JP2007068990A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device, obtaining an endoscope image without color irregularity. <P>SOLUTION: This light source device includes: a first light emitting element (a light emitting element 10R for R) generating illuminating light with a first light emission intensity for irradiating an object; and a second light emitting element (a light emitting element 10G for G) generating illuminating light with a second light emission intensity, wherein the light source device is disposed so that a peak part 100-3 of a first light emission intensity coincides with a peak part 100-1 of a second light emission intensity to emit light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source device including a plurality of light emitting elements that emit light having a plurality of different wavelengths.

For example, Japanese Patent Laid-Open No. 11-225953 discloses an electronic endoscope in which an imaging device for observation and light emitting elements of three colors R (red), G (green), and B (blue) are arranged at the distal end of an insertion portion. Is disclosed.
Japanese Patent Application Laid-Open No. 11-225953

  However, in the conventional technique represented by Japanese Patent Laid-Open No. 11-225953, the light emission points of the R, G, and B LEDs are different from each other for an image pickup device such as a CCD. There was a problem of unevenness.

  The present invention has been made paying attention to such a problem, and an object of the present invention is to provide a light source device capable of obtaining an endoscopic image without color unevenness.

  In order to achieve the above object, a light source device according to a first aspect of the present invention includes a first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject, and at least the first light emission. A second light emitting element that generates illumination light having a second light emission intensity, including light having a wavelength different from that of the illumination light generated from the element, wherein the peak portion of the first light emission intensity and the first light emission element It arrange | positions so that the peak part of the emitted light intensity of 2 may correspond, and it makes it light-emit.

  The light source device according to the second aspect of the present invention includes a first light emitting element that generates illumination light having a first light emission intensity to irradiate a subject, and illumination light generated from the first light emitting element. And a second light-emitting element that generates illumination light having a second emission intensity, and at least one of the first light-emitting element and the second light-emitting element is plural. Are arranged, and the first emission intensity peak portion and the second emission intensity peak portion are arranged so as to coincide with each other to emit light.

  The light source device according to a third aspect of the present invention is the light source device according to the second aspect, wherein the peak portion of the first light emission intensity and the peak portion of the second light emission intensity of the image sensor that captures an image of a subject. It is arranged so as to coincide with the center position and emits light.

  According to a fourth aspect of the present invention, there is provided a light source device including a first light emitting element that generates illumination light having a first light emission intensity to irradiate a subject, and illumination light generated from the first light emitting element. Are different wavelengths, and the second light emitting element that generates the illumination light having the second light emission intensity, and the peak portion of the first light emission intensity and the peak portion of the second light emission intensity coincide with each other. And a control means for controlling the light emission amount of the first light emitting element and the second light emitting element, and at least one of the first light emitting element and the second light emitting element is arranged in plural. Has been.

  A light source device according to a fifth aspect of the present invention includes a first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject, and illumination light that is generated from the first light emitting element. Are different wavelengths, and the second light emitting element that generates the illumination light having the second light emission intensity, and the peak portion of the first light emission intensity and the peak portion of the second light emission intensity coincide with each other. And a control means for controlling the light emission amount of the first light emitting element and the second light emitting element, and a plurality of at least one of the first light emitting element and the second light emitting element is arranged. Then, the light emission amounts of the plurality of light emitting elements are independently controlled.

  According to the present invention, it is possible to provide a light source device capable of obtaining an endoscopic image without color unevenness.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a field sequential endoscope apparatus 1 according to an embodiment of the present invention, in which an electronic endoscope 2 including a light emitting diode 10 and light emission for controlling driving of the light emitting diode 10 are illustrated. A diode drive control unit 3, a video processor 4 as a signal processing device that performs signal processing on an image signal acquired by the electronic endoscope 2, and a color monitor 5 that displays the image signal processed by the video processor 4 With. The electronic endoscope 2, the light emitting diode drive control unit 3, the video processor 4, and the color monitor 5 are connected to each other by signal lines or the like. Further, in FIG. 1, only one light emitting diode 10 is shown, but in reality, three light emitting diodes are arranged for each of R (Red), G (Green), and B (Blue).

  In the above-described configuration, when a light emitting diode 10 emits light to illuminate a subject (not shown), an optical image of the illuminated subject is placed on the focal plane by the objective optical system 12 in the electronic endoscope 2. The image is formed on the CCD 11. The optical image is photoelectrically converted by the CCD 11 and accumulated as signal charges.

  When a CCD drive signal is applied from the CCD driver 81 in the video processor 4 to the CCD 11, the signal charge accumulated in the CCD 11 is transferred and output to the outside as an imaging signal output.

  The output signal of the CCD 11 is amplified by a preamplifier 83 in the video processor 4 and then converted into a digital signal by an A / D converter 84. The R, G, and B image signals converted into digital signals are stored in the R, G, and B memories 86R, 86G, and 86B, respectively, by switching the selector 85 in synchronization with the frame sequential illumination.

  The imaging signals stored in the R, G, B memories 86R, 86G, 86B are simultaneously read out and converted into analog signals by the D / A converters 87R, 87G, 87B, respectively, to become R, G, B signals. The R, G, and B signals are output to the color monitor 5 together with a synchronization signal (not shown) via the buffers 88R, 88G, and 88B, and the subject image is displayed in color on the display surface.

  The R, G, and B signals output through the D / A converters 87R, 87G, and 87B are input to the dimming signal generation circuit 89, and for example, a dimming signal that is integrated for one field period is generated. The dimming signal is input to the lighting / dimming control circuit 71 of the light emitting diode drive control unit 3.

  A reference voltage Er is applied to the lighting / dimming control device 71 from a reference level generation circuit 72 that generates a reference level corresponding to brightness suitable for observation. The reference level can be made variable. The lighting / dimming control device 71 compares the reference voltage Er with the inputted dimming signal, generates a difference signal, and outputs the lighting / dimming signal for which the difference signal becomes 0 to the light emitting diode driver 73. The light emission intensity and light emission period of the light emitting diode 10 are varied.

  FIG. 2 is a time chart showing the timing relationship of each operation of turning on the light emitting diode 10, driving the CCD 11, and storing the imaging signal. The timing controller 82 is driven by a vertical synchronization signal (VD) generated by a synchronization signal generation circuit (not shown). The operation timing of the CCD driver 81 and the lighting / dimming control circuit 71 is determined by an output signal from the timing controller 82.

  That is, the lighting / dimming control device 71 outputs a light emitting diode drive signal to the light emitting diode driver 73 in synchronization with the output signal from the timing controller 82. The light emitting diode driver 73 causes the light emitting diode 10 to emit light in the order of R, G, and B in synchronization with the light emitting diode drive signal. The light emission / dimming control of the light emitting diode 10 is performed based on the reference voltage generated by the reference level generation circuit 72.

  The CCD driver 81 outputs a CCD drive signal to the CCD 11 in synchronization with the output signal from the timing controller 82 after the R, G, and B light emission periods. As a result, the CCD 11 is driven to perform an imaging operation. The imaging signals acquired by this imaging operation are stored in the R, G, B memories 86R, 86G, 86B, respectively, according to the repeating operation of the selector 85. The above-described light emission of the R, G, and B light emitting diodes 10, the driving of the CCD 11, and the storing of the imaging signal are performed within a 1 VD period indicating the separation of the two screens.

  Incidentally, as shown in FIG. 1, a CCD 11 as an imaging device and a light emitting diode 10 as a light source are disposed at the distal end portion of the electronic endoscope 2, and these elements are disposed at the distal end portion having a small diameter. In this case, there is a problem that color unevenness occurs in the endoscopic image depending on the arrangement method. In the following, it will be considered how the R, G, and B light emitting diodes 10 should be arranged with respect to the CCD 11.

(First embodiment)
In the first embodiment of the present invention, a case will be described in which the CCD is arranged at a position shifted from the center position of the distal end portion of the endoscope. FIG. 3 is a diagram for explaining the problems of the conventional arrangement. The light emitting diodes 10R, 10G, and 10B are arranged in a vertical row, and the light emitting diodes 10R, 10G, and 10B for R, G, and B are not arranged in consideration of light distribution. When the light emitting diodes 10R, 10G, and 10B emit light in such an arrangement state, the light emitting points of the light emitting diodes 10R, 10G, and 10B are different from each other with respect to the CCD 11, so that the light distribution is emitted within the angle of view of the CCD 11. Since the diodes 10R, 10G, and 10B shift the illumination peak position, color unevenness occurs in the endoscopic image.

  FIG. 4 shows the arrangement of the distal end portion of the endoscope according to the first embodiment of the present invention, and the illuminance (vertical (Y-axis) direction in the drawing) on a plane separated by a certain distance from the distal end of the endoscope. Yes. The horizontal (X-axis) direction in the drawing indicates a distance on a straight line passing through the centers of two light emitting elements of the same type. In FIG. 4, portions with high illuminance illuminated by light of each wavelength of R, G, B are referred to as emission intensity peak portions 100-3, 100-1, 100-2, respectively. The peak portions 100-3, 100-1, and 100-2 of these three emission intensities are on the optical axis of the CCD 11 and coincide with each other.

  Here, the light emitting diodes 10R and 10R-1, 10G and 10G-1, 10B and 10B-1 for R, G and B are arranged so as to sandwich the CCD 11 respectively. Further, since the light emitting diodes 10R and 10R-1 are arranged at positions that are separated from the CCD 11 by an equal distance, the peaks of the respective light emission intensities coincide with each other. The same applies to the light emitting diodes 10G and 10G-1, 10B and 10B-1 of other colors.

  Here, two light emitting elements for R, G, and B are disposed, but it is sufficient that two or more light emitting elements of any one color are disposed.

  As described above, regarding the arrangement of the light emitting diodes of the respective colors, the peak positions of the light emission intensities of the light emitting diodes of the respective colors as viewed from the CCD 11 are intentional by arranging the light emitting diodes of the respective colors so that the CCD 11 is sandwiched or enclosed. It is possible to set a distance close to the CCD 11 to improve the light distribution of each color.

  From the above, the light emitting points of the respective light emitting diodes 10R and 10R-1, the light emitting points of 10G and 10G-1, and the light emitting points of 10B and 10B-1 are substantially coincident with the CCD 11, so that light is emitted from the same point. Looks like you are doing. In this way, an endoscopic image without color unevenness is obtained.

(Second Embodiment)
The second embodiment of the present invention will be described below. FIG. 5 is a diagram for explaining a problem that cannot be solved only by the first embodiment of the present invention. The light emitting diodes 10R, 10G, and 10B for R, G, and B are, for example, endoscopes. A situation is shown in which the CCD 11 is asymmetrically arranged due to restrictions on the layout of the tip. In such an arrangement, the peaks of the light distribution of the respective light emitting diodes 10R, 10G, and 10B do not coincide within the angle of view of the CCD 11, so that the problem of uneven color that occurs in the endoscopic image cannot be solved in practice. Therefore, in the present embodiment, instead of changing the arrangement of the light emitting diodes 10R, 10G, and 10B, the light emission intensities of the light emitting diodes 10R and 10R-1, 10G and 10G-1, 10B, and 10B-1 are varied. Accordingly, the light distribution peaks of the light emitting diodes 10R and 10R-1 for R, G, and B, the light distribution peaks of 10G and 10G-1, and the light distribution peaks of 10B and 10B-1 are illustrated. As shown in FIG. 6, control is performed so as to substantially match within the angle of view of the CCD 11. Here, the light emission intensity (light emission amount) of each light emitting element may be controlled in relation to other light emitting elements, or may be controlled independently for each light emitting element.

  As a result, the light emitting points of the light emitting diodes 10R and 10R-1, the light emitting points of 10G and 10G-1, and the light emitting points of 10B and 10B-1 substantially coincide with the CCD 11, so that light is emitted from the same point. As a result, an endoscopic image without color unevenness is obtained.

  In the second embodiment described above, two sets of R, G, and B light emitting diodes are arranged so as to be sandwiched between the CCDs 11, but three or more sets of light emitting diodes are arranged so as to surround the CCDs 11, respectively. Also good.

  FIG. 7 shows an example in which three or more light emitting diodes for R are arranged (three in FIG. 7, 10R, 10R-1, and 10R-2). The CCD 11 is composed of 10R, 10R-1, and 10R-2. It is arranged so as to surround. Three or more light emitting diodes of G and B can be used in the same arrangement method.

(Third embodiment)
The third embodiment of the present invention will be described below. In the third embodiment, a case where the CCD is arranged at the center position of the tip will be described. FIG. 8 is a diagram for explaining the problems of the conventional arrangement. If each of the light emitting diodes 10R, 10G, and 10B emits light in such an arrangement, the light emitting points of the light emitting diodes 10R, 10G, and 10B are different from each other with respect to the CCD 11. The diodes 10R, 10G, and 10B do not match, and color unevenness occurs in the endoscopic image.

  Fig.9 (a) has shown the structure of the endoscope front-end | tip part which concerns on 3rd Embodiment of this invention. Here, the light emitting diodes 10R, 10G, and 10B for R, G, and B are arranged and enclosed at substantially point-symmetrical positions with respect to the CCD 11. Further, three sets of R, G, B light emitting diodes 10R-1, 10G-1, 10B-1, 10R-2, 10G-2, 10B-2, 10R-3, 10G-3, 10B-3 are also used. It arrange | positions in the position which encloses CCD11. Here, four R, G, and B light emitting elements are arranged, but it is sufficient that two or more light emitting elements of any one color are arranged. However, in the case of two, the CCD 11 is disposed at a position where it is roughly sandwiched.

  Hereinafter, the light-emitting diodes 10R, 10G, and 10B and the light-emitting diodes 10R-2, 10G-2, and 10B-2 that face the light-emitting diodes 10R, 10G, and 10B will be described, but the same applies to other light-emitting diodes that face each other.

  The distance LR from the center of the CCD 11 to the light emitting diode 10R and the distance LR2 to the light emitting diode 10R-2, the distance LG from the center of the CCD 11 to the light emitting diode 10G and the distance LG2 to the light emitting diode 10G-2, and the center of the CCD 11 By adjusting the light emission intensity of each light emitting diode according to the distance LB to the light emitting diode 10B and the distance LB2 to the light emitting diode 10B-2, the arrangement when the R light emitting diodes 10R and 10R-2 emit light is adjusted. The peak of light, the peak of light distribution when emitting light from the G light emitting diodes 10G and 10G-2, and the peak of light distribution when emitting light from the B light emitting diodes 10B and 10B-2 are shown in FIG. As shown in (b), they can be substantially matched within the angle of view of the CCD 11. In this case, the emission intensity in each of the three orientation distributions has a peak at the center of the CCD 11.

  From the above, the light emitting points of the light emitting diodes 10R and 10R-2, the light emitting points of 10G and 10G-2, and the light emitting points of 10B and 10B-2 are substantially coincident with the CCD 11, so that light is emitted from the same point. Looks like you are doing. In this way, an endoscopic image without color unevenness is obtained.

  In the first embodiment described above, the four R, G, and B light emitting diodes are arranged symmetrically with respect to the CCD 11 with respect to the CCD 11. It may be arranged so as to be symmetric.

  In the third embodiment, the case where the CCD is arranged at the center position of the tip has been described. However, since the emission peak can be moved by adjusting the emission intensity, the CCD is arranged at a position away from the center position of the tip. Even in this case, it is obvious that each color can be controlled so as to appear to emit light from the same point.

  Furthermore, in this embodiment, the light emitting element as the illumination means is a light emitting diode, but a laser diode may be used. In the present embodiment, a CCD is used as the image sensor, but a CMOS may be used. Further, in the present embodiment, the light emitting diode drive control unit 3 is disposed separately, but the inside of the video processor 4, the tip of the electronic endoscope 2, or the operation unit (not shown) of the electronic endoscope 2 (not shown). ) Etc.

1 is a diagram showing a configuration of a field sequential endoscope apparatus 1 according to an embodiment of the invention. FIG. 3 is a time chart showing the timing relationship of each operation of lighting of the light emitting diode 10, driving of the CCD 11, and storing of an imaging signal. In 1st Embodiment of this invention, it is a figure for demonstrating the problem of the conventional arrangement | positioning. It is a figure which shows the arrangement | positioning of the endoscope front-end | tip part which concerns on 1st Embodiment of this invention, and the illumination intensity in the surface away from each light emitting element only by fixed distance. It is a figure which shows the modification of 1st Embodiment. FIG. 10 is a diagram illustrating an example in which control is performed so that light distribution peaks of light emitting diodes for R, G, and B substantially match within an angle of view of the CCD 11 in the second embodiment of the present invention. In 2nd Embodiment of this invention, it is a figure which shows the example at the time of arrange | positioning three R light emitting diodes. It is a figure for demonstrating the problem of the conventional arrangement | positioning in 3rd Embodiment of this invention. (A) is a figure which shows arrangement | positioning of the endoscope front-end | tip part which concerns on 3rd Embodiment of this invention, (b) is a figure which shows the orientation distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endoscope apparatus 2 Electronic endoscope 3 Light emitting diode drive control part 4 Video processor 5 Color monitor 10 Light emitting diode 11 Image pick-up element (CCD)
12 objective optical system 71 lighting / dimming control circuit 72 reference voltage 73 light emitting diode driver 81 CCD driver 82 timing controller 83 preamplifier 84 A / D converter 85 selector 86R R memory 86G G memory 86B B memory 87R, 87G, 87B D / A Converter 88R, 88G, 88B Buffer 89 Dimming signal generation circuit 100-1 to 100-3 Peak part

Claims (5)

A first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject;
A second light emitting element that generates illumination light having a second emission intensity, including at least light having a wavelength different from that of the illumination light generated from the first light emitting element,
A light source device, wherein the first light emission intensity peak portion and the second light emission intensity peak portion are arranged so as to coincide with each other to emit light. A first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject;
A second light emitting element that generates illumination light having a second light emission intensity and a wavelength different from that of the illumination light generated from the first light emitting element,
At least one of the first light emitting element and the second light emitting element is arranged, and the peak portion of the first light emission intensity and the peak portion of the second light emission intensity coincide with each other. A light source device arranged to emit light.   The light emitting device according to claim 2, wherein the peak portion of the first light emission intensity and the peak portion of the second light emission intensity are arranged so as to coincide with a center position of an image sensor that images the subject. Light source device. A first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject;
A second light emitting element that generates illumination light having a second light emission intensity and a wavelength different from that of the illumination light generated from the first light emitting element;
Control means for controlling the light emission amounts of the first light emitting element and the second light emitting element so that the peak part of the first light emission intensity and the peak part of the second light emission intensity coincide with each other;
Comprising
At least one of the first light emitting element and the second light emitting element is arranged in plural. A first light emitting element that generates illumination light having a first light emission intensity that irradiates a subject;
A second light emitting element that generates illumination light having a second light emission intensity and a wavelength different from that of the illumination light generated from the first light emitting element;
Control means for controlling the light emission amounts of the first light emitting element and the second light emitting element so that the peak part of the first light emission intensity and the peak part of the second light emission intensity coincide with each other;
Comprising
A light source device comprising: a plurality of at least one of the first light emitting element and the second light emitting element, and independently controlling light emission amounts of the plurality of light emitting elements.

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