JP2021012287A - Display - Google Patents

Abstract

To provide a display that can be observed through a background, is hardly affected by the background, and displays a high-quality video.SOLUTION: A display 1 comprises: a photochromic layer 11 in which its transmittance is changed upon receiving excitation light in a specific wavelength region; a plurality of excitation light sources 20 that emit excitation light; and a plurality of display light sources 30 that perform light emission according to the details of display. The display can be observed through a background at least in a state where the photochromic layer 11 has a high transmittance, and displays a favorable video by reducing the transmittance of the photochromic layer 11 when performing the display.SELECTED DRAWING: Figure 3

Description

The embodiment of the present disclosure relates to a display device capable of observing through the background in a state where an image or the like is not displayed.

Conventionally, a display device using a very small LED, which is also called a micro LED (light emitting diode), as a light source has been known. It is also known that the display device itself can be made transparent or translucent because the micro LED itself is very small (for example, Patent Document 1).

However, when the display device is transparent or translucent, it is affected by the background, and the quality of the display content displayed by the display device may deteriorate. In particular, when the background is bright, the contrast of the displayed image or the like may be significantly lowered.

JP-A-2019-40203

An object of the embodiment of the present disclosure is to provide a display device which can be observed through the background and has high quality of the image displayed without being affected by the background.

The embodiment of the present disclosure solves the above-mentioned problems by the following solution means. In addition, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiments of the present disclosure, but the description is not limited thereto.

The first disclosed embodiment corresponds to a photochromic layer (11) whose transmittance changes when it receives excitation light in a specific wavelength region, a plurality of excitation light sources (20) that emit the excitation light, and display contents. It is a display device (1, 1B) that includes a plurality of display light sources (30) that emit light, and can be observed through the background at least in a state where the transmittance of the photochromic layer (11) is high.

The second disclosed embodiment is arranged on the front surface side of the photochromic layer (11) in the display devices (1, 1B) according to the first disclosed embodiment, and shields at least a part of the excitation light. Display devices (1, 1B) including a first shielding layer (12) and a second shielding layer (13) arranged on the back surface side of the photochromic layer (11) and shielding at least a part of the excitation light. ).

The third disclosure embodiment is the display device (1) according to the first disclosure embodiment or the second disclosure embodiment, in which the excitation light source (20) is located on the photochromic layer (11) side. The display light source (30) is a display device (1) that emits excitation light toward the opposite side of the photochromic layer (11).

The fourth disclosure embodiment is the display device (1B) according to the first disclosure embodiment or the second disclosure embodiment, wherein the excitation light source (20) is the photochromic layer (11). The excitation light is emitted toward the opposite side, and the display light source (30) emits the display light toward the side opposite to the photochromic layer (11), and the excitation light source (20) and the display light source (30) are emitted. ) Is arranged in the light source layer, which is a display device (1B) having a higher refractive index than the layer arranged adjacent to the front side of the light source layer.

According to the embodiment of the present disclosure, it is possible to provide a display device that can be observed through the background and has high quality of the image displayed without being affected by the background.

It is a figure which shows the 1st Embodiment of the display device 1 by the embodiment of this disclosure. It is sectional drawing which cut | cut the display device 1 at the position of the arrow AA in FIG. It is a figure explaining the state in which the excitation light source 20 and the display light source 30 are made to emit light in the display apparatus 1 of 1st Embodiment. It is a figure which showed the display device 1B of 2nd Embodiment in the same cross section as FIG. It is a figure explaining the state which made the excitation light source 20 and the display light source 30 emit light in the display apparatus 1B of the 2nd Embodiment.

Hereinafter, the best mode for carrying out the embodiment of the present disclosure will be described with reference to the drawings and the like.

(First Embodiment)
FIG. 1 is a diagram showing a first embodiment of the display device 1 according to the embodiment of the present disclosure. The display device 1 has a sheet-like shape, and FIG. 1 shows a plan view seen from a direction perpendicular to the sheet surface. Further, the excitation light source 20 and the display light sources 30R, 30G, and 30B in FIG. 1 are provided with the letters UV, R, G, and B, which are shown for easy understanding and are actually shown. These characters are not displayed in.
FIG. 2 is a cross-sectional view of the display device 1 cut at the position of arrows AA in FIG.

It should be noted that each of the figures shown below, including FIG. 1, is a diagram schematically shown, and the size and shape of each part are appropriately exaggerated or simplified in order to facilitate understanding.
In the present specification, numerical values such as dimensions of each member and material names described are examples of embodiments, and the present invention is not limited to these, and may be appropriately selected and used.
In the present specification, terms that specify a shape or geometric condition, for example, terms such as parallel and orthogonal, have the same function in addition to their strict meanings, and have an error that can be regarded as parallel or orthogonal. It shall also include the state of having.
In this specification, the terms board, sheet, film, etc. are used, but as a general usage, they are used in the order of thickness, board, sheet, film, etc. It is used in the specification as well. However, since there is no technical meaning in such proper use, these words can be replaced as appropriate.
In the present specification, the sheet surface means a surface of each sheet that is in the plane direction of the sheet when viewed as a whole. The same applies to the plate surface and the film surface.

The display device 1 is formed in a plate-like, sheet-like, or film-like shape including a light source layer 10, a photochromic layer 11, a first shielding layer 12, and a second shielding layer 13, and is formed on a sheet surface. The shape seen from the vertical direction (shape in a plan view) is configured as a quadrangle. In the present embodiment, the shape of the display device 1 in a plan view is a quadrangle, but the shape in a plan view may be any shape. The display device 1 is attached to, for example, a window of a building, a window of a vehicle, or the like, and when it is not displaying an image or the like, it is transparent or translucent so that it can be observed through the background.
In the following description, the side shown in FIG. 1, that is, the left side in FIG. 2 is referred to as the front surface, and the right side is referred to as the back surface. When displaying an image or the like, the observer is on the front side of the display device 1. It shall be observed from.

The light source layer 10 is formed of a transparent resin, and includes an excitation light source 20 and display light sources 30R, 30G, and 30B (hereinafter, these are collectively referred to as a display light source 30).

The excitation light source 20 is provided near the front surface side of the light source layer 10, and emits ultraviolet light as excitation light toward the photochromic layer 11. The excitation light source 20 of the present embodiment is an LED light source of a point light source that emits ultraviolet light. As the excitation light source 20, for example, a so-called micro LED having a width, a length, and a height of 0.5 μm to 50 μm can be used.

The display light source 30 (30R, 30G, 30B) is provided near the front side of the light source layer 10, and emits visible light used for displaying an image or the like toward the front side. The display light source 30R emits red display light, the display light source 30G emits green display light, and the display light source 30B emits blue display light, whereby full-color image display is possible. The display light source 30 of the present embodiment is a point light source LED light source like the excitation light source 20. As the display light source 30, for example, a so-called micro LED having a width, a length, and a height of 0.5 μm to 50 μm can be used.

In the present embodiment, as shown in FIG. 1, a light source group in which the excitation light source 20 and the display light source 30 are arranged close to each other is formed, and the light source groups are arranged in a matrix on the display surface of the display device. Therefore, in the present embodiment, the same number of the excitation light source 20, the display light source 30R, the display light source 30G, and the display light source 30B are arranged. Further, a transparent wiring (not shown) provided in the light source layer 10 is connected to the excitation light source 20 and the display light source 30.
The number of excitation light sources 20 does not have to be the same as that of the display light source 30, and the number of excitation light sources 20 may be increased or the number of excitation light sources 20 may be decreased. In that case, the excitation light source 20 may be arranged without being included in the light source group of the display light source 30.

Further, the excitation light source 20 has been described as an LED that emits ultraviolet light, and the display light source 30 has been described as an LED that emits visible light of each corresponding color. However, any or all of these are referred to as a light emitter. May be configured to emit light of a desired wavelength by exciting a separately arranged phosphor, or may be configured to emit light of a desired wavelength by combining a color filter or the like.

Further, in FIG. 2, the positions of the excitation light source 20 and the display light source 30 in the front-rear direction (positions in the thickness direction of the display device 1) are shown as the same positions. For example, the display light source 30 is arranged on the front side. The excitation light source 20 may be arranged on the back side.

The photochromic layer 11 is a layer having photoresponsiveness in which the transmittance changes when receiving excitation light in a specific wavelength region. The photochromic layer 11 of the present embodiment usually has a high visible light transmittance and is substantially transparent to visible light, and when it receives ultraviolet light, it changes color to gray or black and the visible light transmittance is lowered. It becomes a state. Further, the photochromic layer 11 that has received the ultraviolet light gradually increases the transmittance of the visible light and returns to the transparent state when the reception of the ultraviolet light is completed.
The photochromic layer 11 is made of a resin containing a photochromic material. Examples of the photochromic material include, but are not limited to, diarylethene compounds, spiropyran compounds, spiroperimidine compounds, flugide compounds, hexaarylbiimidazole compounds, naphthopirane compounds, and the like. It can be used as appropriate.

The photochromic layer 11 of the present embodiment has a maximum transmittance of 80% of vertically incident visible light in a state where it is not discolored by ultraviolet light at 430 nm to 700 nm, and a minimum transmittance in a state where it is most deeply discolored by ultraviolet light. The rate is 20% at 430 nm to 700 nm.

The first shielding layer 12 is a layer that is arranged on the front surface side of the photochromic layer 11 and shields the transmission of ultraviolet light that is excitation light. More specifically, the first shielding layer 12 may be configured as an ultraviolet absorbing layer or an ultraviolet reflecting layer. Since the first shielding layer 12 transmits light in a band other than the ultraviolet light to be blocked (transmittance is sufficiently high), it is substantially transparent to visible light. In the present embodiment, the first shielding layer 12 is arranged on the outermost surface on the front surface side of the display device 1.

The second shielding layer 13 is a layer that is arranged on the back surface side of the photochromic layer 11 and shields the transmission of ultraviolet light that is excitation light. More specifically, the second shielding layer 13 may be configured as an ultraviolet absorbing layer or an ultraviolet reflecting layer. Since the second shielding layer 13 transmits light in a band other than the ultraviolet light to be blocked (transmittance is sufficiently high), the second shielding layer 13 is substantially transparent to visible light. In the present embodiment, the second shielding layer 13 is arranged on the outermost surface on the back surface side of the display device 1.

In the present embodiment, the first shielding layer 12 and the second shielding layer 13 have the same configuration and are configured as an ultraviolet absorbing layer, and 90% or more of vertically incident ultraviolet light of 280 nm to 380 nm is emitted. Shield (absorb). More preferably, the first shielding layer 12 and the second shielding layer 13 shield (absorb) 95% or more of the vertically incident ultraviolet light of 280 nm to 380 nm.

Since the photochromic layer 11 is sandwiched between the first shielding layer 12 and the second shielding layer 13, most of the ultraviolet light that reaches the display device 1 from the front side and the back side is the first shielding layer 12 and It is shielded by the second shielding layer 13 and does not reach the photochromic layer 11. Therefore, the photochromic layer 11 does not change its transmittance depending on the external light.

In the state shown in FIG. 2, neither the excitation light source 20 nor the display light source 30 emits light, most of the background light BL can pass to the front side, and the observer on the front side can see the display device. It is possible to observe the background that has passed through 1.

FIG. 3 is a diagram illustrating a state in which the excitation light source 20 and the display light source 30 are made to emit light in the display device 1 of the first embodiment. In FIG. 3, the state in which the photochromic layer 11 is discolored and the transmittance is lowered is expressed by densely showing the dots.
When the excitation light source 20 emits light, the excitation light (ultraviolet light) reaches the photochromic layer 11, and the transmittance of the photochromic layer 11 decreases. When the transmittance of the photochromic layer 11 decreases, most of the background light BL cannot reach the front side.
Since the decrease in the transmittance of the photochromic layer 11 occurs substantially at the same time as the excitation light source 20 emits the excitation light, the response speed of the change in the transmittance is fast. Further, as described above, the photochromic layer 11 has a maximum transmittance of 80% and a minimum transmittance of 20%, so that the dynamic range of the transmittance is higher than that of a dimming member using a liquid crystal or the like, and the transmittance is higher during transmission. There is a large difference between when dimming and when dimming (when the transmittance decreases).
When the excitation light source 20 emits excitation light and the transmittance of the photochromic layer 11 is low, the display light emitted by the display light source 30 is hardly affected by the background light BL. Therefore, the display device 1 can perform high-quality display with high contrast without being affected by the background light BL.
Further, the display device 1 is configured such that the photochromic layer 11 is sandwiched between the first shielding layer 12 and the second shielding layer 13. Therefore, the photochromic layer 11 does not change its transmittance due to external light. Further, it is possible to prevent the excitation light from being emitted from the display device 1.

(Second Embodiment)
FIG. 4 is a diagram showing the display device 1B of the second embodiment in the same cross section as that of FIG.
FIG. 5 is a diagram illustrating a state in which the excitation light source 20 and the display light source 30 are made to emit light in the display device 1B of the second embodiment. In addition, also in FIG. 5, the state in which the photochromic layer 11 is discolored and the transmittance is lowered is expressed by densely showing the dots.
The display device 1B of the second embodiment is the same as the display device 1 of the first embodiment except that the low refractive index layer 14 is provided and the arrangement and orientation of the excitation light source 20 and the display light source 30 are different. Therefore, the same reference numerals are given to the parts that perform the same functions as those of the first embodiment described above, and duplicate description will be omitted as appropriate.

The excitation light source 20 and the display light source 30 of the second embodiment are different from the case of the first embodiment in that they are arranged closer to the back side of the light source layer 10, and the excitation light source 20, the display light source 30, and the light source layer are different from each other. An appropriate distance is maintained from the front side of the 10. Further, in that both the excitation light source 20 and the display light source 30 of the second embodiment emit the excitation light and the display light toward the front surface, that is, toward the side opposite to the photochromic layer 11. It's different from the case.

The low refractive index layer 14 is arranged adjacent to the front surface side of the light source layer 10, and has a lower refractive index than the light source layer 10. It is desirable that the low refractive index layer 14 is formed by using a material having a high visible light transmittance.
By providing the low refractive index layer 14, at the interface between the low refractive index layer 14 and the light source layer 10, the excitation light from the excitation light source 20 that reaches these interfaces at an angle larger than the critical angle is totally reflected. .. As a result, the excitation light can be directed toward the photochromic layer 11.
Further, in order to prevent total reflection from occurring at the interface between the light source layer 10 and the photochromic layer 11, it is desirable that the refractive index of the photochromic layer 11 is higher than the refractive index of the light source layer 10.

According to the display device 1B of the second embodiment, the directions of emitting the light of the excitation light source 20 and the display light source 30 are aligned on the front side, so that the wiring configuration for the excitation light source 20 and the display light source 30 can be simplified. ..

(Transformed form)
Not limited to the embodiments described above, various modifications and changes are possible, which are also within the scope of the embodiments of the present disclosure.

(1) In each embodiment, the excitation light source 20 and the display light source 30 have been described with reference to an example in which a micro LED is used. Not limited to this, for example, when the size of the screen is very large, an LED larger than the micro LED may be used, or a light emitting body other than the LED may be used.

(2) Although the layer configurations of the display devices 1 and 1B have been illustrated in each embodiment, these layer configurations may be changed as appropriate. For example, a support plate for increasing the rigidity of the light control member may be further laminated, or another layer such as a printing layer or various optical functional layers may be laminated.

(3) In each embodiment, a photochromic layer that uses ultraviolet light as excitation light has been described as an example. Not limited to this, any photochromic layer whose transmittance changes depending on the excitation light can be applied to the dimming device of the embodiment of the present disclosure.

Although each embodiment and modified form can be used in combination as appropriate, detailed description thereof will be omitted. Further, the embodiments of the present disclosure are not limited to the embodiments described above.

1, 1B Display device 10 Light source layer 11 Photochromic layer 12 First shielding layer 13 Second shielding layer 14 Low refractive index layer 20 Excitation light source 30 Display light source 30B Display light source (blue)
30G display light source (green)
30R display light source (red)
BL background light

Claims (4)

A photochromic layer whose transmittance changes when it receives excitation light in a specific wavelength region,
A plurality of excitation light sources that emit the excitation light,
Multiple display light sources that emit light according to the display content,
With
A display device capable of observing through the background at least in a state where the transmittance of the photochromic layer is high. In the display device according to claim 1,
A first shielding layer arranged on the front surface side of the photochromic layer and shielding at least a part of the excitation light,
A second shielding layer arranged on the back surface side of the photochromic layer and shielding at least a part of the excitation light, and
A display device comprising. In the display device according to claim 1 or 2.
The excitation light source emits excitation light toward the photochromic layer side.
The display light source is a display device that emits display light toward the side opposite to the photochromic layer. In the display device according to claim 1 or 2.
The excitation light source emits excitation light toward the side opposite to the photochromic layer.
The display light source emits display light toward the side opposite to the photochromic layer.
A display device in which the refractive index of the light source layer in which the excitation light source and the display light source are arranged is higher than that of the layer arranged adjacent to the front surface side of the light source layer.

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