JP5185520B2 - Electronic endoscope device - Google Patents

Description

  The present invention relates to an electronic endoscope apparatus using a semiconductor laser as a light source.

  Endoscopic devices are widely used in the medical field and the industrial field. As an endoscope apparatus used in the industrial field, for example, as disclosed in Japanese Patent Application Laid-Open No. 2004-275359, an elongated endoscope insertion portion is inserted into a jet engine or a power plant piping. There are those that can observe the test site and perform various treatments. Moreover, as an endoscope apparatus used in the medical field, for example, an electronic endoscope system disclosed in Japanese Patent Application Laid-Open No. 2001-218735 has an insertion portion that can be inserted into a body cavity, and the distal end of the insertion portion. An image in the body cavity imaged by the objective optical system disposed in the unit is imaged by an imaging means such as a solid-state imaging device and output as an imaging signal, and the image in the body cavity is displayed on a display means such as a monitor based on the imaging signal It has an operation and configuration of displaying the image.

  On the other hand, the endoscope apparatus requires illumination light for illuminating the subject in the lumen, and color information of the observation image is important for visual inspection of the illuminated subject. Conventionally, a light source device using a xenon lamp, a metal halide lamp or the like has been used.

  Further, as an illumination light source that is small in size, power efficient, and capable of vivid color reproduction, a light source device using a semiconductor laser such as a laser diode element is disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-205195. is there.

In an endoscope apparatus equipped with a light source device using such a semiconductor laser, an excitation light laser is oscillated from the semiconductor laser, and this excitation light laser is transmitted by an optical fiber for communication installed in the insertion portion of the endoscope. The subject is illuminated with white light from the phosphor by transmitting to the distal end and irradiating the phosphor provided inside the distal end of the insertion portion with an excitation light laser.
Japanese Laid-Open Patent Publication No. 2004-275359 JP 2001-218735 A JP 2005-205195 A

However, in the endoscope apparatus as a light source the semiconductor laser, it is necessary to transmit a laser beam to the leading end of the insertion portion by means of the communication fiber disposed in the endoscope insertion portion, the transmission abnormality of the laser beam In this case, there is a problem that the laser beam cannot be transmitted to the distal end of the insertion portion and desired white light cannot be generated from the phosphor, and the laser beam may leak outside the insertion portion.

The present invention has been made in view of the above circumstances, and detects the presence or absence of a clock component in the waveform of an imaging signal from a solid-state imaging device . An object of the present invention is to provide an electronic endoscope apparatus capable of controlling the output.

In order to achieve the above object, an electronic endoscope apparatus according to an aspect of the present invention includes an insertion portion that is inserted into a space to be inspected, a laser oscillation portion that oscillates laser light, and a solid-state imaging device. In the endoscope apparatus, a signal transmission unit that passes through the insertion unit, a status detection unit that detects a transmission status of a signal transmitted by the signal transmission unit, and the laser oscillation unit based on a detection result by the status detection unit A laser output control unit for controlling the output of the imaging signal, wherein the status detection means detects a clock component of the waveform of the imaging signal in a signal line for transmitting a transmission signal from the solid-state imaging device, and outputs the laser output The control unit controls the output of the laser oscillation unit when the status detection unit does not detect the clock component of the waveform of the imaging signal .

According to the electronic endoscope apparatus of the present invention, the presence or absence of the clock component of the waveform of the imaging signal from the solid-state imaging device is detected, and if the clock component cannot be detected , the output of the laser oscillation unit is controlled as a transmission abnormality has occurred. There is an effect that can be done.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 3 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of the endoscope apparatus, FIG. 2 is a block diagram showing a detailed configuration of the endoscope apparatus of FIG. FIG. 5 is a block diagram showing a detailed configuration of a modification of the endoscope apparatus of FIG. 2.

  As shown in FIG. 1, the endoscope apparatus 1 of the present embodiment has an elongated and flexible insertion section 2, a light source connected to the insertion section 2, and a signal processing section, and is observed on a monitor 4. The apparatus main body 3 displays an image.

  The apparatus body 3 includes an LD light source 6 that drives a laser diode (hereinafter referred to as LD) that is a semiconductor laser element and oscillates laser light. The laser light oscillated from the LD light source unit 6 is transmitted through a communication fiber 7 which is a laser beam transmission means installed in the insertion unit 2, and is irradiated to the phosphor filter 8 provided in the distal end portion of the insertion unit 7. . The phosphor filter 8 emits white light by the irradiated laser light and illuminates a subject (not shown).

  In the distal end portion of the insertion portion 7, an imaging unit 9 including an image sensor is provided adjacent to the phosphor filter 8. The imaging unit 9 is driven by a camera control unit (CCU) 5 that is a signal processing unit provided in the apparatus main body unit 3, and the CCU 5 processes an imaging signal from the imaging unit 9 to process an endoscopic image. It is displayed on the monitor 4.

  As shown in FIG. 2, the imaging unit 9 includes, for example, a CCD 9 a as an image sensor. The CCD 5 includes a CCD driver 51 that drives the CCD 9 a and a CDS 53 that samples an imaging signal from the CCD 9 a via a preamplifier 52. And a video processor 54 that performs signal processing on the signal sampled by the CDS 53. The LD light source unit 6 includes an LD 62 and an LD driver 61 as laser oscillation means for driving the LD 62 to oscillate.

  The CCD 5 and the imaging unit 9 are connected by a cable 100. The cable 100 is connected to the power source line 101 to the CCD 9a, the CCD drive pulse line 102 for driving the CCD 9a, and the CCD-OUT line for transmitting the imaging signal from the CCD 9a. 103.

  In the CCU 5 of this embodiment, a detection resistor 55 (for example, resistance value = 10 to 30Ω) for detecting disconnection / short circuit of the power supply line 101 is inserted in the power supply line 101. The detection potential at the detection resistor 55 is compared with two reference voltages 57a and 57b (input terminal B) by two comparators 56a and 56b (input terminal A), and the comparison result is an LD as laser output control means. It is output to the control unit 58. The LD control unit 58 is configured to control the LD driver 61 based on the comparison result.

  In this embodiment, the situation detection means is constituted by a detection resistor 55, two comparators 56a and 56b, and two reference voltages 57a and 57b.

  The operation of this embodiment configured as described above will be described.

Disconnection of cable 100:
When the cable 100 is disconnected in the insertion portion 2, the CCD 9 a and the CCU 5 are electrically disconnected, and no current flows through the power line 101. Then, no current flows through the detection resistor 55 as a result, and as a result, the voltage drop at the detection resistor 55 decreases, and the potentials at the input terminals A of the two comparators 56a and 56b rise.

  Specifically, for example, assuming that the power supply voltage of the CCD 9a is 15V and the consumption current (current flowing through the power supply line 101) is 10 mA, the potential after passing through the detection resistor 55 when the resistance value of the detection resistor 55 is 30Ω is In normal operation, it is 0.3V lower

  When the cable 100 is disconnected, the CCD 9a is disconnected from the CCD 5. Therefore, the current flowing through the detection resistor 55 becomes 0, and the potential of the input terminal A increases accordingly.

  Therefore, if the reference voltage 57a (input terminal B) of the comparator 56a is set to about “normal potential × 1/4 to 3/4 (preferably normal potential × 1/2)”, the cable 100 At the time of disconnection, the reference voltage 57a is exceeded, and the comparison result of the comparator 56a is reversed from the normal state (abnormality detection).

  The comparison result of the comparator 56a is determined by the LD control unit 58. When the comparator 56a determines that an abnormality has been detected, the LD control unit 58 sends a drive stop control signal (OFF signal) to the LD driver 61. The LD driver 61 stops the oscillation of the LD 62.

  The LD controller 58 does not control the LD driver 61 in a toggle manner (ON / OFF), but A / D-inputs the comparison result of the comparator 56a and continuously varies based on the difference from the reference voltage. The output may be controlled so as to be gradually reduced. Of course, the LD output may be controlled to be sufficiently low.

  In addition, the output control of the LD is not illustrated, but the output is reduced by a light amount adjusting means such as a diaphragm provided between the LD and the condenser lens, other than simply turning off the LD power supply or reducing the LD drive current. You may do it. Also, a power supply circuit (not shown) that supplies power to the LD or the LD driver may be stopped, or the output of the power supply circuit may be cut by a switch circuit configured with a semiconductor FET or the like.

Short circuit of cable 100:
When the cable 100 is disconnected, the cable 100 is not only opened, but the bare bare wire is likely to come into contact with the mesh wire of the coaxial cable, the metal blade on the exterior of the insertion portion, etc., and may be short-circuited to GND. When the cable 100 is short-circuited to GND, an abnormal current flows through the detection resistor 55. The current usually flows to the capacity limit of the drive circuit. Since the impedance of the cable 100 is about several tens of ohms, the output end of the detection resistor 55 is half or less of the power supply voltage.

  Therefore, if the reference voltage 57b of the comparator 56b is set to a voltage of about “power supply voltage × 1/2 to 5/6 (preferably power supply voltage × 2/3)”, the comparator 56b is connected when the cable 100 is short-circuited to the GND. The output is reversed from the normal value, and abnormality can be easily detected.

  The comparison result of the comparator 56b is determined by the LD control unit 58. When the comparator 56b determines that an abnormality has been detected, the LD control unit 58 sends a drive stop control signal (OFF signal) to the LD driver 61. The LD driver 61 stops the oscillation of the LD 62.

  If the design is such that the protection circuit on the CCD driver 51 side works when the cable is short-circuited, the LD driver 61 may be stopped using the result.

  In the present embodiment, the change in current is detected by the detection resistor 55. However, the present invention is not limited to this. For example, a non-contact sensor or detector using a change in electromagnetic field phenomenon such as a current probe (current probe). A similar effect can be obtained even if current detection is performed using the.

  As described above, according to the present embodiment, not only the disconnection of the cable but also a short circuit to the GND is detected only by the detection resistor and a simple comparator, and the laser output is considered to be abnormal, and the output of the LD is controlled. can do.

  In the case of an electronic endoscope, as shown in FIG. 3, an HIC (Hybrid IC) 80 may be mounted at the distal end in addition to the CCD 9a. The HIC 80 includes amplification of the output of the CCD 9a, a drive pulse waveform shaping circuit, and the like. Even when the power line 105 of the HIC 80 is used for detection, the same operation / effect as in the present embodiment can be obtained.

  That is, FIG. 3 is a modification of FIG. 2, and an HIC 80 that performs waveform shaping of the CCD drive pulse is provided in the vicinity of the imaging unit 9. In this HIC 80, the drive waveform that has been sunk by passing through the cable 105 is shaped like a short wave. In this example, there are HIC80 strokes, but the action is exactly the same as in the embodiment of FIG.

  4 and 5 relate to the second embodiment of the present invention, FIG. 4 is a block diagram showing a detailed configuration of the endoscope apparatus, and FIG. 5 is a diagram showing a waveform of a CCD drive pulse on the CCD drive pulse line of FIG. It is.

  Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

  In the present embodiment, the detection resistor 55 is provided by being inserted into the CCD drive pulse line 102. Other configurations are the same as those of the first embodiment.

  FIG. 5 shows the waveform of the CCD drive pulse. As shown in FIG. 5, the CCD drive pulse is a pulse in which the L level and the H level are usually fixed. Since it is necessary to pay attention to an actual pulse effective period with a short period, in this embodiment, a signal S (see FIG. 4) indicating the pulse effective period is input from the CCD driver 51 to the LD control unit 58, and the LD control unit 58 The pulse effective period can be grasped at.

  The operation of this embodiment configured as described above will be described.

Disconnection of cable 100:
Since the operation is the same as that of the first embodiment except that the power supply line 101 is replaced with the CCD driving pulse line 102, the description thereof will be omitted. Since the power supply line 101 is smaller than the case of the power supply line 101, the setting of the reference voltage 57a is also required to be delicate. For example, although not shown, an amplifier circuit may be provided in front of the comparator 56a so that the change is amplified and then detected by the comparator 56a. Further, abnormality detection is performed only within the actual pulse effective period, and this detection process is excluded during other periods.

Short circuit of cable 100:
Since the operation is the same as that of the first embodiment except that the power line 101 is replaced with the CCD drive pulse line 102, the description is omitted. However, the abnormality detection is performed only within the actual pulse effective period, and in other periods. This detection process is excluded.

  Thus, also in the present embodiment, the same effect as that of the first embodiment can be obtained.

  6 and 7 relate to the third embodiment of the present invention, FIG. 6 is a block diagram showing the detailed configuration of the endoscope apparatus, and FIG. 7 shows the waveform of the CCD-OUT signal on the CCD-OUT line of FIG. FIG.

  Since the third embodiment is almost the same as the first embodiment, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

  In this embodiment, abnormality detection is performed by the output of the preamplifier 52 instead of the detection resistor 55. Since the output of the preamplifier 52 is weak, the amplifiers 90 and 91 are provided in front of the input terminals A of the comparators 56a and 56b to increase the signal amplitude to facilitate abnormality detection. Here, when the amplifiers 90 and 91 are connected by AC coupling, the DC component changes due to a change in APL (Average Picture Level), so that accurate comparison cannot be performed by the comparators 56a and 56b. In such a case, in this embodiment, although not illustrated, a clamp circuit for fixing a DC component is provided between the amplifiers 90 and 91 and the comparators 56a and 56b.

  The operation of this embodiment configured as described above will be described.

  As shown in FIG. 7, the CCD-OUT signal of the CCD-OUT line 103 is usually output in a form in which the reset gate pulse of the CCD drive pulse penetrates and the reset gate pulse is superimposed. The waveform shape of the CCD-OUT signal is, for example, a waveform that remains even when the CCD 9a captures a dark image and outputs a dark image. That is, it is a signal on which a clock is superimposed. In this embodiment, abnormality detection is performed using this feature.

  When the cable 100 is disconnected, opened (disconnected), or contacted with GND (short circuit), the waveform of the reset gate pulse included in the CCD-OUT signal disappears and a simple DC signal is obtained.

  Therefore, in this embodiment, the reference voltages 57a and 57b are set so that the comparators 56a and 56b can detect the presence or absence of the clock component that is the pulse of the reset gate pulse.

  With this setting, if the cable 100 is disconnected, the clock component cannot be detected and the abnormality of the cable 100 can be detected.

  As shown in FIG. 7, since the clock component (reset gate pulse) has a stop period, the LD control unit 58 may not detect an abnormality during the stop as in the second embodiment. It can also be judged whether the comparator output has a pulse component.

  In this embodiment, the case where a direct output signal from the CCD is used has been described as an example. However, the CCD output is once input to the HIC (see FIG. 3), impedance-converted, and output from the HIC. In the case of the configured endoscope, it can be applied and used in the same manner.

  As described above, in this embodiment as well, attention is paid to the fact that the clock component is superimposed on the CCD-OUT signal, and the presence or absence of this clock component is detected to detect an abnormality, so that the same effect as in the first embodiment can be obtained. Can do.

  In each of the above-described embodiments, the CCD has been described as an example of the image sensor.

  The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

1 is a configuration diagram showing a configuration of an endoscope apparatus according to Embodiment 1 of the present invention. The block diagram which shows the detailed structure of the endoscope apparatus of FIG. The block diagram which shows the detailed structure of the modification of the endoscope apparatus of FIG. FIG. 5 is a block diagram showing a detailed configuration of an endoscope apparatus according to Embodiment 2 of the present invention. The figure which shows the waveform of the CCD drive pulse on the CCD drive pulse line of FIG. Block diagram showing a detailed configuration of an endoscope apparatus according to Embodiment 3 of the present invention. The figure which shows the waveform of the CCD-OUT signal on the CCD-OUT line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus 2 ... Insertion part 3 ... Apparatus body part 4 ... Monitor 5 ... CCU
6 ... LD light source section 7 ... Communication fiber 8 ... Phosphor filter 9 ... Imaging unit 9a ... CCD
51 ... CCD driver 52 ... Preamplifier 53 ... CDS
54 ... Video processor 55 ... Detection resistors 56a, 56b ... Comparators 57a, 57b ... Reference voltage 61 ... LD driver 62 ... LD
DESCRIPTION OF SYMBOLS 100 ... Cable 101 ... Power supply line 102 ... CCD drive pulse line 103 ... CCD-OUT line

Claims (4)

In an electronic endoscope apparatus provided with an insertion portion that is inserted into a space to be inspected, a laser oscillation portion that oscillates laser light, and a solid-state imaging device,
A signal transmission means passing through the insertion portion;
Status detection means for detecting the transmission status of the signal transmitted by the signal transmission means;
A laser output control unit that controls the output of the laser oscillation unit based on a detection result by the situation detection unit;
With
The situation detection means detects a clock component of the waveform of the imaging signal on a signal line that transmits a transmission signal from the solid-state imaging device, and the laser output control unit uses the situation detection means to detect the waveform of the imaging signal. An electronic endoscope apparatus that controls an output of a laser oscillation unit when no clock component is detected . An optical fiber for transmitting the laser beam;
2. The fluorescent light emitting means that receives the laser light transmitted through the optical fiber and emits white light, which is controlled by the laser output control means, is provided in the insertion portion. The endoscope apparatus described in 1.   The electronic endoscope apparatus according to claim 1, wherein the status detection unit detects the presence or absence of a reset gate pulse of the imaging signal as the clock component.   The electronic endoscope apparatus according to claim 3, wherein the status detection unit does not detect a change in a waveform of the imaging signal during a stop period of the clock component.

Images