JP2007203568A - Display and display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display body which is composed of a surface relief-type diffraction grating or hologram, which hardly causes a color change and the blurring of an image, which enables the stable observation of a multicolor image (particularly, a full-color image), which exerts a high anticounterfeit effect and which facilitates the determination of truth or falsehood, and a display unit. <P>SOLUTION: This display body is a plate-like one in which a plurality of planar light guide bodies are laminated together. The front-side planar part and/or backside planar part of each light guide body is equipped with the surface relief-type diffraction grating or hologram, which displays the image by grating the guided light and emitting light from the light guide body. The display body displays the multicolor image, which is composed of the sum of reproduction information brought about by diffracted light (image display light) from the diffraction grating or the hologram, by guiding the light with a predetermined wavelength to each light guide body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement in a display body and a display device comprising a surface relief type diffraction grating or hologram.

  Display bodies composed of surface relief type diffraction gratings or holograms are widely used mainly for security applications. These displays realize three-dimensional image display using diffracted light under general lighting conditions such as sunlight and fluorescent lamp lighting, but the color changes to iridescent due to the spectral action during diffraction. It is called a rainbow hologram because it can be seen. (For example, see Patent Document 1)

On the other hand, a hologram incorporating a light source includes a multiplex hologram.
In a multiplex hologram, a stereoscopic image can be observed from a 360 degree direction in the horizontal direction by combining a cylindrical hologram and a point-like illumination light source. (For example, see Patent Document 2)

JP-A-5-88600 JP-A-8-70974

However, in a display body composed of a general surface relief type diffraction grating or hologram, the display image observed depends on the illumination conditions, and a stable display image can be obtained with color change and image blurring. difficult.
In particular, illumination conditions and observation conditions for full color display are extremely limited, and it is extremely difficult to observe a good full color image. Also, in security applications, the forgery prevention effect is decreasing due to the widespread use of this type of diffraction technology.

  On the other hand, a type such as a multiplex hologram incorporating a light source has a large size of a hologram and an illuminating device, impairs portability, and uses are extremely limited. Also in this case, the observation conditions for full color display are extremely limited, and it is very difficult to observe a good full color image.

  Further, in any of the above display bodies, stereoscopic image display with horizontal parallax is common, and it is difficult to provide parallax in the vertical direction in a surface relief type diffraction grating or hologram.

The present invention has been made in view of such circumstances, and an object of the present invention is to stably observe a multicolor image (particularly, a full-color image) by a diffraction grating or a hologram while being a plate having excellent portability. An object of the present invention is to provide a display body and a display device with improved security.
In particular, in the stereoscopic image display, not only the horizontal direction but also the vertical direction parallax can be realized.

The display according to the present invention is
A plate-like body in which a plurality of planar light guides are laminated,
A surface relief type diffraction grating or hologram for diffracting light to be guided and displaying an image by emitting light from the light guide on the front and / or back plane of each light guide,
By guiding light having a predetermined wavelength to each light guide, a multicolor image composed of a reproduction information sum by diffracted light (image display light) from the diffraction grating or hologram is displayed. And

A display device using the display body according to the present invention,
It is characterized in that the same number of light sources having different wavelengths are installed at the side end of each light guide in the display body.

Hereinafter, an average light traveling direction (F in the figure) when light is guided through a planar light guide will be described as a leading light direction.
According to the first aspect of the present invention, a plurality of light guides each having a diffraction grating or a hologram are provided, and light having a predetermined wavelength is guided to each light guide, thereby providing stable multicolor display. It is possible.
Further, by guiding light of a predetermined wavelength to each light guide, a spectroscopic phenomenon at the time of diffraction does not occur, and a high-quality display image of always stable color with very little blur can be obtained.
Furthermore, as a display image, a stereoscopic image having a parallax in a direction orthogonal to the main light direction can be displayed, and a stereoscopic image having a parallax can also be displayed in a direction parallel to the main light direction.
At this time, by providing a coating layer having a lower refractive index than the material constituting the light guide on the front and back of the planar portion of each light guide, avoid mixing light guided in each light guide in advance. Multi-color display with the set color can be realized reliably.
Due to the above effects, the display result according to the present invention can be used for reliable authenticity determination, and further, forgery, imitation, and alteration are extremely difficult due to the laminated structure of the light guides on which diffraction gratings or holograms are formed. Therefore, a display body with extremely high security can be provided.
In addition, since the diffraction grating or hologram of each light guide is a surface relief type, high-mass productivity techniques such as embossing and injection molding can be used, and it can be configured at low cost.

  According to the second aspect of the invention, before the light guided (propagating) through the light guide reaches diffraction (image display) by the diffraction grating or hologram, crosstalk between the light guides is eliminated. It is effective in.

  According to the invention of claim 3, by guiding light of wavelengths corresponding to R, G, and B with the three light guides, images of preset colors are respectively obtained from the respective light guides. A full-color image that is displayed and reproduced with a preset color expressed as a whole can be obtained with certainty.

  According to the fourth aspect of the present invention, when displaying a stereoscopic image, the difference in position in the thickness direction of each light guide in the display body is diffracted in advance for the position of the image to be reproduced for each light guide. By compensating at the position in the depth direction of the image to be recorded on the grating or hologram, the position in the depth direction of the three-dimensional image of each color displayed from each light guide accurately matches, and there is no color shift in the depth direction, A high-quality multicolor stereoscopic image can be obtained.

  According to the invention of claim 5, since the display body is card-like and the printed display layer is provided on the front surface and / or the back surface, the display under general illumination conditions by printing and the light guide body In addition, it is possible to use in combination with the display when light is guided, and reliable authentication can be performed in a very short time. In particular, by performing printing on the back surface, the contrast between the image displayed by the diffraction grating or the hologram and the printed image can be emphasized, and a further visual effect can be obtained. Further, by associating the front / back printed image and the display image by the diffraction grating / hologram, the authenticity determination can be more easily ensured.

  According to the invention which concerns on Claim 6, it is set as a simple structure using light sources, such as cheap LED, by installing the same number of the light sources from which a wavelength respectively differs in the side edge part of each light guide. The effect which the display body of Claims 1 thru | or 4 has can be exhibited reliably.

  According to the invention of claim 7, a plurality of light sources are arranged side by side in a direction orthogonal to the thickness direction of the display body, and the side end portions of the respective light guides are shielded except for portions corresponding to the positions of the respective light sources. By being covered with the material, the display body can be thinned, and light can be easily incident on the light guide, which can be reliably realized, and a high-quality image display can be obtained very easily.

  According to the invention which concerns on Claim 8, a spectroscopic element is arrange | positioned between the side edge part of each light guide of a display body, and a white light source, and it presets in each light guide among the light which dispersed by the spectroscopic element. Since the light source, the spectroscopic element, and the light guides are arranged so that light of the specified wavelength is incident, the effect of the display body can be realized with only one light source, and a very inexpensive display device is configured. it can.

  According to the ninth aspect of the present invention, the lens for condensing light is disposed between the light source and each light guide in the thickness direction of the light guide, and the side end of the light guide near the light collection position of the lens. By arranging the portion, the light emitted from the light source can be effectively incident on the light guide, and a bright display with high light utilization efficiency can be performed.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing a cross section of a display body of the present invention.
FIG. 2 is a perspective view illustrating a configuration example of the display body and the display device of the present invention.

  In the display according to the present embodiment, diffraction gratings or holograms 21, 22, and 23 made of surface relief are formed on the three light guides 11, 12, and 13, respectively. ing. For example, light incident on the light guide 12 from the side surface from the light source 32 is guided in the leading light direction F while being totally reflected in the light guide, and diffracted light 62 is generated by the diffraction grating or the hologram 22 in the observation direction D. Light emitted from the light guide toward the display, that is, display light can be obtained.

At this time, the diffracted light 62 passes through the diffraction grating / hologram 21 and the like, but only a part of the diffracted light 62 is disturbed, and the display image is not greatly affected.
In particular, when it is desired to improve the image quality and brightness of the display image, the diffraction grating / holograms 21, 22, and 23 are formed as a collection of stripe-shaped or cell-shaped areas. It is only necessary to arrange the areas so that they do not become. If the stripe-like or cell-like region is sufficiently small with respect to the resolution of the observer's eyes, a satisfactory display image can be observed without substantially affecting the resolution.

Further, since the light sources 31, 32, and 33 having different wavelengths are used for the light guides 11, 12, and 13, respectively, the display light is a multicolor image expressed by a mixed color of three wavelengths. By selecting the wavelengths corresponding to R, G, and B as the wavelengths of the light sources 31, 32, and 33, the display image can be made full color.
Moreover, as a display image, a plane image, a three-dimensional image, etc. can be selectively used by the function of a diffraction grating or a hologram. For example, it is possible to display a full-color stereoscopic image with parallax in the vertical and horizontal directions with reference to the observation direction D.

  Here, when an accurate stereoscopic image is displayed, a difference in depth is likely to occur when observed from the observation direction D due to a difference in position in the thickness direction of the diffraction gratings / holograms 21, 22, and 23. In this case, if the reproduction position of the stereoscopic image recorded on the diffraction grating / holograms 21, 22, 23 is set so as to compensate for the difference in position in the thickness direction, the diffraction grating / holograms 21, 22, 23 The display image can be completely matched in the depth direction.

  In the present invention, “wavelength” is used to mean not only a single wavelength but also a wavelength distribution with a band. Therefore, an LED light source or the like can be used as the light sources 31, 32, and 33, and a compact display device can be realized.

The covering layer 10 is made of a material having a refractive index lower than that of the light guides 11, 12, and 13, and can efficiently guide light without mixing light incident on the respective light guides.
At this time, by covering the front and back of the light guides 11, 12, and 13 layered with the coating layer 10, scratches and dirt on the light guides 11, 12, and 13 can be prevented, and over a long period of time. And good display can be obtained.
In addition, as for the material of the light guides 11, 12, 13 and the coating layer 10, a material with high transparency is desirable. Thereby, the attenuation of the light 52 to be guided can be suppressed, the diffracted light 62 passing through the light guide and the coating layer can be effectively emitted, and a bright display image can be obtained.
For example, when polycarbonate is used as the material of the light guide and PMMA is used as the coating layer, both the transparency can be increased and a refractive index difference of about 0.1 can be obtained, so that the display of the present invention can be easily configured. Further, when the coating layer between the light guides is air, a larger refractive index difference can be given between the light guides and it becomes easier to guide light more efficiently.

FIG. 3 shows an example in which the display body of the present invention is formed in a card shape.
FIG. 4 shows a configuration example in which printed layers and magnetic stripes are provided on the front and back of a card-like display body. FIGS. 5 and 6 show the display body shown in FIG. 4 in a regenerator 80 incorporating light sources 31, 32, and 33. It is an example of a structure which was made into an insertion and a display apparatus.

A card shape is formed of a plastic material or the like so as to cover the light guides 11, 12, and 13, thereby forming a card 70. Of course, the material forming the card shape may also serve as the coating layer 10.
However, as shown in the figure, the incident end face needs to be exposed at the card end so that light can enter.

It is possible to print on the front and back of the card 70, and it is possible to adopt a usage pattern suitable for security applications by providing design properties or describing information. As shown in the figure, a magnetic stripe (black portion at the top of the card) and embossing (numeral portion) can be used in combination, but it is preferable that the position does not overlap with the light guide.
Printing can be performed on the entire surface of the card 70, and the display light by the diffracted light can be made more prominent by printing dark or dark on the back surface.
When printing on the surface of the card 70, it is preferable that characters, logo marks, and the like are printed on the display areas of the diffraction grating / holograms 21, 22, and 23. However, the entire area is printed with diffracted light. You can also produce the uplift of.
In addition, as shown in the figure, by associating the printed pattern (“壺”) with the display images (“stars”) by the diffraction gratings / holograms 21, 22, and 23, it is possible to prompt the observer 90 to easily determine the authenticity. It is also possible to do this.
Note that the “star” in FIG. 6 expresses the sensation that the stereoscopic image appears to the observer.

7 and 8 show an example in which the display images by the diffraction grating / holograms 21, 22, and 23 are planar images. In particular, in the case of a planar image, a high-luminance display image can be obtained, and the eye catching effect can be enhanced.
In addition, when the card 70 is carried alone, display images by the diffraction grating / holograms 21, 22, and 23 are not observed, and an accurate multicolor image is displayed when the dedicated player 80 is used. In addition, an accurate determination can be performed while intuitively and instantaneously performing authentication determination.

FIG. 9 shows a configuration example of the display body and the display device when the thickness of the light sources 31, 32, and 33 is thicker than the thickness of the light guide bodies 11, 12, and 13.
FIG. 10 is a diagram illustrating a relationship between the light source and the light guide plate as viewed from the incident end side of the light guide, and FIG. 11 is a diagram illustrating an arrangement example of the light shielding layer 40 as viewed from the incident end side of the light guide.
A light shielding layer 40 is disposed between the light source and the light guide so that the light from the light sources 31, 32, and 33 is incident on the light guides 11, 12, and 13 independently of each other regardless of the size of the light source. I have to. Thereby, a stable display image can be obtained even if the display body is thinned.

  FIG. 12 shows a configuration example of the display device of the present invention in which a white light source is used as a light source and a spectroscopic element is arranged between the light guide. A diffraction grating or the like can be used as the spectroscopic element. In this case, a display device can be simply configured with only one light source.

FIG. 13 is a configuration example of a display device that uses a cylindrical lens so that convergent light is incident on a light guide. In this case, the light from the light source can be incident on the light guide without loss, and the light utilization efficiency can be improved.
In addition, it is possible to obtain a bright display image by using a combination of a white light source and a spectroscopic element to increase the incident efficiency to the light guide body with a simple configuration.

As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to this structure.
Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The side view which showed the cross section in the display body of this invention. The perspective view which shows the structural example in the display body and display apparatus of this invention. The perspective view which shows the card-like structural example of the display body of this invention. The top view which shows the card-like structural example of the display body of this invention. FIG. 6 is a top view illustrating a display example in the display body and the display device of the present invention. Explanatory drawing which shows the example of a display in the display body and display apparatus of this invention. The top view which shows another card-like structural example of the display body of this invention. The top view which shows another example of a display in the display body and display apparatus of this invention. The perspective view which shows another structural example in the display apparatus of this invention. FIG. 10 is a side view of the incident side in the configuration example of FIG. 9. Explanatory drawing of the light shielding layer in the structural example of FIG. The side view which shows the structural example using the spectroscopic element in the display apparatus of this invention. The side view which shows the structural example using the cylindrical lens in the display apparatus of this invention.

Explanation of symbols

  F ... Average light guide direction, D ... Observation direction, 11, 12, 13 ... Light guide, 21, 22, 23 ... Diffraction grating or hologram, 30 ... White light source, 31, 32, 33 ... Light source of specific wavelength, 40 ... light shielding layer, 50 ... white light, 51, 52, 53 ... light being guided, 61,62,63 ... diffracted light (display light), 70 ... card, 80 ... regenerator, 82 ... spectral element, 84 ... Cylindrical lens array, 90 ... observer

Claims (9)

A plate-like body in which a plurality of planar light guides are laminated,
A surface relief type diffraction grating or hologram for diffracting light to be guided and displaying an image by emitting light from the light guide on the front and / or back plane portion of each light guide,
By guiding light having a predetermined wavelength to each light guide, a multicolor image composed of reproduction information sum by diffracted light (image display light) from the diffraction grating or hologram is displayed. Display body.   2. The display body according to claim 1, further comprising a covering layer made of a material having a refractive index lower than that of the material constituting the light guide body between the light guide bodies.   The full-color image is displayed by using three light guides as a plurality of light guides and guiding light having wavelengths corresponding to R, G, and B, respectively. The display body.   The display image is a stereoscopic image, and the difference in the thickness direction position of each light guide in the display body, the depth direction of the image in which the position of the image to be reproduced for each light guide is recorded in advance on the diffraction grating or hologram The display body according to claim 1, wherein the display body is compensated at the position.   The display body according to any one of claims 1 to 4, wherein the display body has a card shape, and a printed display layer is provided on a front surface and / or a back surface.   6. A display device comprising: a light source having the same number of different light sources as the light guide at the side end of each light guide in the display body according to claim 1. At the side end of each light guide, the light sources are arranged in a direction orthogonal to the thickness direction,
The display device according to claim 6, wherein a side end portion of each light guide is covered with a light shielding material except a portion corresponding to a position of each light source. Disposing the display body according to any one of claims 1 to 5 and a white light source, disposing a spectroscopic element between a side end of each light guide body of the display body and the light source,
A display device comprising: a light source, a spectroscopic element, and each light guide so that light having a predetermined wavelength is incident on each light guide among light emitted from the light source and dispersed by the spectroscopic element .   A lens that collects light in the thickness direction of the light guide is disposed between the light source and each light guide, and a side end portion of the light guide is disposed in the vicinity of the light collection position of the lens. The display device according to claim 6.

Images