JP2002112960A - Electronic endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an endoscope image free from uneven color despite the bias in the spectral sensitivity characteristic of an image sensor of a scope by using at least bicolor light emitting diodes as a light source unit in an image signal processing unit of the electronic endoscope apparatus for a sufficient quantity of illumination light. SOLUTION: The light source unit (30) comprises at least a group of bicolor light emitting diodes to obtain a sufficient quantity of illumination light, and the number of the light emitting diodes with respective colors is so set as to offset the bias in the spectral sensitivity characteristic of individual colors for the image sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a scope (endoscope), an image sensor provided at a distal end of the scope, and an image signal processing unit connected to a proximal end of the scope. The present invention relates to an electronic endoscope apparatus configured to appropriately process a pixel signal obtained by an image sensor in an image signal processing unit and to output a video signal therefrom.

[0002]

2. Description of the Related Art As is well known, an electronic endoscope apparatus is used to observe the inside of an organ, for example, typically the inside of a stomach. Therefore, it is necessary to illuminate the front of the distal end of the scope, that is, the front of the imaging sensor, in order to obtain an internal image of the organ (a so-called endoscopic image) with the imaging sensor of the scope of the electronic endoscope apparatus. . Therefore, a light guide cable is inserted through a scope of the electronic endoscope apparatus, and a distal end thereof is optically connected to an illumination lens provided on a distal end surface of the scope. On the other hand, a light source unit is provided in the image signal processing unit of the electronic endoscope apparatus, and a proximal end of the light guide cable is optically connected to the light source unit when a scope is connected to the image signal processing unit. Thus, when the scope of the electronic endoscope apparatus is inserted into the organ, the front side of the distal end of the scope is illuminated, so that the inside of the organ can be observed by the imaging sensor.

Conventionally, a white light lamp such as a halogen lamp or a xenon lamp is used as a light source unit in an image signal processing unit. However, the life of such a lamp is short. 80
Or about 120 hours. Therefore, the conventional electronic endoscope apparatus has a problem that the troublesome replacement of the lamp must be performed frequently. Another issue is that
Since the color temperature distribution of such a white lamp changes over time during its life, in order to obtain an endoscope with an appropriate color balance, it is necessary to perform cumbersome white balance correction every time the electronic endoscope apparatus is used. Another point is that it must be done.

Therefore, it has been proposed to use a light-emitting element, for example, a light-emitting diode (LED), instead of the above-mentioned white lamp as a light source for illumination of an electronic endoscope apparatus. For example, Japanese Patent Application Laid-Open No. 63-260526 proposes providing an LED of three primary colors, for example, red, green and blue, at the distal end of a scope of an electronic endoscope and using it as a white light source. Specifically, under the same operating current, generally, the red LED emits the largest amount of light, and the blue LED emits the largest amount of light.
Is the smallest, and the green LED emits light in the middle. Therefore, the number of red LEDs to be provided at the distal end of the scope of the electronic endoscope device is minimized, and the green LED is
By setting the number of blue LEDs to the middle and increasing the number of blue LEDs to the maximum, a white light source using three primary color LEDs can be obtained.

Of course, the life of each color LED is much longer than that of the above-described halogen lamp, xenon lamp, etc.
The operator or the administrator of the electronic endoscope can be released from the troublesome lamp replacement work as described above. However, since the opening of the forceps channel, the water supply port, the air supply port, etc. are provided in addition to the imaging sensor at the distal end of the scope of the electronic endoscope, three primary color LEDs are provided at the distal end of the scope. In a mode in which a white light source is used, there is a problem in that the total number of LEDs to be provided there is limited, and a sufficient amount of illumination light cannot be obtained.

More specifically, an image sensor is combined with an objective lens having a large depth of focus, so that the image sensor can obtain an in-focus image from a relatively distant subject. Sufficient illumination light does not reach a distant subject, so that a clear reproduced image cannot be obtained for a relatively distant subject. In short, the LED light source device disclosed in the above-mentioned patent publication can clearly observe a subject near the imaging sensor but cannot clearly observe a distant subject. Becomes

Further, in the above-mentioned patent publication, the number of each of the three primary color LEDs is adjusted so as to obtain a white light source. Since the sensors themselves exhibit unique spectral sensitivity characteristics, white balance correction is indispensable processing to obtain an endoscope image without color unevenness, as in the conventional case. In short, it can be said that it is preferable to obtain a white light source by adjusting the number of each of the three primary color LEDs to obtain an endoscope image without color unevenness, but in consideration of the specific spectral sensitivity characteristics of the imaging sensor itself. In some cases, adjusting the number of each of the three primary color LEDs to provide a white light source does not immediately lead to obtaining an endoscope image without color unevenness.

[0008]

Accordingly, it is an object of the present invention to provide an electronic endoscope device of the type described above,
The light source unit in the image signal processing unit is configured to use a light emitting diode of at least two colors so that a sufficient amount of illumination light can be obtained, and there is no color unevenness regardless of the bias of the spectral sensitivity characteristic of the imaging sensor of the scope. An object of the present invention is to provide an electronic endoscope apparatus configured to obtain an endoscope image.

[0009]

SUMMARY OF THE INVENTION An electronic endoscope apparatus according to the present invention includes a scope, an imaging sensor provided at a distal end of the scope, and an image detachably connected to a proximal end of the scope. A signal processing unit, and pixel signals for one frame sequentially obtained by the image sensor are appropriately processed by the image signal processing unit, and then output as a video signal therefrom. In addition, the electronic endoscope further includes a light guide cable inserted through the scope to guide illumination light for illuminating the front of the distal end of the scope, and a light source unit provided in the image signal processing unit. With
When connecting the scope to the image signal processing unit, the proximal end of the light guide cable is optically connected to the light source unit. According to the present invention, in such an electronic endoscope device, the light source unit includes at least two color light emitting diode groups for obtaining a sufficient illumination light amount, and the number of light emitting diodes of each color light emitting diode group is reduced. It is characterized in that the setting is made so as to offset the bias of the spectral sensitivity characteristics of each color of the image sensor.

[0010] Preferably, the light source unit has at least two light sources.
It includes an LED array light source in which light emitting diode groups of colors are arranged, and an LED driver for driving the LED array light source. The LED array light source is detachable from the LED driver. In such a case, the scope is
At least two types are available and LED
Two types of array light sources corresponding to the respective types of the scope are prepared.

In the electronic endoscope apparatus according to the present invention, preferably, one of the two types of the scope is connected to the image signal processing unit, and one of the two types of the LED array light source is the one of the one type. Is LED
Determining means for determining whether the scope and the LED array light source correspond to each other when connected to the driver; and the determining means does not correspond to the scope and the LED array light source. Display means for displaying an error when it is determined that the error has occurred.

In the electronic endoscope apparatus according to the present invention, preferably, when the LED array light source is connected to the LED driver, a determination means for determining which type of the LED array light source is provided, The driving mode of the LED array light source by the LED driver can be changed according to the type determined by the determination means.

[0013]

Next, an embodiment of an electronic endoscope apparatus according to the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, a first embodiment of an electronic endoscope apparatus according to the present invention is schematically shown as a block diagram. The electronic endoscope apparatus includes a scope (endoscope) 10 and an image signal processing unit (a so-called processor) 12 to which the scope 10 is detachably connected. In the present embodiment, as will be described later, two types of scopes 10 are prepared, and the image signal processing unit 12 is shared by these two types of scopes 10.

The scope 10 has a solid-state image sensor such as CC
An image sensor 14 including a D (charge-coupled device) image sensor is provided, and the image sensor 14 includes an objective lens 16 combined with the CCD image sensor. An illumination light guide cable 18 composed of an optical fiber bundle is inserted into the scope 10, and the distal end of the light guide cable 18 is combined with the illumination light distribution lens 20. In FIG. 1, a part of the tissue in the body cavity is schematically illustrated by reference numeral T.

Referring to FIGS. 2 and 3, two types of scopes 10 are respectively shown schematically, and the appearance of these scopes 10 is substantially the same, but is used in one type of scope 10. Image sensor 14 used in the other type of scope 10
Is different. Here, FIG.
The scope 10 shown in FIG. 3 is referred to as an A type and a B type, respectively. In the A type scope 10 shown in FIG. 2, the image sensor 14 is constituted by a so-called monochrome (single color) CCD, and the B type scope 10 shown in FIG.
It comprises a CCD having a color filter.

Regardless of the type, the scope 10 comprises a rigid operating portion 10a and a flexible conduit or insertion portion 10b extending from the operating portion 10a. The operation section 10a is provided with operation culms and various switches for operating the tip of the insertion section 10b, but these operation culms and switches are omitted in FIGS. 2 and 3. The objective lens 16 and the illumination light distribution lens 20 described above are disposed on the distal end, that is, the distal end surface of the insertion portion 10b.

As is apparent from FIGS. 2 and 3, the scope 10 further includes a flexible connection cable 10c extending from the operation portion 10b, and a connection portion 10d is provided on the proximal end side. The connection portion 10d includes an electrical connector 10e and an optical connector 10f, and a predetermined number of contact pins are provided inside the electrical connector 10e.
f is configured as a light guide rod, the inner end of which is optically connected to the proximal end of the light guide cable 18.

Referring to FIG. 4, the external appearance of the image signal processing unit 12 is schematically shown. The image signal processing unit 12 comprises a rectangular housing 12a, and one wall surface thereof is connected to an electrical connector 10e. And an optical socket 12c adapted to receive an optical connector or optical guide rod 10f. By manually operating the connection portion 10d of the scope 10, the electric connector 10e and the light guide rod 10f are connected to the electronic socket 12 of the image signal processing unit 12.
b and the optical socket 12c. In addition,
In FIG. 4, reference numeral 12d denotes a main power ON / OFF switch of the image signal processing unit 12.

As shown in FIG. 1, an input line 22 and an output line 24 extend from the image sensor 14. The input line 22 and the output line 24 are connected to the image signal processing unit when the electrical connector 10e and the electronic socket 12b are connected. CCD driver 26 and CCD process circuit 2 in 12
8 respectively. The CCD driver 26 outputs a read clock pulse for reading one frame of pixel signals from the image sensor 14, and the read clock pulse is input to the image sensor 14 through the input line 22. The pixel signal read from the image sensor 14 is output to the CCD process circuit 28 through the output line 24, and the CCD process circuit 28 performs various processes on the read pixel signal. For example, the read pixel signal is sampled after being once amplified by the CCD process circuit 28 and then subjected to appropriate image processing such as gamma correction.

A portion of the light guide cable 18 on the proximal end side is also inserted into the connection cable 10c, and when the light guide rod 10f and the optical socket 12c are connected, the distal end surface of the light guide rod 10f is used for image signal processing. It is optically connected to the light source unit 30 in the unit 12. The light source unit 30 includes an LED array light source 32 composed of a number of light emitting diodes (LEDs) as a light source, an LED driver 34 for operating the LED array light source 32 to emit light, and L
The light emitted from the ED array light source 32 is transmitted to the light guide rod 10f.
And a condenser lens 36 for condensing the light on the tip end surface of the lens. Thus, the light emitted from the LED array light source 32 is used as illumination light as the light guide cable 18 and the illumination light distribution lens 2.
The object T is emitted from the distal end of the scope 10 through the light source 0, and the emitted light illuminates the subject T.

The LED array light source 32 is an LED driver 3
4 and the LED array light source 32 is L
A micro switch 37 is provided in the light source unit 30 to detect whether or not the light source unit 30 is connected to the ED driver 34 (FIG. 1). That is, when the LED array light source 32 is LE
When connected to the D driver 34, the microswitch 3
7 is turned on, and when the LED array light source 32 is disconnected from the LED driver 34, the microswitch 37 is turned off.

The LED array light source 32 includes three primary color light emitting diode groups, that is, a red light emitting diode group, a green light emitting diode group, and a blue light emitting diode group. The total number of these three primary color light emitting diodes is, for example, 49 in this embodiment. You. As shown in FIG. 4, the LED array light source 32 includes a rectangular plate member 32a, and a total of 49 light emitting diodes are arranged in a 7 × 7 matrix in a partial area of the rectangular plate member 32a. Some areas are light emitting areas 32
b.

In this embodiment, as in the case of the scope 10, two types of LED array light sources 32 are prepared. Any type of LED array light source 3
Whether 2 is used depends on the type of the scope 10 connected to the image signal processing unit 12.

Referring to FIGS. 5 and 6, two types of LED array light sources 32 are shown, respectively, which are LE
The appearance of D-array light source 32 is substantially the same, but is used in one type of LED array light source 32.
The ratio of the number of each color of the three primary color light emitting diodes in the light emitting diodes to the ratio of the number of each color of the three primary color light emitting diodes in the 49 light emitting diodes used in the other type of LED array light source 32 will be described later. So different from each other. Here, similarly to the case of the scope 10 described above, the LED array light source 3 shown in FIGS.
2 are referred to as A type and B type respectively. When the A type scope 10 (FIG. 2) is connected to the image signal processing unit 12, the A type LED array light source 32 (FIG. 5) is used, Type Scope 1
When 0 (FIG. 3) is connected to the image signal processing unit 12, a B type LED array light source 32 (FIG. 6) is used.

As shown in FIGS. 5 and 6, a connector 32c is attached adjacent to a lower end on the back side of the rectangular plate member 32a.
2c has five contact pins 32d ₁ , 32d ₂ , 32
d ₃ , 32d ₄ and 32d ₅ , for which B
The connector 32c of the LED array light source 32 of the type
Contact pins 32d ₁ , 32d ₂ , 32d ₃ and 3
2d ₄ is provided. Four contact pins 32d ₁ , 3
2d ₂ , 32d ₃ and 32d ₄ are connected to an LED driver 34 so that the individual light emitting diodes are powered by the LED driver 34.

[0027] The contact pins 32d ₅ are used to identify whether any of the A-type LED array light source 32 and the B-type LED array light source 32 is connected to the LED driver 34, the LED driver 34 detection circuit for detecting connection of the contact pins 32d ₅ as will be described later is incorporated.

As shown in FIG. 4, a notch opening 12e for mounting the LED array light source 32 is formed in the housing 12a of the image signal processing unit 12, and a contact pin is formed at the bottom of the notch opening 12e. (32d ₁ ,
32d ₂ , 32d ₃ , 32d ₄ , 32d ₅ ) are provided for receiving contact pins (32d ₁ , 32d ₂ , 32d ₂ , 32d ₂ , 32d ₅ ) through the socket.
32d ₃ , 32d ₄ , 32d ₅ ) are connected to predetermined signal lines of the LED driver 34. In short, the LED array light source 32 is inserted into the notch opening 12e by holding the upper side of the rectangular plate member 32a by hand, whereby the contact pins (32d ₁ , 3d) for the above-described socket are formed.
2d ₂ , 32d ₃ , 32d ₄ , 32d ₅ ) are manually connected.

[0029] Of course, LED array light source 32 is mounted at a predetermined position in the notch opening 12e of the housing 12 contact pin _{(32d 1, 32d 2, 32d} 3, 32d 4,
32d ₅₎ and when the connection between the socket has been performed properly,
The center of the light emitting area 32b of the rectangular plate member 32a is substantially aligned with the optical socket 12c.
When the light guide rod 10f is connected to the light guide rod 2e, the light emitted from the light emitting area 32b is efficiently focused on the end face of the light guide rod 10f (FIGS. 2 and 3) by the condenser lens 36 (FIG. 1). .

The above-mentioned microswitch 37 (FIG. 1) is arranged at an appropriate position at the bottom of the notch opening 12e, and is normally off. An LED driver 34 is mounted in the notch opening 12e.
Is connected to the micro switch 37, the micro switch 37 engages with a part of the rectangular plate member 32a.
Reference numeral 6 switches from the OFF state to the ON state, and the ON state of the microswitch 37 is maintained while the LED array light source 32 is mounted. Of course, when the LED array light source 32 is extracted from the notch opening 12e, the microswitch 37 returns from the on state to the off state.

A guide groove for receiving the lower edge of the rectangular plate member 32a is formed at the bottom of the notch opening 12e, and the lower end edge is inserted into the guide groove, whereby the contact pin (32d) is formed. _1, 32d _2, 32d
₃ , 32d ₄ , 32d ₅ ) and the socket are preferably securely connected.
Contact pin (32d ₁ from the lower edge periphery provided with a skirt portion extending downwardly _{of, 32d 2, 32d 3, 32d} 4, 32
It is also preferred that d ₅ ) can be protected.

As shown in FIG. 1, a system controller 38 is provided in the image signal processing unit 12, and the system controller 38 is composed of, for example, a microcomputer. That is, the system controller 38 includes a central processing unit (CPU), a program for executing various routines, a read-only memory (ROM) for storing constants and the like, and a writable / readable memory (ROM) for temporarily storing data and the like. RAM) and an input / output interface (I / O), and controls the overall operation of the electronic endoscope as described later.

Further, a timing generator 40 is provided in the image signal processing unit 12, and control clock pulses of various frequencies are output from the timing generator 40, and individual operation of the electronic endoscope is performed according to the control clock pulses. Timing is controlled. For example, the output timing of the read clock pulse from the CCD driver 26 to the image sensor 14 and the processing timing of the read pixel signal in the CCD process circuit 28 are controlled according to a predetermined control clock pulse from the timing generator 40. Also, the LED driver 34
Is also operated according to the control clock pulse output from the timing generator 40, whereby the light emission of the light emitting diodes of the LED array light source 32 is controlled in a predetermined manner as described later.

As described above, the A type scope 10
The image sensor 14 of the B type scope 10 is constituted by a CCD having an on-chip color filter. In this case, the number of pixels for one frame obtained by both types of imaging sensors 14 is different from each other.
And the frequency of the read clock pulse to be output to each of the image sensors 14 of the B-type scope 10 are different from each other. Similarly, the processing timing of the read pixel signal in the CCD process circuit 28 differs between the case of the imaging sensor 14 of the A type scope 10 and the case of the imaging sensor 14 of the B type scope 10. Therefore, A type scope 10 and B type scope 1
0 is connected to the image signal processing unit 12, a control clock pulse corresponding to the type of the scope 10 (imaging sensor 14) is generated by the system controller 38.
Is output from the timing generator 40 under the control of.

The A-type LED array light source 32 and the B-type LED array light source 32 differ from each other in the manner in which light emitting diodes of the three primary colors emit light, as will be described later. Then, a control clock pulse corresponding to the type is output from the timing generator 40 under the control of the system controller 38.

Referring to FIG. 7 and FIG.
The circuit configuration when the ED array light source 32 is connected to the LED driver 34 and the B type LED array light source 32
The circuit configuration when connected to the D driver 34 is shown.

As shown in FIGS. 7 and 8, in both types of LED array light sources 32, the red light emitting diode (R), the green light emitting diode (G) and the blue light emitting diode (B) are connected in series, respectively. The above-mentioned contact pins 32d ₂ , 32d ₃ and 32d ₄ are connected to the cathode side of the light emitting diode rows of each color.

On the other hand, the LED driver 34 is provided with a power supply circuit (not shown) for light emitting diodes of three primary colors.
With this power supply circuit, the power supply voltage _Vcc is applied to the contact pins 32d on the anode sides of the light emitting diode rows of the respective colors.
Applied via ₁ . Also, the LED driver 34 transistor T _r1, T _r2 and T _r3 are provided, as the collectors of the transistors T _r1, T _r2 and T _r3 are respectively connected to the contact pins 32d _2, 32d ₃ and 32d ₄ And each of the transistors (T _r1 , T _r2 , T
The emitter of _r3) is grounded via a suitable resistor _{(R 1, R 2, R} 3). The base of each transistor _{(T r1, T r2, T} r3) is connected to the timing generator 40, applied from the timing generator 40 controls the clock pulses of a predetermined frequency to the base of each transistor _{(T r1, T r2, T} r3) Is done. Of course, each transistor (T _r1, T _r2,
When a control clock pulse is applied to the base of _Tr3 ),
The light emitting diodes (R, G, B) of the corresponding color emit light for a time corresponding to the pulse width of each control clock pulse. In the present invention, the light emitting diodes (R, G, B) of each of the three primary colors are controlled so as to emit light at the same intensity. For such control, resistors R ₁ , R ₂ and R _{2 are used.}
It is possible by appropriately adjusting the resistance value of ₃ .

As will be described later, an A-type LED
Depending on whether any of the array light source 32 and the B-type LED array light source 32 is connected to the LED driver 34, the frequency of the control clock pulses to be applied to the base of each transistor _{(T r1, T r2, T} r3) Are different,
When the A-type LED array light source 32 is used, the light-emitting diodes of the three primary colors emit light periodically in a predetermined order, whereas the B-type LED array light source 32 is used. When you are
The light emitting diodes of each of the three primary colors are caused to emit light simultaneously at a predetermined cycle.

The LED driver 34 further includes a detection circuit 34
a is provided, and the resistor R ₄ the detection circuit 34a having a relatively large resistance, consisting of an analog / digital (A / D) converter 34b. As shown in FIG. 7, when the A-type LED array light source 32, i.e., the LED array light source 32 with the contact pins 32d ₅ are connected to the LED driver 34, one end of the resistor R ₄ is connected to the contact pins 32d _5, contact pins 32d ₅ are connected to the power supply voltage V _cc through a resistor R ₅ having a sufficiently small resistance value than the resistance R _4. One end of the resistor R ₄ is connected to the system controller 38 via the A / D converter 34b branches, the other end of the resistor R ₄ is grounded. Therefore, when the LED array light source 32 of the A-type to the LED driver 34 is connected, a voltage determined by the power supply voltage V _cc and the resistor R ₄ and R ₅ is generated at the one end of the resistor R ₄ of the detection circuit 34a ,
This voltage is detected by the system controller 38 after being converted into a digital value by the A / D converter 34b.

On the other hand, as shown in FIG.
D array light source 32, that is, when the LED array light source 32 having no contact pins 32d ₅ are connected to the LED driver 34 is not that the voltage V _cc is applied to one end of a resistor R _4, Accordingly resistor R The potential at one end of ₄ is at the ground level. Thus, the system controller 38
Is by this detecting the voltage level at one end of the resistor R ₄ of the detection circuit 34a, or LED array light source 32 connected to the LED driver 34 is of the A type B
Type.

It should be noted that whether the LED array light source 32 is mounted in the notch opening 12e of the image signal processing unit 12 is determined by detecting the on / off state of the micro switch 37 by the system controller 38. Can be determined by

As described above, A type scope 1
0 is constituted by a monochrome CCD, and the A type scope 10 is connected to the image signal processing unit 12.
When connected, the A-type LED array light source 32
(FIG. 5) is used. In order to obtain a color endoscopic image with the image sensor 14 composed of a monochrome CCD, a plane sequential method is adopted.
The light emitting diodes of each of the two primary colors emit light periodically in a predetermined order.

More specifically, for example, as shown in the timing chart of FIG. 9, the control clock pulses A-CLCK1, AC
LK2 and A-CLK3 are outputted to each of the bases of the transistors T _r1, T _r2 and T _r3 from the timing generator 40, these control clock pulses A-CLCK1, A-CLK
2 and A-CLK3, A-type LED array light source 3
The two red light emitting diodes, the green light emitting diodes, and the blue light emitting diodes emit light sequentially and sequentially. When the light emitting diode of each color emits light, the image sensor 14 is exposed to the light of that color.
Is formed by the objective lens 16. That is, a red object image, a green object image, and a blue object image are sequentially formed by the objective lens 16, and the object image of each color is photoelectrically converted by the imaging sensor 14 into an analog pixel signal for one frame.

On the other hand, as is clear from the timing chart of FIG. 9, when the exposure of each of the three primary colors is completed, a series of read clock pulses are output from the CCD driver 26 to the image sensor 14, whereby the image is captured. The analog pixel signals for one frame of the corresponding color are sequentially read from the sensor 14, and the read analog pixel signals are sequentially subjected to the processing as already described in the CCD process circuit 28. The analog pixel signal processed by the CCD process circuit 28 is once converted into a digital pixel signal by an analog / digital (A / D) converter 42 (FIG. 1). The conversion from the analog pixel signal to the digital pixel signal in the A / D converter 42 is performed according to a control clock pulse (a so-called sampling clock pulse) output from the timing generator 40.

Next, digital pixel signals for one frame are divided into three frame memories 44R and 44G according to the color.
And 44B. That is, the red digital pixel signal for one frame is written to the frame memory 44R, the green digital pixel signal for one frame is written to the frame memory 44G, and the blue digital pixel signal for one frame is written to the frame memory 44B. As is clear from the timing chart of FIG.
When the frame period ends, three frame memories 4
Writing of a red digital pixel signal for one frame, a green pixel signal for one frame, and a blue pixel signal for one frame to each of 4R, 44G, and 44B is completed.

On the other hand, while the digital pixel signals of the respective colors are sequentially written in the frame memories 44R, 44G and 44B, the frame memories 44R, 44G and 4
From 4B, digital pixel signals of the three primary colors having a corresponding relationship are simultaneously read out at a predetermined timing and output as digital component video signals. Writing digital pixel signals to frame memories 44R, 44G and 44B and frame memories 44R, 44G and 4
The reading of the digital pixel signal from 4B is performed according to the write clock pulse and the read clock pulse output from the memory controller 46. The output timing of the write clock pulse and the read clock pulse is controlled by the control clock output from the timing generator 40. Controlled by pulses. The synchronization signal component of the component video signal is created by the timing generator 40.

Frame memories 44R, 44G and 44B
Is converted into an analog component video signal by a digital / analog (D / A) converter 48, and the analog component video signal is converted to a TV monitor 50.
The synchronization signal component is output from the timing generator 40 to the TV monitor 50, and the subject image of the subject T is reproduced and displayed on the TV monitor 50 as an endoscope image. Note that analog components
The video signal is sent from the D / A converter 48 to the color encoder 5.
2 and the synchronizing signal component is also output to the color encoder 52, where the analog component video signal is converted to a composite video signal or S-video signal and then output to the outside, and the composite video signal or S-video is output. The signal is used in peripheral equipment such as a video tape recorder (not shown).

The image sensor 14 of the A type scope 10 is composed of a monochrome CCD as described above, and such an image sensor 14 has a biased spectral sensitivity characteristic as shown in the graph of FIG. Can have AS. That is, the imaging sensor 1 of the A type scope 10
4 is most sensitive to red light having a wavelength of about 580 to about 720 nm, then sensitive to green light having a wavelength of about 480 to about 620 nm, and about 380 to about 5
It has the lowest sensitivity to blue light having a wavelength of 20 nm. In short, the spectral sensitivity characteristic AS of the imaging sensor 14 of the A type scope shows a bias such that the sensitivity becomes gradually higher toward the longer wavelength side of the visible light region.

On the other hand, in the A type LED array light source 32, the light emitting diodes (R, G,
B) is controlled to emit light at the same intensity. That is, as shown in the graph of FIG.
, The light-emitting intensity distribution of the green light-emitting diode (R) and the light-emitting intensity distribution of the blue light-emitting diode (B) are substantially the same. Nevertheless, due to the bias of the spectral sensitivity characteristic AS (FIG. 10) of the image sensor 14, the emission intensity distribution of the red light emitting diode (R), the emission intensity distribution of the green light emitting diode (R), and the blue light emitting diode (B) Is apparently as shown in the graph of FIG. That is, the emission intensity distribution of the red light emitting diode (R) is maximum, and the emission intensity distribution of the green light emitting diode (R) and the emission intensity distribution of the blue light emitting diode (B) are sequentially reduced.

Therefore, if the number of light-emitting diodes of each of the three primary colors of the A-type LED array light source 32 is equal, and a reference white image is taken by the image sensor 14, a schematic diagram in FIG. As shown, the red signal component (R) of the analog component video signal output from the D / A converter 48
Is the highest, its green signal component (G) is next highest, and its blue signal component (B) is the lowest. Of course, when the subject T is photographed by the image sensor 14 under such conditions and the subject image is reproduced and displayed as an endoscope image on the TV monitor 50, the color balance of the endoscope image is biased to the red side, For this reason, an endoscope image with an appropriate color balance cannot be obtained.

However, in practice, as schematically shown in FIG. 14, among the three primary color light emitting diodes of the A type LED array light source 32, a red light emitting diode (R), a green light emitting diode (G) and a blue light emitting diode (G). The numbers of the diodes (B) are set to 9, 12, and 24, respectively, so that the bias of the spectral sensitivity characteristics of the image sensor 14 of the A type scope 10 is offset. That is, the ratio of the numbers of the red light emitting diode (R), the green light emitting diode (G), and the blue light emitting diode (B) is approximately 1: 2: 3, so that the spectral sensitivity characteristic AS of the image sensor 14 is substantially equal. Is flattened. Of course, under such conditions, the reference white
4, the red signal component (R) and the green signal component (G) of the analog component video signal output from the D / A converter 48 are schematically shown in FIG. It becomes uniform and an endoscope image with an appropriate color balance is obtained.

On the other hand, the image sensor 14 (FIG. 3) of the B-type scope 10 is constituted by a CCD having an on-chip color filter, and the B-type scope 10 is connected to the image signal processing unit 12. Then, the B type LED array light source 32 (FIG. 6) is used. In this embodiment, the above-mentioned on-chip
The color filters are three primary color filters of red, green and blue arranged in a mosaic pattern. In order to obtain a color endoscopic image with the image sensor 14 having such an on-chip color filter, a so-called simultaneous imaging method is adopted. In the present embodiment, a B-type LE is used.
The light emitting diodes of the three primary colors of the D array light source 32 emit light simultaneously and periodically.

For example, as shown in the timing chart of FIG. 16, the control clock pulses B-CLCK1, B-CLK2 and BC
LK3 are output for each of the bases of the transistors T _r1, T _r2 and T _r3 from the timing generator 40 in synchronism with the vertical synchronizing signal, these control clock pulses B-
B-type LED according to CLCK1, B-CLK2 and B-CLK3
The red light emitting diode, the green light emitting diode, and the blue light emitting diode of the array light source 32 emit light simultaneously and periodically.

More specifically, the light emitting diodes of the three primary colors emit light simultaneously over one field period defined by the vertical synchronizing signal, and the object image of the object T is displayed on the light receiving surface of the image sensor 14 over the light emitting period.
6 is imaged. That is, the light emission period of the light emitting diodes of the three primary colors is an exposure period for the CCD photosensitive portion of the image sensor 14. However, until the electronic shutter function is activated, the accumulated charges are swept out of the CCD photosensitive section. When the electronic shutter function is activated, the CCD
The photosensitive section starts charge accumulation to obtain a pixel signal, terminates charge accumulation at the end of the light emission period of the three primary color light emitting diodes, and transfers the accumulated charge to the CCD transfer section as a pixel signal.

As is clear from the timing chart of FIG. 16, when the exposure of the CCD photosensitive portion of the image sensor 14 is completed, a series of read clock pulses are output from the CCD driver 26 to the image sensor 14, whereby an image is picked up. Three primary color analog pixel signals for one field are sequentially read from the DDC transfer unit of the sensor 14, and the read analog pixel signals are sequentially subjected to the processing described above in the CCD process circuit 28. The analog pixel signal processed by the CCD process circuit 28 is once converted into a digital pixel signal by an analog / digital (A / D) converter 42 (FIG. 1), and is converted from the analog pixel signal by the A / D converter 42 to a digital signal. For conversion to pixel signals,
This is performed according to a control clock pulse (a so-called sampling clock pulse) output from the timing generator 40. Of course, the control clock pulse output from the timing generator 40 is an A-type scope 10
Has a frequency different from that in the case of (1), the reading of the analog pixel signal from the image sensor 14, the processing of the analog pixel signal and the sampling of the digital pixel signal in the A / D converter 42 are different from those in the case of the A type scope 10. It is performed at different timings.

Next, the digital pixel signals included in the three primary color digital pixel signals for one field are written into one of the three frame memories 44R, 44G and 44B according to the color. That is, the red digital pixel signal, the green digital pixel signal, and the blue digital pixel signal for one field are written into the frame memories 44R, 44G, and 44B, respectively. As is clear from the timing chart of FIG. 16, when one field period ends,
Writing of the red digital pixel signal for one field, the green pixel signal for one field, and the blue pixel signal for one field to each of the three frame memories 44R, 44G, and 44B is completed. In addition, NTSC
If the system is adopted, 1 field period is 1 /
60 seconds.

On the other hand, while the digital pixel signals of the respective colors are sequentially written into the frame memories 44R, 44G and 44B, the frame memories 44R, 44G and 4
4B, the three primary color digital pixel signals corresponding to each other are simultaneously read at a predetermined timing. That is,
As in the case of the A type scope 10, digital pixel signals of respective colors are read out from the frame memories 44R, 44G and 44B as digital component video signals. Of course, the frame memories 44R, 4R
The write clock pulse when writing the digital pixel signal to 4G and 44B and the read clock pulse when reading the digital pixel signal from the frame memories 44R, 44G and 44B are the image sensor 1 of the B type scope 10.
4.

Frame memories 44R, 44G and 44B
Is converted into an analog component video signal by a digital / analog (D / A) converter 48, and then the subject image of the subject T is reproduced and displayed as an endoscope image on a TV monitor 50. This is the same as in the case of the A type scope 10. Further, the analog component video signal is output from the D / A converter 48 to the color encoder 52, where the analog component video signal is converted to a composite video signal or an S video signal and then output to the outside. A type scope 1
It is similar to the case of 0.

Incidentally, the image sensor 14 of the B type scope 10 has an on-chip color filter as described above, and such an image sensor 14 is biased, for example, as shown in the graph of FIG. It may have a spectral sensitivity characteristic BS. That is, the image sensor 14 of the B type scope 10 has the same sensitivity to red light having a wavelength of about 580 to about 720 nm and green light having a wavelength of about 480 to about 620 nm, and about 380 to about 380. It is somewhat less sensitive to blue light having a wavelength of about 520 nm. In short, the spectral sensitivity characteristic BS of the image sensor 14 of the B-type scope has a high sensitivity in the middle region of the visible light region, but shows a bias such that the sensitivity becomes low on the short wavelength side and the long wavelength side.

On the other hand, as described above, the B type LED
Also in the array light source 32, assuming that the light emitting diodes (R, G, B) of each of the three primary colors are controlled to emit light with the same intensity, the light emitting intensity distribution of the red light emitting diode (R), the green light emitting diode ( The emission intensity distribution of R) and the emission intensity distribution of the blue light emitting diode (B) are made substantially the same as each other (FIG. 1).
1). Nevertheless, due to the bias of the spectral sensitivity characteristic BS (FIG. 17) of the image sensor 14, the emission intensity distribution of the red light emitting diode (R), the emission intensity distribution of the green light emitting diode (R), and the blue light emitting diode (B) The light-emission intensity distribution of ()) is apparently as shown in the graph of FIG.
That is, the light emission intensity distributions of the red light emitting diode (R) and the green light emitting diode (R) are substantially equal, and the light emission intensity distribution of the blue light emitting diode (B) is slightly lower.

Therefore, if the number of light emitting diodes of each of the three primary colors of the B type LED array light source 32 is equal and the reference white is photographed by the image sensor 14, the D / A conversion is performed. Vessel 4
8, only the blue signal component (B) of the analog component video signal output from the analog component video signal becomes lower. Of course,
When the subject T is photographed by the image sensor 14 under such conditions and the subject image is reproduced and displayed as an endoscope image on the TV monitor 50, the color balance of the endoscope image is distorted and green and red are emphasized. Therefore, an endoscope image having an appropriate color balance cannot be obtained.

Therefore, in practice, as schematically shown in FIG. 19, among the three primary color light emitting diodes of the A type LED array light source 32, a red light emitting diode (R), a green light emitting diode (G) and a blue light emitting diode (G). The number of the diodes (B) is set to 14, 14, and 21, respectively.
4 is offset. That is, the ratio of the numbers of the red light emitting diode (R), the green light emitting diode (G), and the blue light emitting diode (B) is approximately 2: 2: 3.
The spectral sensitivity characteristic AS of No. 4 is substantially flattened. Of course,
When the reference white image is captured by the image sensor 14 under such conditions, the red signal component (R) and the green signal component (G) of the analog component video signal output from the D / A converter 48. Becomes uniform, and an endoscope image having an appropriate color balance is obtained.

Referring to FIG. 20, there is shown a flowchart of a timing generator setting routine executed by the system controller 38. This timing generator setting routine is configured as a time interruption routine executed at predetermined time intervals, for example, every 20 ms. . The execution of this routine is started after the power ON / OFF switch 12d (FIG. 4) of the image signal processing unit 12 is turned on. As long as the power ON / OFF switch 12d is turned on, the execution of this routine is performed every 20 ms. The execution is repeated.

In step 2001, it is determined whether or not the micro switch 37 is on. That is, either the A type or B type LED array light source 32
Is mounted in the notch opening 12e of the image signal processing unit 12. Micro switch 37
Is off, that is, when neither type of LED array light source 32 is mounted, the process proceeds to step 2002, where the setting confirmation flag F is set to "0", and this routine ends once. Thereafter, this routine is executed every elapse of 20 ms, but there is no progress as long as the microswitch 37 is off. The setting confirmation flag F is a flag for instructing whether or not the setting for the timing generator has been completed. In the initial state immediately after the power ON / OFF switch 12d is turned on, F = 0.

In step 2001, the microswitch 37
Is turned on, that is, when it is confirmed that either the A type or the B type LED array light source 32 is mounted, the process proceeds to step 2003, where the flag F is set to "0".
Is determined. At this stage, since F = 0, the process proceeds to step 2004, where the output voltage DV of the detection circuit 32a of the LED driver 34 is detected. Next, in step 2005, it is determined whether the detection voltage DV is equal to or higher than 0 volt. That is, it is determined whether the LED array light source 32 mounted on the image signal processing unit 12 is of the A type or the B type.

When DV> 0 in step 2005, that is, when the A-type LED array light source 32 is mounted, the process proceeds to step 2006, where the timing generator 40 is set to the A-type scope 10 and the A-type LED array. This is performed so as to match the light source 32.
In short, for example, the timing generator 40 is set so that exposure to the image sensor 14 and reading of pixel signals therefrom follow the timing chart of FIG.

On the other hand, when DV = 0 in step 2005, that is, when the B type LED array light source 32 is mounted, the process proceeds to step 2007, where the timing generator 40 is set to the B type scope 10 and the B type. This is performed so as to match the LED array light source 32. In short, for example, the timing generator 40 is set such that exposure to the image sensor 14 and reading of pixel signals from the image sensor 14 follow the timing chart of FIG.

In any case, when the setting for the timing generator 40 is completed, the process proceeds to step 2008, where the setting confirmation flag F is rewritten from "0" to "1", whereby the setting of the timing generator 40 is completed. Is indicated. Thereafter, this routine is executed every 20 ms, but unless the LED array light source 32 is removed, only the routine consisting of steps 2001 and 2003 is repeated, and the setting of the timing generator 40 is maintained.

If the LED array light source 32 is also changed from one type to the other type with the replacement of the scope 10 of one type to the scope 10 of the other type, the microswitch 37 shifts from the on state to the off state. At this time, the setting confirmation flag F is once returned to “0” (step 2002), and when the replacement of the LED array light source 32 is completed, the setting of the timing generator 40 is performed again according to the type (step 2006 or 2007). ).

Referring to FIG. 21, a second embodiment of the electronic endoscope according to the present invention is shown as a block diagram. In the second embodiment, a character signal generating circuit 54 is provided in the image signal processing unit 12. Point provided and scope 1
The EEPROM (electrically electrically
It is substantially the same as the above-described first embodiment except that an erasable programmable read-only memory (56) is provided. In FIG. 21, the same reference numerals are used for the same components as those shown in FIG.

The character signal generating circuit 54 comprises a video RAM and a character generator. In the second embodiment, the TV of the TV monitor 50 is stored in the ROM of the controller 38.
Stores character code data corresponding to various character information to be displayed. The predetermined character information is transmitted to the TV monitor 50.
Is displayed, character code data corresponding to the predetermined character information is read from the system controller 38 and written to a predetermined address of the video RAM of the character signal generation circuit 54. At this time, the character generator of the character signal generation circuit 54 Then, a character pattern signal corresponding to the character code data is generated, and this character pattern signal is output from the analog / digital converter output from the D / A converter 48.
This is superimposed on the component video signal, whereby predetermined character information is displayed on the TV monitor 50 together with the endoscope image at a predetermined position. The display position of the character information on the display screen of the TV monitor 50 corresponds to the address of the character code data written in the video RAM.

As is well known, in an electronic endoscope, T
Various types of character information are displayed on the display screen of the V monitor 50. As character information particularly relevant to the present embodiment, for example, a message "Please replace the LED array" is given. Can be

In the second embodiment, an A type scope 1
Type information indicating that the scope 10 is the A type is stored in the EEPROM 56 of 0, and type information indicating that the scope 10 is the B type is stored in the EEPROM 56 of the B type scope 10. . As is apparent from FIG. 21, either the A type or B type scope 10 is connected to the image signal processing unit 12.
Is connected to the system controller 38 of the image signal processing unit 12, and if the power switch of the image signal processing unit 12 is turned on at this time, the type information described above is fetched from the EEPROM 56 by the system controller 38. Thereby, it can be determined whether or not the scope 10 is connected to the image signal processing unit 12.

Referring to FIG. 22, there is shown a flowchart of a timing generator setting routine executed by the system controller 38 of the second embodiment shown in FIG.
As in the case of the first embodiment, the time interruption routine is executed at predetermined time intervals, for example, every 20 ms. As in the above-described timing generator setting routine, the start of the execution of the timing generator setting routine is determined by turning on / off the power of the image signal processing unit 12.
The operation after the switch 12d (FIG. 4) is turned on is also the same as in the first embodiment.

At step 2201, it is determined whether or not the micro switch 37 is on. That is, either the A type or B type LED array light source 32
Is mounted in the notch opening 12e of the image signal processing unit 12. Micro switch 37
Is off, that is, when no type of LED array light source 32 is mounted, the process proceeds to step 2202, where the setting confirmation flag F is set to "0". Thereafter, this routine is executed every elapse of 20 ms, but there is no progress as long as the microswitch 37 is off. The setting confirmation flag F is a flag that indicates whether or not the setting for the timing generator has been completed, as in the case of the first embodiment.
In an initial state immediately after the switch 12d is turned on, F = 0.

At step 2201, the micro switch 37
Is turned on, that is, if it is confirmed that either the A type or B type LED array light source 32 is attached, the process proceeds to step 2203, where the flag F is set to "0".
Is determined. At this stage, since F = 0, the process proceeds to step 2204, where it is determined whether or not the scope 10 is connected to the image signal processing unit 12. If the connection of the scope 10 is not confirmed, the present routine ends once. After that, this routine
It is executed every 20 ms, but does not make any progress unless the connection of the scope 10 is confirmed.

When the connection of the scope 10 is confirmed in step 2204, the process proceeds to step 2205, where the LED is
The output voltage DV of the detection circuit 32a of the driver 34 is detected. Next, at step 2206, it is determined whether the detection voltage DV is equal to or higher than 0 volt. That is, the LED array light source 32 attached to the image signal processing unit 12
Is determined to be of type A or B.

If DV> 0 in step 2206, that is, if the A-type LED array light source 32 is mounted, the process proceeds to step 2207, where the scope 10 connected to the image signal processing unit 12 is of A-type. Is determined. Of course, such a determination is made based on the type information taken from the EEPROM 56 of the scope 10.

At step 2207, if the scope 10
If it is of the type, the scope 10 has an LED array light source 32 (A
Type) is not the same as in step 220.
In step 8, the TV monitor 50 displays an error. That is, a message “Please replace the LED array” is displayed on the TV monitor 50. Of course, for such an error display, the character code data corresponding to the character information "Please replace the LED array" is read from the ROM of the system controller 38 and written to a predetermined address of the video RAM of the character signal generating circuit 54. This is done by: After that, this routine
This is executed every ms. Unless the scope 10 is changed from the B type to the A type, or
As long as the array light source 32 is not changed from the A type to the B type, no progress is made.

If it is confirmed in step 2207 that the scope 10 is of the A type, the process proceeds from step 2207 to step 2209, where an error display, that is, a message "Please replace the LED array" is displayed. It is determined whether or not it has been performed. If an error is displayed, the process proceeds to step 2210, where the error is deleted. On the other hand, if no error display is made, the process bypasses step 2210.

In any case, in step 2211,
The setting of the timing generator 40 is performed so as to match the A type scope 10 and the A type LED array light source 32. In short, for example, the timing generator 40 is set so that exposure to the image sensor 14 and reading of pixel signals therefrom follow the timing chart of FIG. Next, the routine proceeds to step 2212, where the setting confirmation flag F is rewritten from "0" to "1", thereby indicating that the setting of the timing generator 40 is completed. Thereafter, this routine is executed every 20 ms, but unless the LED array light source 32 is removed, only the routine consisting of steps 2201 and 2203 is repeated, and the setting of the timing generator 40 is maintained.

On the other hand, when DV = 0 in step 2206, that is, when the B type LED array light source 32 is mounted, the process proceeds to step 2213, where the scope 10 connected to the image signal processing unit 12 is of the A type. Is determined. Of course, such a determination is made based on the type information taken from the EEPROM 56 of the scope 10.

At step 2213, if the scope 10
If it is of the type, the scope 10 has an LED array light source 32 (B
(Type) is not the same as that of Step 221.
4 and an error display similar to that described above is displayed on the TV.
This is performed on the monitor 50. Thereafter, this routine is executed every elapse of 20 ms.
No progress will be made unless the LED array light source 32 is replaced from a B type to an A type.

If it is confirmed in step 2213 that the scope 10 is of the B type, the process proceeds from step 2213 to step 2215, where it is determined whether or not an error is displayed. If an error indication has been made, the process proceeds to step 2216, where the error indication is deleted. On the other hand, when the error display is not made, step 2216 is bypassed.

In any case, in step 2217,
Therefore, the setting of the timing generator 40 is performed so as to match the B-type scope 10 and the B-type LED array light source 32. In short, for example, the timing generator 40 is set such that exposure to the image sensor 14 and reading of pixel signals from the image sensor 14 follow the timing chart of FIG. Then, step 2
At 212, the setting confirmation flag F is rewritten from "0" to "1", thereby indicating that the setting of the timing generator 40 is completed. afterwards,
This routine is executed every 20 ms, but as long as the LED array light source 32 is not removed, only the routine consisting of steps 2201 and 2203 is repeated, and the setting of the timing generator 40 is maintained.

As is clear from the above description, in the second embodiment, the scope 10 connected to the image signal processing unit 12 and the L attached to the image signal processing unit 12
When the ED array light source 32 and the ED array light source 32 do not match each other, an error is displayed on the TV monitor 50, so that the operator of the electronic endoscope apparatus can be immediately notified of the mismatch problem.

In the first and second embodiments described above, the total number of the light-emitting diodes of the three primary colors is 49. However, if necessary, the total number is further increased to provide a sufficient illumination light amount. It may be obtained.

In the above embodiment, the LE
A red light emitting diode, a green light emitting diode, and a blue light emitting diode are used as the D array light source, but an image sensor having almost the same spectral sensitivity characteristics for two of the three primary colors. In a scope provided with a light emitting device, light of three primary colors may be obtained by using light emitting diodes of two colors. For example, for a B-type scope equipped with an image sensor having almost the same spectral sensitivity characteristics for red light and green light, only two color light emitting diodes of a yellow light emitting diode and a blue light emitting diode are used as an LED array light source. It can be used. As is well known, yellow light is composed of red light and green light. Therefore, by appropriately changing the numbers of yellow light emitting diodes and blue light emitting diodes, the bias of the spectral characteristics of the image sensor of the B type scope is canceled. be able to.

Further, the present invention can be applied to an image sensor having a color filter of a complementary color (four colors) system. In this case, the bias of the spectral sensitivity characteristic is canceled by appropriately changing the number of light emitting diodes of three primary colors. can do.

[0091]

As is apparent from the above description, the electronic endoscope apparatus according to the present invention is disclosed in
Rather than providing a light emitting diode at the distal end of the scope as in US Pat.
Since the D array light source is provided on the image signal processing unit side, the total number thereof is not substantially limited, and therefore, it is possible to secure a sufficient illumination light amount by the light emitting diode. Further, according to the present invention, by appropriately changing the number of light-emitting diodes of each of the three primary colors, it is possible to offset the bias of the spectral sensitivity characteristics of the image sensor, so that an endoscope image with an appropriate color balance is obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a first embodiment of an electronic endoscope apparatus according to the present invention.

FIG. 2 is a schematic view of an A-type scope of the electronic endoscope apparatus according to the present invention.

FIG. 3 is a schematic view of a B-type scope of the electronic endoscope apparatus according to the present invention.

FIG. 4 is a perspective view showing an LED array light source together with an image signal processing unit of the electronic endoscope apparatus according to the present invention.

FIG. 5 is a side view of an A-type LED array light source used in the electronic endoscope apparatus according to the present invention.

FIG. 6 is a side view of a B-type LED array light source used in the electronic endoscope apparatus according to the present invention.

FIG. 7 is a circuit configuration diagram when an A-type LED array light source is connected to an LED driver.

FIG. 8 is a circuit configuration diagram when a B-type LED array light source is connected to an LED driver.

FIG. 9 is a timing chart for explaining the operation of the electronic endoscope apparatus when the A type scope and the A type LED array light source are used.

FIG. 10 is a graph showing a bias of a spectral sensitivity characteristic of an image sensor of an A type scope.

FIG. 11 is a graph showing light emission intensity distributions of light emitting diodes of the three primary colors of the A type LED array light source.

12 is a graph showing the emission intensity distribution of each of the three primary colors when the emission intensity distribution of the light emitting diodes of the three primary colors shown in FIG. 11 has undergone an apparent change due to the bias of the spectral sensitivity characteristics shown in FIG. is there.

FIG. 13 shows a red signal component, a green signal component, and a blue signal of an analog component video signal to be obtained when it is assumed that the number of light-emitting diodes of each of the three primary colors of the A-type LED array light source is the same. It is explanatory drawing which shows the intensity | strength of a component typically.

14 is an explanatory diagram schematically showing how to change the ratio of the number of light emitting diodes of each of the three primary colors of the A-type LED array light source to offset the bias of the spectral sensitivity characteristics shown in FIG. is there.

15 is an explanatory diagram schematically showing respective intensities of a red signal component, a green signal component, and a blue signal component of an analog component video signal to be obtained by the A-type LED array light source shown in FIG.

FIG. 16 is a timing chart for explaining the operation of the electronic endoscope apparatus when a B-type scope and a B-type LED array light source are used.

FIG. 17 is a graph showing a bias of a spectral sensitivity characteristic of the image sensor of the B type scope.

18 is a graph showing the emission intensity distribution of each of the three primary colors when the emission intensity distribution of the light emitting diodes of the three primary colors shown in FIG. 11 has undergone an apparent change due to the bias of the spectral sensitivity characteristics shown in FIG. is there.

19 is an explanatory diagram schematically showing how the ratio of the number of light emitting diodes of each of the three primary colors of the B-type LED array light source is changed to offset the bias of the spectral sensitivity characteristics shown in FIG. is there.

FIG. 20 is a flowchart of a timing generator setting routine executed as a time interrupt routine by the system controller shown in FIG. 1;

FIG. 21 is a schematic block diagram of a second embodiment of the electronic endoscope apparatus according to the present invention.

FIG. 22 is a flowchart of a timing generator setting routine executed by the system controller shown in FIG. 21 as a time interrupt routine.

[Explanation of symbols]

 Reference Signs List 10 scope 12 image signal processing unit 14 imaging sensor 30 light source unit 32 LED array light source 34 LED driver 38 system controller 40 timing generator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kuniyoshi Kaneko 2-36-9 Maenocho, Itabashi-ku, Tokyo Inside Asahiko Gaku Kogyo Co., Ltd. (72) Inventor Minoru Matsushita 2-36, Maenocho, Itabashi-ku, Tokyo No. 9 Asahi Kogaku Kogyo Co., Ltd. F term (reference) 2H040 CA04 GA02 GA10 4C061 GG01 JJ06 JJ17 JJ18 NN01 QQ07 QQ09 RR04 RR25 5C022 AA09 AB15 AC42 5C065 AA04 BB12 BB41 CC01 DD02 EE19 EE20 GG18GG30

Claims (5)

[Claims] A scope, an image sensor provided at a distal end of the scope, and an image signal processing unit detachably connected to a proximal end of the scope.
The image signal processing unit is configured to appropriately process pixel signals for one frame sequentially obtained by the image sensor and output the video signals therefrom as a video signal, and further to illuminate the front of the distal end of the scope. A light guide cable inserted through the scope to guide the illumination light, and a light source unit provided in the image signal processing unit, wherein the light guide is connected to the image signal processing unit when the scope is connected. An electronic endoscope device wherein a proximal end of a cable is optically connected to the light source unit, wherein the light source unit includes at least two color light emitting diode groups for obtaining a sufficient amount of illumination light, and emits light of each color. The number of light emitting diodes of the diode group is set so as to offset the bias of the spectral sensitivity characteristics of each color of the image sensor. An electronic endoscope apparatus characterized by the above-mentioned. 2. The electronic endoscope apparatus according to claim 1, wherein said light source unit includes an LED array light source in which said at least two color light emitting diode groups are arranged, and said LED.
An electronic endoscope apparatus comprising: an LED driver for driving an array light source; wherein the LED array light source is detachable from the LED driver. 3. The electronic endoscope apparatus according to claim 2, wherein at least two types of scopes are prepared, and two types of said LED array light sources are provided according to each type of said scope. An electronic endoscope apparatus, wherein: 4. The electronic endoscope apparatus according to claim 3, wherein one of the types of the scope is connected to the image signal processing unit, and one of the two types of the LED array light source is used. When one type is connected to the LED driver, a discriminating means for discriminating whether or not the scope and the LED array light source correspond to each other; An electronic endoscope apparatus, further comprising: display means for displaying an error when it is determined that the LED array light sources do not correspond to each other. 5. The electronic endoscope device according to claim 3, wherein when the LED array light source is connected to the LED driver, the type of the LED array light source is determined. Determination means is provided,
According to the type determined by the determination means,
An electronic endoscope apparatus wherein a driving mode of the LED array light source by an ED driver is changed.