JPS63234766A - Scanning optical system - Google Patents

Abstract

PURPOSE:To realize the high resolution of a solid-state image pickup element by respectively vibrating two pieces of light transmitting plate inserted between a lens and the solid-state image pickup element and allowing them to always contact with the movable part of an actuator. CONSTITUTION:The two pieces of planar plate (the filters 6 and 7) which transmit light are inserted between the lens 2 and the solid-state image pickup element 5 in parallel, respectively vibrated by the laminated type piezo-electric actuators 8 and 9 at high speed in a horizontal and a vertical direction to be scanned. The movable parts 8a and 9a of the actuators 8 and 9 are brought always into contact with a part of the filters 6 and 7 or a protruding potion 10a attached to a rotary shaft 10 in a state pressuring at any time. Then in such a contacting state, the actuators 8 and 9 are vibrated by shifting the respective frequency and the phase of them. As the result, the narrow region among each picture element of the image pickup element can be scanned at high speed and the image having the high resolution can be obtained.

Description

[Detailed Description of the Invention] [Summary] In order to improve the resolution of a solid-state image sensor, the present invention uses two light beams between an optical system (lens) that condenses emitted light from an object and a solid-state image sensor. A transmissive plate is inserted, and each of the two light transmissive plates is vibrated in two different directions (horizontal and vertical) perpendicular to the optical axis using a stacked actuator to scan the field of view of the solid-state image sensor. It is.

Further, in order to smoothly rotate and vibrate the light transmitting plate by the actuator, the movable part of the actuator is configured to be in contact with each other under pressure at all times.

[Industrial application field]

The present invention relates to a scanning optical system for an imaging device, and more particularly to a scanning optical system that interpolates dead areas between pixels of a solid-state imaging device to achieve high resolution.

In order to obtain high-resolution images in imaging devices, the number of elements has been increased by miniaturizing solid-state image sensors, but due to problems in element manufacturing technology, the number of elements has not yet reached a sufficient number. It is difficult to achieve an increase in the short term. Therefore, attempts have been made to achieve higher resolution using an external mechanism.

[Conventional technology]

In order to achieve high resolution using a conventional external mechanism, a plane mirror was installed in front or behind the lens, and the field of view of the solid-state image sensor was scanned by rotating the plane mirror.

FIG. 6(a) shows the case of objective plane scanning using the conventional scanning method, in which a scanning mirror 3 is provided between the lens 2 and the subject l, and a galvano scanner 4 is driven to scan the luminous flux emitted from the subject l. Then, the image formed on the solid-state image sensor surface via the lens 2 is displaced (scanned) by a predetermined amount.

In addition, Fig. 6 (mountain) shows the case of image plane scanning using the conventional scanning method, in which a scanning mirror 3 is provided between the lens 2 and the solid-state image sensor 5, and the radiation from the object l focused by the lens 2 is The light is displaced (scanned) by a predetermined amount on the surface of the solid-state image sensor 5.

[Problem that the invention seeks to solve]

In the conventional scanning optical system described above, the size of the scanning mirror 3 and the drive mechanism that drives the scanning mirror becomes large, which increases the size of the imaging device and requires a long optical path for reflection by the scanning mirror 3. As a result, the optical system becomes larger. In addition, a mechanical drive unit such as a galvano scanner is generally used to drive the scanning mirror 3, and feedback control is required to ensure smooth drive, which complicates the configuration of the control system and requires installation space. shall be.

The present invention was created in view of these points, and an object of the present invention is to provide a scanning optical system that is compact, performs high-speed scanning, and is capable of responding to higher resolution of solid-state image sensors.

[Means for solving problems]

FIG. 1 shows a schematic diagram of the principle of the scanning optical system of the present invention, in which two flat plates (a first filter 6, a second filter 7 ) are inserted in parallel, and the first light transmitting plate (filter) 6 and the second light transmitting plate (filter) 7 are respectively connected to a laminated type first piezoelectric actuator 8 and second piezoelectric actuator 9.
It is configured to perform vibration scanning at high speed.

In addition, the movable parts 8a and 9a of the laminated actuator 8.9 are brought into contact with a part of the first and second filters or the protrusion part 10a attached to the rotating shaft 10 under constant pressure, and the contact state is The two sets of actuators are each vibrated with one frequency phase shifted from the other.

[Effect]

Although the laminated piezoelectric actuator has the disadvantage of a small vibration amplitude (displacement amount), it has the advantage of being small, having a large load capacity, and having a fast response speed (accurate displacement amount can be obtained).

The first filter 6 and the second filter 7 vibrate by a predetermined amount in the horizontal and vertical directions by driving the first piezoelectric actuator 8 and the second piezoelectric actuator 9, respectively, and scan an area within the plane of the solid-state image sensor. do. In addition, signals with different frequencies and phases are applied to each piezoelectric actuator, and the horizontal scanning of the first filter 6 and the second
The vertical scanning order of the filter is defined so that the area within the plane of the solid-state image sensor is scanned.

According to this invention, by adopting a method of scanning within a narrow area between each pixel of a solid-state image sensor, the vibration amplitude of a laminated piezoelectric actuator can be improved! (displacement amount) compensates for the shortcoming of being small. Further, by taking advantage of the advantages of being small, having a large load capacity, and having a fast response speed, it is possible to obtain a high-resolution image by scanning the area at high speed.

〔Example〕

FIG. 1 is a schematic diagram of the scanning optical system of the present invention, FIG. 2 is a diagram for explaining scanning of the scanning optical system of one embodiment of the present invention, and FIGS. 3(a) and (b) are one embodiment of the scanning optical system. FIG. 3 shows a drive voltage waveform diagram of an example piezoelectric actuator.

In FIG. 1, the optical axis H is scanned in the horizontal direction by the rotational vibration of the first filter 6 in the horizontal direction, and
Due to the rotational vibration of the filter in the vertical direction, the light is scanned in the vertical direction and enters the solid-state image sensor 5.

A second method of scanning a solid-state image sensor using the above-described scanning optical system is described below.
This will be explained with reference to the figures and FIG.

FIG. 3 shows a voltage waveform diagram for driving the first and second piezoelectric actuators 6 and 7, and (a) shows that when each filter is driven at the same frequency with a phase difference, shows the case where each filter is driven at a different frequency. At H level in the figure, the field of view of the solid-state image sensor is scanned to the right in the horizontal direction and downward in the vertical direction, and at L level, it is scanned in the opposite direction.

FIG. 2 is a diagram showing a pixel arrangement of a COD (charsite coupled device) of 5 (horizontal) x 5 (vertical) pixels, and each pixel 13-1 to 13-25 in the COD has a width V of the pixel. The pixels are arranged with the same dimensions and the interval W between the pixels.

In such a COD, now Fig. 3 (al, (bl
At timing A, the field of view of the solid-state image sensor corresponds to ■ in Figure 2, and at timing B, the field of view corresponds to ■ in Figure 2,
The timing C corresponds to the visual field ■ in FIG. 2, and the timing D corresponds to the visual field ■ in FIG. 2.

By performing such scanning, the number of pixels is 10×10
= 100, the number of elements using the conventional scanning method is 5X
This results in a resolution four times higher than 5=25.

FIG. 4 is a schematic diagram of a filter scanning mechanism according to an embodiment of the present invention, and FIG. 5 is a mechanical diagram of a piezoelectric actuator movable part according to an embodiment.

In FIG. 4, the filter 6 (7) is fixed on the rotating shaft 10, and is repeatedly vibrated by a predetermined amount in the horizontal and vertical directions about the rotating shaft 10 by the piezoelectric actuator 8 (9).

Moreover, the mechanism of the piezoelectric actuator movable part is as shown in FIG.
The tip A of (9a) is processed into a steel ball shape so that it contacts at one point with one surface of the passive plate 11 provided on the filter shaft. Further, the passive plate 11 is pressurized by a spring 12 from the back side of the contact surface of the movable part 8a (9a), and constantly applies a load to the piezoelectric actuator 8.9. This constant load causes the passive plate 11 and the piezoelectric actuator 8.9 to come into close contact with each other, thereby stabilizing the operation of the piezoelectric actuator. The closer the contact point of the piezoelectric actuator on the passive plate 11 is to the axis, the larger the displacement amount of the filter becomes, thereby making it possible to compensate for the low displacement amount, which is a drawback of the piezoelectric actuator.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to realize a high-speed scanning optical system that compensates for the shortcoming of low displacement while maintaining the high-speed response of a stacked piezoelectric actuator, thereby increasing the frame time of a solid-state image sensor. It is possible to increase the resolution without causing any problems.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the principle of the scanning optical system of the present invention, Fig. 2 is a diagram for explaining scanning of the scanning optical system of one embodiment of the present invention, and Fig. 3 is a drive of the piezoelectric actuator of one embodiment. Voltage waveform diagram, Figure 4 is a schematic diagram of the filter scanning mechanism of one embodiment, Figure 5 is a schematic diagram of the piezoelectric actuator movable part of one embodiment, and Figure 6 is a schematic diagram of a conventional scanning optical system. . In the figure, ■ is the subject, 2 is the lens, 3 is the scanning mirror, and 4
is a galvano scanner, 5 is a solid-state image sensor (CCD),
6.7 is a light transmitting plate (filter), 8°9 is a piezoelectric actuator, 8a, 9a are movable parts, 1o is a rotating shaft, 10a is a protrusion, 11 is a passive plate, 12 is a spring, 13-1-
13-25 are pixels. Fig. 1 Fig. 2 Fig. 3 Fig. 4 (missing) Sheet f'J/11tγ Kuzai Eta Sheet '7Q Nihiru 2゛b mouth Fig. 5 (CI) n#J plane scan (b) Fig. 6

Claims (1)

[Claims] An optical system (2) that collects radiation light from a subject (1);
A rotating scanning mirror (3) is inserted between the solid-state imaging device (5) that detects the condensed light, and the scanning mirror is vibrated to form an image on the solid-state imaging device surface by the optical system. In the scanning optical system that displaces the image position, two sets of light transmitting plates (6, 7) are used instead of the scanning mirror (3).
The movable parts of the laminated actuators (8, 9) are brought into contact with a part of each of the light transmitting plates or the protrusion attached to the rotating shaft under constant pressure, and in the contact state, the two sets of A scanning optical system characterized in that the actuators are vibrated with different frequencies and phases, and the image formed on the surface of the solid-state image sensor is vibrated and scanned within a region within the surface of the solid-state image sensor.