JPH10206606A - Lenticular plate and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lenticular plate which can be easily manufactured and can be easily mass-produced by arranging a transparent medium to periodically cover a part of the surface of a base board having a lenticular. SOLUTION: A lenticular plate is formed by periodically arranging a convex part (lenticular) 11 on the surface of a base board 10 whose plane is polished. A part of the surface of the lenticular plate is periodically covered with a transparent thin film 12. The transparent thin film 12 is formed in a checker shape. It is desirable that the size of checkers is about several times the size of the lenticular 11. A thickness of the transparent thin film 12 is formed so that a surface of the transparent thin film 12 becomes a plane. Or it is formed so that the thickness itself of the transparent thin film 12 becomes uniform. Here, it is desirable that an average optical thickness is about half of an average wave length λ of visible radiation, that is, about λ/2n when a refractive index of the transparent thin film 12 is denoted by (n).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of a lenticular plate (also referred to as a lenticular disk) and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, this type of lenticular plate has
It is a kind of optical element provided in the focal plane of the objective lens system and the projection lens system in the optical optical path from the observation object to the observer's eyes, and intended to provide an enlarged exit pupil to the observer's eyes. . An optical device (a magnifying optical system such as a microscope) incorporating this type of lenticular plate does not require an eyepiece and allows the observer to observe a clear image without being disturbed by the formation position of the observed image. One example is disclosed in Japanese Patent Publication No. 50-19936.

The function of a lenticular plate, its configuration and shape will be described with reference to the drawings, taking a microscope using a lenticular plate as an example. First, the shape of the lenticular plate is shown in FIGS. FIG. 8 shows a lenticular plate used in a microscope in which a reflection system is used in the optical path and having a curved convex portion 1 formed on a polished surface.

In this figure, pixels forming a lenticular plate (hereinafter also simply referred to as lenticular)
Is shown, which is formed two-dimensionally over the entire surface. FIG. 9 shows a lenticular plate used in an optical device using a transmission system such as a screen projector. In this case, the convex lens 4 of the transparent plate 3 is laid two-dimensionally.

The lenticular plate having the above-mentioned shape is formed into a disk shape or a belt shape, and is used by rotating or moving it at an appropriate speed. When an image is projected through an optical system that forms a real image at a focal position on a stationary lenticular disk, an observer sees a light spot on the lenticular surface with a diameter smaller than the diameter of the lenticular. Can be.

As the observer changes his eye position, these spots move regularly across the lenticular surface. Therefore, when the disk is rotated, the light spot moves on the lenticular surface, and the individual images formed on the image plane from the curved convex portion 1 also move on the image plane. Is formed in proportion to the exit pupil. The number (the number of lenticulars), the diameter and the arrangement of the curved convex portions 1 of the lenticular disk are defined as the whole image of an object generated on the lenticular disk when the lenticular disk is rotated. The movement of a light spot from one lenticular to an adjacent lenticular that is covered up cannot be perceived due to visual inertia, and the observer can see the object image in the image plane without the need to use an eyepiece. Determined to be able to. Then, the rotation speed of the lenticular disk is determined so that the observer cannot see the grid formed by the convex portions of the lenticular disk. Thereby, image observation can be easily performed without using an eyepiece.

An example of a microscope using a lenticular disk will be described with reference to FIGS. 10 and 11.
FIG. 11 is a plan view of FIG. 10 as viewed from above. In FIG. 10, the image of the object at point B is magnified by the main objective lens C, further magnified by the projection lens D, and forms an image at the focal position on the lenticular disk G through the beam splitting prism E. I do.

If the lenticular disk G is a plane mirror, two exit pupils are formed on the observation plane A.
Then, a pupil is formed on the observation plane A by the lens H and the lens F (integrated with the lenticular disk). The lens H is for enlarging the image on the lenticular G. On the lenticular disk G,
Since a lenticular is formed, an exit pupil proportional to the angle α is formed on the observation plane A.

As described above, an optical device using a lenticular plate has an advantage that an eyepiece is generally not required, and that an observer does not need to worry about an accurate and troublesome observation position. is there. here,
Although an example in which a convex lenticular is used has been described, the same effect is obtained if the radius of curvature is the same. Which type to use is a matter of design and manufacture.

[0010]

However, according to the above-mentioned prior art, the observation image cannot be obtained depending on the method of arranging the lenticular plates forming the lenticular plate and the method of forming the gap between the lenticulars. Diffraction interference images resulting from the regularity of the arrangement are superimposed, deteriorating the quality of the image, and hindering observation.

Therefore, conventionally, as shown in FIG. 12 or FIG. 13, measures have been taken to take measures such as smoothly connecting the gaps between the lenticulars or arranging them so as to form a multiple periodic structure. Was. FIG. 12 is a three-dimensional bird's-eye view of a conventional lenticular plate observed with an interference microscope. Lenticulars having the same shape are regularly arranged at regular hexagonal lattice points. It can be seen that the gaps between the lenticulars are smoothly connected.

FIG. 13 shows another example of a conventional lenticular plate. In this, lenticulars are arranged at lattice points of a regular square, and also in this case, the gaps between the lenticulars are smoothly connected. In addition, the size differs depending on the position of each grid point. That is, it is understood that the lenticulars are arranged so as to have a multiple periodic structure.

However, it is technically difficult to form such a lenticular plate, it is difficult to mass-produce, and the cost is high. Therefore, an object of the present invention is to provide a lenticular plate that is easy to manufacture and that can be mass-produced, and a method of manufacturing the same, which solves the above problems.

[0014]

In order to achieve the above object, the present invention provides: [1] a lenticular plate in which lenticulars are periodically arranged on the surface of a polished substrate; A transparent medium that is periodically covered is provided on a part of the surface of the substrate.

[2] In a lenticular plate in which lenticulars are periodically arranged on the surface of a polished substrate, a part of the surface of the substrate having the lenticulars is periodically covered with a thin film, and A metal reflection film formed by coating is provided. [3] In a lenticular plate in which lenticulars are periodically arranged on the surface of a polished substrate, a semi-transparent negligible thickness which is periodically covered by a part of the surface of the substrate having the lenticulars. A film is provided.

[4] In the method of manufacturing a lenticular plate, a step of periodically arranging the lenticular on the surface of the polished substrate, and periodically arranging a part of the surface of the substrate having the lenticular with a transparent medium. And a covering step. [5] In the method of manufacturing a lenticular plate, a step of periodically arranging the lenticular on the surface of the polished substrate, and periodically covering a part of the surface of the substrate having the lenticular with a thin film, Coating a metal reflection film.

[6] In the method of manufacturing a lenticular plate, a step of periodically arranging the lenticular on the surface of the polished substrate, and periodically ignoring the thickness of a part of the surface of the substrate having the lenticular. Covering with a possible translucent film.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, the first of the present invention
An example will be described. FIG. 1 is a partial sectional view of a lenticular plate showing a first embodiment of the present invention, and FIG. 2 is a plan view of the lenticular plate.

As shown in FIG. 1, a substrate 1 having a flat surface polished
0, a periodically curved convex portion (lenticular) 1
1, a part of the surface of the lenticular plate is periodically formed with a transparent thin film 12.
Covered with. As shown in FIG. 2, a transparent thin film 12 shown with a shadow overlaid on a lenticular 11 shown by a circle,
It is formed in a checkered pattern (a pattern of base stripes in which black and white squares are alternately arranged). The positional relationship between the lenticular 11 and the checkered transparent thin film 12 may be arbitrary.

The size of the checkered pattern is preferably several times the size of the lenticular 11. The thickness of the transparent thin film 12 may be such that the surface of the transparent thin film 12 is flat as shown in FIG. 1 or the thickness of the transparent thin film 12 may be uniform. However,
When the average optical thickness is about half of the average wavelength λ of visible light, that is, when the refractive index of the transparent thin film 12 is n, λ / 2n
Desirably.

Next, a second embodiment of the present invention will be described. FIG. 3 is a partial sectional view of a lenticular plate showing a second embodiment of the present invention. In this embodiment, as shown in FIG. 3, in a lenticular plate in which curved convex portions (lenticules) 21 are periodically arranged on the surface of a substrate 20 whose surface is polished, one surface of the lenticular plate is formed. The part is periodically thinned (regardless of whether it is transparent or not) 22
, And the entire surface may be coated with the metal reflection film 23. The structure of the second embodiment is most preferable in terms of manufacturing.

Hereinafter, the operation of the lenticular plate will be described. First, the reason why an interference image (hereinafter, also referred to as interference fringes or ghost) due to a periodic arrangement of lenticulars appears in an observation image of an optical microscope incorporating a lenticular plate will be described. In general, light is incident on a structure (also referred to as a diffraction grating) that periodically modulates the phase (phase modulation type; phase grating) or amplitude (amplitude modulation type; black and white grating) of light, and the transmitted light or reflected light is projected onto a screen. When the image is projected on the image, the contrast of the brightness (interference image) is observed.

In the reflection type lenticular plate according to the present invention, a hemispherical convex or convex structure is laid on the plane periodically over the entire surface without any gap, and in order to realize high reflection on the surface. And a thin metal film such as aluminum. Here, considering a case where a parallel light beam is incident on the lenticular plate, the lenticular plate plays a role of periodically modulating the phase of the incident light. That is, it can be regarded as a phase modulation type optical diffraction grating. Therefore, when the reflected light from the lenticular plate is projected on a screen, an interference image is observed.

The above-described interference image is observed anywhere in the space where the reflected light reaches the screen (the interference image is said to be non-localized). Therefore, FIG.
Since the observation image by the microscope described in FIG. 11 and the interference image described above enter the eyes of the observer from the same direction,
Both are observed overlapping, and this interference image hinders the observation.

That is, the above problem can be solved by preventing the interference image from appearing, by forming a sufficiently fine pattern, or by sufficiently reducing the contrast of the interference fringes. Therefore, conventionally, measures have been taken to take measures such as arranging the lenticulars so as to have a multiplex periodic structure as shown in FIG. 12 or FIG. 13 and smoothly coupling the gap between the lenticulars. .

The reason for introducing a multi-periodic structure in this conventional method is to make interference fringes sufficiently fine. On the other hand, the smooth coupling between the lenticulars is as follows. This is intended to sufficiently reduce the contrast of interference fringes. Therefore, in the present invention, the surface of the lenticular plate is periodically covered (coated) with a transparent thin film (in a checkered pattern) in order to sufficiently reduce interference fringes.

[0027] Coating the surface of the lenticular plate with a transparent medium can be easily realized by using the photolithography technique, so that it can be produced at low cost and with good mass productivity. The reason why interference fringes can be made sufficiently fine by such a method will be described below. FIG. 4 is a conceptual diagram of a two-dimensional cross section of a checkered lenticular plate of the present invention. The shaded portion is a phase material, and this portion is coated so as to have a checkered pattern.

The straight lines indicated by a, b, and c represent the respective portions from the lenticular plate, that is, a represents the reflected light from the lenticular of C, b represents B, and c represents the light from the lenticular of A. Consider how the light reflected from each part interferes on the screen. Consider an optical path difference of each reflected light beam at a representative point P on the screen. Assuming that the phase material is not coated, and assuming that the phase of the reflected light from all parts of the lenticular plate is aligned at point P on the screen, this part becomes bright and slightly Conversely, it becomes darker at distant points. That is, a light and shade pattern appears at a constant cycle. The lenticular plate acts as a so-called phase grating.

However, this phase grating does not simply have a part where the phase is delayed by a certain value and a part where the phase is advanced periodically, and each lenticular has a complicated shape such that a hemisphere is turned down. For this reason, the shading pattern (interference fringe) is very complicated. Also, no matter how far the screen is from the lenticular plate, the dimensions change, but this shaded pattern always appears. That is, the interference fringes are non-localized.

Therefore, this complicated pattern of light and shade always overlaps with the observation image, thus deteriorating the quality of the observation image.
It is essentially difficult to prevent the occurrence of this interference fringe,
By making this pattern as fine as possible or reducing the contrast of light and shade, the adverse effect on the observed image can be reduced.

As described above, since the lenticular plate is rotated during the image observation, the interference fringes are averaged concentrically symmetrically with respect to the center of rotation, so that the interference pattern can be made as fine as possible. By doing so, the degree of lightness and darkness overlapping with the observation image is reduced.
Therefore, in order to make this interference image finer or lower the contrast, as shown in FIG. 4, a phase material is coated three-dimensionally on the lenticular.

In this case, as will be described below, the interference image becomes finer and the contrast decreases. The reason why the interference image becomes finer and the contrast is lowered is that the periodic structure of the lenticular array and the periodic structure of the thin film array (checkerboard pattern) made of a phase material are superimposed on each other. Are superposed, and the periodic structures of the two are different. Therefore, it is the theory that the interference fringes become finer when superimposed. This point will be described more specifically with reference to FIG.

Consider the phase of light at the point P on the screen. Reflected light a from lenticular A;
Assuming that the phase of the reflected light b from the lenticular B becomes equal at the point P, the phase of the reflected light c from the lenticular C is different from this. In contrast to this, this part does not light up when coated with phase material.

Also, part of the reflected light b from the lenticular B is affected by the phase material, and does not completely have the same phase at the point P, and the brightness decreases. By coating the phase material in this way, it can be said that it plays a role of destroying interference fringes formed before coating. The same applies not only to the point P but also to the entire screen.

As described above, the phase material is not limited to the checkered pattern of the above-described embodiment, and any pattern can be similarly applied. It need not be a periodic structure. However, it is desirable that the period of the arrangement of the lenticulars and the fineness of the distribution shape of the arrangement pattern of the phase substance be approximately the same. That is, it is desirable that the average spatial frequency of the distribution shape of the arrangement pattern of the phase material and the arrangement cycle of the lenticulars be approximately the same.

This is because the average spatial frequency of the interference fringes produced by the lenticular and the average spatial wave number of the interference fringes produced by the phase substance are not so far apart, so that the interference fringes are averagely fine over the entire surface. Also,
The checkerboard pattern has an essential role to disturb the periodic structure of the conventional lenticular plate. Therefore, it is not always necessary to form a checkered pattern with a transparent thin film, but a thin film (which may be transparent or opaque) is formed on the checkered pattern on a conventional lenticular plate, and a metal reflective film is coated thereon. Good.

Further, the effect of the present invention was verified by observing a part of the ruler with a microscope incorporating a lenticular plate in which lenticulars having a diameter of 125 mm were arranged without gaps. FIG. 5 is a photograph of a fine pattern formed on the substrate showing the result of the experiment, and FIG.
Is a microscope image using a conventional lenticular plate not coated with a phase material, and FIG. 5B is a microscope image using a conventional lenticular plate coated with a phase material in a checkered pattern. .

The lenticular plate used here is formed by laminating a conventional lenticular plate, forming a thin film in a checkered pattern, and coating this with a metal reflective film. It can be seen that the image of the conventional lenticular plate shown in FIG. On the other hand, in the microscope image shown in FIG. 5B using a checkerboard-shaped phase material coated with a phase material according to the present invention, there is almost no difference in brightness, and the entire image has uniform brightness. You can see that.

The size of one side of the checkered pattern used in this experiment is 1 mm, the average thickness is 1.5 mm, and the material is photoresist (OFPR800: manufactured by Tokyo Ohka Kogyo Co., Ltd.). Next, a third embodiment of the present invention will be described. FIG. 6 is a partial sectional view of a lenticular plate showing a third embodiment of the present invention.

In this embodiment, as shown in FIG. 6, a lenticular 3 is periodically applied to the surface of a substrate 30 whose surface is polished.
1 is provided with a translucent film 32 of negligible thickness that is periodically covered on a part of the surface of the lenticular plate. Here, as in the first embodiment, the positional relationship between the lenticular and the translucent film may be arbitrary. Further, it is desirable that the average spatial frequency of the distribution of the translucent film is substantially equal to the average spatial frequency of the lenticular.

The transmissivity of the translucent film need not be uniform, but rather it may be desirable to be non-uniform according to certain rules. It has already been described that the conventional lenticular plate illustrated in FIGS. 8 and 9 can be regarded as a kind of phase diffraction grating. Here, first, what happens to an interference image when a phase type diffraction grating is formed so as to overlap with an amplitude type diffraction grating will be considered.

The above will be discussed with reference to FIG. For the sake of simplicity, consider an amplitude transmission type diffraction grating in which opaque portions are formed at a constant period. The light from this diffraction grating at a certain point P in the screen shape reinforces each other if the optical path difference between the light beams a, b, c, and d transmitted through the diffraction grating is shifted by one wavelength. At this point it becomes brighter. If the optical path difference is a half wavelength, the light paths weaken each other and darken at this point.

Although the above description relates to an amplitude transmission type diffraction grating, it is apparent that the same holds true for an amplitude reflection type diffraction grating. Next, when every other transmission portion of the above-mentioned amplitude transmission type diffraction grating is covered with a phase material, what happens at the point P will be considered. Assuming that the optical thickness of the phase material is 波長 wavelength, the light beams a and c interfere with each other in a constructive manner, but the light beams b and d
Since an optical path difference of 波長 wavelength is added to c, the total of the light rays a, b, c, and d is weakened this time. The same applies to other points, and the brightness is averaged over the entire screen.

The same applies to the amplitude reflection type diffraction grating. However, in this case, the optical thickness of the phase material needs to be １ ／ wavelength. In the description of FIG.
The opaque area was a simple model in which the light was completely impervious and the thickness of the phase material was completely equal to 1/4 wavelength. Actually, the phase delay of the lenticular plate is given by the curvature of the spherical surface, and it is impossible to make the opaque portion completely opaque because the observed image becomes dark. However, qualitatively, the considerations given in the above description of the operation are correct. In principle, even in this case, if the lenticular plate can be coated so that the transmittance of the translucent film changes continuously and gradually, interference fringes can be completely eliminated.

The third embodiment is fundamentally different from the first embodiment in that interference fringes can be almost completely eliminated in principle. Instead, coating the translucent film lowers the average reflectance of the lenticular plate and darkens the image. However, the latter problem is not an essential problem as long as the illumination system is made brighter. Of course, in order to completely eliminate the interference fringes, there is a difficult problem that the transmittance of the translucent film must be continuously and smoothly changed.

In any case, the effect of eliminating the interference fringes is higher in the second embodiment in exchange for the problem that the observed image becomes darker. The present invention has the following usage modes. The lenticular plate described above is a reflection type, but the same applies to a transmission type. In the case of a transmission type lenticular plate, an optical system that brings the observation position A behind the rotating disk in FIGS. 10 and 11 may be used. Which one to use depends on the use of an applied device such as a microscope. However, in the case of the transmission type, since the rotation center mechanism of the lenticular plate is an obstacle, a method of continuously shifting the lenticular in a constant direction at a constant speed in a belt shape is excellent.

It should be noted that the present invention is not limited to the above-described embodiment, but various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0048]

As described above, according to the present invention, it is possible to obtain a lenticular plate which is easy to manufacture and rich in mass production. Also, the interference image becomes finer,
The contrast can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a lenticular plate showing a first embodiment of the present invention.

FIG. 2 is a plan view of a lenticular plate showing the first embodiment of the present invention.

FIG. 3 is a partial sectional view of a lenticular plate showing a second embodiment of the present invention.

FIG. 4 is a conceptual diagram of a two-dimensional cross section of a checkered lenticular plate of the present invention.

FIG. 5 is a photograph of a fine pattern formed on a substrate, showing a result of an experiment.

FIG. 6 is a partial sectional view of a lenticular plate showing a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of an example of combining a phase grating and an amplitude grating according to a third embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a lenticular plate used in a conventional microscope using a reflection system in an optical path.

FIG. 9 is a partial sectional view of a lenticular plate used in an optical device using a transmission type system such as a conventional screen projector.

FIG. 10 is a diagram showing an example of a microscope using a conventional lenticular disk.

FIG. 11 is a plan view of FIG. 10;

FIG. 12 is a diagram showing an arrangement (part 1) of a conventional lenticular.

FIG. 13 is a diagram showing an arrangement (part 2) of a conventional lenticular.

[Explanation of symbols]

 10, 20, 30 Planar polished substrate 11, 21, 31 Curved convex portion (lenticular) 12 Transparent thin film 22 Thin film 23 Metal reflective film 32 Translucent film

Claims (6)

[Claims] 1. A lenticular plate in which lenticulars are periodically arranged on a surface of a polished substrate, comprising a transparent medium that is periodically covered by a part of the surface of the substrate having the lenticulars. A lenticular plate. 2. A lenticular plate in which lenticulars are periodically arranged on the surface of a polished substrate, wherein a part of the surface of the substrate having the lenticulars is periodically covered with a thin film, and the entire surface is coated. A lenticular plate having a metal reflective film formed as described above. 3. A lenticular plate in which lenticulars are periodically arranged on the surface of a polished substrate, wherein the thickness of the lenticulars periodically covered by a part of the surface of the substrate having the lenticulars can be neglected. A lenticular plate comprising a translucent film. 4. A method for manufacturing a lenticular plate, comprising: (a) periodically arranging a lenticular on the surface of a polished substrate; and (b) periodically arranging a part of the surface of the substrate having the lenticular. And a step of selectively covering with a transparent medium. 5. A method of manufacturing a lenticular plate, comprising: (a) periodically arranging a lenticular on a polished surface of a substrate; and (b) periodically arranging a part of the surface of the substrate having the lenticular. Covering the entire surface with a thin film and coating a metal reflective film over the entire surface. 6. A method for manufacturing a lenticular plate, comprising: (a) periodically arranging a lenticular on the surface of a polished substrate; and (b) periodically arranging a part of the surface of the substrate having the lenticular. Covering the surface with a translucent film having a negligible thickness.