage. Is done.

It is the figure which showed roughly the external appearance of the electronic endoscope system of embodiment of this invention. It is the block diagram which showed the structure of the electronic endoscope system of embodiment of this invention. The block diagram which extracted the structure of CCD and DSP board | substrate of embodiment of this invention is shown.

Explanation of symbols

10 Electronic Endoscope System 100 Electronic Endoscope 156 CCD
170 DSP board 171 CCD power supply circuit 172 Chip ferrite bead 173 FPGA
174 CCD drive circuit 175 CCD signal processing circuit 176 Voltage detection circuit 200 Processor 300 Monitor

Claims (6)

In an electronic endoscope equipped with an image sensor,
A power supply for supplying power to the image sensor;
A power supply line connecting the power supply unit and the imaging device;
A noise removing unit for removing noise in the power line;
Voltage drop measuring means for measuring a voltage drop by the noise removing unit;
An electronic endoscope comprising: power supply control means for controlling power supply to the image pickup device by the power supply unit in accordance with a measurement result by the voltage drop measurement means.   The electronic endoscope according to claim 1, wherein the noise removing unit is a ferrite bead for removing unnecessary radiation noise from the power supply line.   The electronic endoscope according to claim 1, wherein the noise removing unit is a noise removing filter that removes noise flowing through the power supply line.   The power supply control means continues the power supply when the value of the voltage drop measured by the voltage drop measuring means is below a predetermined value, and the measured voltage drop value is equal to or greater than the predetermined value. The electronic endoscope according to any one of claims 1 to 3, wherein the power supply is cut off in the case of (1). A drive control unit that outputs a drive control signal for driving and controlling the image sensor based on a signal input from an external device;
5. A drive control stop means for stopping output of the drive control signal from the drive control section when the power supply control means shuts off the power supply. An electronic endoscope according to 1. 6. An electronic endoscope according to claim 4, and a signal processing device that is connected to the electronic endoscope and that processes an image picked up by the image pickup device so that the image can be displayed on a monitor. An electronic endoscope system,
When the power supply is cut off by the power supply control means, the drive control stop means outputs a notification signal to notify the interruption of the power supply to the signal processing device,
An electronic endoscope system, wherein the signal processing device displays a predetermined character superimposed on the video on the monitor in response to the received notification signal.

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