JPH0576010B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to an electronic endoscope device, and in particular, to an electronic endoscope device that lowers the emission intensity of an irradiation light source and emit enhanced light for a short period of time to produce movement. The present invention relates to an electronic endoscope device having a modulated irradiation function that captures still images of a target.

(Prior art) Light emitted from a light source is introduced into the body cavity through a light guiding path built into an endoscope, illuminates the object to be imaged, and the reflected light is imaged by an image sensor. Still images of moving objects are used in electronic endoscopy devices that process image signals in a signal processing circuit and display them on a display unit such as a TV monitor, allowing multiple doctors to simultaneously observe diagnostic objects inside body cavities. (also called a frozen image) may be requested.

If the irradiation time for irradiating the inside of a body cavity when capturing such a still image is as long as when capturing a normal moving image, there is a problem in that the obtained image will be blurred.

For this reason, conventionally, for example, a fixed amount of illumination light emitted from a light source is blocked using an aperture and a stopper, and is allowed to pass through at specific short time intervals.
The light was irradiated as a pulsed light, but this method had a problem in that the absolute amount of light was insufficient when the time width of the pulsed light was made small.

Therefore, a modulation lighting method is used in which the light emission intensity of the light source is made weak and the light is emitted intensified only at specific short time intervals to obtain pulsed irradiation light. With this modulation lighting method,
It is possible to obtain pulsed light emission with a small pulse width and a large amount of output light. However, when a discharge lamp is used as a light source, it is difficult to completely stop the discharge lamp from emitting light at specific pulse intervals, resulting in a delay in response when turning on and off, a change in spectrum, etc. Therefore, during the non-emission period, the lowest power input is required to maintain arc discharge, but the weak light emitted during this period also irradiates the inside of the body cavity and contributes to imaging, causing the problem that images become distorted when frozen. The dot was hot.

(Problems to be Solved by the Invention) As described above, in the conventional electronic endoscope device, when capturing a still image of a moving object, if the irradiation time is long as in normal shooting, it is possible to obtain an advantage. There is a problem in that the resulting image is blurred, and for this reason, even if you try to take an image by passing the irradiated light from the light source for a short time while blocking it with an aperture or a stopper, etc., to obtain pulsed irradiated light, the absolute light intensity is insufficient. Therefore, it was not possible to reduce the pulse width too much. Alternatively, even with a modulation lighting method in which the light emission intensity of the light source is made weak and the light is emitted intensified for a specific short period of time to obtain pulsed irradiation light, the light emission from the light source cannot be turned on and off in a perfect pulsed manner. There was a problem that weak light was captured, causing blur.

In view of these problems, we provide an electronic endoscope device equipped with an irradiation mechanism that uses a modulation lighting method that produces strong pulsed irradiation light, but does not generate weak irradiation light during the non-enhanced emission period. The purpose of this invention is to do so.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a flexible guiding tube to be inserted into a body cavity, and a body cavity provided in the guiding tube. A light guide path that guides illumination light into the body cavity, an imaging device that photographs the inside of the body cavity and converts it into a video signal, and normally emits light during video shooting, and increases the light emission intensity of the light source for a specific period of time in response to a still image shooting request. a light source, and a light shielding means provided in the light incident surface of the light guide path and the optical path of the light source to block the passage of light;
The light shielding means is kept in a closed state at the start of a field for photographing a still image of the video signal, the light shielding means is opened almost at the same time as the light source starts to emit enhanced light, and the light blocking means is closed almost at the same time as the enhanced light emission ends. The present invention is characterized by comprising a cutoff control means for setting the state.

(Function) An electronic endoscope device with such a configuration uses a modulation lighting method to obtain pulsed irradiation light by weakening the light emission intensity of the light source and emitting enhanced light at specific short time intervals. , while performing pulsed light emission with a small pulse width and large output light amount, in synchronization with the enhanced light emission of the light source, the irradiation light that enters the light guide path from the light source during the non-enhanced light emission period is blocked by a light blocking means. By preventing even weak light from being irradiated during the non-enhanced light emission period, a still image without blur can be obtained.

(Embodiment) FIG. 1 shows a schematic diagram of the main parts of an electronic endoscope apparatus as an embodiment to which the present invention is applied. Inside the light source unit 11 of the electronic endoscope device, there are a lamp 1 using a xenon lamp as an irradiation light source, a lamp power source 3, a reflector 2 for light from the lamp 1, and a condenser lens 4. 1 and a shutter 12 serving as a light shielding means between the reflecting mirror 2 and the condensing lens 4.
is installed. The light emitted from the lamp 1 is focused by a condenser lens 4 on the light source side end surface of a light guide 5 installed in an endoscope (not shown), and is guided to the other end surface of the light guide 5. An object to be imaged inside the body cavity is irradiated through an optical system 6 disposed at the tip of the introduction section of the endoscope. The reflected light from the object to be imaged is received by a CCD (solid-state image sensor) 7, which is also placed at the tip of the scope introduction part, and converted into an electrical image signal, which is then sent to a signal installed in the endoscope (not shown). It reaches the image processing circuit 9 via the line 8, where the image is processed and displayed on the display 10.
The image will be displayed.

Further, FIG. 2 is a timing chart showing changes in the light emission intensity of the light source section in the same embodiment.

A light emission waveform 14 indicates the light emission intensity of the lamp 1. A portion 15 to be shaded by the shutter 12 of the light blocking means is indicated by diagonal lines. Also, a in Figure 2,
f is the normal light emission period, b, c, and e are the weak light emission periods,
d is the enhanced light emission period.

The lamp 1 generates the amount of light necessary for video shooting during the normal emission period, and during the enhanced emission period, it generates an amount of light several times to several tens of times that of the normal emission period. Further, the amount of light during the weak light emission period is the amount of light when the lowest voltage that allows the lamp 1 to maintain arc discharge is applied.

Field index pulse 13 indicates the imaging timing pulse of CCD 7 using the interlaced method, and is used for EVEN field (even field) and ODD field (odd field).
One image is captured using these two fields. In addition, field index pulse 1
If the voltage V in 3 is high, it represents an EVEN field, and if the voltage V is low, it represents an ODD field.

Periods c, d, and e represent freeze image shooting periods. At this time, the center of the enhanced light emission period is
It is almost the same as the switching point between the ODD field and the EVEN field. In other words, the amount of light applied to the ODD field and the amount of light applied to the EVEN field are made equal during the freeze image shooting period.

Next, to explain the operation, in FIG. 2, when the freeze switch (not shown) for obtaining a still image of the object to be imaged is turned on, the light emission intensity I of the lamp 1 is changed to
As shown in the light emission waveform 14, the input value is lowered to the lowest value that can maintain the arc discharge of the xenon lamp. Then, before and after the charge intake of CCD7 changes from ODD field to EVEN field,
Ramp 1 so that it spans both fields equally.
A large amount of input is applied to the light to cause it to emit enhanced light. Furthermore, during the freeze image capturing period other than this enhanced light emission period, that is, during the shaded portions 15 shown in c, d, and e of FIG. 2, the light emitted from the lamp 1 is blocked by the shutter 12. In this way, imaging by the CCD 7 is performed only during the short enhanced light emission period, making it possible to prevent blurring of still images.

Further, in the above embodiment, the input voltage to the lamp 1 is reduced during the period of the shaded portion 15 by the shutter 12, but a configuration may be adopted in which the input voltage is not reduced.

[Effects of the Invention] As explained above, the electronic endoscope device to which the present invention is applied can stabilize the operation of the lamp when the same lamp is used for light emission for normal imaging and enhanced light emission. It is possible to prevent image shift when taking frozen images. Further, the effects of reducing power consumption and heat generation of the lamp and extending the life of the lamp can be obtained. In this way, it is possible to obtain the effect that the light source device that reduces the power consumption and heat generation of the lamp can be miniaturized.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the main parts of an electronic endoscope apparatus according to an embodiment of the present invention, and FIG. 2 is a timing chart showing changes in the light emission intensity of a light source section in the embodiment. 1...Lamp, 2...Reflector, 3...Lamp power source, 4...Condensing lens, 5...Light guide, 6
...Optical system, 7...CCD, 8...Signal line, 9...
...Image processing circuit, 10...Display, 11...
...Light source section, 12...Shutter, 13...Field index pulse, 14...Emission waveform, 15
...Shaded area.

Claims (1)

[Scope of Claims] 1. A flexible guiding tube inserted into a body cavity;
A light guide path provided in the guide tube to guide illumination light into the body cavity, an imaging device that photographs the inside of the body cavity and converts it into a video signal, and a light source that normally emits light during the video recording period and responds to a request for still image recording. a light source that emits light whose intensity is enhanced for a specific period of time; a light shielding means provided in the light incidence surface of the light guide path and the optical path of the light source for blocking the passage of light; and a light shielding means for photographing a still image of the video signal The light shielding means is kept in a closed state at the start of the field, the light shielding means is opened almost at the same time as the light source starts to emit enhanced light, and the light shielding means is closed almost at the same time as the enhanced light emission ends. Endoscope equipment. 2. The endoscope apparatus according to claim 1, wherein the light source generates a smaller amount of light at the start of a field for photographing a still image than when normally emitting light.