JP2013167796A - Display body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display body which has a new design so as to enable an observer to feel a pseudo stereoscopic effect and has a high anti-counterfeit effect.SOLUTION: In the display body, each of unit pixel groups displaying faces of a polyhedron respectively comprises a plurality of unit pixels, and each unit pixel has a plurality of light reflecting surfaces 4. The light reflecting surfaces 4 are inclined in the same directions per unit pixel to form fine irregularities 5 so that a light emission direction is different among the faces of the polyhedron with respect to an observer observing the faces displayed by the unit pixel groups.

Description

  The present invention relates to a display body.

It is desirable that authentication items such as cash cards, credit cards and passports, and securities such as gift certificates and stock certificates are difficult to counterfeit. Therefore, conventionally, a label that is difficult to counterfeit or counterfeit and is easy to distinguish from counterfeit or counterfeit is attached to such articles in order to prevent counterfeiting.
Holograms have an excellent design and have been used in many ways due to the difficulty of forgery and alteration that cannot be duplicated even on color copiers. However, in recent years, sophisticated counterfeit products have appeared in holograms, and there are cases in which it is difficult to determine authenticity at first glance.

As one of the methods for improving the difficulty of counterfeiting and improving the design, a latent image-containing diffraction grating display using a blazed grating has been proposed (Patent Document 1).
Further, a display body using a diffractive structure (blazed) as shown in Patent Document 2 has also been proposed.

Japanese Patent No. 4179534 JP 2011-123266 A

In a display body using a conventional diffraction grating or blazed grating, the angle at which the latent image can be observed is limited. Therefore, the authenticity determination is not always easy, and the display body must be rotated by 180 °. Authenticity cannot be determined and is complicated. In addition, there are many display bodies in which it is difficult to say that the design is necessarily improved by inserting a latent image.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a display body having a new design so that an observer can obtain a pseudo three-dimensional effect. Another object of the present invention is to provide a display that is difficult to duplicate and has a high effect of preventing forgery.

  In order to solve the above-mentioned problem, the invention of claim 1 is a display body in which a polyhedron having a plurality of surfaces is displayed by a plurality of unit pixel groups each being an assembly of unit pixels, and the unit pixel includes a plurality of unit pixels. The light reflecting surface is inclined in a uniform direction with the unit pixel as a unit so that a light emitting direction is different for each surface of the polyhedron with respect to an observer observing the polyhedron. It is characterized by forming minute irregularities.

According to a second aspect of the present invention, in the display body according to the first aspect of the present invention, there are at least two types of the fine irregularities.
According to a third aspect of the present invention, in the display body according to the first or second aspect, the cross section of the minute irregularities is a sawtooth shape.
According to a fourth aspect of the present invention, in the display body according to any one of the first to third aspects, the depth or height of the minute unevenness is constant.

According to a fifth aspect of the present invention, in the display body according to any one of the first to fourth aspects, a repeating pitch of the minute unevenness is constant.
A sixth aspect of the present invention is the display body according to any one of the first to fifth aspects, wherein the repeating pitch of the minute irregularities is 10 μm or more.
A seventh aspect of the invention is characterized in that in the display body according to any one of the first to sixth aspects, the minute unevenness has a linear lattice structure in plan view.
According to an eighth aspect of the present invention, in the display body according to any one of the first to seventh aspects, a vertical dimension and a horizontal dimension of the unit pixel are 300 μm or less.

  According to the present invention, since the light reflected by the micro unevenness is emitted from the unit pixel so that it is different for each surface of the polyhedron, the polyhedron can be displayed in three dimensions, thereby observing the polyhedron. A pseudo three-dimensional feeling can be given to the person.

It is a top view which shows the display body which concerns on one Embodiment of this invention. It is a top view which shows the example of the unit pixel which comprises the unit pixel group of the display body which concerns on one Embodiment of this invention. It is a figure which shows the XX 'cross section of FIG. It is a figure which shows the example of observation of the polyhedron displayed on the display body which concerns on this invention. It is a figure which shows the positional relationship of the direction of the slope which forms the fine unevenness | corrugation of FIG. 3, and a light source. It is a figure which shows typically the relationship between the incident angle of the light which injects into a fine unevenness | corrugation from a light source, and the emission angle of diffracted light. It is a top view which shows the display body which concerns on other embodiment of this invention.

Preferred embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise described, the present invention is not limited to these forms.
FIG. 1 is a plan view showing a display body according to an embodiment of the present invention. In this embodiment, for example, three surfaces 2A, 2B, 2C among six surfaces forming a hexahedron are displayed by the display body 1. FIG. Shows the case.

The portions for displaying the surfaces 2A, 2B, and 2C are each composed of a unit pixel group including a plurality of unit pixels 3. That is, the surfaces 2A, 2B, and 2C shown in FIG. 1 are synonymous with the unit pixel group of the display body 1.
As shown in FIG. 1, the unit pixel group of the display body 1 may be composed of unit pixels 3 whose outer shape is rectangular, or may be composed of unit pixels 3 as shown in FIG. good.
The shape of the unit pixel 3 may be determined so as to be easily divided in accordance with the shape of the polyhedron to be displayed and the surface 2 to be expressed, and the effectiveness of the effects of the present invention to be described later is completely lost depending on the shape of the unit pixel 3. No.

Three examples of the unit pixel 3 are shown in FIG. 2, and a cross section of the unit pixel 3 is shown in FIG. As shown in FIG. 2, the unit pixel 3 has a plurality of inclined surfaces (light reflecting surfaces) 4 inclined in a uniform direction, and these inclined surfaces 4 form minute irregularities 5 as shown in FIG. 3. Yes.
The minute unevenness 5 has a sawtooth cross-sectional shape, and has a function of strongly emitting incident light in one direction. Specific effects will be described below.
The unit pixel 3 behaves as shown in FIGS. 3A and 3B with respect to the incident light I from above and below, respectively. That is, for incident light I from above, light is emitted in the front direction as shown in FIG. On the other hand, as shown in FIG. 3B, the incident light I from the lower direction is emitted in the direction of the regular reflection angle.

For example, consider a case where the observer 20 observes the surfaces 2A to 2C displayed on the display body 1 in the positional relationship shown in FIG. When the surface 2A is displayed by the minute unevenness 5 having a cross-sectional shape as shown in FIG. 3, the observer 20 can observe the light emitted from the minute unevenness 5 and can visually recognize the surface 2A as a bright surface. It becomes possible.
In the present invention, the direction of the inclined surface (light reflecting surface) 4 of the minute unevenness 5 is determined in correspondence with each surface 2 to be displayed. In the display body 1 shown in FIG. 1, the slope 4 of the minute unevenness 5 of the portion displaying the surface 2A is inclined so as to face the front direction, and the slope 4 of the minute unevenness 5 of the portion displaying the surface 2B is upward. The slope 4 of the minute unevenness 5 of the portion displaying the surface 2C is inclined so as to face the right direction.

By determining the direction of the inclined surface 4 according to the shape of the surface displayed by each unit pixel group of the display body 1, the direction of the light emitted from the minute unevenness 5 corresponding to the surfaces 2A, 2B, 2C can be controlled. It is possible to emit light having different brightness for each surface to the observer 20.
When the incident direction of light, the direction of the display body 1, and the direction of the observer 20 are relatively changed, the same reflected light change occurs as when the polyhedral shape exists as a solid. Therefore, it is possible to give the observer 20 an impression that the display body 1 is shaded in a polyhedral shape, and a pseudo three-dimensional effect can be obtained.

  As the micro unevenness 5 for realizing the above function, there is a cross-sectional structure as shown in FIG. 3, that is, a cross-section of the micro unevenness 5 is a saw-toothed lattice (the cross-sectional lattice as shown in FIG. Called the lattice). If the sawtooth grating is used, the intensity of the light emitted from the unit pixel 3 can be modulated by changing the intensity of the diffracted light for each unit pixel. A high-quality display can be provided.

A method of changing the intensity of the emitted light from the sawtooth grating can be easily realized by changing the height D (see FIG. 3) of the sawtooth grating. The height (or depth) D is a distance from one convex portion to the concave portion of the minute irregularities 5.
If the height D is constant, there is an advantage that the minute unevenness 5 can be easily manufactured and the accuracy of the height D can be easily increased. In addition, by making the height D of the sawtooth lattice constant, the light emitted from the unit pixel group is free from unevenness, and high-quality display with less noise is possible.

Further, when the sawtooth-like lattice as shown in FIG. 3 is used as the minute unevenness 5 shown in FIG. 2, if the repetition pitch P between the convex part and the convex part or the concave part and the concave part is constant, one direction The accuracy of the function of emitting light strongly is improved. Further, if the pitch P is constant, there is an advantage that it is easy to manufacture a highly accurate structure with the same pitch when forming the minute irregularities 5.
When the repetition pitch P is 10 μm or more, it becomes difficult to be affected by the diffracted light assumed when the periodic structure is used, and an easy-to-view display that exhibits white is possible. The reason is described below.

FIG. 6 shows the relationship between the incident angle of light incident on the minute unevenness 5 having a constant repetition pitch P and the emission angle of light (diffracted light) reflected by the inclined surface 4 of the minute unevenness 5. Assuming that the wavelength of the incident light I shown in FIG. 6 is λ, the incident angle of the incident light I is α, and the emission angle of the first-order diffracted light (emitted light O) is β, each relationship is P = λ / (sin α− sinβ)
It is represented by

  For example, when the repetitive pitch P of the minute irregularities 5 is P = 10 μm, the incident angle α of the incident light I is α = 45 °, and the wavelength λ of the incident light I is λ = 450 nm (light exhibiting blue), the first-order diffracted light Can be calculated as β = 41.5 °. Further, when light of λ = 514 nm (green light) is incident on the minute irregularities 5 under the conditions of P = 10 μm and α = 45 °, the emission angle β of the first-order diffracted light is β = 41.5 °. Become. When light of λ = 633 nm (red light) is incident on the minute unevenness 5 under the same conditions as described above, the emission angle β of the first-order diffracted light is β = 40.1 °.

From the above results, it can be seen that diffracted light is emitted at almost the same angle at any wavelength. It can also be seen that the angle is close to the regular reflection angle of 45 degrees.
Usually, when a display body is observed, a white light source in which red (R), green (G), and blue (B) light is mixed is used. At this time, considering the diffraction principle as described above, the red (R), green (G), and blue (B) diffracted light emitted from the minute irregularities 5 with a pitch P = 10 μm or more are respectively at regular reflection angles. It is injected at a close angle.

Therefore, the observer cannot recognize the so-called seven colors of light separated by RGB, and can observe a white color in which RGB is mixed.
If the unit pixel group is configured by using unit pixels 3 in which the repetition pitch P of the minute irregularities 5 is 10 μm or more, it differs from the rainbow-colored diffracted light observed when using a periodic structure such as a conventional diffraction grating. White light can be emitted from the display body 1, and the design of the display body 1 can be improved.

When a sawtooth lattice is used as the minute unevenness 5, when the minute unevenness 5 is viewed in plan, a linear lattice structure as shown in FIG. 5 is obtained. Therefore, when changing the direction of the inclined surface 4, the direction of the sawtooth lattice is arbitrarily set. Rotate in the direction.
A unit pixel group using unit pixels 3 which are lattices in a linear sawtooth shape (plan view is shown in FIG. 3 and cross-sectional view is shown in FIG. 5) with a constant pitch P and height D of the minute unevenness 5 If it is comprised, it will become easy to produce the fine unevenness | corrugation with the high precision of the pitch P or the height D. FIG.

Further, there is no unevenness in the light emitted from the unit pixel group, the intensity is constant, there is little noise, and high-contrast display with high reflected light change contrast is easily made possible. Further, when setting the orientation of the inclined surface 4 corresponding to each surface of the polyhedron, the direction of the lattice may be rotated, and it is easy to set the orientation of the inclined surface 4 corresponding to each surface of the polyhedron. Become.
As shown in FIG. 5, when a sawtooth lattice (cross-section or sawtooth-shaped lattice) is used as the minute unevenness 5, the orientation of the slope 4 can be controlled by changing the orientation direction of the sawtooth lattice. Changing the direction of the inclined surface 4 leads to a change in the incident angle of light when light is emitted from the minute unevenness 5 in the front direction.

FIG. 5A shows an example in which light from the light source 21 is emitted in the front direction when the light source 21 is above the minute unevenness 5, and FIG. 5B is an oblique upward direction of the light source 21 from the minute unevenness 5. The example which inject | emits the light from the light source 21 in the front direction in the case where it exists is shown. FIG. 5C shows an example in which light from the light source 21 is emitted in the front direction when the light source 21 is in the lateral direction of the minute unevenness 5.
That is, when observation is performed with the light source 21 fixed at a position as shown in FIG. 4, the unit pixel group of the display body 1 emits light toward the observer 20. In this case, since only the surface 2A appears bright, the other surfaces 2B and 2C can be visually recognized as being shaded, and the observer 20 can observe the display body 1 as a pseudo three-dimensional image.

Even if the light source 21 is fixed, moving the display body 1 changes the relative positional relationship, so there are also places where the surface 2B and the surface 2C appear brightest. In that case, since the surface other than the surface that looks bright is visually recognized as being shaded in the same manner as described above, the display body 1 does not impair the pseudo three-dimensional effect.
Of course, the inclined surface 4 of the minute unevenness 5 may be in a plurality of directions within the same in-plane section (surface 2A to surface 2C). By doing so, it is possible to subdivide the range where the observer looks bright by finely changing the incident angle of the light source and tilting the display body, and it is also possible to improve the design and expand the range of design .

If a structure having an asymmetrical slope such as a sawtooth lattice is used for the minute irregularities 5, it is extremely difficult to imitate, and further optical duplication is impossible. Because the optically duplicated hologram technology has a structure having a sinusoidal or rectangular cross-sectional shape, and a display body that simultaneously displays a false stereoscopic image, which is completely different from the stereoscopic image display body of the present invention. Because it becomes. For this reason, it has a high effect on identification of counterfeit / counterfeit / replica.
In order to provide the observer with an observation image having a sufficient resolution as the display body 1, it is sufficient to make the size of an apparent pixel smaller than the discrimination ability based on the visual acuity (eye resolution) of the observer. It is. Considering normal observation conditions, it is desirable that both the vertical dimension H and the horizontal dimension W of the unit pixel 3 are 300 μm or less.

DESCRIPTION OF SYMBOLS 1 ... Display body 2A, 2B, 2C ... surface (unit pixel group)
3 ... Unit pixel 4 ... Slope (light reflecting surface)
5 ... Minute unevenness 20 ... Observer 21 ... Light source
I ... Incident light O ... Emission light H ... Vertical dimension W ... Horizontal dimension P ... Pitch D ... Height (or depth)
α: Incident angle β: Ejection angle

Claims (8)

  A display body in which a polyhedron having a plurality of planes is displayed by a plurality of unit pixel groups that are aggregates of unit pixels, the unit pixel having a plurality of light reflecting surfaces, and an observer observing the polyhedron On the other hand, the display body is characterized in that the light reflecting surface is inclined in a uniform direction with the unit pixel as a unit to form minute irregularities so that the light emission direction is different for each surface of the polyhedron.   The display body according to claim 1, wherein there are at least two kinds of the micro unevenness.   The display body according to claim 1, wherein a cross section of the minute unevenness has a sawtooth shape.   The display body according to any one of claims 1 to 3, wherein the depth or height of the minute unevenness is constant.   The display body according to claim 1, wherein a repetition pitch of the minute unevenness is constant.   The display body according to claim 1, wherein a repetition pitch of the minute unevenness is 10 μm or more.   The display body according to any one of claims 1 to 6, wherein the minute unevenness has a linear lattice structure in a plan view.   The display body according to claim 1, wherein a vertical dimension and a horizontal dimension of the unit pixel are 300 μm or less.

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