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EP-3761074-B1 - DISPLAY BODY, TRANSFER FOIL, ADHESIVE LABEL, AND ARTICLE WITH DISPLAY BODY

EP3761074B1EP 3761074 B1EP3761074 B1EP 3761074B1EP-3761074-B1

Inventors

  • MASUNAGA, YUKO
  • NAGANO, AKIRA
  • KAMATA, Yasumasa
  • HONMA, HIDEAKI

Dates

Publication Date
20260506
Application Date
20190116

Claims (7)

  1. A display (1) comprising a plurality of pixels (PX) each including a plurality of first subpixels (SPX1) and a plurality of second subpixels (SPX2), wherein the display comprises a relief structure forming layer (11) having a relief structure on a surface thereof, and a reflective layer (12) covering the surface, the relief structure is provided with a diffraction grating at an interface between the relief structure forming layer and the reflective layer, or on a surface of the reflective layer, in each of the plurality of pixels (PX), when illumination light is applied to the plurality of first subpixels (SPX1) from a normal direction, no diffracted light emerges from the plurality of first subpixels, or first diffracted light emerges from the plurality of first subpixels in a first angular range, and when the illumination light is applied to the plurality of second subpixels (SPX2) from the normal direction, no diffracted light emerges from the plurality of second subpixels, or second diffracted light having a wavelength equal to that of the first diffracted light emerges from the plurality of second subpixels in a second angular range wider than the first angular range, an angular range indicates a difference between the maximum and minimum values of the angles of the length directions of crests or troughs of the diffraction grating provided to the subpixels, relative to the lateral direction of the display, the plurality of pixels (PX) are configured to display a continuously changing image using the first diffracted light and the second diffracted light, the continuously changing image referring to an image in which position and/or shape continuously changes when the angle of the display is continuously changed relative to the illumination direction and the observation direction, with these directions being maintained constant, and wherein the display has the following feature (i) or (ii): (i) second diffracted light having a wavelength equal to that of the first diffracted light emerges from the plurality of second subpixels in the second angular range at an intensity lower than that of the first diffracted light; (ii) the plurality of first subpixels included in each of the plurality of pixels include two or more first subpixels in which emergence angles of the first diffracted light are different from each other; the plurality of second subpixels included in each of the plurality of pixels include two or more second subpixels in which emergence angles of the second diffracted light are different from each other, and a minimum value of difference between emergence angles of the first diffracted light emerging from the two or more first subpixels is smaller than a minimum value of difference between emergence angles of the second diffracted light emerging from the two or more second subpixels, characterised in that each second subpixel (SPX2) is designed to have an area (S2) smaller than the area (S1) of each first subpixel (SPX1).
  2. The display according to claim 1, which has feature (i) and wherein the plurality of first subpixels included in each of the plurality of pixels include two or more first subpixels in which emergence angles of the first diffracted light are different from each other; the plurality of second subpixels included in each of the plurality of pixels include two or more second subpixels in which emergence angles of the second diffracted light are different from each other; and a minimum value of difference between emergence angles of the first diffracted light emerging from the two or more first subpixels is smaller than a minimum value of difference between emergence angles of the second diffracted light emerging from the two or more second subpixels.
  3. The display according to claim 1, which has feature (i) and wherein the plurality of pixels each further include a plurality of third subpixels; in each of the plurality of pixels, when the illumination light is applied to the plurality of third subpixels from the normal direction, no diffracted light emerges from the plurality of third subpixels, or third diffracted light having a wavelength equal to that of the first diffracted light emerges from the plurality of third subpixels in a third angular range adjacent to the second angular range with the first angular range sandwiched therebetween, at an intensity lower than that of the first diffracted light; and the plurality of pixels are configured to display a continuously changing image using the first diffracted light, the second diffracted light and the third diffracted light; and wherein preferably the first area S1 of each of the plurality of first subpixels is larger than a third area S3 of each of the plurality of third subpixels.
  4. The display according to claim 3, wherein the plurality of first subpixels included in each of the plurality of pixels include two or more first subpixels in which emergence angles of the first diffracted light are different from each other; the plurality of second subpixels included in each of the plurality of pixels include two or more second subpixels in which emergence angles of the second diffracted light are different from each other; the plurality of third subpixels included in each of the plurality of pixels include two or more third subpixels in which emergence angles of the third diffracted light are different from each other; and a minimum value of difference between emergence angles of the first diffracted light emerging from the two or more first subpixels is smaller than a minimum value of difference between emergence angles of the second diffracted light emerging from the two or more second subpixels and a minimum value of difference between emergence angles of the third diffracted light emerging from the two or more third subpixels; and wherein preferably the first area S1 of each of the plurality of first subpixels is larger than a third area S3 of each of the plurality of third subpixels.
  5. The display according to claim 1, which has feature (ii) and wherein the plurality of pixels each further include a plurality of third subpixels; in each of the plurality of pixels, when the illumination light is applied to the plurality of third subpixels from the normal direction, no diffracted light emerges from the plurality of third subpixels, or third diffracted light having a wavelength equal to that of the first diffracted light emerges from the plurality of third subpixels in a third angular range adjacent to the second angular range with the first angular range sandwiched therebetween; the plurality of pixels are configured to display a continuously changing image using the first diffracted light, the second diffracted light and the third diffracted light; the plurality of third subpixels included in each of the plurality of pixels include two or more third subpixels in which emergence angles of the third diffracted light are different from each other; and a minimum value of difference between emergence angles of the first diffracted light emerging from the two or more first subpixels is smaller than a minimum value of difference between emergence angles of the third diffracted light emerging from the two or more third subpixels; and wherein preferably the first area S1 of each of the plurality of first subpixels is larger than a third area S3 of each of the plurality of third subpixels.
  6. The display according to claim 1, wherein a ratio of the first area S1 to the second area S2 expressed by S1/S2 is 1.2 or more.
  7. The display according to any one of claims 3, 4 and 5, wherein a ratio of the first area S1 to the second area S2 expressed by S1/S2, and a ratio of the first area S1 to the third area S3 expressed by S1/S3 are each 1.2 or more.

Description

[Technical Field] The present invention relates to a display, a transfer foil, an adhesive label, and an article having a display. [Background Art] Relief holograms which are difficult to counterfeit or replicate have been used for proving articles, such as commercial products, as being genuine products. Relief holograms include a plurality of relief diffraction gratings. The colors or angles of diffracted light emerging from relief holograms can be appropriately determined according to the pitch or length directions of the troughs. Accordingly, appropriately designed relief holograms can display an image whose shape and/or position change with changes of illumination or observation direction, e.g., can display a continuously changing image such as an animated image or stereoscopic image (three-dimensional image) (JP H6-281804 A and JP H7-104211 A). Furthermore, US 5 032 003 A1 describes an optically variable surface divided into grating elements. Each grating element is divided into at least two sub-portions. [Summary of the Invention] Relief holograms, which are designed to display a continuously changing image in a narrow angular observation range, can display a clear image across this angular range. However, the inventors of the present invention have found that the observers may have a feeling of unease observing an image displayed by relief holograms which are designed to display a continuously changing image in a wide angular observation range, in particular, relief holograms which are designed to greatly change shape and/or position of an image with changes of illumination or observation direction. The present invention aims to display a continuously changing image in a wide angular range without causing a feeling of unease to observers. According to the present invention, there is provided a display as defined in appended claim 1. The "continuously changing image" refers to an image in which position and/or shape continuously changes when the angle of the display is continuously changed relative to the illumination direction and the observation direction, with these directions being maintained constant. The "continuously changing image" may also be referred to as an "animation". The display presenting the "continuously changing image" is designed to sequentially display images which are slightly different in position and/or shape when the angle of the display is continuously changed relative to the illumination direction and the observation direction. The "continuously changing image" refers to an image in which an initially displayed image fades out and an image slightly different in position and/or shape from the initial image fades in, when the observation direction is slightly changed with the illumination direction being maintained constant, and changes of these images are visually recognized as a continuous change. The "continuously changing image" includes an animated image, stereoscopic image and the like. In the above display, one or more subpixels included in each pixel are used as a part of an image (pixel elements) to be perceived by the observer, when the angle of the display relative to the illumination direction and the observation direction is a specific angle. This display is designed to display an image with a group of subpixels distributed over a plurality of pixels and display another image with another group of subpixels distributed over the plurality of pixels. It should be noted that if pixels are designed such that the same image is perceived by both the right and left eyes, a planar image (or an animated image) is displayed. Furthermore, if pixels are designed such that the right- and left-eye images corresponding to images obtained by observing the same object at different angles or positions are respectively perceived by the right and left eyes, a stereoscopic image utilizing binocular parallax is displayed. The above display can display a continuously changing image in a wide angular range without causing a feeling of unease to the observer. Also, the above display can display a clear continuously changing image. In other words, the above display can display an image having high visibility and definition. This mechanism will be described below. Indoors, usually, the light source used for illuminating a display is neither a point light source nor a light source emitting parallel rays. In other words, indoors, usually, light is incident on a display from various directions. Therefore, if the display is observed from a specific direction, an image that should be perceived when the display is observed from this direction (termed a normal image hereinafter) may be partially overlapped with one or more images that should be perceived when the display is observed from other directions (termed ghost images hereinafter). However, actually, light of the same intensity does not necessarily enter the display from all directions. Usually, the light entering from a specific direction