JP2002107508A - Micro lens array and display unit using micro lens array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micro lens array and display unit which can exhibit a function as a lens of a minute lens enough even if the minute lens is miniaturized in a display unit which displays a two-dimensional display image as an image having a stereoscopic effect through the micro lens array in which many minute lenses are arranged. SOLUTION: The observer's line of sight is inclined more obliquely relative to the curved surface of the lens of a minute lens by such means as that which constitute the micro lens array by using a lens region separated from its optical axis as a minute lens, or that which places the micro lens array by inclining it or gives a curvature to the micro lens array, or the micro lens array is obliquely placed oppositely to the display image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a signboard, a signboard, a display tower, and a TV set placed indoors or outdoors, and more particularly, to converting a two-dimensional image into a three-dimensional image having a perspective. The present invention relates to a display device for displaying. Further, the present invention relates to a microlens array configured by arranging small lenses used in the display device.

[0002]

2. Description of the Related Art Several methods for viewing a two-dimensional image such as a photograph or a printed matter as a three-dimensional image are already well-known, and are arranged and presented in Takayoshi Ohkoshi's "Three-dimensional image engineering". As a typical example, photographs (or drawn images) obtained by photographing a target object from two different directions are individually viewed with the left eye and the right eye, and there is a type in which a stereoscopic effect is sensed by binocular parallax. In this method, it is necessary to look into a device made so that different images can be seen by the left and right eyes, or to use glasses, or the like, which is not suitable as a normal signboard or guide board.

[0003] As another example, a three-dimensional image using a lenticular plate having a number of vertically long lenses in a semi-cylindrical shape arranged in a horizontal direction and having a back surface facing the opposite side of the lens curved surface as a focal plane. There is. This is a lenticular plate, in which a two-dimensional image viewed from a plurality of different directions is cut into strips (elongated rectangles) on the back surface, which is the focal plane of the lenticular plate, and a discontinuous design display screen arranged side by side is displayed on the lenticular plate. With this lens, the right eye and the left eye each can view a strip-shaped image viewed from different directions and recognize it as a three-dimensional image.

In this method, the display image is complicated, for example, it is necessary to arrange display images viewed from a plurality of positions in a strip shape during one arrangement interval of the cylindrical lenses constituting the lenticular plate, and the focus position is not correct. There are drawbacks such as an expensive display device such as arrangement. As a third alternative to the method using glasses and the method using a lenticular plate, a two-dimensional display image consisting of a series of pictures such as photographs taken by ordinary means or pictures drawn by ordinary means is displayed in three dimensions. Japanese Patent Application No. 11-218313 and Japanese Patent Application No. 11-319176 are Japanese patents.
No. 2000-53954, Japanese Patent Application 2000-15
No. 6608 and Japanese Patent Application No. 2000-162231, filed by the present applicant.

In the display device disclosed in the above-mentioned patent, a microlens array composed of minute lenses sufficiently smaller than the length of one side of a display effective area is arranged to face the two-dimensional display image, and the display image is displayed. By forming an image at a position distant from a certain position of a display image without enlargement or reduction, a three-dimensional display with a sense of depth is performed by a kind of illusion.

[0006] In the above-mentioned patent application, the disclosure of the invention relating to a display device for displaying a three-dimensional image comprising a microlens array and a display image or an image support is disclosed, and a microlens excellent in application of this display device is disclosed. An invention relating to an array is disclosed. That is, the focal length is relatively short,
It is not possible to use a lenticular plate with a focal plane on the back as it is. In order to obtain a microlens array with a relatively long focal length, the boundary surface between air with a small refractive index is not a curved lens surface, but a solid-solid or a solid-liquid liquid with a relatively close refractive index. An invention relating to a microlens array having a boundary surface as a lens curved surface is disclosed.

Further, in order to make it easy to change the focal length relatively easily in response to various requirements such as viewing from a distant position or a near position, a first lens unit composed of a collection of minute lens curved surfaces arranged at a sufficiently short arrangement pitch. By combining one kind of lens curved surface with a second kind of lens curved surface having a curvature radius sufficiently larger than the curvature radius of the minute lens curved surface, the equivalent focal length of the microlens can be relatively easily adjusted. It discloses controlling.

The microlens array disclosed in these patents has a lens curved surface composed of a collection of minute lens curved surfaces arranged at a sufficiently short arrangement pitch.

[0009]

SUMMARY OF THE INVENTION The present invention relates to Japanese Patent Application No.
No. 218313, Japanese Patent Application No. 11-319176, Japanese Patent Application No. 2
000-53954, Japanese Patent Application No. 2000-156608, and Japanese Patent Application No. 2000-162231, which provide an improved microlens array and provide an improved display using the microlens array. Provide equipment.

[0010] For convenience of explanation, the following explanation is based on Japanese Patent Application No. Hei.
-218313, Japanese Patent Application No. 11-319176, Japanese Patent Application No. 2000-53954, Japanese Patent Application No. 2000-156608.
And the invention disclosed in Japanese Patent Application No. 2000-162231 are referred to as prior inventions. According to the prior invention, a microlens array in which microlenses are arranged sufficiently small with respect to the length of one side of the effective area is arranged before a two-dimensional display image, and the display image is viewed through the microlens array. It discloses a display device that allows a two-dimensional display image to be viewed as a three-dimensional image with a sense of depth, and various microlens arrays used therein. A basic feature of these disclosed microlens arrays is that the focal length of the microlenses is large, that is, the radius of curvature of the lens curved surface of the microlenses is relatively large.

When the observer faces the lens curved surface from directly in front, the very narrow range of the lens surface that intersects with the line of sight of the observer is that the object viewed through the lens is located closer to the lens curved surface than the focal point. The closer it is to a plane that can be regarded as a plane that is approximately orthogonal to the line of sight. That is, the amount of refraction is small, and the function as a lens is weakened.

On the other hand, the farther away from the optical axis the further the lens position, the more the light incident parallel to the optical axis is refracted, and the stronger the function as a lens. The focal length of the focal point defined by the intersection of the refracted light with the optical axis also decreases. The focal length of the microlenses in the microlens array constituting the display device for displaying stereoscopically needs to be sufficiently larger than the length of the shorter side of the microlenses. By securing such a long focal length and reducing the size of the microlenses in response to the high definition of the displayed image, the proportion of the lens portion that is regarded as a plane orthogonal to the observer's line of sight increases. I do. As a result, the function as a microlens becomes extremely weak, and the microlens array for displaying three-dimensionally lacks the microlens properly.

It is desired that a stronger three-dimensional effect be exhibited.
An object of the present invention is to provide a display device exhibiting more excellent three-dimensional display characteristics, and to use such a device, a new microlens which is more excellent in display quality and further develops a stronger stereoscopic effect. It is to provide an array.

[0014]

The present invention employs the following means in order to solve the above-mentioned problems. The microlens according to the first aspect of the present invention has a configuration in which microlenses that are sufficiently small with respect to the length of one side of the effective area are arranged, and the optical axes or optical axis planes of the two microlenses nearby are independent from each other. An array, wherein an optical axis or an optical axis surface of the microlens deviates from a central part of the microlens, is located at a marginal part of the microlens, or is located outside the microlens. This is a characteristic microlens array.

According to the first aspect of the present invention, the proportion of the portion where the angle between the line of sight of the observer and the normal of the lens curved surface increases is increased. In addition, the use of the optical axis or a lens curved surface that is distant from the optical axis surface makes it possible to firmly function as a lens. Further, since the optical axes of the two minute lenses located in the vicinity are independent of each other, it is possible to avoid that the images of the individual minute lenses are combined into one large image, and the size of the minute lens is partially increased. It is not considered to be.

According to a second aspect of the present invention, minute lenses that are sufficiently small with respect to the length of one side of the effective area are arranged, and the optical axes or optical axis planes of two nearby minute lenses are independent of each other. A boundary surface forming the microlens array including a virtual lens forming surface for arranging the microlenses is uniform and smooth enough for the thickness of the microlens array. A microlens array characterized by being curved with a large radius of curvature.

According to the second aspect of the present invention, the curvature of the micro lens array allows the micro lens to be regarded as a lens curved surface having a different distance from the optical axis depending on the position in the micro lens array. As a result, the focal length of the microlenses changes depending on the position in the microlens array, and a portion of the entire image of the displayed image can be located at different positions in the depth direction according to the focal length. However, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible.

Further, since the optical axes of the two minute lenses located close to each other are independent of each other, it is possible to avoid that the images of the individual minute lenses are combined into one large image, and the size of the minute lens is partially reduced. Is not considered to have grown. The invention according to claim 3 is a microlens array in which microlenses that are sufficiently small with respect to the length of one side of the effective area are arranged, and the focal length of the microlenses changes with the position in the microlens array. And a group of microlenses having approximately the same focal length as a group, and a region where groups with different focal lengths are distributed,
A microlens array comprising at least one or both regions.

According to the third aspect of the present invention, since the focal length of the microlens of the microlens array changes depending on the position in the microlens array, a portion of the whole image of the displayed image varies in the depth direction according to the focal length. Position. However, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible. Further, since the optical axes of the two minute lenses located in the vicinity are independent of each other, it is possible to avoid that the images of the individual minute lenses are combined into one large image.

According to a fourth aspect of the present invention, there is provided the microlens array according to the third aspect, wherein the two-dimensional display image is arranged so as to face the microlens array.
Among image supports for supporting the two-dimensional display image,
A display device comprising at least one or both of them.

According to the fourth aspect of the present invention, the whole image of the display image viewed through the microlens array is such that the soot portions are located at different positions in the depth direction according to the focal length of the microlenses of the microlens array. it can. In addition, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible. Further, the optical axes of the two minute lenses located in the vicinity are independent of each other, and it is possible to avoid that the images of the individual minute lenses are combined into one large image.

According to a fifth aspect of the present invention, two or more transparent members having different refractive indices from each other and having a refractive index sufficiently larger than the refractive index of air are laminated so that the transparent members are in contact with each other. Having the above boundary surface, at least one of the boundary surfaces is arranged at an arrangement pitch sufficiently smaller than the length of one side of the effective region, and two optical members near the boundary surface are different from each other, Alternatively, a lens curved surface composed of a collection of minute curved surfaces having an optical axis surface is formed, and each of the boundary surfaces that are lens curved surfaces includes a boundary surface between the lens curved surface and the external surface that is not a lens curved surface and faces the boundary surface that is the lens curved surface. For any of the surfaces, the radius of curvature r of the minute curved surface of the boundary surface that is the lens curved surface, the absolute refractive index n _p of one material in contact with the minute curved surface, and the absolute refraction of the other material in contact with the minute curved surface Rate n _s , The curvature radius R of the other boundary surface, and the absolute refractive index N _p of one material in contact with the other boundary surface, the following relationship between the absolute refractive index N _s of the other material in contact with the other boundary surface inequalities (1) A microlens array characterized by the following. _{| R / (N p -N s} ) | »| r / (n p -n s) | According to ............... (1) The invention of claim 5, the relationship of inequality (1) is satisfied The boundary surface that functions as the lens as the strongest function can be one or more boundary surfaces composed of minute curved surfaces where two or more transparent members are in contact with each other, and the performance of the lens can be determined by this boundary surface. it can. Moreover, the focal length can be controlled by appropriately selecting the refractive indices of the transparent members on both sides having the lens curved surface as a boundary surface.
In particular, by making the radius of curvature R of the boundary surface with the outside world as air close to a sufficiently large plane, a lens with a small radius of curvature r and a large focal length can be obtained.

Further, since the optical axes of the two minute lenses located near each other are independent of each other, it is possible to avoid that the images of the individual minute lenses are combined into one large image. According to a sixth aspect of the present invention, there is provided the microlens array according to the fifth aspect, wherein the focal point of the microlens formed by the composite optical system in which the minute curved surface of the boundary surface which is the lens curved surface is connected in a multistage is formed. A microlens array, wherein the microlens array is located at an external position distant from the body and is separated from the closest minute curved surface by at least five times the shortest arrangement interval of the minute curved surfaces.

According to the sixth aspect of the invention, in addition to the same effect as the fifth aspect of the invention, the length of the focal length can be secured to a certain value or more, and the focal point is separated from the microlens array formed body. Since it is located outside, the display image can be placed at a position closer to the lens curved surface than the focal point, avoiding the vicinity of the focal point.

According to a seventh aspect of the present invention, the microlens array according to the fifth or sixth aspect, and the microcurved surface facing the lens curved surface of the microlens array, and the micro curved surface of the boundary surface which is the lens curved surface are connected in multiple stages. A continuous lens disposed at a position between the focal point of the microlens formed by the synthetic optical system and the lens curved surface of the microlens, avoiding the position of the focal point of the microlens and the position of the lens curved surface of the microlens. A two-dimensional display image composed of a symbol and a focal point of a microlens formed by a composite optical system in which the microcurved surface of the boundary surface that is the lens curved surface facing the lens curved surface of the microlens array is connected in multiple stages. A two-dimensional display arranged at a position between the lens curved surface of the micro lens and the position near the focal point of the micro lens and the position near the lens curved surface of the micro lens Among the image support for supporting an image, a display device characterized by comprising at least one or both, the.

According to the seventh aspect of the present invention, a microlens array having a sufficiently long focal length can be used even when a minute lens is miniaturized and high definition is achieved. Can be placed in a position near the focal point and the side of the lens curved surface within a range close to. As a result, the image of the microlens, which is a microcurved surface of the microlens array, becomes an erect image, and the degree of appearance of the three-dimensional effect of the entire image can be adjusted by changing the position where the display image is placed in the above range. Furthermore, the optical axes of the minute curved surfaces in the vicinity are independent, and the size of the pixels of the entire image is limited.

According to an eighth aspect of the present invention, minute lenses which are sufficiently small with respect to the length of one side of the effective area are arranged, and the optical axes or the optical axis planes of the two adjacent minute lenses are independent of each other. A micro lens array, and a position near a focal point of the micro lens and a position near a lens curved surface of the micro lens between the focal point of the micro lens and the lens curved surface facing the micro lens array. A microlens array comprising: a two-dimensional display image; and at least one or both of an image support for supporting the two-dimensional display image, such that the two-dimensional display image is arranged at the avoiding position. Is a display device characterized in that the two-dimensional display image is displayed to the observer via a microlens array.

According to the present invention, the image formed by each micro lens constituting the micro lens array is regarded as a new pixel, and the group of pixels is viewed as the entire image of the display image attached to the image support. become. For this reason, the entire image of the display image is not enlarged or reduced, and only the position is shifted from the position of the display image by the lens rule of the minute lens.

The displayed image is located at a position opposed to the microlens array, between the focal point of the microlens and the curved surface of the microlens, excluding the position near the focal point of the microlens and the position near the curved surface of the lens of the microlens. , The image formed by the microlenses is an erect image, and the enlargement ratio and the reduction ratio can have a significant size that is neither abnormally large nor small. Further, since the optical axes of the two microlenses located in the vicinity are independent of each other, it is possible to avoid that the images of the individual microlenses are combined into one large image, and the size of the microlenses is partially increased. It is not considered to be.

The image support can determine the positional relationship between the display image and the lens curved surface of the microlens array, and can maintain the positional relationship even when the display image is exchanged. Claim 9
The display device according to claim 8, wherein the boundary surface of the microlens array is uniformly and smoothly formed on the boundary surface of the microlens array including a virtual lens forming surface on which the microlenses are arranged. Being curved with a radius of curvature that is sufficiently large with respect to the thickness, and increasing the angle between the line of sight of the observer and the normal to the lens curved surface of the microlens in the direction in which the area ratio inside the microlens increases. A display device characterized in that at least one or both of the microlens arrays are inclined with respect to the observer.

According to the ninth aspect of the present invention, the displayed image can be placed in a position closer to the lens curved surface than the focal point and at a position avoiding the focus and the side of the lens curved surface, so that the image of the minute lens becomes an erect image. Further, the optical axes of the minute curved surfaces in the vicinity are independent, and the size of the pixel of the whole image is limited.

When the microlens array is tilted with respect to the observer, the portion where the line of sight of the observer enters the lens curved surface increases, and the curved portion of the microlens has a large curved portion. Only by changing the angle at which the microlens array is inclined with respect to the observer, the focal length of the microlens can be changed.

When the micro lens array is curved,
Since the focal length of the microlens in the microlens array changes depending on the position in the microlens array, a portion of the entire image of the displayed image can be located at different positions in the depth direction according to the focal length. However, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible.

According to a tenth aspect of the present invention, there is provided a microlens array in which a plurality of minute lenses which are sufficiently small with respect to the length of one side of the effective area are arranged, and the plurality of minute lenses have an irregular focal length. A microlens array characterized in that: According to the tenth aspect of the present invention, since the focal length of each microlens of the microlens array is not constant, a portion of the entire image of the displayed image can be located at different positions in the depth direction according to the focal length. However, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible. Further, since the optical axes of the two minute lenses located in the vicinity are independent of each other, it is possible to avoid that the images of the individual minute lenses are combined into one large image, and the size of the minute lens is partially increased. It is not considered to be.

According to an eleventh aspect of the present invention, the two-dimensional display image and the two-dimensional display image are arranged such that the two-dimensional display image is arranged so as to face the microlens array. A display device comprising at least one or both of an image support for supporting.

According to the eleventh aspect of the present invention, when a display image placed via the microlens array is viewed, a part of the whole image of the display image is shifted in the depth direction according to the focal length of the microlens of the microlens array. Can be in different positions. In addition, the whole image is not enlarged or reduced in the vertical and horizontal directions. Further, distortion of the entire image due to the curvature itself of the microlens array is so small as to be negligible. In addition, it is not considered that the size of the microlens is partially increased, and there is no portion in the whole image that is abnormally enlarged or reduced.

[0037]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a display device according to the first embodiment of the present invention.
In FIG. 1, the display device includes a microlens array 1 composed of microlenses 4 and an image support 2 that supports a display image depicting a design to be displayed. The display image is drawn directly on the surface of the image support 2 or a display image already drawn on paper or the like is fixed to the image support 2.
In the first embodiment, the image support has a plate shape, and a display image is drawn on the surface facing the microlens array 1. Although the display image itself is omitted in FIG. 1, it is a two-dimensional image composed of a series of well-known continuous pictures such as ordinary photographs or printed matter. In such a display device, an observer 3 observing a display image
View through the microlens array 1 a display image supported by the image support 2 or a two-dimensional display image directly drawn on the image support 2. The space between the microlens array 1 and the image support 2 is a normal space filled with air.

The whole image of the display image viewed through the microlens array 1 can be located at a position distant from the display image.
Due to this difference in position, the entire image of the display image appears as a three-dimensional image. This whole image is formed by using the image of the minute lens as a pixel, and is not enlarged or reduced. The above-described appearance of the image is fundamental when a two-dimensional display image is viewed through the microlens array in the following description. Therefore, hereinafter, this basic description will not be made as an image viewed through the microlens array.

The lens curved surface of the micro lens 4 constituting the micro lens array 1 is a cylindrical surface and has a shape extending from top to bottom through the paper surface. The optical axis of each microlens 4 penetrates an imaginary lens curved surface obtained by extending the lens curved surface of the microlens 4 as shown by a straight line g in the drawing.

The optical axes or optical axis planes of the two minute lenses in the vicinity are independent of each other. Here, the optical axis of the minute lens 4 is clarified. Generally, an imaginary straight line connecting the most protruding vertex of the lens and the spherical center of the lens curved surface is defined as the optical axis. However, when the lens is tilted, the position of the vertex changes and is not fixed. Here again, the optical axis is defined as follows without using vertices.

The optical axis is an imaginary perpendicular drawn from the center of the lens curved surface to the lens forming surface located near the minute lens. Here, the center of the lens curved surface is a spherical center if the lens is a spherical lens, or a section perpendicular to the central axis of the cylinder if the lens is a cylindrical lens like the micro lens 4 of the first embodiment. Is the point of the central axis.

The lens forming surface is a virtual surface assuming a state in which the irregularities of the minute lenses are leveled, and is a virtual lens forming surface on which the minute lenses are arranged. Even with a flexible and bent microlens array,
Since the radius of curvature of the curved portion that is bent with respect to the radius of curvature of the microlens is extremely large, the lens forming surface near the microlens can be regarded as one plane approximately in practical use. Optical axis is applicable.

Further, the optical axis plane is defined. If the micro lens is a spherical lens, the optical axis becomes a straight line. However, if the micro lens is a cylindrical lens as in the first embodiment,
Many optical axes are connected to a single microlens, and connecting the optical axes forms one surface. A surface formed by connecting the continuous optical axes is defined as an optical axis surface.

In general, unless the microlens array is used by being bent consciously, the microlens array is usually flat and oriented directly to the observer. In this case, the observer's line of sight is perpendicular to the array of microlenses,
The line of sight of the observer coincides with the optical axis. In this case, it is assumed that the observer is at a sufficiently distant position. Hereinafter, the description will be made assuming that the observer is at a sufficiently distant position unless otherwise specified.

In the first embodiment, the lens forming surface is a flat surface, and the display image is arranged parallel to the lens forming surface. The observer 3 correctly faces the display device having such a configuration and views the display image via the microlens array 1. The optical axis of each microlens 4 is represented by g as a representative in the figure, and the virtual curved surface shown by a dotted line in the figure, which is an extension of the lens curved surface, intersects the optical axis g at the intersection p outside the actual lens curved surface. I have.

The true lens curved surface of the micro lens 4 constituting the micro lens array 1 is located at a position away from the optical axis g. For this reason, the angle θ between the optical axis g and the normal line i at an arbitrary point on the lens curved surface becomes a certain value or more. The line of sight h of the observer 3 who is far enough is parallel to the optical axis g, and the angle θ between the line of sight h of the observer 3 and the normal line i at an arbitrary point on the lens curved surface also increases. As compared with the case where the optical axis g is located at the center of the microlens 4, the light that has exited the display image is sufficiently refracted in the entire area of the microlens 4 and reaches the observer 3, so that the lens functions as a lens. Will be firm.

The first embodiment is an example in which the intersection point p between the lens curved surface (virtual curved surface) and the optical axis g is located outside the true lens curved surface of the micro lens 4. The intersection of the lens surface and the optical axis is still inside the true lens surface,
Even when the microlens is located at a marginal portion deviating from the central portion, the region where the microlens is sufficiently refracted is widened as compared with the case where the microlens is located at the central portion, so that the function as a lens is firm.

When the intersection between the lens curved surface and the optical axis deviates from the center of the minute lens, a step occurs at the boundary between the minute lenses. Although shown in FIG. 1 as a step-like change, a certain degree of gradient is formed due to actual manufacturing conditions and the like. Conversely, a gradual change may be made to improve the image quality. In any case, this boundary is limited to a very narrow range.

If the optical axes of two nearby microlenses are common to each other, each microlens becomes a part of one large lens, and the images of the individual microlenses are combined into one large image. Become. As a result, a large pixel portion is generated in the whole image of the display image, and only this portion is enlarged or reduced in accordance with the magnification of the minute lens, unlike the other regions, to degrade the quality of the whole image. If the optical axes of two nearby microlenses are independent of each other, the images of the individual microlenses can be prevented from being combined into one large image,
Since the pixel size is kept uniform and dispersed, the image quality of the entire image can be improved.

Next, a second embodiment of the present invention will be described with reference to FIG. A second embodiment of the present invention
This is an embodiment in which a microlens array is arranged obliquely with respect to an observer to make the function of the microlens as a lens more remarkable.

FIG. 2 is a sectional view of a display device according to the second embodiment of the present invention. In FIG. 2, the display device includes a microlens array 11 composed of microlenses 14 and an image support 12 that supports a display image depicting a design to be displayed. The display image is the image support 1
2 or a two-dimensional image already drawn on paper or the like is fixed to the image support 12. The display image itself is omitted in FIG. 2, and the relationship between the microlens array 11 and the display image is the same as in the first embodiment described with reference to FIG.

The basic difference between the second embodiment and the first embodiment described with reference to FIG. 1 is that the difference in the state of the arrangement of the micro lenses 14 constituting the micro lens array 11 is as follows. This is the direction (angle) of the microlens array 11 with respect to the observer 13. The lens curved surface of the micro lens 14 constituting the micro lens array 11 is a cylindrical surface, and has a shape that penetrates the paper surface and is long from top to bottom. The microlenses 14 are arranged symmetrically with respect to the optical axis g. On the other hand, the microlenses according to the first embodiment are arranged asymmetrically with respect to the optical axis.

In the second embodiment, the lens forming surface is a flat surface, and the image support 12 is arranged parallel to the lens forming surface. This condition is the same as in the first embodiment. The display device having such a configuration is placed so that the microlens array 11 is inclined by the angle θ with respect to the observer 13. Of course, the lens forming surface is also the image support 1
2 also inclines by an angle θ with respect to the observer 13. The observer 13 will see the display image supported or drawn on the image support 12 via the microlens array 11.
In this case, the line of sight of the observer 13 indicated by h in the figure is inclined by an angle θ with respect to the optical axis g of the microlens 14.

When the line of sight h is tilted from the optical axis g by an angle θ, the angle between the line of sight h and the normal to the lens curved surface of the micro lens becomes
As shown in the figure, it changes by θ. That is, the angle of incidence of the line of sight h with respect to the lens curved surface changes by θ. θ,
Both β are positive and negative signed values based on the optical axis g. The angle between the line of sight h and the normal to the lens surface of the microlens is (β
−θ), which is also represented by a signed value. Since then
The angle formed by the line of sight h and the normal to the lens curved surface of the micro lens will be simply described as the angle formed by the line of sight and the micro lens. For the function as a lens, the absolute value of the angle between the line of sight and the micro lens is important, and the sign of the sign has no significant meaning. Therefore, unless otherwise specified, the angle between the line of sight h and the normal to the lens surface of the micro lens will be described as an absolute value.

When the angle between the lens and the line of sight increases in one region with respect to the optical axis, the angle decreases in the other region. In the case of the second embodiment in which the optical axis g is located at the center of the microlens, a portion where the angle between the line of sight and the microlens increases and a portion where the angle between the line of sight and the microlens increases in a small range of θ,
Inside the microlens, there are many increasing area portions, and the area ratio to the decreasing area portion increases. When θ further increases, the angle formed by the line of sight and the microlens increases with increasing θ in all regions of the microlens.

On the other hand, when the optical axis g is not located at the center of the microlens but at a position deviated from the central portion inside the microlens or outside the microlens, depending on the direction in which the microlens array is inclined. It can be easily understood from the above description that the area ratio of the minute lens in which the angle formed between the line of sight and the minute lens increases increases or decreases.

When the angle between the line of sight h and the normal of the lens curved surface becomes larger, the light refracted more by the micro lens 14 reaches the observer 13 and the micro lens 1
The function as the lens of 4 becomes firm. In the above description of the second embodiment, the microlens array 1
4 has been described as an example of tilting the lens 13 with respect to the observer 13 in the tilt direction. Even when the axis of the cylindrical lens, which is a direction orthogonal to this, is inclined toward the observer, the angle of the observer's line of sight to the normal of the lens curved surface is increased, and the function of the microlens as a lens becomes more firm. it can. This gives a stronger three-dimensional effect.

As is clear from the above description of the second embodiment, the microlens array 1 of the first embodiment
Can be regarded as a structure in which the micro lens 4 is tilted in advance in the tilt direction of the lens. In the microlens array according to the first embodiment, it is not always necessary to tilt the microlens array with respect to the observer, but the microlens array is further inclined so as to increase the angle between the line of sight and the normal to the lens curved surface. You may be inclined to.

In the second embodiment, both the microlens array 11 and the image support 12 are arranged obliquely with respect to the observer 13, but the displayed image is correctly positioned in front of the observer 13. For example, the display image may be tilted with respect to the microlens array 11. In short, the relationship between the microlens array 11 and the observer 13 is important.
The relationship between the image and the display image is not important.

Next, a third embodiment of the present invention will be described with reference to FIG. A third embodiment of the present invention
This is an embodiment in which a microlens array is curved and arranged to face a viewer and a display screen. FIG. 3 is a sectional view of a display device according to the third embodiment of the present invention.

In FIG. 3, the display device comprises a microlens array 21 in which microlenses are arranged sufficiently small with respect to the length of one side of an effective area, and an image support for supporting a display image depicting a design to be displayed. 22. The display image is drawn directly on the surface of the image support 22 or a two-dimensional image already drawn on paper or the like is fixed to the image support 22. The display image itself is omitted in FIG.

The observer 23 observing the display image sees the two-dimensional display image supported on the image support 22 or the two-dimensional display image drawn directly on the image support 22. In the third embodiment, the microlens array 21 has a thin shape that is flexible with respect to bending, and is sufficiently larger than the size of the arrangement pitch of the microlenses and the thickness of the microlens array 21. It is placed facing the image support 22 in a state of being curved to a curved surface having a radius of curvature.

Microlens array 21 before bending
Is a microlens array 11 according to the second embodiment.
It has the same structure as that described above, and is a flat surface, the lens curved surface of the microlens is a cylindrical surface, and has a shape extending from top to bottom through the paper surface. The micro lenses are arranged symmetrically with respect to the optical axis. Note that individual micro lenses are omitted in FIG.

The micro lens array 21 having a thin shape
Indicates that all the boundary surfaces included in the microlens array 21 including the boundary surface in contact with the outside air, including the virtual lens forming surface on which the microlenses are arranged, are curved with the same radius of curvature. Can be considered as Therefore, a display image placed at a position sufficiently close to the microlens array 21 than the radius of curvature of the curvature is generated by the curvature itself of the microlens array 21 in the entire image viewed through the curved microlens array 21. There is almost no distortion, and the whole image of the display image does not look partially distorted. This can be easily understood from the fact that even when a flat sheet-like film is curved, distortion due to the curvature can be ignored. The reason for this is that even if it is bent at a certain boundary surface, it is bent in the opposite direction at another boundary surface, and the refraction of light due to the bending of the microlens array 21 as a whole becomes negligibly small.

However, the degree of inclination of the portion of the microlens array 21 changes depending on its position, and the lens curved surface of the micro lens also changes its inclination angle depending on its position in the microlens array. When the microlens array 21 is used in a curved manner as described above, a stronger three-dimensional effect is exhibited. This is phenomenally apparent, and a three-dimensional effect appears irrespective of whether the microlens is a cylindrical lens or a spherical lens, irrespective of the unevenness of the curvature and the direction of the curvature.

The curved surfaces of the micro lenses at different positions on the micro lens array 21 can be regarded as lens surfaces having different distances from the optical axis, and the focal length of the micro lenses changes. As a result, the position of the whole image of the display image in the depth direction is different between the partial portions. That is, the entire image is distorted in the depth direction. It is presumed that an even stronger three-dimensional effect is exhibited in such an image. It should be noted that almost no distortion or the like is felt in the whole image. This is because the whole image of the display image is made up of the image of the minute lens as a pixel, so there is no enlargement or reduction in the left, right, up and down directions of the whole image.
Only a part of the whole image changes the position in the depth direction. It is presumed that this change in the position in the depth direction is not perceived as a consciousness as a distortion of the whole image, but is perceived only unconsciously only in the brain and expresses a strong stereoscopic effect. The feature is that a very strong stereoscopic effect can be obtained without any distortion in the visible whole image. It goes without saying that the case where the minute lens is large and distortion of the image of the minute lens can be seen is out of the question. In this case, the image of the minute lens does not function as a pixel.

In the above description, it is assumed that the cause of the distortion in the depth direction of the whole image is due to the difference in the focal length of the minute lens. However, as a result of the change in the positional relationship between the microlenses and the displayed image depending on the position in the microlens array due to the curvature, the effect of changing the position of the image is also synergistic.

It is to be noted that the angle formed between the microlens and the line of sight of the observer 23 also increases by curving the microlens array. Therefore, the function of making the function of the micro lens firm is the same as the case where the micro lens array 11 of the second embodiment is tilted. The focal length can also be controlled by changing the degree of curvature.

In the third embodiment described with reference to FIG. 3, the focal length of the microlenses is changed depending on the position in the microlens array due to the curvature of the microlens array 21. If the focal length of the micro lens is changed in advance according to the position in the micro lens array, the same effect can be obtained without bending the micro lens array 21.

In order to change the focal length of the micro lens according to the position in the micro lens array, means for changing the radius of curvature of the lens curved surface of the micro lens, or by fixing the radius of curvature of the lens curved surface of the micro lens, There is a means for changing the refractive index of one or both of the materials forming the boundary surface. Further, there is a means for arranging lens curved surfaces having different distances from the optical axis. The change of the focal length depending on the position in the microlens array will be described later in detail. In the third embodiment, the convex and concave portions of the microlens array 21 are one convex and one concave respectively with respect to the effective area. The radius of curvature of the curvature is different between the convex and concave portions. If the period of curvature is from the convex vertex to the convex vertex, or from the concave bottom point to the concave bottom point,
The curvature existing in the effective area may be for a period of several tenths or for several periods. Further, both the period and the radius of curvature may be changed by the curvature. The change in the depth direction of the partial portion that occurs in the whole image only needs to be felt unconsciously by the brain of the observer 23. An appropriate curvature may be set according to the display state such as the distance between the observer 23 and the display image.

In the first to third embodiments, the minute lens is a cylindrical lens, but may be a spherical lens.
Further, it is not necessary to uniformly arrange the area shape and the like. Further, it does not require completeness as a lens. Since the whole image of the display image is recognized using the image of the microlens as a pixel, it is easily understood that there is no problem even if the image of the pixel is slightly distorted. This micro lens condition is applied to all the micro lens arrays described above.

Although the microlenses of the first to third embodiments have been described with reference to the optical axis in spite of being cylindrical lenses, they are described as optical axis planes. On the other hand, in the case of a spherical lens, it is not the optical axis plane but the optical axis. In addition,
The microlens in the microlens array used for three-dimensional display has no problem even if there is relatively large distortion unless it is extreme. This is because the image of the microlens becomes a new pixel to display the entire image of the display image, and distortion inside the pixel hardly causes a problem.

It is also easily understood that, when the microlens array constituted by the cylindrical lenses is curved, the cylindrical lenses may be subdivided and regarded as constituted by small cylindrical lenses. You. In the first and second embodiments, the lens curved surface of the microlens of the microlens array is a single boundary surface that is a contact surface with air.

Japanese Patent Application No. 11-218313, which is the invention of the prior application
Micro-lens arrays, which have a solid-solid or liquid-solid interface between them, as described in detail in (1), or a micro-lens array consisting of multiple stacked lens surfaces. be able to. Of course, the microlens array of the third embodiment can also be used as these microlens arrays.

A microlens array having a solid-solid or solid-liquid boundary surface as a lens forming surface and a microlens array in which a plurality of lens curved surfaces are stacked are already described in detail in the above specification of the prior application. , And will be briefly described here.

A plurality of boundary surfaces, which are significant lens curved surfaces related to the microlenses of the microlens array, are laminated, and the focal length of one of the focused curved surfaces as a lens is approximately as follows. Equation (2),
Given by (3). Note that the thickness of the transparent member and the thickness of the microlens array forming each layer are sufficiently smaller than the radius of curvature of the minute curved surface. Hereinafter, unless otherwise specified, it is assumed that the thickness of the microlens array satisfies this thin condition.

F _s = r / (n _{p1 −ns 1} ) (2) f _p = r · n _p / (n _{p1 −ns 1} ) (3) where f _p is the focal length of the display image side, f _s is the focal length of the side opposite to the display image. r is the radius of curvature of the lens,
When the center of the radius of curvature is on the display image side of the lens curved surface, r is set to a positive value, and when it is on the opposite side, the value is set to a negative value. Further, n _p1 is the absolute refractive index of the material on the display image side forming the lens curved surface, and n _s1 is the absolute refractive index of the material located on the opposite side to the display image forming the lens curved surface. And n
_p is the absolute refractive index of the material in contact with the display image. If this display image faces the microlens array with air in between, then n _p = 1 and f _s = f _p .

[0078] the focal length of the micro lenses is important in the context of where to place the display image, hereinafter will be described with reference to f _p as a representative of the focal length. If the focal length is positive, the lens becomes a convex lens, and if the focal length is negative, it becomes a concave lens. It can control the focal length f _p by selecting the material of the two sides in contact with the curved lens surface as is clear from equation (3) properly.

When a significant lens surface has a plurality of boundary surfaces superposed in multiple stages, the focal length f _p of the lens on which the minute curved surfaces on each boundary surface act collectively corresponds to the optical axis of each minute curved surface. It is well known that the case is given by the following equation (4). _{1 / f p = Σ (n} pi -n si) / n p · r i ............... (4) where, r _i, n _pi, the boundary n _si is forming the i-th significant curved lens surface, respectively The radius of curvature of the minute curved surface of the surface, the absolute refractive index of the material on the display image side, and the absolute refractive index of the material on the side opposite to the display image.

As is apparent from equation (4), the radius of curvature of the minute lens at the boundary surface that is a lens curved surface is r, the absolute refractive index of the material on the display image side is n _p , and the absolute value of the material on the opposite side of the display image is absolute. the refractive index and n _s, the radius of curvature of the other boundary surface without the curved lens surface facing the curved lens surface R, the absolute refractive index n _p of the material of the display image side, the absolute refractive index of the other side of the material as the display image Is N _s , when the following inequality (5) is satisfied, the lens characteristics of the microlenses of the microlens array are dominated by the boundary surface of the lens curved surface, and the influence on the lens characteristics of the other boundary surfaces is affected. Can be weakened. | R / (N _p −N _s ) | ≫ | r / (n _p −n _s ) |... (5) Note that between each lens surface and the other boundary surface excluding all lens surfaces. When the inequality (5) is satisfied, the lens characteristics of the microlens array are governed by the boundary surface of the lens curved surface, and it is natural that the influence on the lens characteristics of the other boundary surfaces can be ignored.

In the case where there is only one lens curved surface, the optical axis of the micro lens when the boundary surface is a solid and a solid or a solid and a liquid is clear, and the optical axis of the micro curved surface in the lens curved surface becomes the optical axis of the micro lens. . When the boundary surface that becomes a significant lens curved surface overlaps in multiple stages, a microlens array can be equivalently formed by a single lens curved surface as a composite lens formed by a composite optical system in which microscopic curved surfaces of multiple lens curved surfaces are connected in multiple stages. Can be regarded as a minute lens. Therefore, this compound lens is also called a micro lens. In addition, when it is easy to understand that the composite is added, the description will be given with “composite”.

When the minute curved surfaces in each lens curved surface have the same area shape and the same positional relationship, and their optical axes overlap at the same position, the focal length of the composite minute lens can be easily obtained from the equation (4). And its optical axis coincides with the optical axis of the minute curved surface. On the other hand, in the case where the minute curved surfaces of the lens curved surfaces have different area shapes, a portion where the minute curved surfaces of the lens curved surfaces overlap each other becomes a new composite minute lens. For example, in the case of two lens surfaces A and B, when the minute surface c of the A lens surface is in a positional relationship such that the minute surface x and the minute surface y of the B lens surface overlap,
The composite microlens is formed by the overlapping portion of the minute curved surface c and x, and the composite minute lens is formed by the overlapping portion of the minute curved surface c and y.

The optical axis of the composite microlens is such that, even if the optical axes of the minute curved surfaces of the lens curved surfaces are different, if the optical axes are parallel to each other and the distance is sufficiently smaller than the radius of curvature of the minute curved surface. The optical axis of any minute curved surface can be regarded as the optical axis of the composite minute lens as a representative. However, strictly, each has a different optical axis. If the optical axes of the minute curved surfaces are independent of each other on the curved surfaces of the lenses, the optical axes of the composite minute lenses are also independent of each other.

The micro lens array according to the present invention
Generally, the above conditions can be satisfied. Even if the above condition cannot be satisfied as a special case, the microlens array can be regarded as equivalent to one lens curved surface on which composite microlenses are arranged. Of course, the optical axis of this composite microlens can also be approximately determined.

There is no problem in simply calling this composite microlens a microlens. Even if the microlens forming the microlens array is a lens formed by a single boundary surface, or a plurality of boundary surfaces. Each of the lenses is a micro lens of a micro lens array, even if the lens has a minute curved surface and is formed by a composite optical system connected in multiple stages. Also, it can be considered that one lens curved surface exists in the microlens formed by the multistage combined optical system. When the thickness of the microlens array is sufficiently small, the lens curved surface of any boundary surface may be regarded as a lens curved surface of a microlens formed by a composite optical system in which multiple stages are connected in multiple stages.

The microlens array in which the lens forming surface is not a gas-contact surface but a solid-solid or a solid-liquid boundary surface, and a microlens array in which a plurality of lens curved surfaces are stacked are both effective areas. Is a microlens array in which microlenses sufficiently smaller than the length of one side are arranged.

As is clear from the above description, in the first and second embodiments, the lens curved surface of the microlens of the microlens array is a single boundary surface that is in contact with air, It is obvious that the microlens array can be replaced by a microlens array in which a boundary surface between a solid and a liquid or a solid and a liquid has a curved lens surface of a microlens, or a microlens array in which a plurality of curved lens surfaces are laminated.
Further, the microlens array according to the third embodiment can be replaced.

Next, the change in the focal length of the minute lens according to the position of the micro lens array for obtaining a strong stereoscopic effect will be described. If the microlens array is formed in a region where the focal length of the microlens gradually changes with the position, a strong three-dimensional effect is exhibited. This change may be a smooth change or a change with some increase or decrease. Further, a rapid change such as a change in a range smaller than several micro lenses may be accompanied. For example, microlenses with approximately equal focal lengths may last for a range and change at some point, and microlenses with approximately equal focal lengths may last for some range, then the focal length may change again, and so on. The change may be such that a microlens having substantially the same focal length lasts for a certain range. Even if the microlens array is formed in the region where the groups having different focal lengths are distributed, a strong stereoscopic effect is exhibited. There are at least two types of groups having different focal lengths, and there may be three or more types. The change between groups having different focal lengths may be a gradual change or a sudden change. Microlenses with different focal lengths may be scattered in the same group.

Naturally, a strong stereoscopic effect is exhibited even if the area where the focal length of the microlens gradually changes with the position and the area where the groups having different focal lengths are distributed are mixed. The degree of the change, the interval of the change, and the like may be determined according to the application, such as the size of the display image, the arrangement pitch of the minute lenses, and the degree of the required three-dimensional appearance. What is necessary is that the focal length of the microlenses in the effective area of the microlens array is not constant but changes depending on the position. Of course, the focal length does not need to be changed in the entire effective area.

As a microlens array having a smooth lens curved surface, a microlens array in which convex lenses and concave lenses are alternately arranged is disclosed in Japanese Patent Application No. 2000-156 of the prior invention.
No. 608 and Japanese Patent Application No. 2000-162231. In such a microlens array, if one lens is regarded as a microlens, the other can be regarded as a part connecting the microlenses, and the adjacent convex and concave lenses can be regarded as one microlens again. If the focal length is changed as described above, a three-dimensional effect is further enhanced.

As described above, the microlens array in which the focal length changes depending on the position of the microlens can be relatively easily formed by using a configuration in which a boundary surface between solids is a curved lens surface and a configuration in which a plurality of boundary surfaces is a curved lens surface. Can be made. By changing the material forming the boundary surface that is a lens curved surface according to the position in the microlens array, the focal length can be changed according to the position in the microlens array. Further, at the time of manufacturing, if two materials having different refractive indexes in a liquid state are alternately arranged to form a mottled layer,
At the boundary, a layer in which both materials are mixed and the refractive index continuously changes can be formed.

Also, there is a boundary surface which is at least two significant lens curved surfaces A and B, a minute curved surface of a minute lens is formed on one A surface, and a lens having a diameter sufficiently larger than the minute lens is formed on the other B surface. Are formed at intervals, a lens on the surface A and a lens on the surface B are combined to form a microlens array in which minute lenses having different focal lengths are distributed. These are merely examples, and by arranging various lenses on a plurality of boundary surfaces in various distribution states, a microlens array in which microlenses having different focal lengths depending on positions can be formed.

It has already been described in the description of the first embodiment that it is important for the display quality of the display device that the optical axes of the two minute lenses located in the vicinity are independent of each other. This is true for any microlens. In a microlens array consisting of a plurality of significant lens surfaces, which are boundary surfaces, the two microlenses located in the vicinity of the microlens array are a composite micro lens array that considers the microlens array to be composed of a single boundary lens surface. The same applies to a lens or a micro lens having a micro curved surface on the same boundary surface as a lens curved surface. However, even if the microlenses having different boundary surfaces are close to each other, they cannot be compared.

In a display device for displaying a two-dimensional image three-dimensionally, the position of the display image is important in relation to the focal point of the microlens array, that is, the focal point of the minute lens. Since the details of the invention of the prior application have been described in detail, the detailed description thereof will be omitted here, and matters necessary for the present application will be briefly described.

In order to view a two-dimensional display image as a three-dimensional image through a microlens array, the position of the entire image must be separated from the position of the display image by an appropriate distance. This distance differs depending on the distance from the observer to the display image, and it is necessary to increase the distance when viewing from a far position. Also, there is an appropriate distance to feel the stereoscopic effect,
It does not mean that the greater the distance, the better.

The whole image of the display image is a composite image of the pixels using the image of the micro lens as a pixel. In order to perform display with high resolution and high display quality, it is necessary to reduce the size of the pixel by making the microlens finer and to improve the consistency of the images of the adjacent microlenses. In other words, the rate at which the image of the microlens is enlarged or reduced is made as small as possible, and the adjacent images are made to appear as continuous as possible.

Even if the micro lens is a convex lens or a concave lens, a three-dimensional effect is exhibited. If the micro lens is a convex lens, place the display image at an appropriate position between the focal point of the micro lens and the curved surface of the micro lens, avoiding the close position of the focal point of the micro lens and the close position of the curved surface of the lens of the micro lens. Thereby, a three-dimensional image with excellent display quality can be obtained.

When the display image is placed at a position closer to the lens curved surface than the focal point, the image of the microlens, which is a pixel of the whole image, is an erect image, and the degree to which the pixels seem to be continuous is different. high. By changing the position of the display image within this range, the entire image of the display image can be
Can be changed over a wide range up to a large distance. When the display image is placed at a position close to the lens curved surface, the entire image of the display image is abnormally close to the display image, and the stereoscopic effect does not appear. Also,
The display image placed close to the focal point has an abnormally large magnification, and although the microlens originally has the role of displaying the image area corresponding to its area, it displays only a very small part of the light near the point. become unable. For this reason, the display light amount of the entire screen decreases and the screen becomes dark. Another reason is that a slight change in the position of the display image causes a large change in the position of the display image, thereby deteriorating the display quality such as causing a glare. If the display image is placed farther than the focal point, the image of the minute lens becomes an inverted image, and the image quality is reduced.

When the micro lens is a concave lens, the image of the micro lens becomes a reduced erect image. Since the image is reduced, the image is displayed up to the area corresponding to the next pixel (adjacent minute lens) beyond the image area corresponding to the area of the minute lens. For this reason, the whole image is blurred. If the position of the display image is more than the lens curved surface than the position of the focal point, the reduction ratio is 以下 or less, the display is limited to half of the corresponding image area of the left, right, upper and lower minute lenses, and the degree of blur can be limited. .

This condition also applies to a microlens array having a plurality of boundary surfaces forming a significant lens curved surface. This also applies to the case where the microlens array is inclined with respect to the line of sight of the observer and the case where the microlens array is curved. In this case, it is natural that it is desirable to satisfy this condition for all of the microlenses constituting the microlens array.

As is apparent from the above description, it is important that the focal point of the microlens is outside the microlens array formed body and that the focal length is large to some extent in forming the display device. These things are indispensable for setting the micro lens array in a curved state,
It is also important for the easiness of exchange of display images, and also for the position adjustment of display images to develop an appropriate three-dimensional effect.

As described above, the focal point is located outside the microlens array formed body, and the focal length is long. This is fundamentally different from a known lenticular plate in which the focal point is located on the back surface of the formed body. A microlens array in which a contact surface between a solid and a solid or a contact surface between a solid and a liquid instead of a contact surface with a gas is used as a lens surface is extremely important in increasing the focal length. In order to reduce the arrangement pitch of the microlenses in response to the higher definition of the display image, the radius of curvature of the microlenses has to be reduced inevitably. As a result, the focal length is reduced, and the arrangement pitch of the display pixels is about 200 μm, as in a recent liquid crystal display, and the arrangement pitch of the microlenses is about 200 μm.
It is required to be μm. It is difficult to realize this with a micro lens at the interface with the gas, and if an interface in which materials having similar refractive indices are joined is used here, an inexpensive micro lens array can be relatively easily realized.

Further, the limit at which a display image is arranged inside the focal point and a stable whole image can be obtained is up to a focal length of about 1 mm, which is about five times the arrangement interval of 200 μm. If the focal length is shorter than this, it is difficult to obtain a three-dimensional effect, and it is difficult to place a display image. When the arrangement interval of the microlenses is 200 μm or more, the focal length is further increased even at the same 5 times, and the range where the displayed image can be placed inside the focal point is expanded, which is advantageous. Even if the arrangement interval of the microlenses is small, if the focal length is increased by making it larger than 5 times, more flexibility can be obtained in the position where the display image is placed.

Here, the meaning of the microlens array formed body described so far will be clarified. The microlens array forming body refers to the whole thing forming the microlens array. The portion from the lens curved surface of the micro lens to the boundary surface with air or the display image is the micro lens array formed body. For example, when a sheet on which a lens curved surface of a microlens is formed is adhered to the surface of a cathode ray tube with an adhesive, a set of display pixels formed on the back surface of the glass tube of the cathode ray tube is a display image, so that the lens curved surface is formed. Everything, including the coated sheet, adhesive, and the back of the glass of the cathode ray tube, is a microlens array formed body.

In an electronic display such as a cathode ray tube or a liquid crystal display of a TV receiver, minute display pixels are systematically arranged at a constant pitch. It is well known that when this display image is viewed through a microlens array in which microlenses are arranged at a constant pitch, moire fringes generally occur. As a countermeasure, it is effective to randomly arrange micro lenses having different sizes. For example, if the micro lenses are cylindrical lenses, micro lenses having different widths may be arranged at random. Of course, pseudo random arrangement may be used instead of complete random arrangement. In this case, it is preferable that the focal lengths of the individual microlenses are equal, but a slight difference is acceptable. Up to now, the focal point or focal length of the microlens has been used as a parameter for various conditions, but the focal point of the microlens may have some variation before and after rather than a single point. Therefore, as the focal length, an average value, a minimum value, a maximum value, or a value determined by defining a certain allowable range may be applied. In short,
The focus or focal length of the microlens array (microlens) may be considered as a problem of the quality of the display image which is important in relation to the position of the display image.

[0106]

As described above, the present invention includes:
The following effects are obtained. According to the first aspect of the present invention, the function of the microlens as a lens is firm even in a general display device having a microlens array and a general display device in which a display image is directly opposed to an observer, and the stereoscopic display characteristics are improved. Is improved. With the independence of the optical axis of the micro lens, it is possible to eliminate large pixel parts that are abnormally enlarged / reduced,
Display quality can be improved. Further, by changing the optical axis position of the micro lens at the time of design, the focal length of the micro lens can be controlled.

According to a second aspect of the present invention, the whole image of the display image is
Since the portions can be located at different positions in the depth direction, a very strong three-dimensional effect is exhibited. Moreover, distortion due to the curvature of the microlens array can be eliminated. Further, the whole image can be viewed as a good quality image, which is not enlarged or reduced vertically and horizontally. Furthermore, due to the independence of the optical axis of the minute lens, a large pixel portion which is abnormally enlarged / reduced can be eliminated, and the display quality can be improved.

According to the third aspect of the present invention, as in the second aspect of the present invention, the whole image of the display image can be formed at different positions in the depth direction, thereby exhibiting a very strong three-dimensional effect. Further, the whole image can be viewed as a good quality image, which is not enlarged or reduced vertically and horizontally. Furthermore, due to the independence of the optical axis of the minute lens, a large pixel portion which is abnormally enlarged / reduced can be eliminated, and the display quality can be improved.

Further, a strong three-dimensional effect can be obtained without bending the microlens array, and there is an effect of reducing a mounting space in use. According to the fourth aspect of the present invention, the two-dimensional display image appears as a three-dimensional image having a strong stereoscopic effect. Further, the image seen in this display device has very little distortion and is excellent in image quality.

The fifth aspect of the present invention is an air-conditioning system in which minute curved surfaces having a small radius of curvature r are arranged at a high density by making the radius of curvature R of the boundary surface with the outside world which is air particularly close to a sufficiently large plane. If the boundary surface is a curved lens surface, it is possible to obtain a microlens array composed of minute lenses having a large focal length, which is extremely difficult to realize, at a relatively low cost.

Further, since the image is not displayed as a partially enlarged or reduced large pixel, a high quality image can be obtained. According to the sixth aspect of the present invention, in addition to the same effect as the fifth aspect of the present invention, the display image can be placed at a position closer to the lens curved surface than the focal point while avoiding the vicinity of the focal point. When used in a display device that performs excellent image quality, a display device with excellent image quality can be configured.

According to the seventh aspect of the present invention, a high-definition two-dimensional display image can be displayed as a high-quality three-dimensional image. In particular, since the minute lens can be miniaturized, a smooth and high-definition display without perceiving pixels can be performed, and the three-dimensionalness is enhanced. According to the invention of claim 8, the two-dimensional display image is displayed as a three-dimensional image having an excellent display quality. In addition, the reproducibility of the position when exchanging the display image is facilitated.

According to a ninth aspect of the present invention, the two-dimensional display image is
The image is displayed as a three-dimensional image with excellent display quality.
In addition, the reproducibility of the position when exchanging the display image is facilitated.
Further, when the micro lens array is inclined with respect to the observer, the function of the micro lens as a lens becomes firm, and a three-dimensional effect is strongly felt. Further, when the microlens array is inclined with respect to the observer, a stronger three-dimensional effect is exhibited. There is no distortion of the whole image due to the curvature itself of the microlens array.

According to the tenth aspect of the present invention, in the whole image of the two-dimensional display image viewed through the microlens array, the portions can be located at different positions in the depth direction, so that a stronger three-dimensional effect is exhibited. Further, the whole image can be viewed as a good quality image, which is not enlarged or reduced vertically and horizontally. Furthermore, due to the independence of the optical axis of the minute lens, a large pixel portion which is abnormally enlarged / reduced can be eliminated, and the display quality can be improved.

Further, a strong three-dimensional effect can be obtained without bending the microlens array, and there is an effect of reducing a mounting space in use. According to the eleventh aspect of the present invention, as in the tenth aspect of the present invention, the entire image of the two-dimensional display image viewed by the display device can be formed at different positions in the depth direction, thereby providing a stronger three-dimensional effect. Is expressed. Further, the whole image can be viewed as a high quality image which is not enlarged or reduced vertically and horizontally. Furthermore, due to the independence of the optical axis of the minute lens, a large pixel portion which is abnormally enlarged / reduced can be eliminated, and the display quality can be improved.

Furthermore, a strong three-dimensional effect can be obtained without bending the microlens array, and there is an effect such as a reduction in a mounting space when used. The two-dimensional display image appears as a three-dimensional image having a strong stereoscopic effect. Further, the image seen in this display device has very little distortion and is excellent in image quality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a display device according to a first embodiment.

FIG. 2 is a cross-sectional view of a display device according to a second embodiment.

FIG. 3 is a cross-sectional view of a display device according to a third embodiment.

[Explanation of symbols]

Reference Signs List 1 micro lens array 2 image support 3 observer 4 micro lens 11 micro lens array 12 image support 13 observer 14 micro lens 21 micro lens array 22 image support 23 observer g optical axis of micro lens o center of lens curved surface p Intersection point of the virtual curved surface obtained by extending the lens curved surface and the optical axis i Normal line of the lens curved surface θ Angle between the optical axis and the normal line of the lens curved surface, or the angle formed between the optical axis and the line of sight of the observer h The line of sight of the observer

Claims (11)

[Claims] 1. A microlens array in which microlenses that are sufficiently small with respect to the length of one side of an effective area are arranged, and the optical axes or optical axis surfaces of two microlenses in the vicinity are independent of each other. The optical axis or the optical axis surface of the microlens deviates from the central part of the microlens and is located at the border of the microlens,
Alternatively, the microlens array is located outside the minute lens. 2. A microlens array in which microlenses that are sufficiently small with respect to the length of one side of the effective area are arranged, and the optical axes or optical axis planes of two nearby microlenses are independent of each other. The boundary surface of the microlens array including the virtual lens forming surface on which the microlenses are arranged is uniformly and smoothly curved with a sufficiently large radius of curvature with respect to the thickness of the microlens array. A microlens array, comprising: 3. A microlens array in which microlenses that are sufficiently small with respect to the length of one side of an effective area are arranged, and an area in which the focal length of the microlenses changes with the position in the microlens array; A microlens array comprising a group of microlenses having substantially the same focal length as a group, and at least one or both of the regions in which groups having different focal lengths are distributed. 4. The microlens array according to claim 3, a two-dimensional display image, and an image for supporting the two-dimensional display image so that the two-dimensional display image is arranged to face the microlens array. A display device comprising: at least one or both of supports. 5. By laminating two or more transparent members having different refractive indexes from each other and having a refractive index sufficiently higher than that of air, one or more boundary surfaces at which the transparent members contact each other are formed. At least one of the boundary surfaces is arranged at an arrangement pitch sufficiently smaller than the length of one side of the effective region, and two adjacent ones of the boundary surfaces have different optical axes or optical axis surfaces. Form a lens curved surface consisting of a collection of minute curved surfaces having, each of the boundary surfaces that are lens curved surfaces with respect to any of the other boundary surfaces including the boundary surface with the outside that is not the lens curved surface facing the boundary surface that is the lens curved surface However, the radius of curvature r of the minute curved surface of the boundary surface that is the lens curved surface, the absolute refractive index n _p of one material in contact with the minute curved surface, and the absolute refractive index n _s of the other material in contact with the minute curved surface
If, following the relationship between the radius of curvature R of the other boundary surface, and the absolute refractive index N _p of one material in contact with the other boundary surface, and the absolute refractive index N _s of the other material in contact with the other boundary surface Inequality (1)
A microlens array characterized by the following. _{| R / (N p -N s} ) | »| r / (n p -n s) | ............... (1) 6. The microlens array according to claim 5, wherein the focal point of the microlens formed by the composite optical system in which the microcurved surface of the boundary surface, which is the lens curved surface, is connected in multiple stages, is shifted from the microlens array formed body. A microlens array, wherein the microlens array is located at a remote external position and is separated from the closest minute curved surface by at least five times the shortest arrangement interval of the minute curved surfaces. 7. A microlens array according to claim 5 or 6, wherein the microlens array is formed by a composite optical system that faces the lens curved surface of the microlens array and has a multi-stage micro curved surface of a boundary surface that is the lens curved surface. 2 consisting of a continuous pattern arranged at a position between the focal point of the micro lens to be formed and the lens curved surface of the micro lens so as to avoid the close position of the focal point of the micro lens and the close position of the lens curved surface of the micro lens. A three-dimensional display image, a focal point of a micro lens formed by a composite optical system in which a micro curved surface of a boundary surface which is the lens curved surface facing the lens curved surface of the micro lens array and a lens curved surface of the micro lens The two-dimensional display image which is arranged at a position between and near the focal point of the minute lens and the lens curved surface of the minute lens is supported. Of the image support, display, characterized in that it comprises at least one or both, the device. 8. A microlens array in which microlenses that are sufficiently small with respect to the length of one side of the effective area are arranged, and the optical axes or optical axis surfaces of two microlenses in the vicinity are independent of each other. A position between the focal point of the microlens and the lens curved surface of the microlens opposite to the microlens array, at a position avoiding a position near the focal point of the microlens and a position near the lens curved surface of the microlens. A two-dimensional display image, and an image support for supporting the two-dimensional display image, such that the two-dimensional display image is arranged.
A display device comprising: at least one or both of: a microlens array facing an observer, and displaying the two-dimensional display image to the observer via the microlens array. 9. The display device according to claim 8, wherein a boundary surface forming the microlens array is uniformly and smoothly including a virtual lens forming surface on which the microlenses are arranged. It is curved with a radius of curvature that is sufficiently large with respect to the thickness of the lens array, and the area ratio inside the microlens where the angle between the line of sight of the observer and the normal of the lens curved surface of the microlens increases is increased. The microlens array is inclined with respect to the observer in at least one or both directions. 10. A microlens array in which a plurality of microlenses that are sufficiently smaller than the length of one side of an effective area are arranged, wherein the plurality of microlenses have an irregular focal length. Micro lens array. 11. The microlens array according to claim 10, a two-dimensional display image, and an image for supporting the two-dimensional display image so as to arrange the two-dimensional display image so as to face the microlens array. A display device comprising: at least one or both of supports.