JPH0777430B2 - Electronic endoscope system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope, and more particularly to an electronic endoscope apparatus having a solid-state image sensor built therein.

[Prior Art] An electronic endoscope device supplies a drive pulse from an external device, that is, a video processor to a solid-state image pickup device built in a distal end portion of the endoscope, and the drive pulse drives the solid-state image pickup device. As a result, a video signal is output from the solid-state image sensor, and the video signal is displayed on the monitor as a transendoscopic image.

[Problems to be Solved by the Invention] In a conventional electronic endoscope apparatus, a drive pulse generation circuit that generates a drive pulse, a delay circuit that delays the drive pulse according to the length of the endoscope, and a delay circuit are provided. A switching circuit is provided in the video processor for switching depending on the type of endoscope. This not only complicates the circuit configuration of the video processor, but also increases the size of the video processor.

Therefore, an object of the present invention is to provide an electronic endoscope apparatus which can be applied to endoscopes of any length without complicating the circuit configuration of the video processor.

[Means and Action for Solving Problems] According to the present invention, an endoscope having a distal end portion in which a solid-state image sensor for converting an optical image into an electric signal and outputting the electric signal is output; And has a video processor for processing the output signal of the solid-state image pickup device and outputting a video signal, and a connector part having one end fixed to the endoscope and the other end detachably connected to the video processor. A cable for transmitting the drive pulse and the output signal of the solid-state image sensor, and a propagation delay time when the signal is reciprocated in the cable provided in the endoscope, the propagation delay time being constant regardless of the length of the cable. An electronic endoscope apparatus having a delay circuit in which a time subtracted from the time is preset as a delay time, wherein the delay circuit is an electric drive pulse or an output signal of the solid-state imaging device. At least one of the above is input and the input signal is delayed by the preset delay time to compensate for the propagation delay time of the cable. An electronic endoscope apparatus is provided. To be done.

Since a delay circuit having a delay time according to the length of the endoscope is provided in each endoscope operation unit or in the vicinity thereof, it is not necessary to provide the video processor with a delay circuit and a switching circuit for switching the delay circuit. , The circuit configuration of the video processor is considerably simplified, and the video processor can be miniaturized.

[Embodiment] As shown in FIG. 1, the electronic endoscope apparatus is an electronic endoscope.
It is composed of 11 and a video processor 21. An objective lens 13 and an illumination lens 14 are attached to a tip portion 11a of the electronic endoscope 11. A solid-state imaging device (CCD) 15 is arranged so as to face the objective lens 13. The endoscope connector 20 is detachably attached to the video processor 21. The endoscope operation section 12 is provided with delay circuits (Delay Lines) 16 and 17, and drivers 18 and 19 connected to the delay circuits 16 and 17, respectively. The drivers 18 and 19 are connected to the CCD 15 via a coaxial cable provided in the endoscope insertion portion. The video signal output terminal of the CCD 15 is connected to the video signal processing circuit 25 of the video processor 21 via the emitter follower amplifier 33 and the coaxial cable.

The drive pulse generation circuit 22 provided in the video processor 21 generates signals PV1, PV2, SH, PR, PH, CLP, SYNC.

The signal (PV1, PV2) output terminals are connected to the endoscope connector socket (not shown) via the drivers 23, 24, respectively.
The signal (PV1, PV2) output terminals are connected to the CCD 15 via the coaxial cable of the endoscope 11. Signal (PR, PH) output terminals are connected to delay circuits 16 and 17 provided in the endoscope connector 11b, respectively. Signal (SH, CLP, SYNC) output terminals are connected to the video signal processing circuit 25. The output terminal of the video signal processing circuit 25 is connected to the monitor television 26.

In the electronic endoscope apparatus having the above configuration, when the drive pulse generation circuit 22 outputs the drive pulses PR and PH shown in FIG. 2, these pulses PR and PH are endoscopically transmitted through the endoscope connector 20 and the coaxial cable. Delay circuit provided in mirror operation unit 12
Supplied to 16 and 17. Drive pulse PR and PH are delay circuits
The driver 18 is delayed by a predetermined time t2 by 16 and 17.
And 19 are entered. The drivers 18 and 19 perform impedance matching with the coaxial cable and output drive pulses φR and φH. Drive pulse φ via coaxial cable
R and φH are input to the CCD 15. Drive pulse signal φR
Is used for operating the image signal output section of the CCD 15, and the drive pulse signal φH is used for horizontal transfer of pixel signals. The CCD 15 is supplied with low-speed drive pulses φV1 and φV2 for vertical transfer from the drive pulse generation circuit 22.

The drive pulse signals φR and φH are high frequency pulse signals of 7 MHz or more, and when such high frequency pulse signals are transmitted through an ordinary electric wire, electromagnetic waves are radiated from the electric wire and interfere with other devices. However, when the coaxial cable is transmitted with impedance matching as in this embodiment, the drive pulse signal can be transmitted without radiation of electromagnetic waves and without causing waveform distortion.

When the CCD 15 is driven by the drive pulse signals φR and φH, the CCD 15 outputs the video signal VO in synchronization with the drive pulse signals φR and φH. The video signal VO is supplied to the video signal processing circuit 25 of the video processor 21 via the coaxial cable.

In the above operation, it takes a time t1 from the output of the drive pulse signals φR and φH from the drivers 18 and 19 to the supply to the CCD 15. This time t1 is proportional to the length of the coaxial cable. Further, the video signal VO of the CCD 15 still requires the time t1 to the operation unit 12. It takes a time t1 ′ from the operation unit 12 to reach the video signal processing circuit 25. This time t1 ′
Is proportional to the length of the coaxial cable from the operation unit 12 to the image signal processing circuit 25. The length of this cable is constant for most types of endoscopes. Therefore, the transmission delay time in this cable is constant.

When the video signal VO input to the video signal processing circuit 25 is processed by the video signal processing circuit 25, the sample hold pulse signal SH output from the drive pulse generation circuit 22.
Sampled by. By this sampling, only the central signal component of the video signal VO is taken out, and the reset noise component and the like are removed.

The pulses of the signals SH, PR, PH are always output by the drive pulse generation circuit 22 in the same phase relationship. However, when the length of the endoscope is different, that is, when the length of the coaxial cable is different, the time t1 is different. As a result, the phase relationship between the video signal VO input to the video signal processing circuit 25 and the sampling pulse signal SH shifts, and the video signal
VO will not be sampled properly. Therefore, the delay circuits 16 and 17 delay the signals PH and PR in advance by the time t2 so that t2 + 2t1 + t1 ′ becomes constant.
A delay of 7 is determined. Further, the drive pulse generation circuit 22 is configured so that the relationship between the video signal VO and the sampling pulse signal SH is always proper.

The video signal processing circuit 25 processes the video signal VO by receiving the signals SH, CLP and SYNC and supplies it to the monitor television 26. The monitor television 26 displays the endoscopic image.

In the electronic endoscope shown in FIG. 3, a unit 27 accommodating the delay circuits 16 and 17 and the drivers 18 and 19 is provided at a position close to the endoscope operating section 12. According to this, the initial purpose can be achieved without enlarging the operation unit 12.

[Advantages of the Invention] According to the above-described electronic endoscope apparatus, since the delay circuit according to the length of the endoscope is provided at or near the endoscope operation unit, the circuit configuration of the video processor is simple. Was converted into
The video processor can be miniaturized.

[Brief description of drawings]

1 is a block circuit diagram of an electronic endoscope apparatus according to an embodiment of the present invention, and FIG. 2 is a time chart diagram of signals for explaining the operation of the electronic endoscope apparatus of FIG. And, FIG. 3 is a side view of an electronic endoscope apparatus of another embodiment. 11 …… Endoscope, 21 …… Video processor, 15 …… Solid-state image sensor, 16,17 …… Delay circuit, 18,19 …… Driver, 22
...... Drive pulse generation circuit, 25 …… Video signal processing circuit, 26
…… Monitor TV.

Claims (1)

[Claims] 1. An endoscope having a tip portion containing a solid-state image sensor for converting an optical image into an electric signal and outputting the electric signal, a drive pulse for the solid-state image sensor, and an output signal of the solid-state image sensor. A video processor for processing and outputting a video signal; and a connector part fixed to the endoscope at one end thereof and detachably connected to the video processor at the other end thereof. A cable for transmitting an output signal, provided in the endoscope, a time obtained by subtracting a propagation delay time when a signal reciprocates in the cable from a fixed time that does not depend on the length of the cable is previously set as the delay time. An electronic endoscope apparatus having a set delay circuit, wherein the delay circuit receives at least one of an electric drive pulse and an output signal of the solid-state imaging device, By delaying the input signal by the preset delay time, an electronic endoscope apparatus characterized by the the to compensate for the propagation delay time of the cable.