JP2003198898A - Solid-state imaging device camera and intercom with camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging device camera that eliminates the need for a dummy filter in spite of provision of an infrared ray-cut filter that is placed in front of a solid-state imaging device and removed therefrom. <P>SOLUTION: The solid-state imaging device camera is provided with: a solid- state imaging device 3 having the sensitivity in a visible light area and an infrared ray area; a photographing lens 2 with a fixed focus placed in front of the solid-state imaging device 3; the infrared ray-cut filter 1 the transmissivity of which with respect to a infrared ray is lower than the transmissivity with respect to a visible light; and a filter drive mechanism 6 that can move the infrared ray-cut filter 1 between a front position of the solid-state imaging device 3 and a position outside the visual field of the solid-state imaging device 3. While the infrared ray-cut filter 1 is placed at a position in front of the solid-state imaging device 3, when the relation of position between the lens 2 and the solid-state imaging device 3 is determined so as to match the focus by using the visible light, after the infrared ray-cut filter 1 is removed, conditions to obtain required resolving power are obtained by using an infrared ray. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-focus solid-state image pickup device camera having an infrared light cut filter arranged in front of a solid-state image pickup device having sensitivity from visible light region to infrared light region. And a door intercom with a camera.

[0002]

2. Description of the Related Art Conventionally, a CCD capable of electronically controlling exposure and the like for the purpose of monitoring intruders and confirming visitors.
There is provided a fixed-focus solid-state image sensor camera using such a solid-state image sensor.

Among the solid-state image pickup devices, for example, CCD
Has a sensitivity up to the infrared light region, the image obtained through the camera will look as if seen with the naked eye when light including not only the visible light region but also the infrared light region enters the solid-state image sensor. Is different. Therefore, an infrared light cut filter whose transmittance for infrared light is lower than that for visible light is arranged at a position in front of the solid-state image sensor to reduce the infrared light.

On the other hand, auxiliary lighting is required to obtain a clear image when the image pickup range is dark such as at night. When a visible light source is used as auxiliary lighting, an intruder can be easily noticed for the purpose of confirming an intruder, and the auxiliary lighting sometimes gives discomfort to a visitor for the purpose of confirming a visitor. Therefore,
A solid-state image sensor camera that uses an infrared light source as auxiliary illumination is provided by utilizing the fact that a CCD generally used as a solid-state image sensor has sensitivity in the infrared light region.

By the way, when the infrared light source is used as auxiliary illumination, the above infrared light cut filter must be removed from the position in front of the solid-state image pickup device in order to effectively use the infrared light.

[0006]

However, as shown in FIG. 8 (a), the infrared light cut filter 1 is arranged on the optical axis of the photographing lens arranged in front of the solid-state image pickup device. In the state, when the infrared light cut filter 1 is not provided, the light beam formed as shown by the broken line is refracted as shown by the solid line at the infrared light cut filter 1, so that the focal length of the lens becomes long. Therefore, in a fixed-focus solid-state image sensor camera, if the lens and the solid-state image sensor are arranged so that the infrared light cut filter 1 is placed in front of the solid-state image sensor, the infrared light cut filter 1 is arranged. The focus shifts when you remove the.

Therefore, in Japanese Utility Model Application Laid-Open No. 2-13364, a correction lens (hereinafter referred to as a dummy filter) for correcting the above-mentioned focus shift is replaced with the infrared light cut filter 1 and the front side of the solid-state image pickup device. Positioning techniques are shown. However, if the dummy filter is used, it is necessary to separately prepare the dummy filter, which increases the cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dummy filter while having an infrared light cut filter capable of disposing and removing the solid-state image pickup device in the front position. An object of the present invention is to provide an unnecessary fixed-focus solid-state image sensor camera and a doorphone with a camera using the solid-state image sensor camera.

[0009]

According to a first aspect of the present invention, there is provided a solid-state image pickup device having a sensitivity from a visible light region to an infrared light region, and a fixed focus image pickup arranged in front of the solid-state image pickup device. Lens, an infrared light cut filter whose transmittance for infrared light is lower than the transmittance for visible light, the infrared light cut filter at a position in front of the solid-state image sensor and outside the visual field of the solid-state image sensor. A filter driving mechanism that is movable between a position and an infrared light source for illumination that irradiates the imaging range of the solid-state image sensor with infrared light, and a video signal process that generates a video signal from the output of the solid-state image sensor. And a thickness d of the infrared light cut filter, a refractive index n _df of the infrared light cut filter for visible light, a focal length f _d of the lens for visible light, and a visible light of the lens. Refraction to and n _dl, and the refractive index n _al of the lens with respect to the infrared light radiated from the illumination infrared light source is 0.
5d (1-1 / n _df ) ≦ f _d (n _dl −n _al ) / (n _al −
1) It is characterized by satisfying ≦ 2d (1-1 / n _df ).

According to a second aspect of the invention, in the first aspect of the invention, the infrared light cut filter has a wall thickness d of 0.3 m.
m, the refractive index n _df of the infrared cut filter for visible light is 1.51, the focal length f _d of the lens for visible light is 2.15 mm, and the refractive index of the lens for visible light is The rate n _dl is 1.492, the wavelength of infrared light emitted from the infrared light source for illumination is 950 nm,
The refractive index n _{al of the} lens with respect to infrared light emitted from the illumination infrared light source is 1.475.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the infrared light cut filter is provided with an antireflection coating for preventing reflection of visible light. .

The invention of claim 4 is the invention of claims 1 to 3.
In the invention described in any one of 1, the infrared cut filter is formed on a surface of the filter substrate made of a translucent member and the filter substrate, and the transmittance for infrared light is lower than the transmittance for visible light. And a thin film.

The invention of claim 5 is the invention of claims 1 to 4.
In the invention described in any one of 1, the solid-state light emitting element is used as the infrared light source for illumination.

The invention according to claim 6 is any one of claims 1 to 5.
In the invention described in any one of 1, the infrared light cut filter is arranged at a position between the lens and the solid-state image sensor.

The invention of claim 7 is from claim 1 to claim 6.
In the invention according to any one of the items 1 to 3, an illumination control unit that turns on and off the infrared light source for illumination, and an illuminance detection unit that detects illuminance in an imaging range of the solid-state image sensor,
The illumination control unit turns on the infrared light source for illumination when the illuminance of the imaging range of the solid-state image sensor detected by the illuminance detection unit is less than a predetermined reference value, and is detected by the illuminance detection unit. In addition, the illumination infrared light source is turned off when the illuminance in the imaging range of the solid-state imaging device is equal to or higher than the reference value.

[0016] The invention of claim 8 is from claim 1 to claim 7.
And a color monitor that receives a video signal from the video signal processing unit and displays an image captured by the solid-state imaging device camera. It is characterized by having a master unit.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) As shown in FIGS. 1 and 2, the solid-state image pickup device camera according to the present embodiment includes a solid-state image pickup device 3 composed of a CCD having a sensitivity from a visible light region to an infrared light region. .

At a position in front of the solid-state image sensor 3, a fixed-focus image-taking lens 2 having a positional relationship with the solid-state image sensor 3 so that an object T in a certain range is focused is arranged. Then, the infrared light cut filter 1 whose transmittance for infrared light is lower than that for visible light is provided between the position in front of the lens 2 and the position outside the visual field of the solid-state image sensor 3 by the filter driving mechanism 6. It is supposed to be movable.

The filter drive mechanism 6 is a rotary solenoid whose rotation axis is arranged along the optical axis of the lens 2, and an arm on which the infrared light cut filter 1 is mounted is provided so as to intersect the rotation axis. Then, the infrared light cut filter 1 is moved by the rotation of the arm.

The solid-state image pickup device camera is composed of a light-emitting diode as a solid-state light-emitting device and has a wavelength range of 95%.
An illumination infrared light source 5 that irradiates 0 nm infrared light, and a video signal processing unit 4 that generates a video signal from the output of the solid-state image sensor 3 are provided.

The illumination infrared light source 5 and the filter driving mechanism 6 are controlled by the controller 7. More specifically, the control unit 7 turns off the illumination infrared light source 5 and places the infrared light cut filter 1 in front of the lens 2 in the visible light use state in which visible light is used for imaging, as shown in FIG. When the infrared light is used, the infrared light source 5 for illumination is turned on and the infrared light cut filter 1 is placed outside the visual field of the solid-state image sensor 3 as shown in FIG. To place. The control unit 7 may be omitted.

Since the illuminating infrared light source 5 is composed of a light emitting diode, it is possible to obtain a necessary amount of light with less electric power as compared with the case of using a light bulb. Further, since the life is long, it is not necessary to provide a socket or a cover for making it possible to replace the irradiation infrared light source 5, and since it is small, the illumination infrared light source 5 can be mounted on a printed circuit board together with the solid-state image sensor 3 or a lens. The solid-state imaging device camera can be miniaturized. Furthermore, since the light emitting diode that emits infrared light is also used for remote control,
It is available in large quantities on the market and can be easily obtained.

Further, the infrared light cut filter 1 is a filter substrate made of glass provided with a thin film on the surface of which the transmittance for infrared light is lower than the transmittance for visible light. This thin film is formed by depositing a layer having a thickness of several tens to several hundreds of nm per layer and stacking layers having different refractive indexes and thicknesses over several tens of layers. Therefore, even if the thickness of the filter substrate is reduced, the infrared light cut filter 1
It is possible to suppress the infrared ray transmittance for infrared light to a low level by using a thin film.

Further, the surface of the infrared light cut filter 1 is coated with an antireflection coating for preventing reflection of visible light. Generally, the surface of glass used as a base material of an optical filter such as the infrared light cut filter 1 has a reflectance of about 4%, and the reflected light on the surface of the infrared light cut filter 1 has a solid-state imaging device 3 When incident on, the phenomenon such as flare or ghost is caused, and the image quality is deteriorated in a state where the infrared light cut filter 1 is arranged in front of the lens 2. However, in the present embodiment, since the antireflection coating is applied to the surface of the infrared light cut filter 1, the brightness of flare and ghost is suppressed, and the infrared light cut filter 1 is positioned in front of the lens 2. It is possible to prevent the quality of the image from being deteriorated in the arranged state. For example, if the reflectance can be suppressed to 1% by applying the antireflection coating to the surface having the reflectance of 4%, if the antireflection coating is applied to only one surface, it becomes ¼,
If it is applied to both sides, the brightness of flare and ghost can be suppressed to 1/16 and the quality of the image can be improved.

Here, as shown in FIG. 8B, the present inventor has found that the lens 2 has a focal length for infrared light longer than that for visible light, and the difference between the focal lengths and the infrared light cutoff. It was noted that the required resolution can be obtained without the dummy filter if the ratio with the width in which the filter 1 is removed and the focal length of the lens 2 is shortened is within a certain range. The details will be described below.

As described above, since the refractive index n _al of the lens 2 for infrared light is smaller than the refractive index n _dl for visible light, the focal length for infrared light shown by the broken line is the focal length for visible light shown by the solid line. It is longer than f _d by the focus shift f _c due to the difference in the refractive index of the lens 2.

In other words, if the defocus f _f due to the infrared light cut filter 1 and the defocus f _c due to the difference in refractive index of the lens 2 are close to each other to some extent, even if the focus is set in the visible light use state. The dummy filter is not necessary because the necessary resolution can be obtained in the infrared light use state. Detailed conditions are derived below.

Assuming that the thickness of the lens 2 is negligible and the distance to the object can be regarded as infinite, the focus shift f _c due to the difference in the refractive index of the lens 2 is f _c = f _d (n _dl −
It is expressed as n _al ) / (n _al −1). Further, the focus shift f _{f due} to the infrared light cut filter 1 is f _f = d (1-1) when the thickness of the infrared light cut filter 1 is d and the refractive index for visible light is n _df. / N _df ).

Even if the positional relationship between the lens 2 and the solid-state image sensor 3 is set so that the lens 2 and the solid-state image pickup device 3 are in focus in the visible light use state, in order to obtain the necessary resolving power in the infrared light use state, the refractive index of the lens 2 is changed. In obtaining the condition to be satisfied by the defocus f _f by defocus f _c and an infrared light cut filter 1 due to the difference, using FIG. The graph shown in FIG. 10 uses infrared light having a wavelength of 950 nm as the infrared light and d line of He as the visible light (wavelength 587.6 nm).
Is used to calculate the ratio f _c / f _f of the difference f _c between the focal length of the lens 2 for infrared light and the focal length of the lens 2 for visible light and the focus shift f _f by the infrared light cut filter 1. 6 is a graph in which 100 pairs of black and white stripes per 1 mm width are drawn on the horizontal axis and the contrast (that is, MTF) obtained using a chart arranged on the optical axis of the lens 2 is plotted on the vertical axis. It can be said that the MTF thus obtained reflects the resolving power. MT obtained in the infrared light use state by adjusting the positional relationship between the lens 2 and the solid-state image sensor 3 so that the MTF shown by the broken line a in the visible light use state is obtained.
F is indicated by a solid line B. Generally, when using the solid-state image sensor camera for the purpose of monitoring suspicious persons and confirming visitors, MT
It is known that if F is 0.3 or more, it is practical. According to FIG. 10, if f _c / f _f is in the range of 0.5 or more and 2 or less, the MTF is kept at 0.3 or more, that is, the necessary resolution is obtained. Expressing this condition _{formula, 0.5d (1-1 / n df)} ≦ f d (n dl -n al) /
(N _al −1) ≦ 2d (1-1 / n _df ).

In this embodiment, the infrared light cut filter is used.
Ruta 1 has a transmittance for infrared light and a transmittance for visible light.
Since a lower thin film is provided on the surface of the filter substrate,
Even if the film is made into a multi-layered film to secure the effect of reducing infrared light
The thickness of the thin film can be suppressed to about ten and several μm,
There is no need to consider refraction, and the thickness of the filter substrate
No matter how the thickness and the materials used for the filter substrate are selected
Ensures the infrared light cut filter 1's ability to reduce infrared light
Therefore, the thickness d and the refractive index n for visible light are _dfAnd up
It is easy to set to satisfy the condition of the formula
It

Incidentally, as the infrared light cut filter, it is conceivable to use a material such as glass in which an infrared light absorbent is mixed, but in the present embodiment, it is not adopted for the following reason. Infrared light absorbers generally react easily with water at high temperatures, and the higher the concentration of infrared light absorbers in an infrared light cut filter, the more cloudy it becomes due to the reaction between infrared light absorbers and water at high temperatures in environmental tests. It's easy to do. Therefore, in order to prevent clouding, the concentration of the infrared light absorber must be kept low, and the transmittance of infrared light in the infrared light cut filter depends on the concentration of the infrared light absorber and the meat of the infrared light cut filter. Since the thickness is determined by the thickness, it is necessary to secure the thickness of the infrared cut filter in order to sufficiently reduce the transmittance for infrared light. Therefore, it is difficult to adjust the refractive index and the wall thickness so as to satisfy the above expressions, and therefore, it is not used in this embodiment.

Here, the thickness d of the infrared light cut filter 1 in this embodiment is 0.3 mm, and the refractive index n _df for visible light is 1.51. The lens 2 has a focal length of 2.15 mm for visible light, a refractive index n _dl for visible light is 1.492, and a refractive index n _al for infrared light emitted from an infrared light source for illumination is 1.475. Is. Therefore,
_{0.76d (1-1 / n df) =} f d (n dl -n al) /
Since it is (n _al −1), the condition of the above equation can be satisfied, that is, the necessary resolution can be obtained. Incidentally, according to FIG. 10, the positional relationship between the lens 2 and the solid-state image sensor 3 is adjusted so that the MTF becomes 0.99 in the visible light use state in which the infrared light cut filter 1 is arranged in the position in front of the lens 2. After that, the MTF measured in the infrared light use state with the infrared light cut filter 1 removed is f _{c of the} present embodiment.
/ F _f is 0.76.

As described above, the thickness d of the infrared light cut filter 1, the refractive index n _df of the infrared light cut filter 1 for visible light, the focal length f _d of the lens 2 for visible light, and the visible light Refractive index n _dl of the lens 2 with respect to the infrared light source 5 for illumination
By setting the refractive index n _al of the lens 2 with respect to the infrared light emitted by the
Even if the positional relationship between the lens 2 and the solid-state image sensor 3 is set so that the lens 2 and the solid-state image sensor 3 are placed in a position in front of the solid-state image sensor 3 in the visible light use state, the infrared light cut filter 1 is outside the visual field of the solid-state image sensor 3. Since the necessary resolution can be obtained in the use state of the infrared light arranged at the position, and therefore the dummy filter is not required, the cost can be reduced by reducing the number of parts as compared with the case where the dummy filter is used.

(Embodiment 2) In the present embodiment, in the visible light use state, the infrared light cut filter 1 is arranged between the lens 2 and the solid-state image pickup element 3 as shown in FIG. Other configurations are similar to those of the first embodiment.

Here, in order to eliminate the vignetting of the image,
As shown in FIG. 4, in the infrared light cut filter 1, the effective diameter of the lens 2, the aperture diameter of the diaphragm 12 that may be applied to the lens 2, and the size of the range where an image is formed in the solid-state image sensor 3 are shown. The area is required to cover the visual field of the solid-state image sensor 3 defined by When the infrared light cut filter 1 is arranged in front of the lens 2, an area that covers at least the angle of view of the lens 2 is required as shown by the chain double-dashed line in FIG. On the other hand, in the present embodiment, the infrared light cut filter 1 is arranged at a position between the lens 2 and the solid-state image sensor 3, and the area required to cover the field of view of the solid-state image sensor 3 is from the front of the lens 2. Since the distance between the lens 2 and the solid-state image sensor 3 is narrower, the infrared light cut filter 1
The area may be smaller than that in the case where the lens is arranged in front of the lens 2. In addition, the space between the lens 2 and the solid-state image sensor 3 is effectively used as compared with the case where the infrared light cut filter 1 is arranged in front of the lens 2 and the infrared light cut filter 1 and the lens 2 are effectively used. By shortening the overall length of the optical system including the solid-state image sensor 3 and the solid-state image sensor 3, the solid-state image sensor camera can be downsized.

(Third Embodiment) As shown in FIGS. 5 and 6, the solid-state image pickup device camera according to the present embodiment is provided with an illuminance sensor 8 as illuminance detecting means for detecting the illuminance in the image pickup range and outputting it to the control section 7. When the illuminance output from the illuminance sensor 8 is equal to or higher than the predetermined reference value, the control unit 7 switches to the visible light use state as shown in FIG. 5, and the illuminance output from the illuminance sensor 8 is less than the predetermined reference value. At times, as shown in FIG. 6, the infrared light is used. That is, the control unit 7 functions as an illumination control unit. CdS as the illuminance sensor 8
Alternatively, a photodiode or the like can be used. Other configurations are similar to those of the second embodiment.

According to the above configuration, the illumination infrared light source 5 is automatically turned on / off according to the illuminance in the image pickup range.
By setting the reference value appropriately according to the sensitivity of the solid-state image sensor, the infrared light source for lighting can be automatically turned on only when necessary, and the power consumption is higher than that when the infrared light source for lighting is always turned on. You can save.

(Embodiment 4) FIG. 7 shows an intercom with a camera as one of examples of use of the solid-state image pickup device camera described in the above embodiment. The intercom with camera is a solid-state image sensor camera based on a slave unit 9 that is equipped with the solid-state image sensor camera 9a of the third embodiment and is placed outdoors and a video signal received from the video signal processing unit 4 via a cable 10. 9a, a color monitor 11a for displaying an image captured by the camera 9a, and a base unit 11 arranged indoors. In addition to the solid-state imaging device camera 9a, the slave unit 9 is provided with a call button 9b for making a ringing sound, a microphone 9c for inputting a visitor's voice, and a speaker 9d for outputting a user's voice. And base unit 1
1 is provided with a transmitter / receiver device 11b that enables a call between the microphone 9c and the speaker 9d.

In order to obtain a color signal for displaying a color image on the color monitor 11a, R (red), G (green) and B (blue) primary color filters are provided in each pixel of the solid-state image sensor 3 in this embodiment. From the output of each pixel,
Three color signals of B can be obtained. Here, the primary color filter and the complementary color filter transmit infrared light with different transmittances for each color, and the solid-state image sensor 3 has a sensitivity up to the infrared light region. Therefore, the solid-state image sensor 3 has only a visible light region. When light including an infrared light region is incident, a color signal for displaying an image in which the color balance is lost on the color monitor 11a is output. The infrared light cut filter 1 in the present embodiment is arranged in front of the solid-state image pickup device 3 in the visible light use state to reduce the infrared light in order to prevent the color balance from being disturbed as described above.

According to this embodiment, since the slave unit 9 is provided with the solid-state image pickup device camera 9a having the solid-state image pickup device 3 having sensitivity up to the infrared light region and the illumination infrared light source 5, the illuminance in the image pickup range is low. Even in such a case, a clear image can be obtained by using the infrared light source 5 for illumination, and since infrared light is used, the visitor is not uncomfortable. Further, since the solid-state image sensor camera 9a that does not require the dummy filter is used, the cost of the solid-state image sensor is reduced as compared with the case where the solid-state image sensor camera using the dummy filter is used, so that the cost is reduced.

Here, the color filters provided in the pixels may be complementary color filters such as Cy (cyan), Mg (magenta), and Ye (yellow) instead of the primary color filters.

As another example of use, the solid-state image sensor camera described in the above embodiment may be used as a surveillance camera. In this case, since the infrared light source for illumination is used as the auxiliary illumination when the illuminance of visible light is low, the presence of the surveillance camera is less noticeable than when the visible light source is used as the auxiliary illumination.

[0044]

According to the invention of claim 1, the thickness d of the infrared light cut filter, the refractive index n _df of the infrared light cut filter with respect to visible light, and the focal length f of the lens with respect to visible light.
_d , the refractive index n _{dl of} the lens for visible light, and the refractive index n of the lens for infrared light emitted by the infrared light source for illumination.
_al is 0.5d (1-1 / n _df ) ≦ f _d (n _dl −n _al ).
By satisfying / (n _al −1) ≦ 2d (1-1 / n _df ), a sufficient resolution can be obtained even in the infrared light use state, and a dummy filter is unnecessary, so that the dummy is used. The cost can be reduced by reducing the number of parts as compared with the case of using a filter.

According to the third aspect of the invention, the brightness of flare and ghost can be suppressed by applying an antireflection coating to the surface of the infrared light cut filter.

According to a fourth aspect of the invention, the infrared light cut filter is a filter substrate made of a light-transmissive member, and a thin film formed on the surface of the filter substrate and having a transmittance for infrared light lower than that for visible light. Since the material and wall thickness of the filter substrate do not affect the extinction effect on infrared light,
Further, in the formula of claim 1, what is related to the infrared light cut filter is the thickness of the infrared light cut filter and the refractive index for visible light, and these are determined by the material and the thickness of the filter substrate. It is easy to set the wall thickness of the infrared cut filter and the refractive index for visible light so as to satisfy the conditions of claim 1.

According to the invention of claim 5, since the solid state light emitting element is used as the infrared light source for illumination, the power consumption can be reduced and the size can be reduced as compared with the case of using the electric bulb.

In the sixth aspect of the invention, the infrared light cut filter is arranged at a position between the lens and the solid-state image pickup element, that is, it is arranged at a portion where the light from the image pickup range is converged. The infrared light cut filter can be smaller than when the external light cut filter is arranged in the position in front of the lens, and the space between the lens and the solid-state image sensor is effectively used, so that the solid-state image sensor camera Can be miniaturized.

According to a seventh aspect of the present invention, there is provided an illumination control section for turning on / off the infrared light source for illumination, and an illuminance detection section for detecting the illuminance in the image pickup range of the solid-state image pickup element.
When the illuminance in the imaging range of the solid-state image sensor detected by the illuminance detection means is less than a predetermined reference value, the infrared light source for illumination is turned on, and the illuminance in the imaging range of the solid-state image sensor detected by the illuminance detection means is Since the infrared light source for illumination is turned off when the value is equal to or more than the reference value, the infrared light source for illumination is automatically turned on only when necessary by appropriately setting the reference value according to the sensitivity of the solid-state image sensor. Therefore, power can be saved as compared with the case where the infrared light source for illumination is constantly turned on.

The invention of claim 8 is any of claims 1 to 7.
Since the solid-state imaging device camera according to any one of 1 above is provided in the slave unit, the cost of the solid-state imaging device camera can be reduced as compared with the case where a solid-state imaging device camera that requires a dummy filter is used. It can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a use state of visible light according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a usage state of infrared light of the above.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of the same principle as above.

FIG. 5 is a block diagram showing a visible light use state according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a usage state of infrared light of the above.

FIG. 7 is a schematic configuration diagram showing a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating the principle of the present invention.

FIG. 9 is a diagram illustrating the principle of the present invention.

[Explanation of symbols] 1 Infrared light cut filter 2 lens 3 Solid-state image sensor 4 Video signal processor 5 Infrared light source for illumination 6 Filter drive mechanism 7 control unit 8 Illuminance sensor 9 cordless handsets 9a solid-state image sensor camera 11 base unit 11a color monitor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) G03B 15/02 G03B 15/02 V H04N 5/33 H04N 5/33 7/18 7/18 HF term ( Reference) 2H083 AA04 AA11 AA19 AA26 AA32 AA51 AA58 5C022 AA06 AB13 AB15 AB21 AC01 AC42 AC54 AC55 AC69 AC74 5C024 AX07 BX04 CX37 EX42 EX51 GY00 5C054 AA01 AA05 CA04 CA05 CC02 CD06 FA00 HA22

Claims (8)

[Claims] 1. A solid-state image sensor having sensitivity from a visible light region to an infrared light region, a fixed-focus photographing lens arranged in a position in front of the solid-state image sensor, and a transmittance for infrared light. An infrared light cut filter having a transmittance lower than that of visible light, and a filter drive that makes the infrared light cut filter movable between a position in front of the solid-state image sensor and a position outside the visual field of the solid-state image sensor. The infrared light cut filter includes a mechanism, an infrared light source for illumination that irradiates infrared light to the imaging range of the solid-state image sensor, and a video signal processing unit that generates a video signal from the output of the solid-state image sensor. , The refractive index n _df of the infrared cut filter for visible light, and the focal length f _{d of the} lens for visible light.
And the refractive index n _{dl of the} lens with respect to visible light and the refractive index n _{al of the} lens with respect to infrared light emitted by the illumination infrared light source are 0.5d (1-1 / n _df ) ≦ f _d (N _dl −
A solid-state image sensor camera satisfying the following condition: n _al ) / (n _al −1) ≦ 2d (1-1 / n _{d f} ). 2. The infrared light cut filter has a thickness d of 0.3 mm, the infrared light cut filter has a refractive index n _df for visible light of 1.51, and the visible light of the lens The focal length f _d is 2.15 mm, the refractive index n _{dl of the} lens with respect to visible light is 1.492, and the wavelength of infrared light emitted by the illumination infrared light source is 950 nm.
The solid-state imaging device camera according to claim 1, wherein the refractive index n _{al of the} lens with respect to the infrared light emitted from the illumination infrared light source is 1.475. 3. The solid-state imaging device camera according to claim 1, wherein the infrared light cut filter is provided with an antireflection coating for preventing reflection of visible light. 4. The infrared light cut filter comprises a filter substrate made of a translucent member and a thin film formed on the surface of the filter substrate and having a transmittance for infrared light lower than a transmittance for visible light. The solid-state imaging device camera according to any one of claims 1 to 3, which is characterized. 5. The solid-state imaging device camera according to claim 1, wherein a solid-state light-emitting device is used as the illumination infrared light source. 6. The solid-state imaging device according to claim 1, wherein the infrared light cut filter is arranged at a position between the lens and the solid-state imaging device. Element camera. 7. An illumination control unit for turning on / off the infrared light source for illumination, and an illuminance detection unit for detecting illuminance in an image pickup range of the solid-state image sensor, the illumination control unit including the illuminance detection unit. When the illuminance in the image pickup range of the solid-state image pickup device detected by is turned on the illumination infrared light source, the illuminance in the image pickup range of the solid-state image pickup device detected by the illuminance detection means. 7. The solid-state imaging device camera according to claim 1, wherein the illumination infrared light source is turned off when is greater than or equal to the reference value. 8. A slave unit comprising the solid-state imaging device camera according to claim 1, and a video signal received from the video signal processing unit, which is imaged by the solid-state imaging device camera. Door phone with a camera, which is provided with a base unit provided with a color monitor for displaying an image.