JPH0683704B2 - Endoscope device - Google Patents

Description

The present invention relates to an endoscope apparatus, and more particularly to an endoscope apparatus that has a solid-state image sensor such as a charge-coupled device (CCD) built in at its tip and images an object. Regarding

[Conventional technology]

In recent years, CCDs have been attached to the tip of endoscopes with the development of solid-state image sensors.
An endoscopic device has been developed which incorporates a solid-state image sensor such as the above, images the inside of a body cavity, displays an image of the inside of the body cavity on a monitor, and diagnoses by observing the display. Usually, in such a device, a light source unit as a signal processing unit is provided separately from the endoscope, and the endoscope is connected to the light source unit via a universal cord, and a light guide fiber passing therethrough. The illumination light is applied to the target object via the. Generally, various types of endoscopes are prepared depending on the application. However, the same CCD is used for all types of endoscopes in order to share the drive circuit and the image processing circuit.

[Problems to be Solved by the Invention]

However, the insertion depth of the endoscope differs depending on the application. Accordingly, the length from the connector part of the universal cord connected to the light source unit to the tip of the endoscope containing the CCD is also different. Here, the drive pulse from the drive circuit in the light source unit and the video signal from the CCD are CC through the signal transmission wire in the universal cord.
Sent / received to / from D. Here, if the length of this signal transmission path becomes long, the waveform of the drive pulse may deteriorate due to the signal line, and the CCD may not be driven accurately. Also, the video signal from the CCD may be delayed during transmission on the signal line. Generally, the video signal from the CCD is a discrete pulse signal, which is clamped or held by the video processing circuit in the light source unit and converted into a continuous signal. The delay of the video signal means that the clamp or hold timing deviates from a predetermined timing, and an accurate continuous signal may not be obtained.

Furthermore, the degree of waveform deterioration and delay time due to this signal transmission line differs depending on the length of the line, so if you try to connect multiple types of endoscopes with different lengths to one light source unit, The amount of adjustment must be changed for each type of mirror, and there is a problem that the adjustment configuration becomes complicated.

The present invention has been made to address the above-described circumstances, and an object thereof is to provide an endoscope in which a signal processing circuit is provided separately from the endoscope and a plurality of types of endoscopes are commonly connected to the signal processing circuit. In a mirror device, the influence of signal waveform deterioration, delay, etc. due to a signal transmission line is adjusted with a simple configuration according to the type of endoscope to be connected.

[Means for Solving the Problems]

The endoscope apparatus according to the present invention has different lengths for each type, and an endoscope in which a solid-state image sensor is provided at its tip, and a drive signal to the solid-state image sensor connected to the endoscope through the endoscope. And an image signal read out from the solid-state image pickup device is input through the endoscope, and a device body that processes the image signal for display, and a means for determining the type of the endoscope. And a means for adjusting the drive signal supplied to the solid-state image sensor based on the discrimination result of the discriminating means, and a means for adjusting the image signal read from the solid-state image sensor based on the discrimination result of the discriminating means. .

[Action]

According to the endoscope apparatus of the present invention, the type of the endoscope is discriminated, the waveform of the drive signal to the solid-state image sensor is corrected according to the discrimination result, and the image signal from the solid-state image sensor is discriminated. By clamping or holding at a timing according to the result and converting to a continuous image signal, the effect of signal waveform deterioration and delay due to the signal transmission line depending on the type of endoscope connected is simple Can be adjusted with.

〔Example〕

An embodiment of an endoscope apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration in the vicinity of a connection portion of a light source unit as a signal processing circuit with an endoscope in one embodiment. A CCD (not shown) as a solid-state image sensor is built in the tip of the endoscope 10. At the connecting portion of the endoscope 10 with the light source unit, a resistor 12 for identifying a scope (endoscope) is provided together with a signal connecting terminal.
The resistance value of the resistor 12 is different for each scope, and the light source unit side is connected to the type of scope by detecting the resistance value, specifically, the terminal for signal connection and disposed in the endoscope. It is possible to identify the length of the signal transmission line that is being used. A control signal from a control circuit (not shown) is supplied to the CCD driver 16 via the isolation transformer 14. CCD driver
16 generates a drive pulse for driving the CCD in response to this control signal. This drive pulse is transmitted to the endoscope 10 side via the matching circuit 18, and is supplied to the CCD via the signal transmission line in the endoscope 10. The matching circuit 18 is specifically a differentiating circuit, and is a circuit for adding a component (differential component) corresponding to a waveform deterioration amount during the rising transmission of the drive pulse. This time constant is the above-mentioned resistance 12 for scope identification.
It is changed by the identification signal from the scope identification circuit 26 connected to the.

On the other hand, the video signal from the CCD at the tip of the endoscope 10 is supplied to the video processing system through the signal transmission line, the terminal, the differential amplifier 20, the insulating transformer 22, and the clamp circuit 24. The video signal from the CCD is a discrete pulse signal, which is clamped at a predetermined interval by the clamp circuit 24 and converted into a continuous signal. The timing generation circuit 32 that determines the clamp timing is determined by the output of the timing switching circuit 30 controlled by the output of the scope identification circuit 26. The timing switching circuit 30 is specifically a delay circuit, and is a circuit that delays the reference pulse supplied from the control circuit in accordance with the transmission delay time of the video signal according to the type of scope and supplies it to the timing generation circuit 32. is there. This delay time is also changed by the identification signal from the scope identification circuit 26.

FIG. 2 is a detailed circuit diagram of the scope identification circuit 26. The identification circuit 26 has a current source 40, and when the endoscope 10 is connected, a constant current is supplied from the current source 40 to the scope identification resistor 12. As a result, the resistance value of the scope identification resistor 12 is output as the inter-terminal voltage. The voltage across the terminals of the scope identification resistor 12 is input to the comparison circuit 48. The comparator circuit 48 is composed of seven comparators, and the voltage between the terminals of the scope identification resistor 12 is applied to the + input terminal of each comparator. The voltage at each voltage dividing point of the voltage divider 44 having seven voltage dividing points is applied as a reference voltage to the-input terminal of each comparator of the comparison circuit 48. The seven comparators constituting the comparison circuit 48 are weighted respectively, and the ones to which the low voltage reference voltage is applied are sequentially 0.
Weights (bits) of ˜6 are attached. Therefore, in the comparison circuit 48, the output of 0-bit to n-bit (0 ≦ n ≦ 6) becomes “1” and the output of (n + 1) -bit to 6-bit becomes “0” according to the voltage between the terminals of the scope identification resistor 12. "It becomes.

The 0-bit to 2-bit output signal of the comparison circuit 48 is an addition circuit
It is supplied to the A2, A3, and A4 input terminals of 54, respectively. Comparison circuit
The output signal of 3 bits to 6 bits of 48 is A1 of the adding circuit 52,
It is supplied to the A2, A3, and A4 input terminals, respectively. Adder circuit 52,
Reference numeral 54 is for adding "1" to the 0-bit to 6-bit output data of the comparison circuit 48 and outputting it. For example, the comparison circuit
When the output data of 48 is "0001111", it becomes "0010000" when "1" is added. In this way, the 0-bit to n-bit output of the comparison circuit 48 is 1, and the (n + 1) -bit to 6-bit output is "0". Therefore, when "1" is added to it, any one of them is output. Only the bit data becomes "1" and the others become "0". In this way, the adder circuits 52 and 54 generate an identification signal in which only one bit data is "1" and the other is "0" in accordance with the voltage between the terminals of the scope identification resistor 12. It is a thing. If the output data of the comparison circuit 48 is "1111111", and "1" is added to this, it becomes "100000".
Since it is "00", 8-bit identification signals ID1 to ID8 are output from the adding circuits 52 and 54.

In this way, the type of endoscope can be identified with a simple configuration by causing a constant current to flow from the light source unit side to the identification resistor provided on the endoscope side and detecting the resistance value as the inter-terminal voltage. Further, the identification signal is data of a plurality of bits, but since only one bit data is "1", the selection elements of the adjustment circuit such as the matching circuit 18 and the timing switching circuit 30 can be selected as they are. Simplifies the configuration.

FIG. 3 is a diagram showing a detailed configuration of the matching circuit 18. The isolation transformer 14 is connected to the CCD driver 16 via the capacitor 60. Matching circuit 18 is a relay switch
S1 to S8 and differentiating circuits (CR differentiating circuits) DL1 to DL8 connected to the relay switches S1 to S8. The output of the CCD driver 16 is passed through relay switches S1 to S8 to differentiate circuits DL1 to DL8.
Is supplied to each. Differentiating circuits DL1 to DL8 have different time constants. The relay switches S1 to S8 are controlled by the identification signals ID1 to ID8, respectively.

As described above, since only one bit data ID1 to ID8 of the identification signal is "1", the relay switch S1 to ID8
Only one of S8 is turned on. Therefore, the driving pulse of the CCD is differentiated with a time constant according to the identification signals ID1 to ID8, and the waveform is adjusted as a waveform to which a component whose waveform is deteriorated during transmission is added in advance. That is, the waveform of the drive pulse is deteriorated during transmission, and the drive pulse is adjusted so that it has the original correct waveform when supplied to the CCD.

FIG. 4 is a detailed circuit diagram of the clamp circuit 24. The video signal from the isolation transformer 22 is supplied to the video processing system via the impedance converter 68, the capacitor 70, and the impedance converter 74. Capacitor 70 and impedance converter
A dynamic clamp circuit 72 is connected between 74.
The dynamic clamp circuit 72 is composed of an analog switch composed of diodes connected in a bridge, and a self-bias transformer 76 for supplying a pulsed bias current to the analog switch. A timing pulse (clamp pulse) from the timing generation circuit 32 is supplied to the self-bias transformer 76, and the pulsed video signal from the CCD is clamped in response to this pulse and converted into a continuous signal.

As described above, the generation timing of this clamp pulse is delayed by the same time as the delay time of the video signal according to the scope identification signal, and the video signal is clamped so as not to be affected by the delay during the transmission of the signal line. The timing switching circuit 30 has the same configuration as the matching circuit 18, and eight one-shot multivibrators each having a different pulse width are provided instead of the CR differentiating circuit. Reference pulses from the control circuit are input to these one-shot multivibrators via relay switches. And
An output pulse signal from any one one-shot multivibrator is supplied to the timing signal generation circuit 32 according to the identification signals ID1 to ID8, and a clamp pulse is generated in synchronization with the trailing edge of the pulse signal.

It should be noted that the present invention is not limited to the above-described embodiments, and can be variously modified without changing the gist of the invention, and the details of the matching circuit 18 and the clamp circuit 24 are not limited to the above-mentioned examples. A sample / hold circuit may be used instead of the clamp circuit 24 as a circuit for converting a discrete signal into a continuous signal.

〔The invention's effect〕

As described above, according to the present invention, on the light source unit side as a signal processing circuit separate from the endoscope, it is possible to identify the type of the endoscope connected thereto with a simple configuration, and drive to the CCD. The waveform is corrected according to this identification result, and the pulse-shaped video signal from the CCD is clamped or sampled at the timing according to this identification result to convert it into a continuous video signal. It is possible to provide an endoscope apparatus that can always image an object under optimum conditions regardless of the type of endoscope.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an endoscope apparatus according to the present invention, FIG. 2 is a detailed circuit diagram of a scope identification circuit of FIG. 1, and FIG. 3 is a matching circuit of FIG. Detailed circuit diagram, FIG. 4 is a detailed circuit diagram of the clamp circuit of FIG. 10 …… Endoscope, 12 …… Scope identification resistor, 16 …… CCD
Driver, 18 ... Matching circuit, 24 ... Clamp circuit, 26 ... Scope identification circuit, 30 ... Timing switching circuit.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Masahide Sugano 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Yutaka Takahashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Within Olympus Optical Co., Ltd. (72) Inventor Katsuyuki Saito 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) Reference JP-A-57-45838 (JP, A) JP Sho 59-69720 (JP, A)

Claims (1)

[Claims] 1. An endoscope having a length different for each type and having a solid-state image sensor at its tip, and a drive signal connected to the endoscope and transmitting a drive signal to the solid-state image sensor via the endoscope. An endoscopic device comprising: a device main body that supplies the image signal read from the solid-state image sensor through the endoscope and processes the image signal for display. At least the means for determining the type of endoscope, the drive signal that deteriorates in the process of being supplied to the solid-state imaging device, and the timing of the image signal and a pulse signal corresponding to the transmission delay time of the image signal An endoscope apparatus comprising: a means for correcting one of the two based on a determination result of the determining means.