JPH0462232B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an imaging device using a lighting device that is less likely to cause blooming and has a high power saving effect.

(Prior Art) Imaging means such as solid-state image sensors and image pickup tubes have a narrow dynamic range with respect to the brightness of the subject, so high accuracy is required for adjusting the amount of incident light.
However, even if such light intensity adjustment is performed accurately, there is a problem in that when strong light enters from a part of the subject, a blooming phenomenon occurs in which carriers overflow over a wide range of the light-receiving surface of the imaging means.

Conventionally, as a countermeasure against this blooming, it has been considered to provide an overflow drain within the light-receiving surface of a CCD image sensor to discharge excess carrier. However, if such a drain is provided within the light-receiving surface, the effective aperture ratio of the light-receiving section will be greatly reduced.
There is a problem in that it hinders resolution improvement. Therefore, as shown in Japanese Unexamined Patent Publication No. 56-138371, for example, an image sensor has been considered in which blooming is prevented by recombining excess carrier on the sensor surface during the horizontal blanking period. .

In such a sensor, and also in a sensor with a drain as described above, blooming still occurs when particularly strong light is incident in a short period of time. It's not perfect. Furthermore, it is known that such a problem occurs not only when imaging is performed outdoors during the daytime, but also under an illumination light source with a relatively low amount of light.

This is because if there is an object with high reflectance, such as a specular surface, as part of the subject, regular reflected light will be incident depending on the illumination angle, and the light source will form an image on the image sensor. Of course, if such a highly reflective object has a curved surface, regularly reflected light will enter the sensor regardless of the illumination angle. The level of such regularly reflected light is hundreds of thousands of times higher in image plane illuminance than that of diffusely reflected light from a general object.

On the other hand, even if dimming control is performed under a normal illumination light source, since these controls are based on average photometry, blooming due to regularly reflected light as described above cannot be prevented.

In particular, in image sensors that reduce blooming by surface recombination as described above,
Since each pixel within the light-receiving surface is separated horizontally by a channel stop, when blooming occurs, vertical white stripes are formed on the screen, significantly degrading the image quality.

Of course, even in an image sensor having an overflow drain, since no drain is provided in the horizontal direction, blooming similarly tends to spread vertically. Furthermore, when capturing images by incorporating an image sensor into a portable video camera, etc., it is desirable that the illumination light source is also portable. It is possible that it will become the property of

However, as the point light source becomes a point light source, the brightness of the light source increases even with the same amount of light emitted, and the level of regular reflected light increases, so this problem, that is, the problem of blooming due to regular reflected light of illumination light, has become more prominent. It is clear that

(Objective) An object of the present invention is to provide an imaging device that can effectively prevent blooming in imaging using a lighting device.

Another object of the present invention is to provide an imaging device that can save illumination energy for subjects where blooming is unlikely to occur.

Another object of the present invention is to provide an imaging device that can effectively predict the occurrence of blooming due to illumination.

(Example) The present invention will be explained below based on Examples.

FIGS. 1a to 1c are diagrams showing a first embodiment of the present invention, and FIG. 1a is a diagram showing an example of the configuration of an imaging device.
FIG. 1B is a diagram showing an example of the configuration of an image sensor, and FIG. 1C is a diagram showing an example of the configuration of a color separation filter.

In the figure, reference numeral 1 denotes an image sensor as an imaging means as shown in FIG. 1b, for example, and the sensor shown in FIG. 1b is a so-called frame transfer type sensor.
Although a so-called CCD is shown, the image sensor of the present invention may be an image pickup tube or a MOS/XY sensor as long as it converts an optical image into electrical information. 1a is a light receiving section, 1b is a light-shielded memory section, 1c is a horizontal shift register, and 1d is an output amplifier.The charge accumulated in 1a is transferred to the memory section 1b during the vertical blanking period of the standard television signal. The data is transferred at high speed and sequentially read out one horizontal line at a time by the horizontal shift register 1c over the next one field period.

For example, a color stripe filter as shown in FIG. 1c is attached to the light receiving section 1a so as to match the pixel pitch in the horizontal direction.

A driver 2 supplies driving pulses for driving the image sensor 1, and forms the driving pulses in response to a timing signal from a clock generator 3.

4 is an LPF (low pass filter) having a cut-off characteristic of about 2MHz, for example, and sensor 1
The point-sequential outputs from are summed to form a pseudo-luminance signal. The output of the LPF 4 is subjected to various processes such as gamma correction and aperture correction in the process circuit 5.

Reference numerals 6 to 8 are sample and hold circuits, which sample and hold the point-sequential output of sensor 1 at different phases, respectively, to obtain R (red), G (green),
Obtain each color signal of B (blue). Next, LPF9-1
1, high-frequency components of, for example, 500 KHz or higher are cut out, and then subjected to various corrections in process circuits 12 to 14, respectively.

The outputs of the process circuits 5 and 12 to 14 undergo appropriate modulation in an encoder 15 as a conversion means, and then are supplied to a recording head 17 via an analog gate circuit 16 and recorded on a recording medium 18. Further, the output of the encoder 15 is reproduced as a monitor by a television monitor TVM or in the form of a print by a printer PT.

Reference numeral 19 is an integrating circuit which outputs a value V ₂ obtained by integrating the output of the LPF 4.

Further, the output V ₂ is also used as a control signal for automatically controlling an aperture (not shown).

20 is a comparator for comparing this output V ₂ with a predetermined reference level, and outputs a low level signal when V ₂ >V ₁ and a high level signal when V ₁ >V ₂ .

The output of this comparator 20 is the delay circuit 3
2, it is used to control ON/OFF of the power switch 22 provided in the power line to the flash light source 21b. The delay circuit, as shown in FIG.
-S flip-flop 36, and the output of a one-shot circuit that forms a pulse synchronized with the fall of the output of comparator 20 is input to the reset terminal of flip-flop 36 via timer circuit 35.

Therefore, the delay circuit 20 outputs a high level signal from when the output of the comparator 20 rises until a predetermined period of time elapses after the output from the comparator 20 falls.

Further, the switch 22 is turned ON while the output of this delay circuit is at a high level.

Furthermore, as will be described later, the power switch 22 is turned on.
By doing so, the electrical energy required for flash light emission begins to be accumulated in the light source 21b.

Further, 24 is a coefficient circuit which multiplies the output of the LPF 4 by a predetermined coefficient. This coefficient value is, for example, a number smaller than 1, such as 0.5, while the output of the delay circuit 32 is at a low level, and is switched to, for example, 0.7 while the output of the delay circuit 32 is at a high level. As a result, when the subject brightness level is low overall, the integral value V ₂ and the level V ₃ obtained by multiplying the brightness level by a coefficient are made to approach each other. Therefore, in this state, if a signal with even a slightly large deviation value is included in level _V3 , this will be detected.

Further, 23 is a comparator as a detection means of the present invention that compares the output V ₂ and the coefficient circuit output V _3. For example, in the coefficient circuit, by multiplying the output of the LPF 4 by a coefficient smaller than 1, pseudo luminance can be obtained. Among the signals, only those with particularly high relative levels are detected by the comparator 23.

Incidentally, the coefficient circuit 24 may be provided within the integrating circuit 19. In that case, the coefficient is set to be larger than 1, for example. Also, in this case, the delay circuit 32
The coefficient in the integrating circuit 19 may be switched to be relatively small or large depending on whether the output is high or low.

Further, when V ₂ >V ₃ , the comparator 23 outputs a low level, and when V ₂ <V ₃ , it outputs a high level. This high level signal is passed through a delay circuit 33 to a spatial irradiation characteristic control circuit 2 which will be described later.
1a, and basically, while the delay circuit 33 outputs a high level, the light emitting angle or direction of the light source 21b is changed to control the illumination to be soft, that is, the area of the light source is apparently expanded. . Here, it is assumed that the delay circuit 33 has the same configuration as the delay circuit 32.

Further, in this embodiment, the power switch 22 to the flash light source is turned on by the AND gate 25, and
Only when the output of the delay circuit 33 is at high level,
This irradiation characteristic control circuit is switched to the software side in order to avoid unnecessary control of irradiation characteristics when the light source is not used.

Further, 26 is an AND gate which inputs the output of the delay circuit 33 and the inverted output of the delay circuit 32 via the inverter 28, and when the integrated value level V ₂ of the pseudo luminance signal is higher than the level V ₁ ,
When the comparator 23 detects a signal with a level extremely higher than this integral level, it outputs a high level. This high-level output activates the blooming warning circuit 27, which gives a warning to the operator by sound or light.

28 is a trigger circuit for still image recording, and an AND gate 29 is synchronized with the first vertical synchronization signal V _D after the output of the trigger circuit 28 is obtained.
High level output can be obtained from.

The output of the AND gate 29 is input to the trigger terminal T of the light source 21b, so that flash light is emitted immediately after the output pulse of the AND gate 29.

The O terminal of the light source 21b is a terminal that outputs a light emission signal in conjunction with a flash light emission operation. AND gate 3 that takes the AND of this light emission signal and the vertical synchronization signal V _D
0, the one-shot circuit 31 forms a pulse with a predetermined time width (for example, 1/60 seconds), and the output of this one-shot circuit opens the gate 16 and guides the output of the encoder 15 to the head 17.

FIG. 2 is a timing diagram of this embodiment, and shows that the power switch of the imaging device (not shown) is turned on.
By doing so, the clock generator 3 forms various pulses at timings synchronized with standard television signals.

The image sensor periodically performs operations such as storage, transfer, and readout using drive pulses generated by the driver 2 based on this pulse.

After the high-frequency components of the point-sequential output from the sensor are removed by the LPF 4, the output is multiplied by a coefficient smaller than 1, for example, in the coefficient circuit 24, and the result is shown in the second diagram.
The waveform will look like V ₃ . On the other hand, the output of the LPF 4 is integrated to form a waveform like _V2 shown in the second diagram. As shown in the figure, when the level _V2 is smaller than the level _V1 , the output of the comparator 20 becomes high level, and the power switch 22 of the light source 21b is turned on via the delay circuit. Also, the coefficients in the coefficient circuit 24 are relatively large. In this state,
For example, once the value of level V ₃ exceeds the value of level V ₂ at time t ₁ , the output of comparator 23 becomes high level, and the output of delay circuit 33 becomes high level for at least several H (horizontal period). Thereafter, when a trigger signal is output from the trigger circuit 28 at an appropriate timing (time t ₂ ), the light source 21 b starts emitting light at time t ₄ in synchronization with the vertical synchronization signal V _D from the clock generator 3. It is done. still,
This light emission timing is selected so that it does not occur within the vertical blanking period in a CCD type image sensor. During flash photography, the amount of flash light is controlled by a dimmer circuit as described below, and the amount of light emitted is controlled at time t ₅ .
Light emission is completed at .

When this light emitting operation is performed, a high level signal is output from the O terminal of the light source, and in synchronization with the vertical synchronizing signal V _D after outputting this high level signal, the gate 1
6 is open for one field period, and recording on the recording medium 18 is performed.

Note that the recording medium 18 is rotationally controlled in synchronization with the driving of the image sensor.

In this way, according to this embodiment, it is possible to detect whether or not there is a subject that is likely to cause blooming by simply detecting the state of the output signal without making any changes to the image sensor. is easy.

In addition, if the overall brightness level of the subject is high, and at least part of it has a relatively high brightness level, a warning is displayed, so you can recognize the presence or absence of blooming even without a TV monitor. .

In addition, since the illumination light source is automatically powered on for a predetermined period of time when the integral level of the luminance signal falls below a predetermined level, the operation is simple and the power saving effect is large.

Further, in this embodiment, the configuration is simple because the image sensor for imaging is also used as a detection means for detecting whether the brightness level of at least a part of the subject image exceeds a predetermined level.

Furthermore, in this embodiment, when the overall subject brightness level is low, the illumination device automatically enters the ready state, and in conjunction with this, the coefficient value of the coefficient circuit 24 changes, so that the overflow prediction sensitivity is improved.

As a result, when the brightness level of the subject is relatively low, if there is even one relatively bright spot, the illumination is switched to the soft side by treating this as an almost mirror surface, and the blooming caused by the illumination light is effective. can be prevented.

In this embodiment, the coefficient circuit 24 is used in order to bring the relative size ratio between the subject brightness level and the predetermined level _V2 close to each other in the preparation state of the illumination device. It is not limited to the examples.

In this embodiment, blooming is confirmed or predicted based on whether or not there is a signal with a deviation value of a predetermined value or more with respect to the average (integral) level of brightness, but the method for obtaining this integral level is In this case, the luminance signal may simply be passed through a low-pass filter, or even only the low-frequency component of the output of the image sensor may be extracted and used as a pseudo-integral level. Alternatively, the average value of the luminance signal may be calculated using a digital calculation circuit.

Further, in this embodiment, the light source is caused to emit light by ANDing the output of the trigger circuit 28 and the vertical synchronization signal V _D , but a signal related to the stable state of the light source and the spatial irradiation characteristic control circuit (for example, a charge completion signal of the light source) is also used.
It is desirable to logically multiply the values before emitting light.

Further, although the light source 21b is a flash light source in this embodiment, it can also be applied to a continuous light source such as a tungsten light source. Of course, in that case, the power switch 22 becomes unnecessary.

FIG. 3a is a diagram showing a first embodiment of the light source and irradiation characteristic control means according to the present invention, and is a sectional view taken along a plane perpendicular to the flash discharge tube axis. In the figure, 37 is a reflecting mirror, 38 is a front panel (protector), and 39, 39' are flash discharge tubes.

Figure 3c shows the flash discharge tube 39 in Figure 3a,
39' is a diagram showing the spatial illumination characteristics when only one of the discharge tubes 39 is illuminated, and A shows the characteristics when only the discharge tube 39 is illuminated, which is the same as the light emission characteristics of a normal flash device. A' is a characteristic when only the discharge tube 39' emits light, and is a bounce irradiation characteristic.

In this embodiment, a plurality of discharge tubes are arranged at mutually shifted positions within a reflecting mirror having one curve, and different irradiation characteristics are obtained by selecting the discharge tube to emit light. That is, in this embodiment, spatial irradiation characteristic control is achieved by changing the irradiation direction by selecting the discharge tube to emit light, and by making the light source appear larger by using bounce lighting.

FIG. 3b is a diagram showing another embodiment of such irradiation characteristic control, in which each discharge tube is placed within a reflecting mirror having a different diffusion characteristic such as a different curve or a different irradiation angle. This example is the third
Compared to the embodiment shown in FIG. a, better performance as an optical system can be obtained.

In the illustrated example, the directions of the reflecting mirrors 37 and 37' are changed, but it is also possible to change only the curve of the reflecting mirror, change the curve and direction, or add a lens system to the end of the protector. good. Further, a plurality of discharge tubes may be made to emit light sequentially or simultaneously.

FIG. 4 shows the electrical circuitry of the flash light source used in the embodiment shown in FIG. In the figure, V _BB is the power supply, 2
2 is the power switch, 100 boosts the DC voltage
DC-DC converter, 101 is a diode, 10
2 and 102' are known discharge tube trigger circuits, which include resistors 108, 108', 112, and 11, respectively.
2', thyristor 109, 109', capacitor 1
10, 110', transformers 111, 111', etc. 106 is a diode connected in series in the opposite direction to the discharge tubes 39, 39' and connected in parallel to the inductor 105; 119 is a light amount control circuit including a commutating capacitor 123; and charging resistors 128, 122 of this capacitor 123. , thyristor 1
20, 126, resistors 121, 125, 127, and a capacitor 124 connected to the gate of the thyristor 120 via the resistor 125. 113 is a main capacitor for causing the discharge tubes 39, 39' to emit light, and 103, 103' are two-input AND gates, one input of which is both connected to the trigger input terminal T. Further, a signal from an irradiation characteristic control input terminal 104 is input to the other input terminal of the gate 103 via an inverter 107. Further, a signal from the control input terminal 104 is input to the other input terminal of the gate 103'. or,
117 is a light receiving element that receives reflected light from the subject; 116 is an integrating capacitor that is charged according to the photocurrent from the light receiving element 117; 114, 115;
is a voltage dividing resistor, and 118 is a comparator for turning on the thyristor 126. Also, TC is resistance 1
This is a timer that outputs a high-level pulse of a predetermined width when the potential at the connection point between 22 and the discharge tube is high.

Next, the operation will be explained.

When the switch 22 is turned on by the output of the delay circuit 32 shown in the first diagram, the DC-DC converter 10
0, the voltage of the power supply _VBB is boosted and applied to the capacitor 113 via the diode 101, thereby charging the capacitor 113.

Next, after the charging voltage of the main capacitor 113 reaches a sufficiently high value for light emission, the AND gate 29 shown in the first diagram is connected to the trigger signal input terminal T.
When a high level signal is input from the control signal input terminal 104, the thyristor 109 or 109' is activated depending on whether the signal input to the control signal input terminal 104 is low level or high level.
One side turns on.

For example, when a high level is input to the input terminal 104, that is, when a signal for softening the irradiation characteristics is input, the thyristor 109' is turned on.
do. Then, the charge stored in the capacitor 110' flows through the closed circuit on the primary side of the transformer 111', and a high voltage pulse of several KV is applied to the trigger electrode of the discharge tube 39', causing the discharge tube 39' to emit flash light. Let's do it. Along with this, a resistance of 1 is applied just before the flash is emitted.
Since the potential at the connection point between 22 and the discharge tube increases, O
A high level signal is output to the terminal for a predetermined period of time via the buffer TC. The reflected light from this emission is detected by the light receiving element 117, and since a current flows through the light receiving element according to the subject brightness, the potential level across the capacitor 116 that integrates this current reaches a predetermined level determined by the resistors 114 and 115. When the threshold is reached, the comparator 118 outputs a high level signal. This signal causes the thyristor 126 to
Since it is turned on, the charges stored in the capacitors 123 and 124 are discharged, and the cathode-anode and gate input terminal of the thyristor 120 are reverse biased. This turns thyristor 120 off.
However, the discharge tube 39' stops emitting light.

According to the embodiment of the present invention described above, when there is a subject where blooming is likely to occur, the spatial illumination characteristics of the light source are controlled by switching the illumination direction of the light source, so bounce illumination is performed. The apparent size of the light source becomes extremely large, and even if a mirror surface exists, the effect of suppressing blooming will be extremely large.Moreover, in principle, the image exposure amount will not change, so the exposure for the entire subject will be appropriate. becomes.

Conversely, if there is no subject that is likely to cause blooming within the angle of view, the illumination direction is directed directly toward the subject, so that the illumination light efficiently illuminates only the main subject. Therefore, the power saving effect is greater than that which can only be achieved by bounce lighting.

Next, FIG. 5 is a diagram showing another example of the spatial irradiation characteristic control circuit of the present invention.
A type of liquid crystal 129 is arranged, thereby changing the irradiation direction as a spatial irradiation characteristic of the light source.

In FIG. 5, the same numbers as in FIG. 4 indicate the same elements. 132 is spatial irradiation characteristic control input terminal 1
A transistor is turned on by a high level signal from 04, voltage dividing resistors 130 and 131, and a capacitor 132 for stabilizing the voltage dividing.

With this configuration, when a high level signal is applied to the terminal 104, the liquid crystal 129 has irregular molecular arrangement and becomes cloudy. As a result, the light emitted from the discharge tube 39 is diffused, and the level of regularly reflected light from a mirror surface or the like can be reduced. In the case of this embodiment, only one light source is required, and the configuration for controlling the switching of spatial illumination characteristics is very simple.

FIG. 6 is a diagram showing another configuration for confirming and predicting blooming according to the present invention.

This embodiment is suitable for an image sensor having an overflow drain within the light-receiving surface.
The detection sensitivity of the detection means is increased by making overflow more likely to occur in a mode using a light source, and the spatial irradiation characteristics of the light source are changed when overflow occurs at this time.

In the figure, reference numeral 40 denotes an overflow drain provided in the light receiving section 1a, and is arranged adjacent to the pixels of the light receiving section via an overflow barrier (not shown). Each overflow drain is connected to power supply potential V _CC via a resistor 47 . 49 is a comparator serving as a detection means for switching the output state when the signal V ₄ corresponding to the amount of current flowing through the resistor 47 exceeds a predetermined level (Vref);
Normally, the signal _V4 contains only noise components, but by setting the value of the level Vref to a value slightly larger than the upper limit level of the noise components, it is possible to determine whether overflow components are included in the noise components. Detect. If an overflow component is included, the comparator 49 outputs a high level signal, which is converted by the delay circuit 50 into a high level pulse of a predetermined duration. This delay circuit 50 has the same configuration as, for example, the delay circuit 32 shown in FIG. 1d. The output of this delay circuit 50 is displayed by sound or light in a display circuit 52, and is logically multiplied by the state of a switch 53 linked to the power switch of the light source by an AND gate 51 to control spatial illumination characteristics. circuit 21
It is used to control the characteristics by a. 61 is an inverter, 62 is an AND gate, the lighting mode is selected by turning on the power switch 22, and the light source is turned on after the light source is in standby mode.
The switch 43 is switched to the b side until a charging completion signal is obtained from the CC terminal.

Note that the charging completion signal can be obtained as the output of a comparator (not shown) that compares the potential across the main capacitor 113 (not shown) with a predetermined reference value. While the switch 43 is on the contact a side, the output of the LPF 4 shown in FIG. 1a is integrated by the integrating circuit 19,
The aperture control circuit 42 performs aperture control in accordance with this integral value. As a result, the diaphragm is servo-controlled so that the integral level of the luminance signal passed through the LPF 4 is always constant.

On the other hand, in the lighting mode, as described above, the contact of the switch 43 is switched to the b side until charging is completed, so the output value of the integrating circuit 19 is reduced to a predetermined correction level value V ₅ by the subtracting circuit 44. After being subtracted, it is input to the aperture control circuit.

Therefore, the aperture tends to overexpose the image. Therefore, if there is relatively strong reflected light in the subject, the carrier will overflow at that position in the screen and will be led to the power supply V _CC via the overflow drain.
At this time, since the potential V ₄ changes, the comparator 4
9 outputs a high level, and the irradiation characteristic control circuit 21
a switches the spatial illumination characteristic of the light source 21b to the soft side. It is assumed that the aperture control such as the auto iris is carried out in the range from a fully closed state to an aperture position that is one or two stops narrower than the fully open state.

In this way, according to this embodiment, by slightly opening the aperture in the mode using the illumination light source, the sensitivity of the detection means is increased by making it easier for overflow to occur in the image sensor, and overflow is detected in that state. Since this is sometimes displayed and the spatial illumination characteristics of the light source are switched to the soft side or the diffuse side, it is easy to see whether there is an object with a relatively high reflectance within the imaging screen. In addition, without making any changes to the image sensor itself, it is possible to know which objects in the subject are likely to overflow, and if such objects occur, the spatial illumination characteristics will be automatically softened. blooming can be suppressed.

In this embodiment, in the illumination mode, the light receiving part of the image sensor is overexposed by the aperture, but for example, in a case where a rotary shutter is used as the shutter, the aperture angle may be opened by a predetermined amount. Needless to say, it's good to do what you do.

In that case, it is sufficient to simply replace the diaphragm 41 in FIG. 6 with a rotary shutter and the diaphragm control circuit with an opening angle control circuit of the rotary shutter.

Of course, both the shutter and the aperture may be controlled to the overexposure side.

In this embodiment, when the charging of the light source 21b is completed, the switch 43 returns to the a side, so the aperture returns to its proper value, and imaging using illumination light is performed in a proper exposure state.

In addition to making it easier to detect overflow carriers by changing the exposure state in this way, overflow carriers of image sensors can also be detected easily.
Use drain gate to prevent overflow.
You can also make it easier to get carriers.

FIGS. 7a and 7b are views showing other embodiments of the present invention. FIG. 7a is a surface view of the image sensor, and FIG. 7b is a sectional view thereof. In the figure, 59 is the channel stop, 60 is the pixel, and OFG is the over
Flow drain gate, OFD is over
Flow drain, 70 is a P-type silicon substrate, 7
1 is a surface oxide film, 72 is a transfer electrode, 73 is a p ⁺ region for forming a channel stop, 74 is an n region for forming a drain OFD, 75 is an OFG electrode, and 76 is the output of the AND gate 62 shown in the sixth figure. It is a controlled voltage source that switches the output voltage according to the output voltage, and applies a relatively high positive voltage when the output of the gate 62 is at a high level, and applies a relatively low positive voltage when the output is at a low level.

Therefore, from the start of power supply to the lighting device 21b until the completion of charging, the potential barrier of the OFG is relatively low, and the carrier tends to overflow.

Note that in this embodiment, the characteristics of the light source are changed by detecting the signal flowing into the overflow drain, but even if an overflow drain is not used, an image sensor generally has a channel shift in the horizontal direction. Since it is partitioned by top or anti-blooming, when blooming occurs, the carrier overflows in the vertical direction rather than in the horizontal direction. This tendency is particularly strong in image sensors that do not have an overflow drain, as shown in FIG. 7b.

FIG. 8a is a diagram showing another embodiment of the present invention, in which blooming in the vertical direction is controlled by blooming in the horizontal direction that is adjacent to the light receiving section in the vertical direction.
Detection is performed using a CCD array, and the same effect as the device shown in FIG. 6 can be obtained. That is, as shown in FIG. 8a, when blooming BLM occurs, carriers overflow especially in the vertical direction. 1e is a light-shielded horizontal shift register for blooming detection according to this embodiment that detects this vertical overflow; when blooming is not occurring at all or is hardly occurring, the register 1e is Only the dark current is formed.

However, once blooming occurs, a given cell within this register receives a large level of carrier. Therefore, if this horizontal shift register is always driven at high speed, the carriers that overflow in the vertical direction immediately after blooming are outputted as a voltage signal at the output amplifier 1f and can be detected.

54 and 55 are CRs for integrating the dark current level
This is an integrating circuit, and 56 is a comparator that compares the output of this integrating circuit with the output immediately after the output amplifier 1f, and outputs a high level signal when there is a particularly large level signal in the output from the register 1e. Output. Reference numeral 57 is a delay circuit that maintains this high level output, and has the same configuration as that shown in FIG. 1d, for example. This delay circuit 5
The output of 7 is supplied via a terminal 58 to one input of a display circuit 52 or an AND gate 51 shown in FIG.

With this configuration, blooming can be easily detected, and since there is no need to provide an overflow drain, the number of horizontal pixels can be increased.

Note that instead of providing an overflow drain, a transparent electrode may be provided in the light receiving section for recombining carriers that have overflowed near the surface of the light receiving section with other carriers.

Such an electrode configuration is described, for example, in the above-mentioned Japanese Patent Application Laid-Open No. 56
- Shown in Publication No. 138371, etc.

In this way, excess carrier can be eliminated to a certain extent within the light receiving section.

As shown in FIG. 8b, if the boundaries between each pixel 60 are formed by channel stops 59, even if blooming occurs, overflowing carriers will only overflow in the vertical direction.
The sensitivity of the blooming detection configuration shown in FIG.

Incidentally, in the above embodiments, an excessive brightness level in at least a part of the subject is detected by the imaging means that forms an imaging signal for electrically recording or reproducing the subject image. The present invention provides a plurality of photoelectric conversion elements separately from the imaging means,
It also includes a device in which the detection is performed by forming an image approximately equal to the subject image formed on the light-receiving surface of the imaging means on the plurality of photoelectric conversion elements.

Further, in this case, the number of the plurality of photoelectric conversion elements may be smaller than the number of pixels on the light receiving surface of the imaging means.

Furthermore, it goes without saying that the ready state of the illumination device in the present invention includes the so-called pop-up state of an imaging device incorporating a light source.

Further, the means for changing the relative ratio between the brightness level of at least a part of the subject image and the reference predetermined level by the detection means in the present invention includes:
In the embodiment shown in the first diagram, the coefficient circuit corresponds to this,
In the sixth illustrated embodiment, the subtraction circuit 44, the aperture control circuit 42, etc. correspond to this, and in the seventh illustrated embodiment, the control voltage source 76, OFG, etc. correspond to this.

(Effects) As explained above, according to the present invention, when the level of the signal formed in each part of the light-receiving surface exceeds a predetermined level, the spatial illumination characteristics of the light source for illuminating the subject Since the control is switched to the soft side, blooming can be suppressed to a large extent.

Furthermore, when there is no subject that is likely to cause blooming, the illumination effect is improved by suppressing the diffusivity of the illumination light, so the power source can be used effectively. Furthermore, in conjunction with setting the illumination device into a ready state, blooming is made easier by increasing the detection sensitivity of the blooming detection means or by increasing the amount of exposure, so the illumination light is pre-emitted, for example. There is no need to check the ease with which blooming occurs, and it is possible to easily perform lighting photography without blooming.

[Brief explanation of the drawing]

FIG. 1a is a diagram showing an example of the configuration of an imaging device of the present invention, FIG. 1b is a diagram showing an example of an image sensor, FIG. 1c is a diagram showing an example of a color filter,
FIG. 1d is a diagram showing an example of the configuration of the delay circuit 32,
Figure 2 is a timing diagram of the circuit shown in Figure 1, Figure 3a
3 is a diagram showing an example of the spatial irradiation characteristic control means of the present invention, FIG. 3b is a diagram showing another example of the spatial irradiation characteristic control means, and FIG. Figures 4 and 5 are diagrams showing configuration examples of the illumination device and spatial illumination characteristic control circuit of the present invention.
The figure shows another example of the configuration of the illumination device and the spatial irradiation characteristic control circuit, FIG. 6 shows another example of the imaging device of the present invention, and FIG. 7a shows the configuration of the light-receiving surface of the image sensor. FIG. 7b is a diagram showing an example of the cross-sectional configuration of an image sensor and an OFG drive circuit, FIG. 8a is a diagram showing another embodiment of the detection means of the present invention, and FIG. 8b is a diagram showing an example. FIG. 2 is a diagram showing another example of the configuration of an image sensor. 1... Image sensor, 19... Integrating circuit, 23...
Comparator as detection means, 21b... light source,
21a...Spatial irradiation characteristic control circuit.

Claims (1)

[Scope of Claims] 1. Imaging means for photoelectrically converting imaging light from a subject; Comparison means for comparing the brightness level of the subject with a predetermined level; Illumination means for illuminating the subject; , a control means for varying the spatial illumination characteristics of the illumination means based on the comparison output of the comparison means; and a control means for variably setting the relative relationship between the predetermined level and the luminance level in the illumination preparation state of the illumination means. An imaging device characterized by comprising means for. 2. The imaging device according to claim 1, wherein the spatial illumination characteristic is a direction or angle characteristic of illumination.