JP3399177B2 - Wide-angle camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide-angle camera such as a CCD camera for taking a still image and a moving image, and more particularly to improvement of a technique for taking an image with a wide angle of view.

[0002]

2. Description of the Related Art Generally, a wide-angle lens used in a wide-angle camera whose angle of view exceeds about 80 degrees is liable to cause chromatic aberration because high refractive power is required, and the number of lenses is increased to compensate for this chromatic aberration. Moreover, the cost of polishing and coating the lens is added, and the cost becomes higher and higher. The wide-angle lens has a large aperture, and the large number of lenses also increases the overall size.

To address these problems, a wide-angle camera for taking a focused image using a convex mirror has been considered. Figure 8
Shows a schematic cross-sectional view of the above-mentioned conventional wide-angle camera. Two types of wide-angle cameras are arranged on the left and right in order to compare and contrast the difference in the angle of view. The line of sight 7 from the CCD camera 1 passes through the imaging lens system 2 and is reflected by the convex mirrors 3 and 4 which are fixed on the cap 8 and are formed into a paraboloid of revolution, and the transparent pipes 5 and 6 which support the convex mirrors 3 and 4. Since it spreads over a wide angle of view via, it is possible to obtain the same captured image as when a wide-angle lens is used. In addition, since it is possible to use a standard lens that is frequently used, and it is sufficient to use one mirror that has good mass productivity, it is possible to increase the price that a wide-angle lens has.
It is possible to solve conventional problems such as an increase in size.

As shown in the right diagram of FIG . 8 , there is a device in which the distance between the CCD camera 1, the image pickup lens system 2 and the convex mirror 3 is set to be short to reduce the size of the device, but the line of sight indicated by the dotted line is the CCD. The field of view is narrowed by being blocked by the camera 1 or the imaging lens system 2. On the other hand, as shown in the left diagram of FIG. 8 , the convex mirror size is increased and the CCD camera 1, the imaging lens system 2 and the convex mirror 3 are separated from each other to widen the field of view, but the device is large. Turn into.

An integrated wide-angle camera as shown in FIG. 9 is also known. This is provided with a light shield 27 and a recess on the upper portion of a hemispherical transparent body 21 formed of a high transmittance transparent resin or glass, and a reflector such as aluminum is vapor-deposited and applied on the recess. A convex mirror 22 is provided, and a concave surface 23 is formed by cutting a part of the transparent body 21 below the transparent body 21 (the incident portion of the line of sight of the camera).
Is an integrated camera in which a transparent cap, a convex mirror, and a transparent pipe are integrally provided.

Also in this example, the line-of-sight 7 emitted from the CCD camera 1 and the image pickup lens system 2 is incident on the concave surface 23 perpendicularly, and then is reflected by the convex mirror 22 to come out from approximately one point in the same manner as described above. It spreads out of the transparent body 21 to a wide angle of view. here,
Refraction occurs due to the difference in refractive index between the transparent body 21 and air,
By making the normal line of the exit surface of the transparent body 21 equal to the line-of-sight direction, deflection due to refraction is suppressed.

[0007]

However, in a wide-angle camera using a convex mirror, C is placed at the center of the captured image.
The CD camera 1, the imaging lens system 2, etc. are reflected in the image,
It is unavoidable in the configuration of the camera that a part of the field of view of the wide-angle camera is wasted. As described above, there are some which are intended to enlarge the visual field range, but if the distance between the CCD camera 1, the imaging lens system 2 and the convex mirror 3 is increased, the size of the entire camera is increased.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a wide-angle camera, which can realize miniaturization, eliminate waste of the field of view, and expand the field of view at low cost. .

[0009]

Therefore, the invention according to claim 1 is, in a wide-angle camera for photographing a formed image obtained through a convex mirror and an imaging lens system , at least the convex mirror.
The normal line of the convex mirror surface in the central part and the imaging lens
An imaginary rotation angle about the optical axis of the tilt angle with the optical axis
Depending on the amount of displacement with respect to the tilt angle of the object surface, the central portion of the convex mirror
To widen the field of view by increasing the deflection angle of the line of sight reflected from the
The deflecting means is provided .

According to this, since the deflecting means increases the deflection angle of the reflection line of sight according to the displacement amount of the inclination angle of the convex mirror, the reflection line of sight is deflected to the same angle as that reflected from the virtual paraboloid of revolution. It is possible to expand the field of view by making the image pickup lens system close to the convex mirror, and to realize miniaturization.

According to a second aspect of the present invention, the deflecting means is a pipe-shaped member arranged around the convex mirror and the wide-angle camera body, and the reflection line of sight from the peripheral portion to the central portion of the convex mirror is deflected. The taper is provided so as to change the wall thickness. According to this
By forming the deflecting means by a pipe-shaped member provided around the convex mirror and the wide-angle camera main body and having a taper with a changed wall thickness, the convex-shaped mirror can be changed from the conventional convex-shaped mirror with a slight design change. Since the reflection line of sight can be deflected, the cost can be reduced.

[0012] According to a third aspect of the invention, the deflection means, a substantially hemispherical member which is provided integrally with the convex mirror, this
The curvature of the exit surface of the substantially hemispherical member of
From the central part
Is different from the deflecting portion .
According to this, the deflecting means can also be applied to the one in which the convex mirror is integrally provided and which is a substantially hemispherical member having a different curvature.

Further, according to the invention of claim 4 , the convex mirror is tilted.
The displacement amount of the oblique angle with respect to the inclination angle of the virtual paraboloid of revolution is such that the inclination of the mirror surface is changed so as to continuously increase from the peripheral portion of the convex mirror toward the central portion. According to this, the vision incident on the central part of the convex mirror
Since the line reflects with a large inclination angle, the line of sight of the reflection is
Without being blocked by the imaging lens system etc., it is possible to eliminate waste of the field of view
In both cases, the image pickup lens system can be brought closer to the convex mirror to make it smaller.
Can be realized. Further, since the inclination of the mirror surface is changed so as to be continuously increased, the distortion of the image formed in the visual field can be suppressed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are schematic cross-sectional views of a wide-angle camera according to a first embodiment of the present invention. In particular, FIG. 1 shows the wide-angle camera according to the present invention on the left side for comparison with the conventional art. On the right side is a conventional wide-angle camera with less wasted field of view. On the other hand, in FIG. 2, the wide-angle camera according to the present invention is arranged on the left side and the conventional wide-angle camera which is downsized even if a part of the field of view is wasted is arranged on the left side for comparison and comparison with the conventional one. It should be noted that components having the same configurations and operations as those of the related art are denoted by the same symbols.

The line of sight 7 from the CCD camera body 1 passes through the imaging lens system 2 and is a convex mirror fixed on the transparent cap 15.
The light is reflected by 13 and diffuses through the transparent pipe 14 that supports the convex mirror 13. Here, the normal line of the convex mirror 13 with the optical axis of the imaging lens system as the rotation axis and the optical axis of the imaging lens system 2 form When the angle is defined as the inclination angle of the convex mirror 13, the inclination angle of the convex mirror 13 with respect to the inclination angle of the virtual paraboloid of revolution having the optical axis as the rotation axis is from the peripheral portion of the convex mirror 13 toward the central portion (rotation). The paraboloid of revolution is additionally processed so that it gradually displaces gradually as it becomes closer to the axis. In Fig. 3, the convex mirror 13 subjected to such additional machining is shown by a solid line, and the virtual paraboloid of revolution is shown. It is indicated by a dotted line.

Therefore, from the CCD camera body 1 to the convex mirror 13
Since the line-of-sight 7 incident on the central portion of the camera is reflected with a large inclination angle, the reflected line-of-sight 7 is not blocked by the CCD camera body 1 or the imaging lens system 2, and the CCD camera body 1
Also, the imaging lens system 2 can be brought sufficiently close to the convex mirror 13, and the size can be reduced as compared with the conventional wide-angle camera. In addition, it is preferable that the inclination of the convex mirror 13 is continuously displaced so as to simply increase. In such a case, the distortion of the image formed in the visual field can be suppressed. Further, the portion to be displaced may be only the central portion of the convex mirror 13 or the entire portion including the peripheral portion can exhibit the same effect.

Further, since the transparent pipe 14 as the deflecting means is provided with a taper having a thickness corresponding to the displacement of the inclination angle of the convex mirror 13, the deflection angle of the reflection line of sight 7 is from the peripheral portion to the central portion of the convex mirror 13. And the line of sight 7 after deflection is deflected at the same angle as that reflected from the virtual paraboloid of revolution. That is, the angle of the line of sight is reduced to the same size as that of the conventional camera shown on the right side of FIG. 1 and the size is reduced to the same size as the conventional camera shown on the right side of FIG. Therefore, it is possible to achieve both conflicting purposes of miniaturization and expansion of the visual field range.

FIG. 4 shows the degree to which the field of view is blocked by the wide-angle camera. The left side of the center is the field of view of the wide-angle camera according to the present invention, and the right side is a part of the conventional field of view. The field of view of the miniaturized wide-angle camera is shown. As is clear from the figure, CC
The proportion of the D camera body 1 and the image pickup lens system 2 reflected is small.

Further, in this embodiment, since the pipe-shaped member for supporting the convex mirror 13 can be provided with the taper, the function of deflecting the line of sight from the convex mirror can be provided by a slight design change, so that the cost can be reduced. It is possible, and by changing the taper thickness of the transparent pipe 14 to set a large deflection angle amount, the field of view range can be further expanded.

The CCD camera body 1 used in this embodiment has a CCD element, a signal processing circuit for the CCD element, a power source, etc. built therein to capture a still image and a moving image.
In particular, since the reflected image from the convex mirror 13 is captured, it is preferable to have a left / right inversion circuit. CCD as a camera
In addition to the camera, an image pickup tube, a still camera for recording an image on a silver halide photographic material, an electronic still camera, or the like may be used.

Further, although the convex mirror 13 is a rotating body having the optical axis which is the center line of the visual field as the rotation axis, various shapes including a non-rotating body are conceivable, and the convex mirror 13 is a paraboloid of revolution. Although the inclination angle is changed with respect to the above, the present invention is not limited to the paraboloid of revolution, and similar effects can be obtained with other curved surfaces. The transparent pipe 14 supporting the convex mirror 13 is made of a material such as a transparent resin having a high transmittance such as acrylic or polycarbonate, or glass. A convex mirror 13 is fixed to a cap 15 attached to the transparent pipe 14, and the cap 15 prevents unnecessary light from entering the transparent pipe 14 and scattering to prevent the transparent pipe 14 from becoming white. .

Next, a second embodiment applied to an integrated wide-angle camera will be described with reference to FIGS.
5 and 6 are schematic cross-sectional views of the integrated wide-angle camera according to the second embodiment. In particular, FIG. 5 shows the wide-angle camera according to the second embodiment on the left side for comparison with the related art. And a conventional wide-angle camera with less wasted field of view on the right side. On the other hand, in FIG. 6, the wide-angle camera of the second embodiment is arranged on the left side and the conventional wide-angle camera which is downsized even if a part of the field of view is wasted is arranged on the left side for comparison and contrast with the conventional case. There is. It should be noted that components having the same configurations and operations as those of the related art are denoted by the same symbols.

Also in this embodiment, the reflection and diffusion of the line of sight 7 is the same as in the above-described embodiment, and the line of sight 7 from the CCD camera body 1 passes through the image pickup lens system 2 and is a convex mirror.
It is reflected by 32 and diffuses through the transparent body 31.
Regarding the inclination angle of the convex mirror 32, additional processing is performed on the paraboloid of revolution so that the convex mirror 32 is gradually displaced greatly from the peripheral portion toward the central portion (closer to the rotation axis). Also, since the exit surface 33 is set with a curvature according to the displacement of the inclination angle of the convex mirror 31, the deflection angle of the reflection line of sight 7 becomes different from the peripheral portion to the central portion of the convex mirror 31, and the reflection after deflection is changed. The line of sight 7 is deflected at the same angle as that reflected from the virtual paraboloid of revolution.

Therefore, from the CCD camera body 1 to the convex mirror 31
Since the line-of-sight 7 incident on the central portion of the image is reflected with a large inclination angle, the reflected line-of-sight 7 is not blocked by the CCD camera body 1 or the imaging lens system 2, and the transparent body 31 is made sufficiently small to allow the CCD camera The convex mirror 13 can be brought sufficiently close to the main body 1 and the imaging lens system 2, and the size can be reduced as compared with the conventional wide-angle camera. Further, the convex mirror 32 has an inclination angle similar to that reflected from the conventional convex mirror 22, and even if the exit surface 33 increases the deflection angle of the reflective visual line of the convex mirror 32, the reflective visual line 7 is virtually The field of view can be expanded by being deflected to the same angle as that reflected from the paraboloid of revolution, and the CCD camera body 1 and the image pickup lens 2 can be brought close to the convex mirror 32 to realize miniaturization. In addition, it is preferable to displace the inclination of the convex mirror 32 so as to continuously and simply increase, and in such a case, distortion of an image formed in the visual field can be suppressed. Further, the portion to be displaced may be only the central portion of the convex mirror 32, or the entire portion including the peripheral portion can exhibit the same effect.

The reflection line of sight 7 emitted from the exit surface 33 of the transparent body 31 at different deflection angles is equal to the line of sight angle shown in the right side of FIG. As a result, the size of the field of view can be reduced to the same size as the conventional camera shown on the right side of FIG. 6 without wasting the field of view, so that both the contradictory objectives of size reduction and expansion of the field of view can be achieved. .

FIG. 7 shows a convex mirror that has undergone such additional processing.
32 and the transparent body 31 are shown by solid lines, and the virtual paraboloid of revolution is shown by dotted lines. (Here, the virtual rotation paraboloid has the rotation axis Z
In the case of cylindrical coordinates having an axis perpendicular to the axis and the rotation axis as the R axis, Z = R ² / (4 × F), and the focus is (R, Θ,
Z) = (0,0, F). Note that the transparent body 31 used in the present embodiment has been described as a combination of a virtual paraboloid of revolution and a hemispherical member, but similar effects can be obtained with other combinations of curved surfaces. is there. Further, like the cap 15, the light shield 27 prevents unnecessary light from entering the transparent body 31 and scattering to prevent the transparent body 31 from becoming white.

[0027]

As described above, according to the first aspect of the invention, the deflecting means is adapted to the displacement amount of the tilt angle of the convex mirror.
Widen the field of view to increase the deflection angle of the reflection line of sight
In addition, the imaging lens system etc. should be brought close to the convex mirror.
It can be miniaturized.

Here, as in the second aspect of the present invention, the deflection means is a pipe-shaped member provided with a taper having a different wall thickness, whereby the cost can be reduced. Further, claim 3
As in the invention described above, the deflecting means can also be applied to a substantially hemispherical member having the convex mirror integrally provided therein and having a different curvature. Further, according to the invention of claim 4 , the convex mirror
Since the inclination of the mirror surface is changed so that the displacement amount of the tilt angle of the convex mirror continuously increases from the peripheral portion to the central portion of the convex mirror, the reflection line of sight from the convex mirror is imaged.
It is possible to eliminate the waste of the field of view without being blocked by the lens system etc.
In addition, the imaging lens system etc. can be brought close to the convex mirror to reduce the size.
realizable. Further, particularly by continuously changing it, it is possible to suppress the distortion of the formed image in the visual field.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a wide-angle camera according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the wide-angle camera according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a convex mirror according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a degree of obstruction of a visual field range according to the first embodiment of the present invention.

FIG. 5 is a schematic sectional view of an integrated wide-angle camera according to a second embodiment of the present invention.

FIG. 6 is a schematic sectional view of an integrated wide-angle camera according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a convex mirror and a transparent body according to a second embodiment of the present invention.

FIG. 8 is a schematic sectional view of a wide-angle camera in a conventional example.

FIG. 9 is a schematic cross section of an integrated wide-angle camera in a conventional example .
Figure

[Explanation of symbols]

1 CCD camera body 2 Imaging lens system 7 gaze 13 convex mirror 14 Transparent pipe 15 cap

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-47-10534 (JP, A) Actually developed 59-60651 (JP, U) Special Table 9-505447 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03B 15/00 G03B 17/17 G03B 37/00

Claims (4)

(57) [Claims] 1. A wide-angle camera for photographing a formed image obtained through a convex mirror and an imaging lens system, wherein a tilt angle formed by a normal line of the convex mirror surface at least at a central portion of the convex mirror and an optical axis of the imaging lens. Of the optical axis
A wide-angle camera provided with a deflecting means for increasing the deflection angle of the line of sight reflected from the central portion of the convex mirror to widen the visual field range according to the displacement amount with respect to the inclination angle of the virtual rotation parabola centered around . 2. The deflecting means is a pipe-shaped member arranged around the convex mirror and the wide-angle camera body, and is tapered so as to change the thickness as the reflection line of sight from the peripheral portion to the central portion of the convex mirror is deflected. The wide-angle camera according to claim 1, further comprising: 3. The deflecting means is a substantially hemispherical member integrally provided with the convex mirror, and a bending of an emission surface of the substantially hemispherical member.
The portion that deflects the line of sight reflected from the peripheral portion of the convex mirror
And the part that deflects the line of sight reflected from the central part
Wide-angle camera of claim 1, wherein the a. Wherein the inclination angle of the convex mirror, the displacement amount with respect to the inclination angle of the virtual rotational paraboloid, varying continuously larger as specularly inclined toward the central portion from the peripheral portion of the convex mirror Claims 1 to 3 characterized by
The wide-angle camera described in any one of 1 .