JPS63232582A - Image pickup device - Google Patents

Abstract

PURPOSE:To make the constitution of an image pickup device for compensating a delay in signal transmission simpler, by detecting a delayed quantity in signal transmission from a camera head to a signal processing section with a phase comparator and controlling the timing of a signal processing circuit by using the output of the phase comparator. CONSTITUTION:A phase comparator 42 which controls the voltage applied across a voltage-controlled oscillator 38 so that the phase difference between the input signal of a timing generator 36 and input signal of a driving pulse generator 22 supplied from a camera head 10 through a cable 14 can be made zero, is provided. Therefore, the processing timing of a signal processing circuit 34 is appropriately controlled always. Moreover, the driving pulse of a solid-state image pickup element 20 is not transmitted from a signal processing section 12, but produced inside the camera head 10. Accordingly, it becomes unnecessary to provide a matching circuit which compensates the deterioration of waveforms during the transmission of driving pulses inside the signal processing section 12 and, as a result, the constitution of the section 12 becomes simpler.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device in which a camera head and a signal processing section are transmitted separately and are connected by a cable.

[Conventional technology]

As such an imaging device, the applicant's %
There is already an endoscope device described in No. 0-225368.

This device incorporates a solid-state imaging device such as a charge-coupled device (COD) at the tip of an endoscope to image an object. The signal processing section is separate from the endoscope and is usually provided within the light source device. Drive pulses for the solid-state image sensor are transmitted from a drive pulse generator provided in the signal processing section to the solid-state image sensor at the tip of the endoscope via a signal IfM in a cable connecting the endoscope main body and the light source device. Similarly, the output of the solid-state image sensor is transmitted to a signal processing unit via a signal line within the endoscope, where it is subjected to signal processing such as flanging, sample and hold, etc., and an image signal of the object is generated.

Here, since the drive pulse is a high-frequency signal, if it is transmitted through a long signal line, the waveform will be distorted during transmission, and when it is supplied to the solid-state m-image element, it will no longer be a rectangular wave. It becomes impossible to drive the element. Therefore, it is necessary to provide a matching circuit on the signal processing section side to compensate for this waveform distortion in advance, and to supply drive pulses to the solid-state image sensor through this matching circuit.

Further, the output of the solid-state image sensor is also delayed while being transmitted to the signal processing section, and the output of the solid-state image sensor when input to the signal processing section is delayed with respect to the timing of the drive i4 pulse. To compensate for this, the timing of each signal processing signal is delayed relative to the timing of the drive pulse according to the S class (signal line length) of the endoscope.

[Problem that the invention seeks to solve]

In this conventional device, multiple endoscopes are connected to the same signal processing unit (
In order to commonly connect the light source equipment (ft), it is necessary to provide as many machining circuits as there are endoscopes to be connected to the signal processing section, which has the disadvantage of increasing the size of the signal processing section.

Furthermore, since the amplitude of the drive noise is quite large, the influence of electromagnetic waves radiated from the signal line during transmission from the signal processing section to the solid-state image sensor on other equipment cannot be ignored.

This issue 8A was developed in order to deal with the above-mentioned situation, and its purpose is to prevent delays in signal transmission between the two and adverse effects caused by waveform deterioration in imaging devices where the camera head and signal processing section are separate. The purpose is to compensate for differences in signal line length with simple transmission. “ [Means for solving the problem] The imaging device according to the present invention connects the camera connected via the cable 14 to the camera 10 and the signal processing unit 12kJL'U.
11, and the camera head 10 has a solid-state image sensor 20 and a first
a drive Z4 pulse generator 2 that generates drive pulses for the solid-state imaging device at timings according to the output of the voltage controlled oscillator 30;
signal processing unit 12#: a timing generator 36 that generates timing pulses to the camera via the t cable 14, and a timing generator 3;
A second voltage controlled oscillator 38 serves as a timing reference for 6.
and the phase difference between the input signal of the timing generator 36 and the input signal of the drive pulse generator 22 supplied from the camera head 10 via the cable 14, or the phase difference between the input signal of the timing generator 36 and the input signal of the drive pulse generator 22 supplied from the camera head 10 via the cable 14, or A phase comparator 42 is provided to control the voltage applied to the second voltage controlled oscillator 38 so that the phase difference with the drive nolus supplied from the second voltage controlled oscillator 38 becomes zero.

[Effect]

According to the imaging device according to the present invention, the amount of phase delay of the signal from the camera head 10° to the signal processing section 12''i is detected by the phase comparator 42, and the phase of the timing pulse is controlled by the output of the phase comparator 42. Therefore, the processing timing of the signal processing circuit 34 is always appropriately controlled.Furthermore, the driving noise of the solid-state image sensor 20 is controlled by the signal processing section fki 1.
Since the signal is generated within the camera head 10 instead of being transmitted from the drive pulse 2, there is no need to provide a circuit in the signal processing unit 12 to compensate for waveform deterioration during drive pulse transmission, and the signal processing This simplifies the transmission of part 12.

〔Example〕

An embodiment of an imaging device according to the present invention will be described below with reference to the drawings. FIG. 1 is a ten-step diagram of the first embodiment.

The imaging device of the first embodiment includes a camera, a door 10, and a signal processing section 12, both of which are connected by a cable 14.

The camera head 10 includes a solid-state imaging device (here, a charge-coupled device: CCD) 20 and a drive pulse generator 22 that generates a drive pulse for the CCD 20 .

The driving norm generator 22 is composed of a divider that divides the output pulses of the first voltage controlled oscillator 30 in the signal processing section 12 . The input signal of the drive/jars generator 22 is connected to the cable 14.
It is transmitted to the signal processing @12 via the signal @16 within.

The signal processing unit 12 includes a first voltage controlled oscillator (VCO) that generates a clock pulse that provides reference timing for the dynamic pulse generator 22, and a port that generates a control voltage that determines the oscillation frequency of the first OVCO 30. A first vcos is provided with a tensiometer 32.

The output of is supplied to the drive pulse generator 22 via cable J4. Furthermore, the signal processing unit 12
a signal processing circuit 34 that performs signal processing such as frang, sample & hold, etc. on the output signal of the signal processing circuit 34; a timing generator 36 that generates various timing pulses for the signal processing circuit 34; and a clock pulse that provides reference timing for the timing generator 36. The second vco s that occurs
s, a delay circuit 40 that delays the output of the second vC038 and supplies it to the timing generator 36, an input of the timing generator 36 (output of the delay circuit 40), and a signal transmitted from the camera head 10 via the signal line 16. A phase comparator 42 detects the phase difference with the drive pulse generator 220 input (the output of the first VCO SO which is reciprocated to the camera via the cable 14 to the do 10), and the output of the phase comparator 42 A level regulator 44 is provided for supplying a corresponding control voltage to the second vcos g. Signal processing circuit 3
The output of No. 4 is supplied to a display section (not shown). The timing generator 36 consists of a frequency divider that divides the output pulse of the second vcos 8. The level adjuster 44 is an operational amplifier that converts the output of the phase comparator 42 into a control voltage for the second vC038.

According to this embodiment, first, the control voltage applied to the first VCQ 30 is finely adjusted by the potentiometer 32. 2nd f) VCOJ O, J & (7) Make the oscillation frequencies almost the same. The drive/flash generated from the drive/flash generator 22 based on the output of the first VCOJ O
The pulse is supplied to the CCD JO, and the CCD 20 is driven.

The signal output from the CCD 20 is subjected to signal processing such as flag processing and sample length hold in the signal processing circuit 34 to generate an image signal of the object.

Timing pulses that determine the timing of these various signal processes are generated from the timing generator 36 based on the output of the second vcoss. ζHere, the oscillation frequencies of the first and second VCOJ O, J 8f) are almost the same, but as mentioned above, the
and the signal processing unit 12 are connected via a cable 14, and the output of the first VCOJO is transmitted via the cable 14 to the driving noise generator 22, so that the CCD
The drive timing of 20 and the various timings of the signal processing circuit 34 do not match. Furthermore, since the output of the CCD 20 is also input to the signal processing circuit 34 via the cable 14, the COD input to the signal processing circuit 30, ? The output of o is delayed with respect to the phase of the driving pulse.

Therefore, unless some kind of phase control means is used, various timings of the signal processing circuit 34 will be shifted.

In this embodiment, the drive pulse generator 220 input in the drive 10 (the output of the first VCO 30 in the signal processing unit 12, which is supplied to the camera head 10 via the cable 14) is connected to the camera via the signal line 16. The signal is supplied to the signal processing unit s12, and the phase difference with the output of the second VCo 3 g in the signal processing unit 12 is detected by the phase comparator 42. If the length of the signal line 16 from the input terminal of the drive pulse generator 22 to the input terminal of the phase comparator 42 is made equal to the length of the signal line from the output terminal of the CCD 20 to the input terminal of the signal processing circuit 34, , the amount of phase delay received before the output of the CCD 20 is transmitted to the signal processing circuit 34 is determined by the phase comparator 3.
It will be detected at 8. Second vCO38II′i
, delay circuit 38, phase comparator 42, and phase control (P
LL) circuit is being transmitted. The delay circuit 40 is VCo 3
This is a circuit for matching the phases as much as possible when a phase difference that cannot be matched by B is generated.j), and may be omitted if the VCOss has a function of matching the phases. This PLL
Due to the circuit, the signals at the two input terminals of the phase comparator 42 match in phase and frequency.

Therefore, the phase of the timing nozzle matches the output signal of the CCD 20 after being transmitted from the door 10 to the signal processing circuit 34 via the cable 14 to the camera, and the CCD 2
A zero output signal is processed at the correct timing. Furthermore, even if the length of the cable 14 changes and the delay time during signal transmission changes, such as in the case of an endoscope as described above, the signal processing unit 12 can handle this with the same transmission, and no adjustment is required. There is also the effect that

In addition, in the first embodiment, since the drive/f pulse generator 22 is provided in the door 10 to the camera, the drive pulse is transmitted to the cable 14.
Since there is no need for transmission through the signal processing unit 12, there is no need to provide a magnetic circuit for compensating for waveform distortion in advance in the signal processing unit 12, and the influence of electromagnetic waves radiated by the drive pulse during transmission is taken into consideration. There's no need to.

The connection position of the delay circuit 40 is not limited to the output of the VCOss, and can be changed in various ways. This modification is shown in Figure 2(a).
, (b) and (a). Figure 2 (in al, v
The output of coss is directly input to the timing generator 36, but a delay circuit 40 is connected in the feedback path from the VCOss to the phase comparator 42. 2l6)
Now, the VCO 30, which is the input to the drive/f pulse generator 22, is supplied from the drive 1o to the camera via the signal line 16.
The output is supplied to the phase comparator 42 via the delay circuit 4o. In FIG. 2(c), the output signal of the CCD 20 is supplied to the signal processing circuit 34 via the delay circuit 40. Second
The same effects as the first embodiment can be obtained in the modified examples shown in FIGS. (a) to Ge).

Next, a second embodiment of the imaging device according to the present invention will be described. FIG. 3 is a professional diagram of the second embodiment. In the second embodiment, the same parts as in the first embodiment are given the same reference numerals.

The second embodiment consists of the same transmission elements as the first embodiment, but
The wiring is slightly different. A first VCOJ O is provided not in the signal processing section 12 but in the camera 10. Instead of detecting the phase difference between the input of the timing generator 36 and the input of the drive pulse generator 22, the phase comparator 42 detects the phase difference between the pivot pulse and the timing pulse. That is, a part of the output of the behavioral pulse generator 22 is transmitted to the signal processing unit 12 via the signal line 16,
It is input to the first input terminal of the phase comparator 42. A part of the output of the timing generator 36 is supplied to a second input terminal of the phase comparator 42 .

According to the second embodiment as well, the timing pulse output from the timing generator 36 is sent to the camera by the driver.
0 to the signal processing circuit 34 via the cable 14, the phase matches the output signal of the CCD 20, and the CCD
Signal processing is performed on the output signal of the CD 20 at the correct timing. Furthermore, in this embodiment, since the frequency-divided drive pulse is transmitted from the camera head 1o to the signal processing unit 12 instead of the output of the VCOJO, the phase of the frequency division can be matched. Further, since the frequency of the drive pulse is lower than that of the output of the VCOSO, there is an advantage that there is less waveform deterioration during transmission.

Modifications of the second embodiment regarding the connection position of the delay circuit 40 are shown in FIGS.
In a), the output of the timing generator 36 is input to the phase comparator 42 via the delay circuit 40. 4th l6
), the output of the drive pulse generation circuit 22 supplied from the camera head 10 via the signal line 16 is input to the phase comparator 42 via the delay circuit 40.

In FIG. 4 (eJ), the output of the C0D 20 is input to the signal processing circuit 34 via the delay circuit 40. The same effects as in the second embodiment can also be obtained with these modifications.

It should be noted that the present invention is not limited to the embodiments described above, and can be modified freely without departing from the gist thereof.

〔Effect of the invention〕

As explained above, according to the present invention, the amount of transmission delay of the signal from the camera to the signal processing unit is detected by the phase comparator in the signal processing unit, and the output of the solid-state image sensor is signal-processed. Since the timing of the processing circuit is controlled by the output of the phase comparator, an imaging device with simple transmission is provided that can compensate for delays in signal transmission by cable between the camera head and the second processing section. . Furthermore, according to the imaging device of the present invention, the driving pulses for the solid-state imaging device are not transmitted from the signal processing section, but are generated within the camera, so that the driving pulses are not being transmitted within the signal processing section. There is no need to provide a matching circuit to compensate for the deterioration of the waveform, and the transmission of the signal processing section becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the transmission of a first embodiment of the imaging device according to the present invention, and FIGS. 2(a), (b), (e)
) is a diagram showing a modification of the first embodiment, FIG. 3 is a diagram showing a transmission of a second modification of the imaging device according to the present invention, and FIGS. 4(a), (bl, ( c+) is a diagram of a modification of the second embodiment. 20... Solid-state image sensor (CCD), J 2... Drive pulse generator, 30. 38... Voltage controlled oscillator (V
CO), 34... Signal processing circuit, 36... Timing generator, 42... Phase comparator. Applicant's representative Patent attorney Atsushi Tsuboi Procedural amendment 1. Indication of the case Japanese Patent Application No. 62-23109 2, Title of the invention Imaging device 3, Person making the amendment Relationship to the case Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, Agent 3, Kasumigaseki, Chiyoda-ku, Tokyo Chome 7-2 UBE Building 7,
Contents of the amendment (1) "Phase comparator 38" written on page 11, line 18 of the specification is corrected to "phase comparator 42." (2) "Delay circuit 38" written on page 11, line 19 of the specification is corrected to "delay circuit 40."

Claims (5)

[Claims] (1) In an imaging device in which a camera head and a signal processing section are connected via a cable, the camera head includes a solid-state imaging device and a means for generating drive pulses for the solid-state imaging device, and the signal processing section a first oscillator for supplying a reference pulse to the drive pulse generation means; a signal processing means for processing the output of the solid-state image sensor; a means for generating a timing pulse for the signal processing means; a second oscillator that supplies a reference pulse; and a phase control that controls the phase of the timing pulse so that a phase difference between the timing pulse and the output of the solid-state image sensor supplied from the camera head via the cable becomes zero. An imaging device comprising: means. (2) The drive pulse generation means includes a pulse generator that frequency-divides the output of the first oscillator to generate a drive pulse, and the timing pulse generation means divides the output of the second oscillator and generates a timing pulse. The phase control means includes a timing generator that generates pulses, and the phase control means includes a signal transmission means that transmits the input of the pulse generator to the signal processing section via the cable, and a signal transmission means that transmits the input of the timing generator and the signal transmission means. detecting the phase difference with the input of the pulse generator transmitted from the camera head through the
Claim 1, further comprising a phase comparator that controls the phase of the second oscillator according to the detection result.
The imaging device described in section. (3) The driving pulse generating means includes a pulse generator that frequency-divides the output of the first oscillator to generate a driving pulse, and the timing pulse generating means divides the output of the second oscillator to generate a timing pulse. The phase control means includes a timing generator that generates pulses, and the phase control means includes a signal transmission means that transmits the driving pulses to the signal processing section via the cable, and a signal transmission means that transmits the driving pulses to the signal processing section through the timing pulses and the signal transmission means. The imaging device according to claim 1, further comprising a phase comparator that detects a phase difference with a drive pulse transmitted from the second oscillator and controls the phase of the second oscillator according to the detection result. Device. (4) The imaging according to claim 2 or 3, wherein a delay circuit is connected between the output of the first oscillator or the second oscillator and the phase comparator. Device. (5) The imaging device according to claim 2 or 3, wherein a delay circuit is connected between the output of the solid-state imaging device and the signal processing means.