JPS5950042B2 - optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical device, more specifically an optical imaging system that produces an image on an image plane. This invention relates to a photographic machine using such a device.

In the design of simple optical devices, such as a camera, the main goal is to minimize the required distance between the objective lens and the focal plane that produces the image, while maximizing the size of the image produced thereon. It is to be.

Various types of single lenses and compound lenses have been designed in the past in an attempt to accomplish this goal, but these have the drawbacks of being relatively expensive and causing significant distortions in the resulting image. An example of a conventional compound lens is the lens disclosed in US Pat. No. 3,704,277.
Arranging small lens groups is a well-known method for creating small images side by side.

The use of this lenslet arrangement has not yet been proposed to solve the above problems of maximizing the image size and minimizing the distance between the lens and the image plane stop. The reason for this is the fact that this small lens group does not produce a single large image, but many small images. According to the invention, an optical device for producing a relatively large image of an object with a relatively small distance between the device and the image plane comprises a predetermined optical device located intermediate the object and the image plane. a lens device having a surface array of lenslets configured to produce a plurality of images; a sampling device disposed intermediate the plurality of lenslets and the image plane to define a plurality of discrete light-conducting paths; an image plane device holding a device for recording an image in an image plane, each of said lenslets having dimensions substantially larger than the smallest dimension resolvable by the naked human eye; said light ray conducting paths, each of said light ray conducting paths indicative of a different portion of a respective image of said plurality of images to said image plane, such that the summation of each of said ray conducting paths produces a complete image at said image plane; and arranged such that the image plane device maintains the image recording device at a distance from the sampling device sufficient to place each of the ray conductive paths in an area approximately equal to the area of a single lenslet. It is characterized by being According to one embodiment of the invention, a number of lenslets each having a relatively short focal length are arranged between the object and the image plane, preferably with a constant periodicity on the plane.
Placed.

Each individual lenslet produces a small image. Each of the beam conduction paths of the sampling device transmits different parts of the corresponding statuette to the image plane. Preferably, the sampling device comprises a mask having an array of pinholes thereon having a period slightly different from that of the array of lenslets. The combined effects of the individual pinholes produce a large image at the image plane. According to another embodiment of the invention, the arrangement of lenslets may be non-planar and non-periodic, but may be random.

The sampling device is then designed such that its distribution and action produce a combined image in the image plane similar to that produced by the above-described preferred embodiment of the invention. Further, according to an embodiment of the present invention, a small lens array as described above, a sampling device, a light-sensitive photographic film placed on the image plane, and a shutter placed between the sampling device and the image plane. You can get a camera with ``small contrast between light and shade''.

The amount of distortion can be controlled by a camera mechanism that changes the periodicity of the lenslets forming the lenslet array or the periodicity of the pinholes of the pinhole array sampling device. Introducing such small amounts of distortion is useful in document copying machines when it is necessary to correct distortions caused by the copier or existing in the original text to be copied. According to yet another embodiment of the invention, a unidirectional lenslet array and a unidirectional pinhole array are arranged in parallel relationship and moved at slightly different speeds transversely to their axis. The result is a scanning camera that produces a combined image on the film. In one variation of the scanning camera, the two-dimensional lenslet array and pinhole array are fixed, and both the film and object are movable. The image thus produced shows the changing position of the object over time. The present invention will be more fully understood and appreciated from the detailed description taken in conjunction with the drawings.

Figure 1 shows an XY lens including a large number of small lenses facing an object 11 and arranged at a period of P1 in the X direction and a period of P2 in the Y direction.
A lenslet array 10 arranged in a plane is shown. P1
and P2 are approximately 0 so that they are the same, and the distance between adjacent small lenses is just below the resolution limit of the human eye.
．． It is preferable to choose a diameter of 2 mm. Assuming that P1 and P2 are equal, P will be used as a representative hereafter. The lenslet array illustrated in FIG. 1 is merely representative of the various lenslet arrays commonly used in accordance with embodiments of the present invention.

For example, a planar lenslet array with mutually different periods P1 and P2 along the mutually orthogonal x and y axes may be used, or a known random periodic distribution of lenslets may be used. Sometimes used instead. The lenslet array is not necessarily arranged on a plane. Alternatively, it may be placed along any known plane. Additionally, the size and period of the lenslets may be varied to suit different applications. Lenslet array 10 is typically made of plastic and is molded to define a number of convex lenslet surfaces.

The exact shape of the individual lenslets will vary depending on design and manufacturing criteria. Any array such as rectangular, hexagonal, or triangular may be used. The master 12 provided with the pinhole array is usually placed parallel to the lenslet array 10 and placed in such a relationship that it receives light on its rear side.

The distance between the small lens array old 0 and the mask 12 is represented by S1, and has the following relationship with the focal length f of each small lens. Here, S is the distance between the object 11 and the small lens arrangement old 0.

Since S is usually much larger than f, it is sufficient to take f as an approximate value of S1. Here, the focal length f of each small lens is
If you choose 1cm, then S1 will also be chosen as 21cm. The pinholes 14 are arranged on the mask 12 at a period of P3 in the Y-axis direction and at a period of P4 in the X-axis direction, and are arranged on the mask 12 at a period of P3 in the Y-axis direction and at a period of P4 in the X-axis direction.
is preferably equal to and slightly different from the period of the lenslets on the lenslet array 10.

When P3 and 7P4 are equal, P3 and P4 will be expressed as Pb from now on. When Pa=0.2mm, P is 0.2 for convenience.
You may choose 2mm. According to more general embodiments of the invention described above, the periods on the X and Y axes on the planar lenslet array are different, or include a random j-known distribution of lenslets. For example, the positional relationship between the center of each individual lenslet on the lenslet array 10 and the corresponding pinhole on the mask 12 is given by the following equation.

Here, X'' is the position of the i-th pinhole in the x-axis direction Y''1 is the position of the i-th pinhole in the Y-axis direction Xi is the coordinate Y1 of the center position of the i-th small lens in the x-axis direction The coordinates ex and ey of the center position of the i-th small lens in the Y-axis direction are constants or smooth functions that vary within a range not larger than 25%.

The absolute values of ex and ey are chosen to be small fractions.

The one small lens above the small lens arrangement old 0 is mask 12.
forming individual statuettes 16 on a plane defined by . A single point on each image is extracted and transmitted through a single pinhole. The remaining portion of the light that forms the image is blocked. Since the period Pb of the pinhole array on the mask 12 is slightly different from the period Pa of the lenslet array old 0, each pinhole conveys a different point of each statuette. The entire set of transmitted points is combined to produce a relatively large image 18 on the image plane 20.
It can be seen that the combination of the small lens array and the pinhole mask has an effective focal length given by the following equation.

Here, P1 is the period of the small lens array, and Pb is the period of the pinhole array.

According to another embodiment of the invention, mask 12 need not include an array of pinholes, but may instead be any type of device that provides an array of discrete light conducting paths.

According to yet another embodiment of the invention, types of radiation other than visible light can also be imaged using the apparatus described herein.

Referring now to FIG. 2, a photographic device is shown which employs an array of lenslets 30 arranged to receive light rays from an object.

Pinhole mask 32 is generally placed parallel to lenslet array 30 and spaced a distance S1 therefrom. Photographic film 34, which may be of any type and in any configuration, is placed at the image plane behind mask 32. Shutter mechanism 36 is operable to selectively allow light to reach film 34 and comprises a drive 38 and a pinhole mask 40 interposed between mask 32 and film 34. Conveniently, mask 40 has a structure such that it has a pinhole distribution with the same period as the period of the pinholes on mask 32. Film 34 is separated from mask 40 by a distance S2 sufficient to diffuse light rays transmitted through the pinholes to form a smooth image. S2 is S1
It is convenient to choose it so that it is almost the same as . The mask 40 is placed slightly out of phase with the mask 32 so that the light beam passing through the mask 32 does not reach the mask 40 when the shutter 36 is in the closed position. Shutter 3
6 is opened, the mask 40 moves slightly, bringing the pinholes in the mask 40 into alignment with the pinholes in the mask 32, thereby allowing the path of the light beam to reach the film 34. According to another embodiment of the present invention, by slightly distorting the period of the lenslets forming the lenslet array 30, particularly along the circumferential edge of the lenslet array, precise reproduction photographs can be obtained. Distortion correction is controlled for convenience.

The precise amount of distortion applied is designed to compensate for other known spurious distortions introduced from other parts of the optical system or present in the original text being reproduced. Similarly mask 3
The periodic distortion of 2 can be used for distortion correction. Now, FIG. 3 shows a camera using a linear array of small lenses 50 and a corresponding linear pinhole mask 52.

The small lens array 50 has a period Px of O. equal to 2mm,
The pinhole array mask 52 has a pinhole period Py=0
．． It may be convenient to have 22 mm.
A drive 5 is provided for moving lenslet array 50 and pinhole mask 52 at a selectable speed independently of photographic film 56 placed behind mask 52.
4 is provided. A movable curtain 58 prevents light rays from reaching the film 56 through the lenslet array. The film 56 remains stationary during exposure and the lenslet array moves at a speed V2 as the pinhole array moves at a speed V2.
1 and move horizontally there. Speed V1 and speed V2
The ratio of Px to Py is chosen to be approximately equal to the ratio of Px to Py, thus producing an image on the film equivalent to that produced by the camera of FIG. According to another embodiment of the invention, the pinhole array mask 52 and the lenslet array 5 are moved while the film 56 and the object to be observed are moved.
0 remains fixed. Such a camera is used for continuous copying or as a racetrack racetrack racetrack camera. In a finish line camera, the lateral position of the image on the film is a function of time at the individual instants at which the exposure is made.
It will be apparent to those skilled in the art that the invention can be constructed and operated in a wide variety of different embodiments all within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an optical device according to an embodiment of the invention placed between an object and an image plane. FIG. 2 is a perspective view of a camera using the apparatus of FIG. 1. FIG. 3 is a perspective view of an operative scanning camera constructed in accordance with an embodiment of the present invention. The reference numbers of the main parts described in the claims are as follows. Small lens・
...10.Object ...11. Pinhole mask...12, Image plane or film...
...20,30,56, pinhole array...
・40, Single row small lens...50, Mask...
...52.

Claims (1)

[Claims] 1. An optical device for creating a relatively large image of an object with a relatively small distance between the device and the image plane, including a predetermined optical device disposed intermediate the object and the image plane. a lens device having a surface array of lenslets configured to produce a plurality of images; a sampling device disposed intermediate the plurality of lenslets and the image plane to define a plurality of discrete light-conducting paths; an image plane device holding a device for recording an image in an image plane, each of said lenslets having dimensions substantially larger than the smallest dimension resolvable by the naked human eye; said light ray conducting paths, each of said light ray conducting paths indicative of a different portion of a respective image of said plurality of images to said image plane, such that the summation of each of said ray conducting paths produces a complete image at said image plane; and arranged such that the image plane device maintains the image recording device at a distance from the sampling device sufficient to place each of the ray conductive paths in an area approximately equal to the area of a single lenslet. An optical device characterized by: 2. The surface arrangement of said lenslets comprises a flat row of substantially identical lenslets, and said image plane device holds said image recording device in parallel relationship with said flat row. Optical device according to Section 1. 3. According to claim 1, wherein the sampling device has a hole mask having a pinhole formed therein through which a light beam representing a portion of the image from the small lens is separated at a separated position. optical equipment. 4. said lens arrangement comprises a flat array of substantially identical lenslets, said aperture mask is generally planar and disposed parallel to said flat lenslet array, and said image plane arrangement comprises: the image recording device is held in a parallel relationship to the planar lenslet array, and each lenslet has a period of pinholes in the pinhole array that is substantially greater than a period of lenslets in the lenslet array; 4. Optical device according to claim 3, characterized in that light beams representing different parts of the image from the mask are passed through the mask. 5. Each of the lenslets has substantially the same focal length and the aperture mask is spaced from the array of lenslets by a distance substantially equal to the focal length. Optical device according to section. 6. Optical device according to claim 5, characterized in that the image plane device holds the image recording device at a distance from the aperture mask substantially equal to the focal length. 7. The optical device according to claim 1, wherein the period of the small lenses in one direction of the small lens array is equal to the period of the small lenses in the direction perpendicular thereto. 8. Optical device according to claim 7, characterized in that the period is about 0.2 mm. 9. Optical device according to claim 1, further comprising a shutter device selectively allowing or preventing the light beam conduction path from reaching an image recording device held by the image plane device. 10. An optical device according to claim 1, wherein said image plane device holds a photosensitive material at said image plane. 11. Claim 4, wherein the width of each of the pinholes has the same ratio to the width of each of the lenslets as the width of each of the lenslets has to the width of the entire array of lenslets. Optical device according to section. 12, wherein the planar array of lenslets comprises a single row of lenslets, and the sampling device comprises a hole mask forming a single row of pinholes parallel to the single row of lenslets; a moving device for moving the lenslet array and the pinhole array in a direction transverse to their axes with respect to an image recording device held by the image plane device; 2. An optical device according to claim 1, further comprising a screen device which prevents the passage of light rays to the image recording device which is held against the image recording device. 13 The period of the pinholes in the pinhole array is greater than the period of the lenslets in the lenslet array by a sufficient amount to allow light rays representing different portions of the image from each lenslet to pass through the mask, and the movement a small lens moving device for moving the small lens array at a first speed; a pinhole moving device for moving the pinhole at a second speed related to the first speed with substantially the same ratio between the periods of the lenslet and held by the image plane device; 13. Optical device according to claim 12, characterized in that the relative movement of said lenslet array and said pinhole array with respect to an image recording device created by the image recording device produces a scanned image on the image recording device.