JPWO2019225484A1 - Display device - Google Patents

Abstract

The present invention includes a planar light source formed by arranging a plurality of light sources and a light diffusing plate arranged to face the planar light source, and the brightness of light emitted from the light diffusing plate is 1000 cd / m2 or more. The clarity of the light diffusing plate is 60% or less, and the clarity x (unit:%) and the distance y (unit: mm) between the planar light source and the light diffusing plate are y. ≧ 7.6x-15.0 ... Regarding a display device having the relationship (1).

Description

The present invention relates to a display device such as a simulated window that allows the landscape to be seen as if it were.

In recent years, the use of underground spaces and the like has been promoted due to the overcrowding of cities, but pseudo windows have been proposed in order to suppress the discomfort of not having windows (Patent Document 1).

Patent Document 1 realizes weight reduction by means of an electronic pseudo-window provided with a flat display device having a thin structure and being held in an open portion of a window frame portion and capable of displaying an image. It is disclosed that even if it is mounted on a wall or the like, it does not cause a sense of discomfort in the room.

Japanese Patent Application Laid-Open No. 9-205602

However, the pseudo window described in Patent Document 1 is premised on displaying a clear image, and is not merely a display.

Therefore, an object of the present invention is to provide a display device that realizes favorable visibility similar to that of a landscape seen from an actual window.

The display device of the present invention includes a planar light source formed by arranging a plurality of light sources and a light diffusing plate arranged to face the planar light source, and the brightness of light emitted from the light diffusing plate is 1000 cd. / M ² or more,
The clarity of the light diffusing plate is 60% or less, and the clarity x (unit:%) and the distance y (unit: mm) between the planar light source and the light diffusing plate are expressed by the following equation (unit: mm). It has the relationship of 1).
y ≧ 7.6x-15.0 ・ ・ ・ (1)

According to the display device of the present invention, the strong brightness of the light source gives a bright feeling close to natural light, and the low clarity of the light diffusing plate blurs each light source to give the softness of natural light and secure a predetermined distance. It is possible to give a sense of depth to the image and realize favorable visibility similar to that of an actual window.

1A and 1B show an example of a display device according to the present invention, FIG. 1A shows a cross-sectional view of the display device, and FIG. 1B shows an array of light sources in the display device. FIG. 2 is a graph showing the relationship between the clarity x (%) of the test piece and the distance y (mm) between the planar light source and the light diffusing plate.

Hereinafter, the details and other features of the present invention will be described based on the embodiment for carrying out the invention. In the following drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, so that duplicate description will be omitted. Further, the drawings are not intended to show relative ratios between members or parts unless otherwise specified. Therefore, the specific dimensions can be appropriately selected in light of the following non-limiting embodiments.

The display device 1 of the present embodiment includes a housing 2, a planar light source 4 housed in the housing 2 and formed by arranging a plurality of light sources 3, and a planar light source 4 in the vicinity of an opening 5 of the housing 2. A light diffusing plate 6 is provided so as to face the surface of the light diffusing plate 6.

The display device 1 is attached to a space isolated from the outside world or a large space away from the entrance, for example, a laboratory, a hospital, a warehouse, an underground mall, or a wall of a hall to realistically display the scenery of the outside world and provide a comfortable space. Is what you do. The display device 1 is a display, digital signage, a simulated window (pseudo window), and the like.

The housing 2 is made of wood, metal, resin, or a composite thereof, and generally has a front view and a substantially rectangular shape, but various shapes such as a square shape, a polygonal shape, a circular shape, and an elliptical shape are possible. Yes, it may be curved as a whole, not limited to a flat surface. The light source 3 preferably has a thin shape, and examples thereof include an LED (Light Emitting Diode), an organic EL (Electroluminescence), a semiconductor laser, and a discharge plasma. An LED having a small area and high emission brightness and dimming is preferable. .. When the light source 3 is an LED, each light source 3 may be a single element or a set of a plurality of elements.

As shown in FIGS. 1A and 1B, the light sources 3 are basically regularly arranged on a predetermined substrate 7, and each light source 3 maintains a predetermined width (pitch) P. .. The arrangement may be changed depending on the intended use of the display device 1. The light source 3 is an LED, and an LED vision used in a so-called large display on a street corner, in which a plurality of the light sources 3 are arranged to form a planar light source 4, may be used.

The pitch P is preferably 2.5 to 60 mm. If the pitch is 2.5 mm or more, it is not necessary to make the LED too small, and the brightness of the LED can be maintained. The pitch is more preferably 5 mm or more, and further preferably 8 mm or more. Further, when the pitch is 60 mm or less, the distance between the planar light source 4 and the light diffusing plate 6 can be shortened, and the size of the display device 1 can be reduced. The pitch is more preferably 40 mm or less, further preferably 20 mm or less, and particularly preferably 10 mm or less.

The light diffusing plate 6 diffuses the light of the light source 3, is made of glass, resin, or the like, and is arranged in the vicinity of the opening 5 of the housing 2 so as to face each other at a distance y from the planar light source 4. ing. Since the light diffusing plate 6 and the planar light source 4 are arranged in parallel or substantially parallel to each other, the distance y can be regarded as constant. In order to obtain a sense of depth, the distance y is preferably 10 mm or more.
Further, since the light diffusing plate 6 is located near the opening 5 of the housing 2, the area of the planar light source 4 is larger than the area of the opening 5, and the image is interrupted even at the end of the opening 5. It is preferable because it can be displayed without any problem.

In the case of glass, the surface (polished surface) of the light diffusing plate 6 is generally rubbed with fine sand to form an uneven surface to form a frosted glass. In the case of resin, a light diffusing agent or the like is applied to the surface. A diffusion film can also be attached to glass or a transparent resin. As the diffusing film, a film having an uneven surface can be obtained by adding fine particles called a light diffusing agent, laminating a resin layer having a fine uneven shape on a substrate film, embossing or molding the surface, and the like. ..
Further, the light diffusing plate 6 may be a template glass in addition to the frosted glass. It is preferable to use the template glass because the focus is changed by the refraction of light and the sense of depth is increased.
Further, the light diffusing plate 6 may be a laminate of a plurality of light diffusing plates 6 or may be a laminated glass. The laminated glass is formed, for example, by forming frosted glass and template glass via an interlayer film such as PVB (polyvinyl butyral). In addition, it may be a laminated glass formed by forming two frosted glasses with an interlayer film. The laminated glass is preferably formed so that the uneven surface of the frosted glass or the template glass is on the outside (visual side). Further, the light diffusing plate 6 may be formed by superimposing frosted glass and template glass without interposing an interlayer film.

When displaying a landscape or the like on a display device, a liquid crystal display, a plasma display, an organic EL display or the like is generally used, and while the image is clear, the landscape to be displayed and the landscape actually seen from the window are used. There is a sense of discomfort with the scenery. That is, the scenery and scenery seen from the window in natural light are recognized through the analog visual sense in soft light, so that it feels calm rather than clear. Therefore, the present inventors should increase the brightness of the light emitted from the light source 3 in order to bring it closer to the brightness of sunlight, while decreasing the degree of diffusion of the light diffusing plate 6 to blur the light emitted from the light source 3. I found.

The brightness of the light emitted from the light diffusing plate 6 of the display device 1 of the present embodiment is 1000 cd / m ² or more. If it is 1000 cd / m ² or more, the brightness is close to that of natural light, so that there is no sense of discomfort. The brightness of the light emitted from the light diffusing plate 6 is measured in the light emitted from the surface 6a facing the planar light source 4 of the light diffusing plate 6 and the surface 6b facing the surface 6b. Luminance is measured by a luminance meter. Brightness of the light emitted from the light diffusion plate 6 is preferably 2000 cd / ^{m 2} or more, more preferably 2500 cd / ^{m 2} or more, more preferably 3000 cd / ^{m 2} or more, particularly preferably 3500 cd / ^{m 2} or more, 4000 cd / ^{m 2} The above is the most preferable. Is not particularly limited brightness maximum of the light emitted from the light diffusion plate 6 may also be 6000 cd / ^{m 2} or less, or may be 5000 cd / ^{m 2} or less.

The luminance of light emitted from the light diffusion plate 6 in order to 1000 cd / ^{m 2} or more, the luminance of the light emitted from the light source 3 is preferably 1200 cd / ^{m 2} or more, 2000 cd / ^{m 2} or more preferably, 2500 cd / ^{m 2} or more, and still more preferably from 3000 cd / ^{m 2} or more, particularly preferably 3500 cd / ^{m 2} or more, 4000 cd / ^{m 2} or more is most preferred. The upper limit of the luminance of the light emitted from the light source 3 is not particularly limited, it may also be 6000 cd / ^{m 2} or less, or may be 5000 cd / ^{m 2} or less.

Clarity was used as an index of the diffusion state of the light diffusion plate 6. Clarity is narrow-angle scattering, which is a percentage of transmitted light that deviates from the angle of incidence of light on the light diffusing plate 6 to an average of 2.5 degrees or less. It is also an indicator of boundary clarity. Clarity is
Clarity = 1- (T- _{2.5 to 2.5-} T ₀ ) / T- _{2.5 to 2.5}
In the formula, T- _{2.5 to 2.5} is the transmittance in the angle range of -2.5 to 2.5 degrees with _{respect to the incident light, and T 0} is with respect to the incident light. It means the transmittance at 0 degrees. That is, the clarity is the transmittance in the angle range of −2.5 to 2.5 degrees with respect to the incident angle of light on the light diffusing plate 6. The transmittance here is the total light transmittance measured by the D65 light source based on ISO 13468-1: 1996. Clarity can be expressed as a unit of%.
Clarity (%) = 100- (T- _{2.5 to 2.5-} T ₀ ) / T- _{2.5 to 2.5}
In the equation, T- _{2.5 to 2.5} is the transmittance (unit:%) in the angle range of -2.5 to 2.5 degrees with _{respect to the incident light, and T 0} is with respect to the incident light. It means the transmittance (unit:%) at 0 degrees.

The clarity of the light diffusing plate 6 is 60% or less. Further, if the diffusing portion of the light diffusing plate 6 is an uneven surface sufficiently larger than the wavelength of light, directional scattering is possible, which can contribute to the reduction of clarity. If the diffusion is small, the boundary of the light source 3 becomes unclear and can be blurred, and a feeling close to a natural image can be obtained. The clarity is more preferably 50% or less, further preferably 40% or less, even more preferably 30% or less, particularly preferably 20% or less, and most preferably 10% or less. The lower limit of clarity is not particularly limited, but may be 1% or more, 2% or more, 5% or more, or 7% or more.

Further, the clarity x (unit:%) and the distance y (unit: mm) between the planar light source 4 and the light diffusing plate 6 have the relationship of the following equation (1).
y ≧ 7.6x-15.0 ・ ・ ・ (1)

The brightness of the light emitted from the light diffusing plate 6 is 1000 cd / m ² or more, the clarity of the light diffusing plate 6 is 60% or less, and the display device 1 according to the present embodiment satisfying the formula (1). It gives a bright feeling with strong brightness, blurs the light from each light source 3 with low clarity, and secures a predetermined distance y to give a sense of depth of the image, so an appropriate display like a natural image can be obtained. can get. As a result, it is possible to obtain an image in which the outside scenery can be seen as it is through the display device 1.

Further, Smr1 was used as an index showing the roughness of the uneven surface of the light diffusing plate 6. Smr1 is a kind of surface texture parameter defined in ISO25178, and the load area ratio (core) at the intersection of the height of the upper part of the core portion and the load curve, which represents the height of the region in contact with other objects after the initial polishing is completed. It represents the load area ratio that separates the part and the protruding mountain part). In the light diffusing plate 6 of the display device 1 of the present embodiment, the Smr1 of at least one main surface is preferably 3% or more. When Smr1 is 3% or more, the boundary of the light source 3 becomes unclear, blurring becomes possible, and a feeling close to a natural image can be obtained. Smr1 is more preferably 5% or more, further preferably 7% or more, particularly preferably 10% or more, and most preferably 13% or more. The upper limit of Smr1 is not particularly limited, but may be 30% or less, 25% or less, 20% or less, or 15% or less.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.
Various test bodies of the display device 1 were prepared and their visibility was evaluated.
The members and abbreviations used in each test piece are as follows.

<Light diffuser>
(K1) Frosted glass (tapestry glass manufactured by Yamada Glass Co., Ltd.) having irregularities formed on one main surface. The clarity was 7.1%, and the Smr1 of the main surface on which the unevenness was formed was 11.3%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness. The surface opposite to the light source was sandblasted.
(K2) Frosted glass (developed by Asahi Glass Co., Ltd.) with one main surface coated with silica by spraying. The clarity was 18.7% and the silica-coated main surface Smr1 was 14.3%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness.
Two pieces of (K3) K2 were prepared, and laminated glass was prepared via PVB (polyvinyl butyral) as an interlayer film so that the silica-coated main surface was on the outside. The clarity was 10.9%.
(K4) Frosted glass (normally etched glass manufactured by Figura Co., Ltd.) having irregularities formed on one main surface. The clarity was 19.5%, and the Smr1 of the main surface on which the unevenness was formed was 10.4%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness.
(K5) A frosted glass (LST40 manufactured by Asahi Glass Co., Ltd.) having irregularities formed on one main surface. The clarity was 37.5%, and the Smr1 of the main surface on which the unevenness was formed was 8.0%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness.
(K6) Frosted glass (tapestry glass software manufactured by Yamada Glass Co., Ltd.) having irregularities formed on one main surface. The clarity was 70.1%, and the Smr1 of the main surface on which the unevenness was formed was 2.5%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness.
(K7) Frosted glass (AGC GLASS EUROPE Materax (registered trademark)) having irregularities formed on one main surface. The clarity was 6.9%, and the Smr1 of the main surface on which the unevenness was formed was 2.5%. The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness.
Two pieces of (K8) K7 were prepared, and laminated glass was prepared via PVB (polyvinyl butyral) as an interlayer film so that the sliding surface was on the outside. The clarity was 4.5%.
(K9) Prepare one piece of template glass (Kura manufactured by Asahi Glass Co., Ltd.) and one piece of K7, and intermediate so that the main surface with the pattern of the template glass and the main surface with the unevenness of K7 are on the outside. Laminated glass was produced as a film via PVB. The clarity was 6.5%.
(K10) Float glass plate ("FL" manufactured by AGC Inc.). The dimensions are 300 mm in length × 300 mm in width × 5 mm in thickness. The clarity was 93.3%.
(K11) One piece of K7 and one piece of K10 were prepared, and laminated glass was prepared through PVB having a thickness of 0.76 mm as an interlayer film so that the sliding surface of K7 was on the outside. The clarity was 2.3%.
Two pieces of (K12) K10 were prepared, and laminated glass was prepared through PVB having a thickness of 0.76 mm as an interlayer film. The clarity was 2.9%.

<Spherical light source>
(L1) LED Vision A (manufactured by LIGHTLINK, CFC8, trees are displayed on a white background as an image). The brightness is 4950 cd / m ² and the pitch is 8.9 mm.
(L2) LED Vision B (manufactured by LIGHTLINK, CFC8, trees are displayed on a green background as an image). The brightness is 2505 cd / m ² and the pitch is 8.9 mm.
(L3) LED Vision C (manufactured by VISS, ES6, trees are displayed on a white background as an image). The brightness is 7430 cd / m ² and the pitch is 6.5 mm.
(L4) Personal computer (manufactured by Toshiba, dynabook R734). The brightness is 701 cd / m ² and the pitch is 0.153 mm.

Clarity was measured with a haze meter (BYK Gardner's Hayes-Guard Plus), and Smr1 was measured with a laser microscope (Keyence's VKX110).
Using the above members, test pieces of the display device 1 of Examples 1 to 66 were prepared. The members used for each test piece are shown in Tables 1 to 5. The distance between the light diffusing plate 6 and the planar light source 4 was adjusted and fixed to the values shown in Tables 1 to 5. In Examples 31 to 35, K2 was adjusted and fixed at a predetermined distance from the screen of L4.
Light was output from the planar light source 4, and the brightness of the light emitted from the surface 6b on the side opposite to the surface 6a facing the light source of the light diffusing plate 6 was measured by a luminance meter (CS-100A, manufactured by Konica Minolta). In addition, the visibility of the display device 1 was evaluated. The visibility was evaluated as follows regarding the appearance and depth of the light source.
Appearance of the light source: The test body in which the light source 3 could not be seen through the light diffusing plate was marked with “◯”, and the test body in which the light source 3 was visible was marked with “x”.
Depth: By visually observing the test piece, the test piece with a sense of depth is marked with "○", the test piece with a sense of depth rather than "○" is marked with "◎", and the test piece without a sense of depth is marked with "x". And said.
The evaluation results of the brightness and visibility of the light diffusing plate are shown in Tables 1 to 5.

Examples 2-4, 8, 12, 16, 19-21, 25, 30, 43-45, 47-50, 53-56, 58-61 and 63-66 test specimens show the appearance and depth of the light source. Are both "○" or "◎", and it was possible to realize favorable visibility similar to that of an actual window.
The specimens of Examples 1, 5-7, 9-11, 13-15, 17, 18, 22-24, 26-29, 36-42, 46, 51, 52, 57 and 62 show the appearance of the light source and The sense of depth was "x" in each case, and the visibility was poor. The LEDs constituting the LED vision, which is a planar light source, were visible through the light diffusing plate, and the same favorable visibility as that of an actual window could not be obtained.
The test bodies of Examples 31 to 35 had a brightness of ^{less than 1000 cd / m 2} , a poor sense of depth, and poor visibility.

FIG. 2 is a graph showing the relationship between the clarity x and the distance y between the planar light source 4 and the light diffusing plate 6 in a test body having a brightness of 1000 cd / m ^{2 or more.} “●” in the graph indicates a test piece in which the evaluation results of the appearance of the light source and the sense of depth are both “○” or “◎”, and the same favorable visibility as that of an actual window can be realized. “Δ” in the graph indicates a test body in which at least one of the evaluation results of the appearance and the sense of depth of the light source was “x” and the visibility was poor. The dotted line indicates "y = 7.6x-15.0".
From this result, it was found that the test body having "y ≧ 7.6x-15.0" had good visibility.

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like. In addition, the material, shape, size, numerical value, form, number, arrangement location, etc. of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on May 21, 2018 (Japanese Patent Application No. 2018-09739), the contents of which are incorporated herein by reference.

The display device of the present invention can be suitably used in a room or the like where a display close to a natural landscape is desired.

1 Display device 2 Housing 3 Light source 4 Planar light source 5 Opening 6 Light diffuser

Claims (8)

A planar light source formed by arranging multiple light sources and
A light diffusing plate arranged to face the planar light source is provided.
The brightness of the light emitted from the light diffusing plate is 1000 cd / m ² or more.
The clarity of the light diffuser is 60% or less,
A display device in which the clarity x (unit:%) and the distance y (unit: mm) between the planar light source and the light diffusing plate have the relationship of the following formula (1).
y ≧ 7.6x-15.0 ・ ・ ・ (1) The display device according to claim 1, wherein the light source is an LED. The display device according to claim 1 or 2, wherein Smr1 of at least one main surface of the light diffusing plate is 3% or more. Further, any one of claims 1 to 3, further comprising a housing having an opening, the light diffusing plate is arranged in the vicinity of the opening, and the area of the planar light source is larger than the area of the opening. The display device described in. The display device according to any one of claims 1 to 4, wherein the light diffusing plate is frosted glass. The display device according to any one of claims 1 to 4, wherein the light diffusing plate is a template glass. The display device according to any one of claims 1 to 4, wherein the light diffusing plate is a laminated glass. The display device according to claim 7, wherein the laminated glass is formed of frosted glass and template glass.

Images