JPH0530435A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent a luminous flux made incident on a dead band of a detector from being collected onto a sensor element when an incident optical axis is not tilted by using an optical tilt unit so as to tilt the incident optical axis and turning the unit. CONSTITUTION:An optical axis tilt unit 2 whose axis made incident on a sensor element 1a is tilted and subjected to precession therearound is provided between an optical system 2 and a two-dimension detector 1. The unit 2 is preferably a prism having a edge-shaped cross section and is an optical unit whose radiation optical axis is tilted with respect to the incident optical axis through the combination of mirrors and its cross section is a wedge type prism. Thus, the incident optical axis of the optical axis tilt unit 2 is tilted and rotated to collect the luminous flux having being made incident on a dead band of the detector 1 when not tilted. Thus, the two-dimension detector 1 is applied even to the application to a retrieval sensor that a small object at a remote distance less than one picture element is retrieved quickly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, and in particular,
The present invention relates to an imaging device using a two-dimensional detector in which detection elements that generate an electric signal with respect to incident power of light, infrared rays, etc. are arranged in a plane (two-dimensional) and the brightness information of a visual field is read as an electric change. is there.

In the case of infrared rays, for example, in the case of an image pickup apparatus, a system in which a light beam incident on one detection element is optically two-dimensionally scanned to obtain information on a scene being imaged, 50 to 200 elements Of a system that obtains information of a scene being imaged by optically scanning a light beam incident on an array arranged in a row in a direction perpendicular to the row,
Then, there is a method of arranging hundreds of elements vertically and hundreds horizontally to obtain information of a scene being imaged without performing optical scanning.

Among the image pickup apparatuses of various types as described above, the above-mentioned second type has been used in recent years with the progress of the element forming technology.
A considerable number of image pickup devices using a two-dimensional detector have appeared, and particularly in visible image pickup devices, a CCD camera occupies the majority as a system using the above two-dimensional detector.

[0004]

2. Description of the Related Art In a two-dimensional detector as described above (a portion indicated by reference numeral 1 in FIG. 1), a surface (a portion indicated by reference numeral 1b in the same figure) on which a detection element (a portion indicated by reference numeral 1a in the same figure) is installed. ), The wiring paths for accumulating the charges generated by these sensing elements, that is, for transferring the charges to an accumulation region for integrating and converting the charges into a high-sensitivity electric signal for improving S / N, and this charge transfer. It is necessary to form a gate circuit etc. for controlling together.

Therefore, it is not possible to make the entire sensing element surface a sensitive region of the incident power (that is, the sensing element surface cannot be filled with sensing elements), but considering the sensing efficiency, the sensing element surface It is desirable to make the fill factor, which is the ratio of the sensitive area area to the area, as close to 100% as possible.

However, in a normal image pickup apparatus, a target object or a background object (portion indicated by reference numeral 4 in FIG. 1) to be imaged is sufficiently large, and optical power from there is somehow on the sensing element surface. Since it is incident on several sensing elements, and the optical power incident on areas other than the sensitive area is the same as the power incident on the surrounding sensing elements, there is no particular problem in image formation.

[0007]

However, when an application such as a search system for detecting a minute target object at a long distance appears, a relative position change between the two-dimensional detector and the target will occur. Is extremely small and the size of the target is smaller than the detection element guard angle, so that the target remains in the blind spot of the detection area and the detection is delayed.

As described above, in an image pickup device using a conventional two-dimensional detector, which has a blind spot in the detection area, the target object cannot be captured as a shape, and there is a possibility that the detection will be significantly delayed. It is considered that it is not applicable to applications, and rather, a one-dimensional array type one-dimensional detector was often used.

Therefore, the present invention provides an image pickup apparatus for applying an incident power from an object to be imaged to a two-dimensional detector having an area occupied by the detecting element on the detecting element surface of less than 100% via an optical system. Even in applications such as a search system that tries to detect a small target object at a long distance, the purpose is to detect its existence and to identify its direction by detecting its optical radiation power. .

[0010]

FIG. 1 is a diagram showing a principle configuration of an image pickup apparatus according to the present invention. In the figure, reference numeral 1 is a two-dimensional detector, which is a sensing element provided on a sensing element surface 1b. What converts the optical power incident on 1a into an electric signal, and 2 is an optical axis tilt unit, which tilts the optical axis incident on the sensing element 1a from the axis in the absence thereof and rotates around it (precession). What is to be moved 3 is an optical system for collecting the optical power from the scene 4 on the detection element 1a. Incidentally, scene 4 is a radiation source of optical power in which an object to be imaged is present, and 4a is the detection element 1 projected on the scene 4.
In the image of a, a circle is drawn according to the precession movement of the optical axis tilt unit 2 and appears in a portion that is not projected when the optical axis tilt unit 2 is not present.

As the optical axis tilt unit 2 in this case, a prism having a wedge-shaped cross section, or an optical unit in which a mirror is combined and the outgoing optical axis is tilted with respect to the incoming optical axis can be used.

[0012]

In the present invention, as shown in FIG. 1, the optical axis tilt unit 2 precesses the optical axis incident on each detection element 1a of the two-dimensional detector 1 by the optical axis tilt unit 2. The optical power from a wider range can be focused on the detection element 1a than when the optical axis is fixed.

That is, as shown in FIG. 2, if the optical axis tilt unit 2 is rotated by an optical axis O '(indicated by ▲) which is tilted by φ with respect to the optical axis O in the absence thereof,
The field of view without the optical axis tilt unit 2 shown by the chain double-dashed line rotates as the field of view shown by the solid line, and therefore the field of view focused on one detection element 1a is as shown by the dotted line in the figure. That is, the field of view ω of one sensing element 1a in a stationary state
The optical power will be condensed from a wider field of view by 2φ.

In this way, one sensing element 1a
If the dead angle ψ formed by the gap between the sensor element 1a and the adjacent sensor element 1a is smaller than 2φ, ω ² / (ω
If + ω / 2) ² × 100 = 34.3% or more, φ can be adjusted to fill the blind spot.

[0015]

FIG. 3 is a block diagram of an embodiment of the optical axis tilt unit 2 used in the image pickup apparatus according to the present invention shown in FIG. As the unit, a prism having a wedge-shaped cross section as shown in FIG. 3A is used, and a schematic view of a sectional structure taken along the arrow A for rotating the prism 2 is shown in FIG.

In FIG. 1B, 5 and 6 are a stator and a rotor, respectively, which constitute a motor. The stator 5 is supported by a support member 7, and the rotor 6 is a frame body 8.
It is fixed to. Then, when the rotor 6 is rotated by passing an electric current through the stator 5, the frame body 8 is also rotated with the bearing 9 provided between the frame body 8 and the support member 7.

Therefore, if the output optical axis of the prism 2 is made to coincide by rotating the frame 8 around the optical axis O, the incident optical axis is from O (corresponding to the rotational axis of the frame 8). It will lean toward O '.

Here, the inclination φ between the optical axes O-O 'is
Wedge-shaped angle θ of prism 2_WDWhen asked from, first,
The refractive index n is n = sin θ_in/ Sin θ_out(Θ_inIs the angle of incidence, θ_outOut
Angle of incidence) Is represented by φ = θ_out−θ_in     = Θ_out(1-arcsin [n ・ sin θ_out]) = Θ_WD(1-arcsin [n ・ sin θ_WD]) Expressed as

Therefore, as the prism 2 rotates, the inclination φ between the optical axes _OO ′ is defined in accordance with the wedge-shaped angle θ _WD , and it is assumed that the detecting element 1a is present on the right side of the drawing. Assuming that the optical axes of the two are always the same, the image 4a of the sensing element 1a projected on the scene 4 as shown in FIG.
2 is wider than the field of view when the prism 2 is not provided as shown in FIG.

FIG. 4 is a block diagram of another embodiment of the optical axis tilt unit 2 used in the image pickup apparatus according to the present invention shown in FIG.
As a unit, an optical unit 2 for combining a mirror and tilting an outgoing optical axis with respect to an incoming optical axis is used. The optical unit 2 is composed of bending mirrors 10a to 10d as shown in FIG. 4 (a). Of these, the mirrors 10b to 10d are 45 ° with respect to the rotation axis O of the optical unit 2 (conventional fixed optical axis) as shown in FIG.
It is fixed only in a tilted state.

Since the mirror 10a gives the angle φ of the optical axis O'which is inclined with respect to the optical axis O shown by the alternate long and short dash line,
It is inclined by φ / 2 with respect to 45 °. Other configurations may be the same as those in the embodiment of FIG.

As a result, the optical axis O '(solid line) incident on the mirror 10a forms 45 ° -φ / 2 with respect to the vertical line of the mirror 10a, so that its output optical axis also forms the axis of the mirror 10a. The angle is 45 ° -φ / 2 with respect to the vertical line, and they coincide with each other.

Therefore, the optical axis from the mirrors 10a to 10b is perpendicular to the optical axis O, and the mirrors 10c and 10d are formed.
The outgoing optical axes O and O'after passing through the optical path coincide with each other.

Therefore, as in the embodiment of FIG. 3, the interaction between the stator 5 and the rotor 6 causes the frame 8 to rotate around the optical axis O, so that the optical axis incident on the unit 2 is O.
To lean to O '.

[0025]

As described above, according to the image pickup device of the present invention, by tilting and rotating the optical axis, the light flux that would otherwise enter the dead zone of the detector will be detected. Since the light can be focused on the top, the two-dimensional detector should be applied to applications such as search sensors for detecting a small target at a long distance, which is less than one pixel, as early as possible. Will be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of an image pickup apparatus according to the present invention.

FIG. 2 is a diagram for explaining the expansion of the visual field by the optical axis tilt unit used in the image pickup apparatus according to the present invention.

FIG. 3 is a diagram showing an embodiment of an optical axis tilt unit used in the image pickup apparatus according to the present invention.

FIG. 4 is a diagram showing another embodiment of the optical axis tilt unit used in the image pickup apparatus according to the present invention.

[Explanation of symbols] 1 2D detector 1a Detection element 1b Detection element surface 2 Optical axis tilt unit 3 Optical system 4 Scenes with imaging targets 4a image of the sensing element projected on the scene, 10a-10d folding mirror In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A two-dimensional detector (1) in which the ratio of the area occupied by the sensing element (1a) on the sensing element surface (1b) is less than 100%.
In the image pickup device which gives the incident power from the image pickup target (4) to the image pickup device (4) through the optical system (3), a detection element is provided between the optical system (3) and the two-dimensional detector (1).
An image pickup device comprising an optical axis tilt unit (2) for tilting an optical axis incident on (1a) and precessing the optical axis around the optical axis. 2. The image pickup device according to claim 1, wherein the optical axis tilt unit (2) is a prism having a wedge-shaped cross section. 3. The optical axis tilting unit (2) according to claim 1, wherein the optical axis tilting unit (2) is an optical unit (10) in which a mirror is combined and the outgoing optical axis is tilted with respect to the incoming optical axis. Imaging device.