JP4940507B2 - Stereoscopic image display body and observation method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a stereoscopic image display body that displays a three-dimensional image (stereoscopic image) and is effective in authenticity determination and an observation method thereof.
[0002]
[Prior art]
When displaying / observing a stereoscopic image based on binocular parallax, a two-dimensional image (planar image) having parallax arranged in the left-right direction (arrangement direction of both eyes) and a different image are viewed by the left and right eyes. However, it is generally performed as a technique for obtaining a stereoscopic effect.
[0003]
Apart from using anaglyph method (blue-red glasses) and polarized glasses, as a method that does not require special equipment, multiple two-dimensional images with parallax are displayed on the same screen through striped barriers arranged in parallel in the horizontal direction. By separating the synthesized image with the left and right eyes using a method of observing the synthesized image (hereinafter referred to as a synthesized image) and a lens (lenticular) having a periodicity in the left-right direction instead of a striped barrier Visual is being done.
[0004]
Further, as a technique for displaying a stereoscopic image by a pattern made of a diffraction grating, Japanese Patent Laid-Open Nos. 3-206401 and 5-2148 proposed by the present applicant have been proposed. (Refer to FIG. 9 and FIG. 10.) In the above method, a cell formed of a diffraction grating (with different grating directions) corresponding to a direction in which parallax is given, that is, a direction in which display light (first-order diffracted light) is emitted is used as a pixel. In this method, a composite image is formed by using the cells for each direction.
[0005]
As shown in FIG. 10A, four types of first-order diffracted light corresponding to each direction of C1 to C4 are emitted from a two-dimensional image obtained by photographing a three-dimensional object as a subject from various directions of C1 to C4. When a composite image is formed using the diffraction grating cells, as shown in FIG. 10B, two-dimensional images corresponding to the directions P1 to P4 (taken from the directions C1 to C4, respectively) are obtained. In this figure, the viewer's left eye sees an image of P2 (C2), and the viewer's right eye sees an image of P3 (C3), so that the viewer feels a stereoscopic effect.
[0006]
If the diffraction grating is a straight line, the emission direction of the first-order diffracted light is limited. Therefore, as shown in FIG. 9, if a grating made up of a collection of curves is used, it becomes possible to make the direction wide and adjacent. It is possible to reduce a region where the first-order diffracted light is not emitted between cells.
This prevents a parallax image to be visually perceived with a jump when the observer moves the viewpoint in the left-right direction, and contributes to a smooth change in parallax.
[0007]
On the other hand, apart from the display of a three-dimensional image (stereoscopic image), for the purpose of security (forgery prevention) and the like, a technique for forming a “latent image” in which a formed pattern cannot be distinguished at first glance and a display body to which the technique is applied are known. In other words, the pattern of the latent image is used to recognize the pattern of the formed latent image and determine the authenticity of the display body.
[0008]
For example, there is a method of observing the pattern of the latent image by superimposing a line pattern (stripe).
However, there is no report example related to the pattern that is visually perceived with a three-dimensional effect, and the conventional latent image pattern is limited to a two-dimensional (planar) pattern.
[0009]
[Problems to be solved by the invention]
The present invention utilizes a technology for forming a “latent image” that cannot be distinguished at first glance, and when identifying a pattern, a new latent image pattern visually observed with a stereoscopic effect and its observation We propose a method and aim to improve both the security (anti-counterfeiting) effect and the eye-catching effect.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, in a stereoscopic image display body that displays a stereoscopic image based on binocular parallax, elements capable of individually setting the light intensity distribution emitted in the direction of giving parallax are arranged in stripes. In addition, when the element is used as a minimum unit constituting a pixel and a pixel composed of a combination of the minimum units is arranged to form a stereoscopic image based on information of the stereoscopic image to be displayed, Pixels composed of a combination of the minimum units are arranged in a substantially striped segment in a direction giving parallax, and the striped segments are arranged in parallel at a constant pitch in a direction perpendicular to the direction giving parallax. Accordingly, to form a color solid images of selected constituted by stripe-like segment group, strongly light such that the light intensity is uniform as the three-dimensional image and each pair Based on the inverted information, when forming a three-dimensional image in inverted relationship of the light intensity by arranging a pixel comprising a combination of the minimum unit, a pixel composed of a combination of the minimum unit of the color that is the selected , By arranging in parallel in the direction to give parallax, and by arranging in parallel as another segment group between the striped segment groups spaced at a certain pitch, forming a three-dimensional image with reversed light intensity , A three-dimensional image display body characterized in that the element comprises a diffraction grating .
[0011]
As another form of the display body, another segment group having a complementary color relationship may be provided in parallel between segment groups spaced at a constant pitch, thereby forming a three-dimensional image having a complementary color relationship.
[0012]
Further, the above-mentioned selection colors constituting the pixel may be in a plurality of types, or may be three colors of R, G, and B.
[0013]
(Delete)
[0014]
The above element is configured by a diffraction grating composed of curved grating stripes, and the element in the pixel has a function of emitting diffracted light having a substantially continuous light intensity distribution in a direction in which parallax is provided. good.
[0015]
The stereoscopic image display body may be constituted by the segments arranged in a matrix instead of the segments arranged in a substantially stripe shape.
[0016]
(Delete)
[0017]
(Delete)
[0018]
In observing the stereoscopic image display body of the present invention, a light-transmitting part and a non-light-transmitting part corresponding to two types of segment groups are provided on the illumination light incident surface or the display light exit surface from the display body. The light selective transmission plate is arranged and observed so that each segment group, the light transmitting portion, and the non-light transmitting portion substantially coincide with each other.
[0019]
The non-light-transmitting portion of the light selective transmission plate may have light absorption or light reflection.
[0020]
The non-light-transmitting portion of the light selective transmission plate may have a stereoscopic image display function corresponding to one of two types of segment groups in the stereoscopic image display body of the present invention.
[0021]
<Action>
Segment groups arranged in a substantially striped pattern (or matrix) form a three-dimensional (three-dimensional) pattern only with the same type of segment group, but under normal observation conditions, the influence of adjacent segment groups Therefore, if they are in a relationship in which the light intensity is inverted, the pixels complement each other in the same viewing area, and if they are in a complementary color relationship, the pixels are mixed in the same viewing area. As a result, the observer is visually perceived and recognized as a pattern with no luminance information (no shading) in the former case, and is visually perceived and recognized as a pattern without color information in the latter case. The formed three-dimensional (three-dimensional) pattern cannot be clearly identified and functions as a “latent image”.
[0022]
In identifying the latent image, a light selective transmission plate having a translucent portion and a non-translucent portion corresponding to two types of segment groups on an incident light incident surface or a display light exit surface from the display member on the display member. Are observed so that each segment group, the light-transmitting portion, and the non-light-transmitting portion substantially coincide with each other.
In this case, since the segment group corresponding to the non-translucent portion is covered and only one type of segment group corresponding to the translucent portion is visible, the three-dimensional (three-dimensional) composed of only the same type of segment group is visible. ) Pattern can be recognized.
[0023]
As described above, the stereoscopic image display body of the present invention can be easily switched between the display state of the uniform surface during normal observation and the stereoscopic image display state when the light selective transmission plate is overlapped. 3D images can be seen / not seen, or the difference between chromatic / achromatic colors is large, especially by attaching to media that require security, etc. It is possible to have it.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
<Relationship between segments in which light intensity is reversed>
In the present embodiment, as a latent image forming method, a method of inverting the light intensity between adjacent segment groups is employed.
[0026]
When a diffraction grating is arranged to form a stereoscopic image based on information of a stereoscopic image to be displayed, pixels formed by a combination of diffraction gratings of a specific color are arranged in a horizontal direction to form a substantially striped segment. The segments are juxtaposed in a vertical direction perpendicular to the longitudinal direction of the stripe and spaced apart at a constant pitch, thereby forming a three-dimensional image composed of a segment group of a specific color.
[0027]
FIG. 1 is an explanatory view showing an embodiment of the display body of the present invention, and shows an enlarged view of arbitrary adjacent pixels A and B in the segment.
The pixel A is composed of unit elements A1, A2, A3,... A5, and each unit element corresponds to a pixel constituting a two-dimensional image of a subject when viewed from a plurality of different directions.
[0028]
Hereinafter, the unit element may be referred to as a “cell”, but each of the cells A1, A2, A3,... Corresponds to the parallax, and for example, on the parallax images 1, 2, 3,. The light having the luminance (brightness and darkness) of the pixel hitting the same position as A is emitted in the corresponding parallax direction. Although it is preferable to use a diffraction grating as the cell having the function, the cell is not limited thereto.
[0029]
The pixel B is also composed of cells B1, B2, B3,... B5, and each cell has the same color as the cells (A1 to A5) of the pixel A, but the light intensity complements each other (the light intensity is inverted). It has become.
[0030]
The relationship in which the light intensity is inverted means that the light intensity as each pair (A1, B1) (A2, B2)... Is uniform.
[0031]
In particular, it is desirable that the pairs are perceived as uniform brightness by human eyes.
That is, if the light intensity of A1 felt by human eyes = 1, the light intensity of B1 = 99. Similarly, if the light intensity of A2 felt by human eyes = 30, the light intensity of B2 = 70. It is a relationship that
The light intensity is controlled not only by the cell area ratio but also by modulation such as concentration and diffraction efficiency (when a diffraction grating is used as a unit element).
[0032]
By arranging a large number of pixels A side by side, a substantially striped segment is formed.
A segment group of a specific color is formed by arranging the segments in the vertical direction so as to be spaced apart by a segment width of H / 2.
Similarly, for the pixel B, a segment group is formed so as to fill between the substantially striped segment and the segment of the pixel A.
[0033]
At first glance, the display body produced in this way gives a uniform (solid) feeling with a single overall color tone and no shading. (See Figure 4)
Microscopically, each unit element functions to form a pattern, but when unit elements are paired, it is recognized that they are not different from adjacent pairs. The same can be said for each other.
[0034]
In order to give the observer the effect of the latent image strongly, it is preferable to make the segment width and the size of the unit element as fine as possible. However, there is a limit to miniaturization and it is difficult to produce a pattern. Therefore, it is sufficient to make the unit finer than the ability to identify the unit element based on the visual acuity (eye resolution) of the observer.
The size of the pixel pair (vertical H, horizontal W in the figure) is preferably 300 μm square or less, depending on the observation conditions.
[0035]
In order to identify the three-dimensional image recorded on the display body (latent image pattern) shown in FIG. 1, the light selective transmission plate shown in FIG. 2 is used.
The light selective transmission plate is a plate (including a film or the like) provided with a substantially stripe-shaped transmission portion / light shielding portion corresponding to the segment structure of the display body of FIG. In the figure, the width L of the light shielding portion is equal to H / 2.
[0036]
The light selective transmission plate is disposed on the illumination light incident surface of the stereoscopic image display body or the light emission surface from the stereoscopic image display body, and each segment, the light transmitting portion and the non-light transmitting portion are substantially aligned with each other. When the segment group is shielded, a three-dimensional pattern composed of unshielded segment groups can be visually recognized, and when the other segment group is shielded by sliding the light selective transmission plate, a three-dimensional pattern composed of another segment group can be visually confirmed.
Visualized three-dimensional patterns are in a state as shown in FIG. 5 or FIG. 6, and are three-dimensional images in which the shading (light intensity) is reversed.
[0037]
In addition, when the light selective transmission plates are overlapped slightly obliquely, a stereoscopic image is observed with a shading pattern.
On the other hand, when the segment of the stereoscopic image display body and the light transmitting portion of the light selective transmission plate intersect at a large angle, typically, the stereoscopic image is not visually recognized in a substantially orthogonal state.
[0038]
FIG. 3 is an explanatory diagram showing an example in which the display body (latent image pattern) shown in FIG. 1 is realized using a curved diffraction grating as a cell.
Here, the light intensity in the corresponding parallax direction is changed by changing the vertical area of the cell. In this case, the total area of the pixels A and B in the corresponding cells is always constant as shown in the figure.
When a curved diffraction grating is used as a cell, it is easy to individually set the light intensity distribution emitted in the direction in which the parallax is given, and a certain range can be given in the emission direction.
[0039]
<When configuring a pattern with multiple colors>
An embodiment in which a pattern is configured with a plurality of types of colors instead of a single color will be described.
When a stereoscopic image is composed of a plurality of colors or a combination of a plurality of colors, the light intensity of both segments is set to complement each other for a plurality of basic colors.
7 and 8 are explanatory diagrams illustrating an example in which a display body is configured using the three primary colors R, G, and B. FIG.
[0040]
In FIG. 7, an arbitrary pixel A is divided into Ar (Ag), Ab (Ab) pixels (sub) corresponding to the three primary colors R, G, and B, respectively, and a color is expressed by a mixed color from a plurality of segments. .
Each of the cells Ar1, Ar2,... Corresponds to parallax, and a plurality of Ar pixels are arranged side by side to form a substantially striped segment (sub).
In the Ar segment (secondary), Br segments (secondary) composed of cells Ar1, Ar2,... And cells Br1, Br2,.
The same applies to the segments (sub) of Ag, Bg, Ab, and Bb.
[0041]
Each pair of segments (sub) (Ar, Br) (Ag, Bg) (Ab, Bb) complements each other as in the above embodiment.
[0042]
In order to identify the three-dimensional image recorded on the display body (latent image pattern) shown in FIG. 7, a three-dimensional image A is obtained by using a light selective transmission plate having a light shielding part width L of H / 2 shown in FIG. And the stereoscopic image B with the light intensity reversed including the color information are separately viewed.
[0043]
In FIG. 8, an arbitrary pixel A is divided into Ar (Ag), Ab (Ab) pixels (sub) corresponding to the three primary colors R, G, and B, but Ar, Br, Ag, Bg, Ab, and Bb. Thus, they are not arranged alternately adjacent to each other, but are arranged as (Ar, Ag, Ab) (Br, Bg, Bb).
In order to identify the three-dimensional image recorded on the display body (latent image pattern) shown in FIG. 8, a light selective transmission plate having a light shielding part width L of H / 2 shown in FIG. 8 is used.
[0044]
In both cases of FIGS. 7 and 8, when the display body is viewed without using the light selective transmission plate, the pixels A and B complement the light intensity for each primary color. The light intensities of the three primary colors, R, G, and B, function equally and feel as a uniform image of white or gray achromatic color.
Therefore, in the case of full color display using a plurality of colors, the visual difference from when the light selective transmission plates are overlapped becomes clearer.
[0045]
When displaying a three-dimensional image by mixing a plurality of colors, a method of arranging a plurality of colors in a pixel (FIG. 7) and a single color in the pixel and displaying a plurality of colors by a plurality of pixels and a plurality of stripes (FIG. 8) May be.
In the former case, even if the width of the segment cannot be reduced, a relatively good color mixture display is possible. In the latter case, there is no large color change even if the arrangement position of the light selective transmission plate is slightly shifted, and an accurate color can be obtained. It is easy to observe the displayed stereoscopic image.
[0046]
Even in a full-color display using a plurality of colors, it is preferable to use a diffraction grating as a cell.
In the case of using a diffraction grating, if it is a surface relief type diffraction grating, a display body can be easily formed by embossing, it can be made very thin and light, and it can also be used as a transfer foil or the like. At this time, a brighter display is possible by using a blazed diffraction grating as the diffraction grating.
When such a diffraction grating is used, the light selective transmission plate can be disposed in close contact, and a high-quality stereoscopic image can be observed.
[0047]
When a diffraction grating having curved lines arranged at equal intervals is used, it is possible to create a continuous first-order diffracted light distribution with respect to the parallax direction, and display a stereoscopic image having a continuous viewing zone.
[0048]
In order to modulate the light intensity for each cell with the diffraction grating, it is necessary to change the first-order diffracted light intensity, and the method for changing the area for each cell corresponding to the brightness and the diffraction efficiency for each cell to be bright. There is a way to change according to. In the latter case, it can be easily realized by changing the depth of the diffraction grating, etc., and since the cell size can be constant, a stereoscopic image is easily observed even if the position where the line pattern is superimposed is slightly shifted, Verification is possible more easily.
[0049]
(Delete)
[0050]
(Delete)
[0051]
Further, the present invention is not limited to the above embodiment, and various modifications can be made. For example,
(A) When observing a stereoscopic image by superimposing a light selective transmission plate on a stereoscopic image display body, if the non-transmission portion of the light selective transmission plate has light absorption, the light transmission portion of the light selective transmission plate Since the light is emitted only from, the stereoscopic image with high contrast can be observed.
[0052]
(B) When the non-transmissive portion of the light selective transmission plate has light reflectivity, it is possible to clearly identify the expression color by the emitted light from the stereoscopic image display body due to the difference from the regular reflection light. Become. In particular, when a diffraction grating is used as a cell, the color and emission direction of specularly reflected light from the light selective transmission plate for the respective colors and emission directions of the 0th-order diffracted light and the 1st-order diffracted light from the stereoscopic image display body. By confirming with reference to the above, more accurate authenticity determination can be performed.
[0053]
(C) The non-light transmitting portion of the light selective transmission plate has a function corresponding to only one of the segment groups in the stereoscopic image display body, and displays the same stereoscopic image as the stereoscopic image display body to be observed. Thus, a brighter three-dimensional image can be observed when the two three-dimensional images match. Further, in authenticity determination of a stereoscopic image display body, three-dimensional stereoscopic images can be compared with each other, and accurate determination with the naked eye is possible.
[0054]
(D) The non-light-transmitting portion of the light selective transmission plate has a function corresponding to only one of the segment groups in the stripe in the stereoscopic image display body, and displays a stereoscopic image different from the stereoscopic image display body to be observed. By doing so, it is possible to observe a three-dimensionally synthesized image in which both stereoscopic images overlap. In the true / false judgment of the stereoscopic image display body, the stereoscopic image displayed on both sides is incomplete only on one side, and the complete stereoscopic image can be observed only when both are overlapped and synthesized, Accurate determination with the naked eye is possible.
[0055]
(E) In the above embodiment, the segment group A and the segment group B are defined as a relationship in which the light intensities of the same color complement each other. However, by defining as a complementary color relationship in which the light intensities are the same, If the selective transmission plate is not used, it will feel as a white or gray achromatic solid image, and it will cause a multicolor stereoscopic image to be recognized as an achromatic one at first glance. The effect of the image is produced.
[0056]
(F) In the present invention, the shape of each segment group is not limited to a stripe shape, and each segment can be arranged in a substantially matrix shape like a checkered pattern.
In this case, the light selective transmission plate is also configured to have a light transmitting / non-light transmitting portion in a substantially matrix shape instead of a stripe shape.
[0057]
【Effect of the invention】
As described above, when a pattern is identified by the display body of the present invention, a novel latent image pattern visually observed with a stereoscopic effect and an observation method thereof are provided, and by applying the display body, Both the security (anti-counterfeiting) effect and the eye catching effect can be improved.
[0058]
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a stereoscopic image display body of the present invention.
2 is a light selective transmission plate used for observing the stereoscopic image display body shown in FIG. 1. FIG. 3 is an explanatory view showing an embodiment of the stereoscopic image display body of the present invention constituted by a diffraction grating composed of curved lattice stripes. .
FIG. 4 is an explanatory diagram showing that, when observed alone, one embodiment of the stereoscopic image display body of the present invention gives a uniform (solid) feeling with a single overall color tone and no shading. .
FIG. 5 is an explanatory diagram illustrating a state in which a stereoscopic image including only one segment group is visually observed when a light selective transmission plate is placed and observed with respect to an embodiment of the stereoscopic image display body of the present invention.
FIG. 6 shows an embodiment of the stereoscopic image display body according to the present invention, in which a stereoscopic image consisting only of the other segment group with inverted light and shade (light intensity) is visually observed when a light selective transmission plate is placed and observed. Explanatory drawing which shows a state.
FIG. 7 is an explanatory diagram illustrating an example in which the three-dimensional image display body of the present invention is configured using three primary colors of R, G, and B.
FIG. 8 is an explanatory diagram illustrating another example in which the three-dimensional image display body of the present invention is configured using three primary colors of R, G, and B.
FIG. 9 is an explanatory diagram showing a method of displaying a stereoscopic image by a pattern made of a diffraction grating.
10 is an explanatory diagram showing the principle of FIG. 9. FIG.
FIG. 11 is an explanatory view showing an embodiment of a stereoscopic image display body of the present invention configured by elements combined with a lenticular sheet formed by printing or transfer and having a periodic curvature in the direction of giving parallax.

Claims (9)

In a stereoscopic image display body that displays a stereoscopic image based on binocular parallax,
The elements capable of individually setting the light intensity distribution emitted in the direction of giving parallax are arranged in a stripe shape, and the elements are used as a minimum unit constituting a pixel,
Based on the information of the stereoscopic image to be displayed, when a pixel composed of the combination of the minimum units is arranged to form a stereoscopic image, the pixel composed of the combination of the minimum units of the selected color is arranged in a direction to give parallax. Side by side to form a substantially striped segment,
By forming the stripe-shaped segments in parallel in a direction perpendicular to the direction of giving parallax and spaced apart at a constant pitch, a three-dimensional image of the selected color constituted by the stripe-shaped segment group is formed,
Based on the information obtained by reversing the light intensity so that the light intensity as each pair becomes uniform with the stereoscopic image, a pixel composed of the combination of the minimum units is arranged to form a stereoscopic image in which the light intensity is reversed. When doing this, the pixels composed of the combination of the minimum units of the selected color are arranged in a direction to give parallax and are segmented,
A three-dimensional image in which the light intensity is inverted is formed by arranging the striped segment groups spaced apart at a constant pitch in parallel as another segment group, and the element is formed of a diffraction grating. 3D image display. In a stereoscopic image display body that displays a stereoscopic image based on binocular parallax,
The elements capable of individually setting the light intensity distribution emitted in the direction of giving parallax are arranged in a stripe shape, and the elements are used as a minimum unit constituting a pixel,
Based on the information of the stereoscopic image to be displayed, when a pixel composed of the combination of the minimum units is arranged to form a stereoscopic image, the pixel composed of the combination of the minimum units of the selected color is arranged in a direction to give parallax. Side by side to form a substantially striped segment,
By forming the striped segments in parallel in a direction perpendicular to the direction of giving parallax, spaced apart at a constant pitch, a three-dimensional image of the color selected by the striped segment group is formed,
Based on the information of the three-dimensional image, when forming a three-dimensional image by arranging pixels composed of a combination of the minimum units of the color that is complementary to the selected color, the selected color is complementary to the color Pixels composed of combinations of the minimum units of colors in the above are arranged in segments in the direction of giving parallax,
A three-dimensional image having a complementary color relationship is formed between the stripe-shaped segment groups spaced apart at a constant pitch as a separate segment group, and the element is made of a diffraction grating. Image display.   3. The three-dimensional image display according to claim 2, wherein the selection color constituting the pixel is related to a plurality of types.   4. The three-dimensional image display according to claim 3, wherein the selected colors are three colors of R, G, and B. The element is constituted by a diffraction grating composed of a curved grating stripe,
The element in the pixel in the direction to have a parallax, substantially continuous diffracted light having the light intensity distribution and having a function of injection claims 1-4 stereoscopic image display body according to one another. Instead of the segments arranged in a substantially striped, stereoscopic display of claim 1-5, wherein the comprising the above segments arranged in a matrix. The translucent part and the non-translucent part corresponding to two types of segment groups in the incident surface of the illumination light with respect to the three-dimensional image display body in any one of Claims 1-6 , or the emission surface of the display light from the said display body By visually observing the selective light transmission plates having the respective segment groups so that the light-transmitting portions and the non-light-transmitting portions substantially coincide with each other, a three-dimensional pattern composed of unshielded segment groups is visually observed. A method for observing a stereoscopic image display body characterized by the above. The stereoscopic image observation method according to claim 7 , wherein the non-light-transmitting portion of the light selective transmission plate has light absorption or light reflection. The non-light-transmitting portion of the light selective transmission plate has a stereoscopic image display function corresponding to one of two types of segment groups in the stereoscopic image display body according to any one of claims 1 to 8. A method for observing a three-dimensional image display, characterized in that there is.

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