JP2002040218A - Display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display performing multicolor display having high saturation by diffracted light with a simple structure. SOLUTION: Diffraction grating patterns consisting of a number of parallel grooves are disposed and formed on the surface or in the inner part of a plate- shaped base material (a card-shaped base material, a seal-shaped base material) and the diffraction grating patterns consist of plural regions 2r, 2g, 2y and 2b having the same groove pitch p in each region and consist of plural regions 2r, 2g, 2y and 2b adjacent to each other having groove pitches p different from each other. Thereby, the diffraction light having prescribed wavelength λ different from each other in every regions 2r, 2g, 2y and 2b is emitted with a specified diffraction angle Dn to realize the display 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffraction grating which emits a diffraction grating which is attached to or integrally formed with a prepaid card, an ID card, a driver's license, a product package or the like to exhibit a forgery prevention effect and a decoration effect. The present invention relates to a display using diffracted light.

[0002]

2. Description of the Related Art Conventionally, prepaid cards, ID cards,
Attached to or integrally formed with an article such as a driver's license or a product package or the like, and used for authenticating the article, or for enhancing the decorativeness of the article, a diffraction grating (grating) or the like. A display (hereinafter, a display) using diffracted light generated by a hologram has been used.

[0003] In these displays, a diffraction grating or a hologram is formed on the surface or inside of a flat substrate made of resin or the like, and diffracted light generated when light enters from the outside is emitted to the outside. Then, a predetermined shape indicated by the shape of the diffraction grating or the hologram, such as a brand mark or a certification mark, is displayed.

If this type of display is configured to be capable of multicolor display instead of single color display, the effect of authenticity verification and decoration effect can be improved, and the function and value of the display can be improved. For example, the following configurations have been conventionally proposed as displays that perform multicolor display by diffracted light.

(1) A configuration in which a hologram having wavelength selectivity and an illuminating means for light of a specific wavelength are combined. In the above configuration, a hologram having wavelength selectivity, which emits diffracted light with respect to the incidence of light of a specific wavelength, is provided on the display side, and a plurality of illumination means having different wavelength characteristics to irradiate the display, for example, R light, A configuration is provided in which an illumination lamp of each wavelength light of G light and B light is provided, and for example, if the illumination means of R light is turned on, only a specific hologram generates a diffracted light of R light to realize a multicolor display effect. Is what you do. (Hereinafter, this will be referred to as "first related art".)

(2) A configuration in which a plurality of “primary color holograms” that emit diffracted light of the primary color wavelength are provided to obtain a predetermined hue by additive color mixing. In this configuration, a pattern composed of a plurality of pixels for representing a predetermined shape such as a brand mark is provided on a display, and each pixel has a plurality of holograms that diffract and emit primary color wavelength light such as R light, G light, and B light. It is intended to obtain a desired hue by performing additive color mixing of diffracted light by changing the area ratio of the primary color hologram in each pixel. (Hereinafter, this will be referred to as "second related art".)

(3) A configuration in which a point which appears to be colored by diffracted light when observed from a moving observation point moves. This configuration is described in Japanese Patent Application Laid-Open No. 7-84110, and is hereinafter referred to as "third prior art". As shown in FIG. 7, the diffraction grating according to the third related art is configured by filling the inside of a shape pattern such as a character or a figure to be displayed with a diffraction grating, and a display including the shape pattern is connected to an external device. When the angle is changed relative to the light source or the observation point (viewpoint), the brightness or color displayed by the shape pattern is changed by the diffracted light. FIG.
In the illustrated example, the inside of the pattern 100 having a T-shape is divided into several blocks, and the orientation, pitch, and line width of the diffraction grating (the adjacent distance between the peripheral edges of the grooves forming the diffraction grating) are divided into blocks. ) Is changed. The directions of the diffraction gratings of the respective blocks included in the upper horizontal line pattern 101 of the T-shaped pattern 100 are all perpendicular to the illumination incident direction and the diffracted light observation direction (the direction in which the observer has a viewpoint) illustrated in FIG. Since the pitches of the diffraction gratings are equal, the observer can observe the diffracted light of the entire pattern. Further, since the line width of the diffraction grating is changed for each block, the intensity of the diffracted light can be changed according to the line width. In the example shown in FIG. Is also displayed darkly. In each block in the T-shaped central vertical line pattern 102, the pitch and line width of the diffraction grating are equal, but the angles of the grooves forming the diffraction grating are different from each other. Therefore, when the entire T-shaped pattern 100 is rotated clockwise or counterclockwise in parallel to the plane of the paper, only a block which is perpendicular to the illustrated illumination incident direction and the diffracted light observation direction at a certain moment emits diffracted light. Inject in the direction of the observer's viewpoint. That is, the glowing block appears to move from top to bottom or from bottom to top in accordance with the rotation of the T-shaped pattern 100, and the decoration effect is improved.

[0008]

The configuration according to the above-described prior art, which is a display for displaying a multi-color image using diffracted light, has the following problems to be solved.

First, the above-described configuration according to the first prior art requires a display having a hologram having wavelength selectivity and illumination means of a specific wavelength. Although it can be implemented in places where special lighting means can be prepared as described above, there is a method of using a card with a sticky display attached to it in multicolor display under ordinary light such as sunlight or fluorescent lighting. Could not be realized.

Further, in the configuration according to the above second prior art, since a predetermined hue is obtained by additive color mixing of diffracted light of primary colors such as R light, G light and B light, precise color mixing is performed. It is necessary to adjust the ratio to obtain a predetermined hue, resulting in a complicated structure. In addition, since the color is not generated by pure color light (single wavelength light), the saturation may not be sufficient.

Further, according to the configuration according to the third conventional technique, since the observation point is moved while the display is observed as described above, when the observation point is fixed, Blocks in the pattern appear to be partially missing or the color display is unclear, making it difficult to display the entire pattern in color.

Accordingly, the present invention provides a diffraction grating pattern comprising a large number of parallel grooves, which is formed on the surface or inside of a flat substrate, and diffracts light having a wavelength corresponding to the pitch of the grooves.

(Equation 2) A display that emits light with a specific diffraction angle based on the diffraction grating pattern, the diffraction grating pattern is composed of a plurality of regions, and has the same groove pitch in the same region, but has different groove pitches in adjacent regions. The structure is such that the diffracted light of a predetermined wavelength different for each is emitted at a specific diffraction angle, so that when viewed from a predetermined observation point (viewpoint), the entire display performs multicolor display, and the display is good. It is an object of the present invention to provide a display having a high saturation and a simple configuration. Here, D _n : diffraction angle, n: diffraction order, λ: diffracted light wavelength,
p: pitch of the diffraction grating.

[0013]

In order to solve the above-mentioned problems, the present invention provides a display having the following constitutions (1) and (2). (1) A diffraction grating pattern composed of a number of parallel grooves is formed on the surface or inside of a flat base material (card-like base material, seal-like base material) and diffracted at a wavelength λ according to the pitch p of the grooves. the light,

(Equation 3) A Based particular display emitted with a diffraction angle D _n (pre-paid cards, ID cards, proof seal) A, the diffraction grating pattern is a plurality of regions 2r, 2
g, 2y, and 2b and have the same groove pitch in the same region, but different groove pitches in adjacent regions, and have different predetermined wavelengths λ for the regions 2r, 2g, 2y, and 2b. display 1, characterized in that for emitting the diffracted light with a said specific diffraction angle D _n. Where D
_n : diffraction angle, n: diffraction order, λ: diffracted light wavelength, p: diffraction grating pitch. (2) The diffraction grating pattern includes the respective regions 2r, 2r
g, 2y, and 2b, the width of the groove (diffraction grating pitch and diffraction grating) with respect to one pitch (diffraction grating pitch) P of the groove so as to set the diffracted light emitted from g, 2y, and 2b to a desired intensity (first-order diffraction light intensity ratio). 2. The display 1 according to claim 1, wherein a difference from the line width (PW) is set.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS. 1 is a plan view of the display of the present embodiment, FIG. 2 is a layout diagram of the display of the present embodiment, FIGS. 3 to 5 are schematic cross-sectional views of the display of the present embodiment in the vicinity of the diffraction grating,
FIG. 6 is a characteristic diagram showing a change in the diffracted light intensity when the ratio between the diffraction grating pitch and the line width in the display of this example is changed.

Now, in a diffraction phenomenon using a diffraction grating,
It is well known that the diffraction angle, the diffraction order, the wavelength of the diffracted light, and the pitch of the diffraction grating satisfy the relationship of the following expression (1).

(Equation 4) Here, D _n is the diffraction angle, n is the diffraction order, and n = ± 1, ± 2.
± 3 ..., λ is the wavelength of the diffracted light, and p is the pitch of the diffraction grating.

In the display 1 of this embodiment, the pitch of the diffraction grating is calculated based on the above equation (1) so as to display a desired color, and the display is designed. A design procedure of the display 1 having a multicolor display pattern as shown in FIG. 2, which is a layout diagram of the display 1 of this embodiment, will be specifically described below.

First, for convenience, a basic diffraction grating pitch, wavelength, and diffraction order, which are starting points for design, are set. In the following description, the pitch of the diffraction grating is set to 1.
10 μm (p = 1.10 in equation (1)), wavelength 0.52 μm green (λ = 0.52 in equation (1)),
The order of the observed diffracted light is represented by the primary light (in the equation (1), n =
Set to 1).

By substituting these values into equation (1), a diffraction angle of 28.2 degrees is obtained. That is, as shown in FIG. 3, which is a cross-sectional view of a principal part for explaining a diffraction phenomenon in the display of this embodiment, white illumination light is vertically incident on a diffraction grating, and a direction at an angle of 28.2 degrees with respect to a vertical line. When observed from the viewpoint in the above section, green light of 0.52 μm is observed. "Green" in Fig. 2 which is the layout diagram of the display
The green display portion marked with is filled with a diffraction grating having a pitch of 1.10 μm.

Further, in order to display a portion of a color other than green in the layout diagram of FIG. 2 with the color specified in FIG. 2,
At the same diffraction angle of 28.2 degrees, all the other diffraction gratings are arranged in parallel with the basic diffraction grating so that the diffracted light of the designated color (at the wavelength) is emitted. Find the pitch.

Specifically, in the layout diagram of FIG.
In order to obtain the pitch of the blue display portion described as follows, λ = 0.42 μm (blue), n = 1, D ₁ = 2
8.2 may be substituted to calculate p, and p = 0.90
μm. In a similar manner, yellow (λ = 0.56 μm),
When the pitch p is determined for red (λ = 0.66 μm),
Yellow, p = 1.20 μm, red, p = 1.40 μm
Becomes FIG. 1 shows a plan view of a display 1 in which a diffraction grating is formed according to the layout shown in FIG. 2 using the pitch calculated above. As shown in FIG. 1, the display 1 is configured by laying out diffraction gratings having pitches corresponding to respective colors so as to fill the pattern. Then, the directions of all the diffraction gratings are arranged in parallel to diffract at the same diffraction angle. That is, in the layout diagram of FIG. 2, the region 2b has p = 0.90 μm and the region 2g has p = 0.90 μm.
1.10 μm, region 2y has p = 1.20 μm, region 2r
Is filled with a diffraction grating of p = 1.40 μm,
Blue, green, yellow,
Red color is observed. In addition, since the above-described diffraction gratings are all formed by grooves provided in the same direction, there is no problem that the color development of a part of the display 1 cannot be observed when the display 1 is observed. When the display 1 is specifically configured, for example, in a display having a configuration in which a diffraction grating is provided directly on the surface of an ID card, the diffraction grating according to the above design is provided on the surface of a card-shaped base material made of a material such as resin. Form. In a display using a transparent resin material as a base material, a structure in which a diffraction grating is formed inside the base material may be adopted. In a configuration in which the display is formed as a seal-shaped display, and the seal-shaped display is affixed to a card, a license, a product package, or the like, the display is formed in the same manner as the above-described base material. The diffraction grating is
The display of this embodiment can be configured by the above-described design method and configuration in any of the reflection type that emits diffracted light as reflected light and the transmission type that emits diffracted light as transmitted light.

Next, the details of the diffraction phenomenon in the display 1 of this embodiment will be described below. FIG. 4 is a cross-sectional view of a main part of the display 1 shown in FIG. FIG. 4 shows an example in which the illumination light 4b is perpendicularly incident on the diffraction grating 4a. In this case, the incidence angle of the illumination light 4b is equal to the emission angle, and when observed at an angle of 28.2 degrees with respect to the emission angle, a multicolor display as shown in the layout diagram of FIG. 2 is observed.

The angle of incidence of the illumination light on the diffraction grating is not necessarily required to be vertical, but may be any angle. FIG. 5 shows an example in which illumination light enters at an arbitrary angle and diffracted light exits. In this case, when observed at an angle of 28.2 degrees with respect to the direction of the reflected light (zero-order light) 5b of the illumination light 5a, the multicolor display shown in the layout diagram of FIG. 2 is observed.

In this embodiment described above, the basic diffraction grating pitch is 1.10 μm and the wavelength is 0.5
Although it is set to 2 μm, it is possible to cope with the case where the diffraction angle is set to be larger, by setting the pitch smaller. Conversely, when the diffraction angle is set smaller, the pitch is set larger. Just set it.

In the present embodiment, the brightness of the diffracted light, which is the display light of the diffraction grating pattern in the display 1, is determined by fixing the pitch of the diffraction grating and the line width of the diffraction grating (the peripheral portion of the groove forming the diffraction grating). (Adjacent distances between adjacent pixels) can be controlled to a desired strength. This will be described below.

By converting the step of the diffraction grating into a phase distribution with the optical depth π and performing Fourier transform, the ratio of the ratio of the line width (W) to the pitch (P) in the diffraction grating cross-sectional view as shown in FIG. The intensity ratio of the first-order diffracted light to the change can be obtained by calculation. FIG. 6 shows the calculation results. In FIG. 6, the horizontal axis is the ratio of the line width to the pitch of the diffraction grating (W / P), and the vertical axis is the first-order diffracted light intensity ratio normalized with the maximum intensity being 1.

As shown in FIG. 6, when W / P = 0.5,
It can be seen that the maximum diffraction light intensity (intensity ratio 1.0) is obtained. Further, when W / P = 0.3, the intensity ratio is 0.8, and W / P =
0.2, intensity ratio 0.6, W / P = 0.12, intensity ratio 0.4, W / P = 0.06, intensity ratio 0.2, W
When / P = 0, the intensity becomes zero. By referring to this value and fixing the pitch of the diffraction grating and changing the line width to set an arbitrary value, it is possible to configure a display in which diffracted light is set to a desired intensity. . In other words, the light is emitted by fixing the pitch (P) of the diffraction grating and configuring the groove width (difference between the pitch and the line width, PW) as a predetermined value for realizing a desired diffracted light intensity. The intensity of the diffracted light can be set to a desired value.

[0027]

As described in detail above, the present invention particularly provides a diffraction grating pattern comprising a large number of parallel grooves arranged on the surface or inside of a flat substrate, and diffracts light having a wavelength corresponding to the pitch of the grooves. ,

(Equation 5) A display that emits light with a specific diffraction angle based on the diffraction grating pattern, the diffraction grating pattern is composed of a plurality of regions, and has the same groove pitch in the same region, but has different groove pitches in adjacent regions. The structure is such that the diffracted light of a predetermined wavelength different for each is emitted at a specific diffraction angle, so that when viewed from a predetermined observation point (viewpoint), the entire display performs multicolor display, and the display is good. It is possible to provide a display having a high saturation and a simple configuration. Where D
_n : diffraction angle, n: diffraction order, λ: diffracted light wavelength, p: diffraction grating pitch.

[Brief description of the drawings]

FIG. 1 is a plan view of a display according to an embodiment of the present invention.

FIG. 2 is a layout diagram of a display according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view near a diffraction grating in a display according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view near a diffraction grating in a display according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view near a diffraction grating in a display according to an embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a change in diffracted light intensity when the ratio between the diffraction grating pitch and the line width is changed in the display according to one embodiment of the present invention.

FIG. 7 is a plan view of a prior art display.

[Explanation of symbols]

1 Display 2r, 2g, 2y, 2b Region of diffraction grating pattern (region) D _n Diffraction angle λ Wavelength of diffracted light p, P Pitch of diffraction grating W Line width W / P Ratio of pitch and line width of diffraction grating P− W Difference between diffraction grating pitch and line width (groove width) P / W Ratio between diffraction grating pitch and line width

Claims (2)

[Claims] 1. A diffraction grating pattern comprising a plurality of parallel grooves is formed on the surface or inside of a flat substrate, and diffracted light having a wavelength corresponding to the pitch of the grooves is expressed by the following equation. A display that emits with a specific diffraction angle based on the diffraction grating pattern, the diffraction grating pattern includes a plurality of regions, and has the same groove pitch in the same region, but has a different groove pitch in adjacent regions, A display, wherein diffracted light having a predetermined wavelength different for each region is emitted at the specific diffraction angle. Here, D _n : diffraction angle, n: diffraction order, λ: diffraction light wavelength, p: diffraction grating pitch. 2. The diffraction grating pattern according to claim 1, wherein the width of the groove relative to one pitch of the groove is set such that the intensity of the diffracted light emitted from each of the regions is set to a desired intensity. Display as described.