Variable image-displaying member

Details Variable image-displaying member Variable image-displaying member

2001-05-30

2003-05-06

Miller, William L. (Department: 3677)

Card, picture, or sign exhibiting

Changing exhibitor

Alphanumeric device

C040S582000, C345S084000

Reexamination Certificate

active

06557279

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a variable image-display that displays variable images comprised of visible pixels.
BACKGROUND
A sign having a static image comprising a retroreflective sheet is disclosed in, for example, U.S. Pat. No. 5,050,327. The image of this sign is formed from a light-transmitting prismatic retroreflective sheet. The prismatic retroreflective sheet comprises a prismatic sheet having prism elements that are called cube comer prisms that can reflect light in a specific direction by the effective use of a refraction function and a total reflection function of the prism elements. In addition, the prismatic sheet is made of a light-transmissive polymeric material, and thus the sheet as a whole allows light to transmit therethrough. Accordingly, the retroreflective sheet effectively reflects the illumination light entering the surface of the prismatic sheet, and allows the sign image to be brightly observed by an observer. On the other hand, the light entering the back surface of the prismatic sheet can transmit through the sheet and thus the prismatic sheet allows the sign image to be brightly observed by an observer.
In addition to reflective sheets that increase the visibility in a relatively narrow observation angle range, wide observation angle type reflective sheets that increase the visibility in a wide observation angle range are used. As a sign-illuminating system that uses a sign having an image comprising a wide observation angle type reflective sheet, Japanese Patent No. 2,910,868 (corresponding to U.S. Pat. No. 5,818,640) discloses an external illumination type sign-illuminating system comprising a sign and an external light source. In this system, the light source is arranged so that it emits light that enters the sign surface at an incident angle in the range between 0 degree and 30 degrees. In general, a retroreflective sheet having a sign image thereon is adhered to the sign surface. The reflective sheet, that is improved to have a wide observation angle range, comprises optical refractive elements such as glass beads, prism elements, etc., and reflection elements such as deposited metal films, etc. In the case of the above described cube comer prism elements, the light can be reflected in a specific direction using the total reflection function of the prisms without reflection elements.
Furthermore, signs are known, that can display variable images comprised of a plurality of light-emitting pixels. Such image-displays commonly have the following components:
(A) a substrate having a front surface which is observed by an observer, and a back surface opposing said front surface, and
(B) a plurality of pixel elements that are arranged on the front surface of the substrate in rows and columns, (i.e. perpendicular to the row directions).
Each pixel element has an internal light source as an essential component. Well known examples of such variable image-displays include electronic signs, and the like. An electronic sign-type image-display is disclosed in, for example, WO97/39436. The variable image-display uses pixel elements comprising light-emitting panels that have one or more light-emitting elements such as an LED as the internal light sources.
In the case of such a variable image-display an observable image is created by a plurality of light-emitting pixels. The background that functions to contrast the image, clear, are composed of comprises pixels that do not emit light. The image can be varied by controlling the light emission from the pixels with the aid of a computer so that pixels at certain positions on the front surface of the substrate are allowed to emit light while other pixels are not.
However, the above-described variable image-displays may not display images, if a part or all of the light-emitting elements cannot emit light because of failure of the light-emitting elements or electronic control circuits.
Therefore, it has been proposed to include the above-described reflective members comprising prismatic sheets (prismatic sheet reflectors) in parts corresponding to the light-emitting panels. The variable image-display is improved so that an image can be observed by reflecting light from an external light source at a high luminance with the reflectors on the surfaces of the light-emitting parts, even if the light-emitting elements do not emit light.
In the case of such a type of a variable image-display a light-transmitting reflector comprising a prismatic sheet is provided on the surface of the light-emitting parts, and thus the light from the light-emitting elements illuminates the light-emitting part from its backside. The light illuminated from the backside of the prismatic sheet passes through the prismatic sheet, and allows the image to be brightly observed by the observer. Accordingly, this type of variable image-display can function in the same way as the above-described electronic sign-type variable image-display when the internal light sources thereof (e.g. light-emitting elements) emit light.
Such a variable image-display has a structure shown in FIG.
6
. In the variable image-display (
9
), each pixel element comprises
(i) a fixed part having a light-emitting part (
93
) formed on the front face of the substrate (
90
), an adjacent area (
94
) that is adjacent to the light-emitting part, and a border line (
96
) formed between the light-emitting part and the adjacent area, and
(ii) an opaque shutter (
91
) that is rotatably fixed to a respective axis in parallel with the border line (
96
), and is movable between a first static state to shield light-emitting part(s) (
93
), and a second static state to expose the light-emitting part(s) (
93
), the shutter having a second face (
912
) facing an observer in a first static state and a first face (
911
) facing the. observer in a second static state.
In the second static state, the light-emitting part (
93
) and the first face (
911
) of the shutter are observed while being arranged parallel with each other on the front face of the substrate form a visible pixel. In this state, the light-emitting part emits light. In general, prismatic sheet reflectors having the same color are arranged on the light-emitting part (
93
) and the first face (
911
) of the shutter.
In the first static state, the light emitting-part (
93
) is shielded. Thus, the light-emitting part (
93
) and the first face (
911
) of the shutter cannot be observed, even when they are externally illuminated. The second face (
912
) of the shutter and the adjacent area (
94
) that faces the observer in the first static state, are generally colored black. Thus, they can effectively form the non-light-emitting pixel as a background, that functions to contrast the image formed with the visible (i.e. light emitting) pixels. Accordingly, the image can be varied by controlling the states of the pixels so that some pixel elements (shutters) are in the second state and the corresponding light-emitting parts (
93
) are allowed to emit light, while the rest of the pixel elements are in the first state. The static states of the pixel elements are determined independently of each other.
In general, the light-emitting part (
93
) consists of (1) an opening (e.g. hole) provided in the substrate and a prismatic sheet reflector provided to cover the entire opening, or (2) a light-emitting-reflection module which is detachably provided in an opening provided in the substrate.
A variable image-display having the light-emitting parts of structure (
1
) is disclosed in, for example, U.S. Pat. No. 5,050,327; while one having the light-emitting parts of structure (
2
) is disclosed in, for example, U.S. Pat. Nos. 5,148,156, 5,500,652 and 5,790,088. The light-emitting-reflection structure (
2
) comprises a small-sized light-emitting device such as an LED, and a prismatic sheet reflector. Thus, in the case of failure of the light-emitting device, the module of each light-emitting part is replaced. To facilitate the exchange of the module, the light-emitting-reflection modules are detachably mounted in the re

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