JP7462218B2 - Display device and optical adjustment sheet - Google Patents

Description

The present invention relates to a display device and an optical adjustment sheet.

As Internet of Things (IOT) home appliances and voice-operated devices become more widespread, the number of display devices such as monitors, tablet devices, and televisions connected to personal computers is increasing in homes and public facilities.

Generally, when a display device is turned off, the display surface of the display device is black. Therefore, the display device does not blend in with the interior or exterior of the home or public facility in which it is installed, and this reduces the design quality of the space, such as the home or public facility.

As a result, display devices aimed at enhancing the design of spaces have been considered.

For example, Patent Document 1 discloses a display device that includes a display surface and a half mirror that covers the display surface. In this display device, the half mirror covers the display surface, making the black color of the display surface less noticeable. This is expected to prevent the design of the space from being impaired.

JP 2006-53277 A

However, when this display device is turned off, the display surface always appears mirror-like, meaning that the display surface is always seen as if it were a mirror, making it difficult to fully enhance the design of the space.

In addition, in order to enhance the design of the space, decorations with low light transmittance (e.g., seals or stickers) may be applied to the black display surface. However, in this case, when the display device is turned on, the display surface is shielded by the decoration, which has the effect of reducing the visibility of the image displayed on the display surface.

Therefore, the present invention provides a display device that has little effect on the displayed image when lit, and can enhance the design of the space when turned off.

A display device according to one aspect of the present invention is a display device illuminated by a first light emitted by a first light source, and includes a display surface portion emitting a second light for displaying an image, and an optical adjustment sheet provided to cover the display surface portion, having a first surface on which the first light is incident and a second surface facing away from the first surface on which the second light is incident, and reflecting light in a predetermined wavelength range among the first light and the second light, wherein the second light has a plurality of emission peak wavelengths, and in the reflection spectrum of the optical adjustment sheet, the reflection peak wavelength is located between two adjacent emission peak wavelengths among the plurality of emission peak wavelengths, and the reflection peak half width is located between the two adjacent emission peak wavelengths. The first condition is that the reflection peak wavelength is between the shortest emission peak wavelength of the plurality of emission peak wavelengths and 380 nm, and the reflection peak half-width is less than or equal to the difference between the shortest emission peak wavelength and 380 nm, and the third condition is that the reflection peak wavelength is between the longest emission peak wavelength of the plurality of emission peak wavelengths and 780 nm, and the reflection peak half-width is less than or equal to the difference between the longest emission peak wavelength and 780 nm. The reflection spectrum satisfies at least one of the first condition, the second condition, and the third condition.

In addition, an optical adjustment sheet according to one aspect of the present invention is an optical adjustment sheet comprising a first surface on which a first light emitted from a first light source is incident, and a second surface facing away from the first surface and on which a second light emitted from a second light source provided in a display device is incident, the optical adjustment sheet is provided so as to cover a display surface portion provided in the display device, and reflects light in a predetermined wavelength range among the first light and the second light, the second light being light for displaying a moving image on the display surface portion, and having a plurality of emission peak wavelengths when incident on the second surface, and in the reflection spectrum of the optical adjustment sheet, the reflection peak wavelength is located between two adjacent emission peak wavelengths among the plurality of emission peak wavelengths, and the reflection peak half When the first condition is that the width is equal to or less than the difference between the two adjacent emission peak wavelengths, the second condition is that the reflection peak wavelength is between the shortest emission peak wavelength among the multiple emission peak wavelengths and 380 nm, and the reflection peak half-width is equal to or less than the difference between the shortest emission peak wavelength and 380 nm, and the third condition is that the reflection peak wavelength is between the longest emission peak wavelength among the multiple emission peak wavelengths and 780 nm, and the reflection peak half-width is equal to or less than the difference between the longest emission peak wavelength and 780 nm, the reflection spectrum satisfies at least one of the first condition, the second condition, and the third condition.

The present invention provides a display device that has minimal impact on the displayed image when lit, and enhances the design of the space when turned off.

FIG. 1 is a perspective view illustrating an example of use of a display device according to a first embodiment. FIG. 2 is an exploded perspective view showing the configuration of the display device according to the first embodiment. FIG. 3 is a cross-sectional view of the optical adjusting sheet according to the first embodiment. FIG. 4 is a diagram showing an emission spectrum of the second light according to the first embodiment. FIG. 5 is a diagram showing the reflection spectrum of the optical adjusting sheet according to the first embodiment. FIG. 6 is a schematic diagram illustrating the behavior of the first light and the second light according to the first embodiment. FIG. 7 is a diagram showing an emission spectrum of the second light for explaining another example of the reflection peak wavelength and the reflection peak half width according to the first embodiment. In FIG. FIG. 8 is an exploded perspective view showing a configuration of a display device according to the second embodiment. FIG. 9 is an exploded perspective view showing a configuration of a display device according to a first modification of the second embodiment. FIG. 10 is an xy chromaticity diagram illustrating the reflection peak wavelength and the reflection peak wavelength according to the first modification of the second embodiment. FIG. 11 is an exploded perspective view showing a configuration of a display device according to a second modification of the second embodiment. FIG. 12 is a schematic u'v' chromaticity diagram of the second light according to the second modification of the second embodiment and the comparative example. FIG. 13 is a schematic diagram showing the configuration of a display device and a projection device according to the third embodiment.

The following describes embodiments of the present invention with reference to the drawings. Note that each embodiment described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component placement positions, and connection forms shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims are described as optional components.

Note that each figure is a schematic diagram and is not necessarily a precise illustration. In addition, in each figure, the same reference numerals are used for substantially the same configurations, and duplicate explanations may be omitted or simplified.

In addition, in this specification, terms indicating the relationship between elements, such as "uniform," terms indicating the shape of elements, such as "rectangular" or "circular," and numerical ranges are not expressions that only express a strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about a few percent.

(Embodiment 1)
[composition]
First, the configuration of a display device 1 according to the first embodiment will be described with reference to the drawings.

Figure 1 is a perspective view showing an example of use of display devices 1, 101, and 201 according to this embodiment.

As shown in FIG. 1, display devices 1, 101, and 201 are, for example, liquid crystal monitors used in a space such as a house. As an example, display device 1 is a television (here, a liquid crystal television) that displays an image to a user U in a space such as a house, display device 101 is a tablet terminal, and display device 201 is a monitor provided in an intercom.

Note that the display devices 1, 101, and 201 are not limited to the above, and may be, for example, a monitor connected to a personal computer, a smartphone terminal, etc.

The display devices 1, 101, and 201 may be devices used in spaces such as public facilities or commercial facilities. The display devices 1, 101, and 201 may be used for advertising as digital signage. Although the display devices 1, 101, and 201 are used indoors as shown in FIG. 1, they are not limited to this and may be used outdoors.

The display devices 1, 101, and 201 are illuminated by a first light L10 emitted by a first light source 300 provided outside the display devices 1, 101, and 201. As shown in FIG. 1, the first light source 300 is a light source provided by a lighting fixture located in the space in which the display devices 1, 101, and 201 are installed. The first light L10 may be any color of light that illuminates the space, but in this case, it is white light. The first light L10 is not limited to this, and may be light of an incandescent color.

The first light source 300 may also be, for example, the sun. In this case, the first light L10 is sunlight that shines in through a window or the like.

The following describes display device 1 as a representative example.

Figure 2 is an exploded perspective view showing the configuration of the display device 1 according to this embodiment.

The display device 1 includes a display surface 2 and an optical adjustment sheet 10.

In this embodiment, the display surface 2 is a liquid crystal panel. The display surface 2 emits a second light L20 that displays an image. In other words, the second light L20 is light emitted from a plurality of pixels that the display surface 2 has. As a result, images including still images and moving images are displayed on the display surface 2 (more specifically, on the display surface that the display surface 2 has). The second light L20 is also light derived from light emitted by a second light source that the display surface 2 has. The second light source (not shown) is a light source provided within the display device 1.

In this embodiment, the second light source is, for example, an LED module having a light emitting diode (LED). The second light source is not limited to the above as long as it can emit visible light.

The second light source can emit white light, for example. More specifically, the second light source has a blue LED that emits blue light and a sealing member that contains a phosphor. The phosphor includes a green phosphor and a red phosphor that emit fluorescence using the blue light emitted by the blue LED as excitation light. The green phosphor and the red phosphor are excited by absorbing a portion of the blue light emitted by the blue LED and emit green light and red light, and this green light and red light are mixed with the blue light that was not absorbed by the green phosphor and the red phosphor to become white light. Furthermore, the phosphor may include a yellow phosphor that emits yellow light.

In the present embodiment, the second light source is a white backlight of the display device 1, which is a liquid crystal monitor. The second light source is used in the display device 1 in an edge-type or direct-type backlight system. For example, in the edge-type, the second light source is a COB (chip on board) structure or a surface mount device (SMD) structure, and in the direct-type, the second light source is an SMD structure, but is not limited to this.

The white light emitted by the second light source is converted into second light L20 including blue light, green light, and red light by, for example, passing through a color filter of the display device 1, and an image is displayed on the display surface 2 by controlling the amount of blue light, green light, and red light contained in the second light L20. This blue light, green light, and red light are emitted, for example, from multiple sub-pixels of multiple pixels. Also, as shown in FIG. 2, the second light L20 including blue light, green light, and red light is incident on an optical adjustment sheet 10 that is provided to cover the display surface 2.

The optical adjustment sheet 10 has a first surface 11 and a second surface 12 facing away from the first surface 11. The first light L10 is incident on the first surface 11, and the second light L20 is incident on the second surface 12. The optical adjustment sheet 10 reflects light in a predetermined wavelength range of the first light L10 and the second light L20.

The optical adjusting sheet 10 is a sheet-like optical member. The optical adjusting sheet 10 may be a rigid sheet member that does not have flexibility, or may be a flexible sheet member that has flexibility. In this embodiment, the planar shape of the optical adjusting sheet 10 is rectangular.

In this embodiment, the optical adjustment sheet 10 is provided so as to cover the entire surface of the display surface 2 (more specifically, the entire display surface of the display surface 2). Therefore, to the user U, the color presented by the optical adjustment sheet 10 appears to be the color presented by the display surface 2. Note that the optical adjustment sheet 10 is not limited to the above, and may be provided so as to cover a portion of the display surface 2.

Here, the optical adjustment sheet 10 will be described in more detail with reference to FIG. 3.

Figure 3 is a cross-sectional view of the optical adjustment sheet 10 according to this embodiment.

In this embodiment, the optical adjustment sheet 10 has a substrate 20 and a colloidal crystal film 30.

The substrate 20 is an optical member that is translucent at least in the visible light region. In other words, the substrate 20 has the optical property of transmitting visible light. The transmittance of the substrate 20 is preferably high, and is preferably at least 50% or more. Specifically, the substrate 20 is preferably transparent to visible light. A transparent substrate 20 has a transmittance high enough that the other side can be seen through. In this case, the transmittance of the transparent substrate 20 to visible light is 70% or more, preferably 80% or more, and even better 90% or more.

The substrate 20 is made of a material having translucency. The substrate 20 is a transparent substrate that is transparent to visible light, such as a transparent resin substrate made of a transparent resin material or a glass substrate made of a transparent glass material. As the transparent resin substrate, an acrylic substrate made of an acrylic resin or a polycarbonate substrate made of a polycarbonate resin can be used. Note that the transparent resin substrate may be a rigid substrate that does not have flexibility, or a flexible substrate that has flexibility. In this embodiment, a rigid and transparent acrylic substrate is used as the substrate 20.

The planar shape of the substrate 20 is rectangular, the same as the optical adjustment sheet 10. The thickness of the substrate 20 is, for example, from several mm to several cm, but is not limited to this. In this embodiment, the substrate 20 functions as a substrate that supports the colloidal crystal film 30 of the optical adjustment sheet 10.

In this embodiment, the colloidal crystal film 30 is provided on one of the main surfaces of the substrate 20. Specifically, the colloidal crystal film 30 is formed over the entire surface of one of the main surfaces of the substrate 20 so as to be in contact with the one of the main surfaces. The thickness of the colloidal crystal film 30 is uniform throughout the entire colloidal crystal film 30. In other words, the thickness of the colloidal crystal film 30 is constant. The thickness of the colloidal crystal film 30 is preferably 5 μm or more and 100 μm or less, but is not limited to this.

Specifically, the colloidal crystal film 30 has a three-dimensional periodic structure. As shown in FIG. 3, the colloidal crystal film 30 is composed of a plurality of nanoparticles 32 and a matrix resin 31 that holds the plurality of nanoparticles 32. In this embodiment, the plurality of nanoparticles 32 (colloidal particles) are arranged three-dimensionally and regularly, and exist as colloidal crystals in the matrix resin 31. Specifically, the plurality of nanoparticles 32 are arranged periodically and regularly in three axial directions, namely, the thickness direction of the substrate 20 and two axial directions (horizontal directions) parallel to one main surface of the substrate 20, to form a colloidal crystal. The plurality of nanoparticles 32 are arranged uniformly throughout the colloidal crystal film 30.

The nanoparticles 32 are particles with a particle diameter on the order of submicrons. In this embodiment, the particle diameters of the nanoparticles 32 contained in the colloidal crystal film 30 are basically uniform, but some variation is acceptable. As will be described in detail later, by adjusting the average particle diameter and/or concentration of the multiple nanoparticles 12a contained in the colloidal crystal film 30, it is possible to change the wavelength range of light reflected by the optical adjustment sheet 10 having the colloidal crystal film 30.

The nanoparticles 32 are, for example, light-transmitting particles that transmit light. As the nanoparticles 32 that are light-transmitting particles, for example, inorganic particles such as silica particles made of _SiO2 , or polymer particles such as polystyrene particles or acrylic particles, may be used. In this embodiment, silica particles are used as the nanoparticles 32.

The matrix resin 31 is a binder that fixes the multiple nanoparticles 32. The matrix resin 31 is made of a resin material that is translucent. In this embodiment, the matrix resin 31 is made of a resin material that is transparent to visible light. The matrix resin 31 may contain at least one resin selected from the group consisting of, for example, acrylic resin, polycarbonate resin, cycloolefin resin, epoxy resin, silicone resin, and styrene resin.

The colloidal crystal film 30 can be produced, for example, as follows:

First, silica particles are added to a monomer made of triethylene glycol dimethacrylate (for example, "NK Ester 3G" manufactured by Shin-Nakamura Chemical Co., Ltd.) so that the content is 40%. Then, ultrasonic dispersion processing is performed to disperse the silica particles in the monomer so that they are regularly arranged in three dimensions. In this way, a dispersion liquid in which the silica particles are uniformly dispersed in the monomer as colloidal particles is obtained. Next, 1.0% by weight of a photopolymerization initiator (for example, IRGACURE-1173 manufactured by IGM Resins B.V.) relative to the weight of the monomer is added to this dispersion liquid. Then, this dispersion liquid is applied to the substrate 20 using a bar coater to form a coating film. At this time, it is recommended to use a bar coater with a number of #10. Then, the obtained coating film is irradiated with ultraviolet light to polymerize the monomer, thereby forming a colloidal crystal film 30 on the surface of the substrate 20.

The colloidal crystal film 30 produced in this manner has a different color in plan view depending on the particle size of the multiple nanoparticles 32 that make up the colloidal crystal. For example, a colloidal crystal film 30 produced by the above method using silica particles with an average particle size of 180 nm as the nanoparticles 32 has a yellow color in plan view. A colloidal crystal film 30 produced by the above method using silica particles with an average particle size of 200 nm as the nanoparticles 32 has a red color in plan view. In this embodiment, silica particles with an average particle size of 180 nm are used.

The optical adjustment sheet 10 may include a dielectric multilayer film instead of the colloidal crystal film 30. The dielectric multilayer film has a structure in which a plurality of dielectric materials having different dielectric constants are laminated. For example, the dielectric multilayer film has a structure in which a dielectric film having a low refractive index and a dielectric film having a high refractive index are alternately laminated. Such a dielectric multilayer film matches the phase of the light reflected at the interface between the dielectric film having a low refractive index and the dielectric film having a high refractive index with the light traveling back and forth through the dielectric multilayer film, and each light reinforces each other in the same reflection direction, thereby becoming a film with high reflectance for light in a predetermined wavelength range. More specifically, a reflection spectrum having a narrow bandwidth reflection peak is realized.

In addition, in this embodiment, the substrate 20 contacts the display surface portion 2 (more specifically, the display surface of the display surface portion 2), but this is not limited thereto, and the colloidal crystal film 30 may contact the display surface portion 2. An adhesive layer may be provided between the optical adjustment sheet 10 and the display surface portion 2, but in this embodiment, no adhesive layer is provided. The adhesive layer is preferably a light-transmitting layer. The transmittance of the adhesive layer is preferably high, and is preferably at least 50% or more. Specifically, the transmittance of the adhesive layer for visible light is 70% or more, preferably 80% or more, and even better 90% or more.

[Light behavior]
Next, the behavior of the first light L10 and the second light L20 according to this embodiment will be described with reference to Fig. 4 to Fig. 6. First, the emission spectrum of the second light L20 will be described in detail with reference to Fig. 4.

Figure 4 is a diagram showing the emission spectrum of the second light L20 according to the present embodiment. More specifically, Figure 4 is a diagram showing the emission spectrum of each of the blue light, green light, and red light that is contained in the second light L20 and is emitted from multiple sub-pixels. In Figure 4, the emission spectra of the blue light, green light, and red light are depicted by a solid line, a dashed line, and a dashed dotted line, respectively. In addition, each emission spectrum is normalized by the intensity of the peak wavelength of the blue light.

The second light L20 has a plurality of emission peak wavelengths in the visible light region, including a first emission peak wavelength λ1, a second emission peak wavelength λ2, and a third emission peak wavelength λ3. The first, second, and third emission peak wavelengths λ1, λ2, and λ3 in FIG. 4 correspond to the peak wavelengths of the emission spectra of blue light, green light, and red light, respectively, emitted from the plurality of sub-pixels. The second emission peak wavelength λ2 is adjacent to the first emission peak wavelength λ1 and has a longer wavelength than the first emission peak wavelength λ1. The third emission peak wavelength λ3 is adjacent to the second emission peak wavelength λ2 and has a longer wavelength than the second emission peak wavelength λ2.

Next, the reflection spectrum of the optical adjustment sheet 10 will be explained using Figure 5.

Figure 5 shows the reflection spectrum of the optical adjustment sheet 10 according to this embodiment. The reflection spectrum shown in Figure 5 was measured with an incident angle of 5°. The reflection spectrum was measured using a spectrophotometer (V-650) manufactured by JASCO Corporation with the measurement option ARMV-734.

In addition, preliminary studies by the inventors have revealed that the optical adjustment sheet 10 including the colloidal crystal film 30 has reflection wavelength selectivity in which the wavelength of reflected light depends on the angle of incidence of the incident light.

As shown in FIG. 5, when the incident angle is 5°, the reflection peak wavelength λr is approximately 570 nm. The reflection peak wavelength λr at the specular reflection wavelength (incident angle is 0°) of the optical adjustment sheet 10 is considered to be in the range of 570 nm to 580 nm. The reflection peak half-width w is approximately 20 nm. The reflection peak half-width w is the wavelength width at which the reflectance at the reflection peak wavelength λr corrected for the baseline of the reflection spectrum is 50%.

In this embodiment, the reflection peak is the peak at which the reflectance is highest, and the reflection peak wavelength λr is the wavelength at which the transmittance is maximum. As shown in FIG. 5, the reflection spectrum of one optical adjustment sheet 10 has one reflection peak.

From the above, in the reflection spectrum of the optical adjustment sheet 10, the reflection peak wavelength λr and the reflection peak half-width w satisfy the following first condition.

The first condition is that the reflection peak wavelength λr is located between two adjacent emission peak wavelengths among a plurality of emission peak wavelengths, and the reflection peak half-width w is less than or equal to the difference between the two adjacent emission peak wavelengths. Specifically, as shown in FIG. 5, the reflection peak wavelength λr is located between two adjacent peak wavelengths (the second emission peak wavelength λ2 corresponding to green light and the third emission peak wavelength λ3 corresponding to red light). Furthermore, the reflection peak half-width w is less than or equal to the difference between the second emission peak wavelength λ2 corresponding to green light and the third emission peak wavelength λ3 corresponding to red light.

The reflectance at the reflection peak wavelength λr is approximately 38%, but is not limited to this and may be 20% or more and 60% or less. The reflectance at the reflection peak wavelength λr is better if it is 25% or more and 55% or less, and even better if it is 30% or more and 50% or less.

In addition, in this embodiment, the optical adjustment sheet 10 includes a colloidal crystal film 30. Therefore, a reflection spectrum having a narrow bandwidth reflection peak is realized. In addition, by adjusting the average particle size and/or concentration of the multiple nanoparticles 12a, the wavelength region of light reflected by the optical adjustment sheet 10 having the colloidal crystal film 30 can be changed. Furthermore, since the substrate 20, the multiple nanoparticles 32, and the matrix resin 31 are all translucent, the optical adjustment sheet 10 also has translucency in the visible light region and is less likely to absorb light.

Next, the behavior of the first light L10 and the second light L20 incident on the optical adjustment sheet 10 will be explained using FIG. 6.

Figure 6 is a schematic diagram illustrating the behavior of the first light L10 and the second light L20 in this embodiment.

As shown in FIG. 6, the first light L10 is incident on the first surface 11, and the second light L20 is incident on the second surface 12. Furthermore, the optical adjustment sheet 10 reflects light of a predetermined wavelength region among the first light L10 and the second light L20. In other words, light of the first light L10 and the second light L20 other than the light of the predetermined wavelength region is transmitted through the optical adjustment sheet 10.

The first light L10 and the second light L20 reflected by the optical adjustment sheet 10 are referred to as the first reflected light L11 and the second reflected light L21, and the first light L10 and the second light L20 transmitted through the optical adjustment sheet 10 are referred to as the first transmitted light L12 and the second transmitted light L22. The first reflected light L11 and the second transmitted light L22 are light emitted toward the space in which the display device 1 is installed and the user U, and the first transmitted light L12 and the second reflected light L21 are light emitted toward the display surface portion 2.

Here, we will explain the effect that the first light L10 and the second light L20 have on the user U. As described above, in this embodiment, the color presented by the optical adjustment sheet 10 appears to the user U as if it were the color presented by the display surface portion 2.

First, when the display device 1 is turned off, that is, when the display surface 2 is not emitting the second light L20 (hereinafter referred to as turned off), the color exhibited by the optical adjustment sheet 10 is mainly the color of the first reflected light L11. In this embodiment, since the first light L10 is white light and the reflection spectrum of the optical adjustment sheet 10 satisfies the first condition, the first reflected light L11 is colored light in the visible light region. More specifically, since the reflection peak wavelength λr is 570 nm or more and 580 nm or less, the first reflected light L11 is yellow light.

Therefore, the user U sees the color of the display surface 2 as a color (e.g., yellow) other than the conventional black, and the display device 1 easily blends in with the interior or exterior of the space. Therefore, the display device 1 can enhance the design of the space.

Next, when the display device 1 is turned on, that is, when the display surface portion 2 emits the second light L20 (hereinafter referred to as when turned on), the color exhibited by the optical adjustment sheet 10 is mainly the color of the second transmitted light L22.

As described above, the reflection spectrum of the optical adjustment sheet 10 satisfies the first condition. Therefore, since the optical adjustment sheet 10 is less likely to reflect light of the second emission peak wavelength λ2 and the third emission peak wavelength λ3, which have high emission intensity, the amount of the second reflected light L21 is small, that is, the amount of the second transmitted light L22 is large. In other words, since the second light L20 that displays an image on the display surface 2 is less likely to be blocked (reflected) by the optical adjustment sheet 10, the visibility of the image is less likely to decrease. Therefore, in the display device 1, the effect on the displayed image is small.

In summary, a display device 1 has been realized that has minimal impact on the displayed image when lit, and can enhance the design of the space when turned off.

Furthermore, in this embodiment, the colloidal crystal film 30 is used to realize a reflection spectrum having a narrow bandwidth reflection peak. Therefore, the amount of light of the second transmitted light L22 can be increased, so that the visibility of the image is less likely to decrease.

As described above, the optical adjustment sheet 10 may include, for example, a dielectric multilayer film instead of the colloidal crystal film 30. In this case, too, a reflection spectrum having a narrow bandwidth reflection peak is realized. This allows the amount of light of the second transmitted light L22 to be increased, making it less likely that the visibility of the image will decrease.

Note that the reflection peak wavelength λr and reflection peak half-width w in the reflection spectrum of the optical adjustment sheet 10 are not limited to the above.

For example, the reflection peak wavelength λr may be between the shortest emission peak wavelength among the multiple emission peak wavelengths and 380 nm, and the reflection peak half-width w may be equal to or less than the difference between the shortest emission peak wavelength and 380 nm (hereinafter, the second condition). As an example, the reflection peak wavelength λr may be between the first emission peak wavelength λ1 and 380 nm, and may be equal to or less than the difference between the first emission peak wavelength λ1 and 380 nm.

For example, the reflection peak wavelength λr may be between the longest emission peak wavelength among the multiple emission peak wavelengths and 780 nm, and the reflection peak half-width w may be less than or equal to the difference between the longest emission peak wavelength and 780 nm (hereinafter, the third condition). As an example, the reflection peak wavelength λr may be between the third emission peak wavelength λ3 and 780 nm, and the reflection peak half-width w may be less than or equal to the difference between the third emission peak wavelength λ3 and 780 nm.

The reflectance spectrum of the optical adjustment sheet 10 satisfies at least one of the first condition, the second condition, and the third condition.

In other words, in this embodiment, the optical adjustment sheet 10 is designed so that the reflection peaks of the optical adjustment sheet 10 overlap less with the blue light, green light, and red light emitted from the sub-pixels in the display surface portion 2.

As a result, the color presented by the display surface 2 is perceived by the user U as a color other than the conventional black, and the display device 1 easily blends in with the interior or exterior of the space. In addition, the second light L20 that displays an image on the display surface 2 is unlikely to be blocked by the optical adjustment sheet 10, so the visibility of the image is unlikely to decrease. In other words, a display device 1 is realized that has little effect on the displayed image when turned on, and can enhance the design of the space when turned off.

Further, for example, the reflection peak wavelength λr and reflection peak half-width w in the reflection spectrum of the optical adjustment sheet 10 may be as follows:

Figure 7 shows the emission spectrum of the second light L20 to explain other examples of the reflection peak wavelength λr and the reflection peak half-width w in this embodiment.

Here, the first and second emission peak wavelengths λ1 and λ2 corresponding to the peak wavelengths of the emission spectra of blue light and green light are used for explanation. In addition, the reflection peak wavelength λr and the reflection peak half-width w may be determined using similar conditions for the second and third emission peak wavelengths λ2 and λ3.

First, the difference between the first emission peak wavelength λ1 and the second emission peak wavelength λ2 is X, and the intermediate wavelength between the first emission peak wavelength λ1 and the second emission peak wavelength λ2 is λm. In other words, λm is the sum of the first emission peak wavelength λ1 and the second emission peak wavelength λ2 divided by 2. In this case, the reflection peak wavelength λr may satisfy the following formula (1), and the reflection peak half-width w may satisfy the following formula (2).

(1) λm-a×(X/2)≦λr≦λm+a×(X/2)
(2) w = b × X

a and b are real numbers, and a should be 0.9 or less, preferably 0.6 or less, and even better 0.3 or less. b should be 0.1 to 0.9 or less, preferably 0.2 to 0.8 or less, and even better 0.3 to 0.7 or less.

The smaller a is, the less likely the reflection peak wavelength λr is to overlap with the first emission peak wavelength λ1 and the second emission peak wavelength λ2, and the smaller b is, the more likely a reflection spectrum with a narrow bandwidth reflection peak is realized. Therefore, the amount of light of the second transmitted light L22 can be increased.

On the other hand, the larger b is, the easier it is to manufacture the optical adjustment sheet 10. For example, when the optical adjustment sheet 10 includes a colloidal crystal film 30, it becomes easier to tolerate disruptions to the periodic arrangement of the multiple nanoparticles 32.

Therefore, by having a and b within the above ranges, the display device 1 blends easily into the interior or exterior of the space, image visibility is less likely to decrease, and it is easy to manufacture.

The second light source has a light emitting diode, but is not limited to this, and may have a light emitter using cathode luminescence or plasma discharge, a cold cathode fluorescent lamp, a light emitting diode, or a laser diode. As a result, in the display device 1 equipped with the above-mentioned second light source, when it is turned on, the effect on the displayed image is small, and when it is turned off, the design of the space can be improved.

(Embodiment 2)
Second Embodiment Next, a display device 1a according to a second embodiment will be described with reference to Fig. 8. Fig. 8 is an exploded perspective view showing the configuration of a display device 1a according to the present embodiment.

The second embodiment differs from the first embodiment in that multiple optical adjustment sheets are provided.

Specifically, the display device 1a has the same configuration as the display device 1 according to embodiment 1, except that it has a first optical adjustment sheet 10a and a second optical adjustment sheet 10b as multiple optical adjustment sheets.

The first optical adjustment sheet 10a has the same configuration as the optical adjustment sheet 10 according to the first embodiment. The second optical adjustment sheet 10b has the same configuration as the optical adjustment sheet 10 according to the first embodiment, except that the average particle diameter of the nanoparticles 32 contained in the colloidal crystal film 30 in the second optical adjustment sheet 10b is different. Here, since the particle diameters in the colloidal crystal film 30 are different from each other, the reflection peak wavelength of the reflection spectrum of the first optical adjustment sheet 10a and the reflection peak wavelength of the reflection spectrum of the second optical adjustment sheet 10b are different. In this embodiment, the particle diameter of the nanoparticles 32 in the colloidal crystal film 30 of the second optical adjustment sheet 10b is 160 nm. At this time, the reflection peak wavelength of the reflection spectrum of the second optical adjustment sheet 10b is 475 nm or more and 485 nm or less.

In this embodiment, in the reflection spectrum of the first optical adjustment sheet 10a, which is one of the multiple optical adjustment sheets, and the second optical adjustment sheet 10b, which is the other, the reflection peak wavelength and the reflection peak half-width are as follows. In the first optical adjustment sheet 10a, the reflection peak wavelength is located between the second emission peak wavelength and the third emission peak wavelength, and the reflection peak half-width is equal to or less than the difference between the second emission peak wavelength and the third emission peak wavelength. In the second optical adjustment sheet 10b, the reflection peak wavelength is located between the first emission peak wavelength and the second emission peak wavelength, and the reflection peak half-width is equal to or less than the difference between the first emission peak wavelength and the second emission peak wavelength.

In addition, in FIG. 8, the light corresponding to the first reflected light L11 in embodiment 1 is described as the first reflected light L11a and 11b. Note that the first light L10 reflected by the first optical adjustment sheet 10a is the first reflected light L11a, and the first light L10 reflected by the second optical adjustment sheet 10b is the first reflected light L11b.

As shown in FIG. 8, in this embodiment, the first and second optical adjusting sheets (10a and 10b) are arranged so as not to overlap in a planar view. The first optical adjusting sheet 10a is provided so as to cover a portion of the display surface portion 2, and the second optical adjusting sheet 10b is provided so as to cover the other portion of the display surface portion 2. In other words, in this embodiment, it appears to the user U as if the color presented by the first optical adjusting sheet 10a is the color presented by a portion of the display surface portion 2, and the color presented by the second optical adjusting sheet 10b is the color presented by the other portion of the display surface portion 2.

For example, when the light is off, the color exhibited by the first optical adjustment sheet 10a is mainly the color of the first reflected light L11a. More specifically, the first reflected light L11a is yellow light, as in embodiment 1. The color exhibited by the second optical adjustment sheet 10b is mainly the color of the first reflected light L11b. More specifically, since the reflection peak wavelength of the reflection spectrum of the second optical adjustment sheet 10b is 475 nm or more and 485 nm or less, the first reflected light L11b is blue light.

As a result, compared to the first embodiment, the colors presented by the display surface 2 appear to the user U to be more diverse. As a result, the display device 1a blends in more easily with the interior or exterior of the space, and the display device 1a can further enhance the design of the space.

Furthermore, for example, by forming a pattern using the first optical adjustment sheet 10a and the second optical adjustment sheet 10b, the display device 1a can more easily blend in with the interior or exterior of the space.

(First Modification of the Second Embodiment)
Next, a display device 1b according to a first modification of the second embodiment will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is an exploded perspective view showing the configuration of a display device 1b according to a first modification of the present embodiment.

Variation 1 of embodiment 2 differs from embodiment 2 in that multiple optical adjustment sheets are stacked.

Specifically, the display device 1b has the same configuration as the display device 1a according to the second embodiment, but as shown in FIG. 9, in this embodiment, the multiple optical adjustment sheets (first and second optical adjustment sheets 10a and 10b) are stacked.

The second optical adjustment sheet 10b is provided so as to cover the entire surface of the display surface portion 2, and the first optical adjustment sheet 10a is provided so as to cover the entire surface of the second optical adjustment sheet 10b. In other words, in this modified example, the user U sees the colors presented by the first optical adjustment sheet 10a and the second optical adjustment sheet 10b as if they were the colors presented by the display surface portion 2.

For example, when the light is off, the color exhibited by the first optical adjustment sheet 10a and the second optical adjustment sheet 10b is mainly a combination of the first reflected light L11a (yellow light) and the first reflected light L11b (blue light).

Note that the second optical adjustment sheet 10b is disposed closer to the display surface 2 than the first optical adjustment sheet 10a, but this is not limited thereto, and the first optical adjustment sheet 10a may be disposed closer to the display surface 2 than the second optical adjustment sheet 10b.

Here, we will explain in more detail the colors exhibited by the first optical adjusting sheet 10a and the second optical adjusting sheet 10b. In addition, the reflection peak wavelength of the reflection spectrum of the first optical adjusting sheet 10a is denoted as λr1, and the reflection peak wavelength of the reflection spectrum of the second optical adjusting sheet 10b is denoted as λr2.

Figure 10 is an xy chromaticity diagram showing the reflection peak wavelength λr1 and reflection peak wavelength λr2 for variant 1 of this embodiment. Region A shown in the xy chromaticity diagram indicates the white region.

As described above, the first reflected light L11a is yellow light corresponding to the reflection peak wavelength λr1 (570 nm or more and 580 nm or less), and the first reflected light L11b is blue light corresponding to the reflection peak wavelength λr2 (475 nm or more and 485 nm or less). The two light colors are approximately in a complementary positional relationship. Therefore, when the light is off, the color exhibited by the first optical adjustment sheet 10a and the second optical adjustment sheet 10b can be within the range of region A, that is, within the range of white light.

Therefore, to the user U, the color presented by the display surface portion 2 is not the conventional black color, but is visually perceived as a composite color of the first reflected light L11a and the first reflected light L11b (e.g., white), and the display device 1 easily blends in with the interior or exterior of the space. Furthermore, compared to the case where one optical adjustment sheet 10 is provided as shown in embodiment 1, there is greater freedom in designing the color presented by the display surface portion 2. Therefore, the display device 1b can enhance the design of the space.

(Modification 2 of the second embodiment)
Next, a display device 1c according to a second modification of the second embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is an exploded perspective view showing the configuration of a display device 1c according to a second modification of the present embodiment.

The display device 1c according to this modification has the same configuration as the display device 1b according to modification 2 of embodiment 2, except that it has four optical adjustment sheets including the first, second, third and fourth optical adjustment sheets 10a, 10b, 10c and 10d.

In the display device 1c according to this modified example, the four optical adjustment sheets are stacked in the order of the first, second, third and fourth optical adjustment sheets. The fourth optical adjustment sheet 10d is arranged to cover the entire surface of the display surface portion 2, and the third optical adjustment sheet 10c is arranged to cover the entire surface of the fourth optical adjustment sheet 10d. The second optical adjustment sheet 10b is arranged to cover the entire surface of the third optical adjustment sheet 10c, and the first optical adjustment sheet 10a is arranged to cover the entire surface of the second optical adjustment sheet 10b. In other words, in this modified example, the colors presented by the first, second, third and fourth optical adjustment sheets 10a, 10b, 10c and 10d appear to the user U as if they were the colors presented by the display surface portion 2. For example, when the light is off, the colors exhibited by the first, second, third, and fourth optical adjustment sheets 10a, 10b, 10c, and 10d are mainly a composite color of the first light L10 reflected by each of the first, second, third, and fourth optical adjustment sheets 10a, 10b, 10c, and 10d.

The reflection peak wavelength and the reflection peak half-width in the reflection spectrum of the third optical adjustment sheet 10c satisfy the second condition above. The reflection peak wavelength and the reflection peak half-width in the reflection spectrum of the fourth optical adjustment sheet 10d satisfy the third condition above.

The display device according to the comparative example has the same configuration as the display device 1 according to the first embodiment, except that it does not have the optical adjustment sheet 10.

Here, the second light according to this modification and the comparative example will be described with reference to FIG. 12. FIG. 12 is a schematic u'v' chromaticity diagram of the second light according to this modification and the comparative example.

In FIG. 12, the emission spectrum of the second light L20 that has passed through the four optical adjustment sheets in this modified example is shown within a dashed line frame, and the emission spectrum of the second light emitted from the display surface portion in the comparative example is shown within a dashed line frame.

The emission spectrum of the second light in this modified example and the comparative example both has an emission spectrum of blue light, green light, and red light.

In this modified example, the first, second, third and fourth optical adjustment sheets 10a, 10b, 10c and 10d satisfy the above conditions, and therefore light in a predetermined wavelength region of the second light L20 is reflected. Therefore, when comparing the emission spectrum of the second light according to this modified example and the comparative example, the emission spectrum of the second light L20 according to this modified example is broader than the emission spectrum of the second light according to the comparative example, and has a sharper emission spectrum. In other words, the emission spectrum of the second light L20 according to this modified example has an emission spectrum of blue light, green light and red light that is closer to monochromatic light.

Furthermore, the u'v' chromaticity diagram shown in FIG. 12 shows the chromaticity based on the blue light, green light, and red light of the emission spectrum of the second light in this modified example and the comparative example.

As shown in FIG. 12, the second light L20 according to this modified example has a wider color gamut than the second light according to the comparative example. As described above, the emission spectrum of the second light L20 according to this modified example has an emission spectrum closer to monochromatic light. Therefore, in this modified example, the color gamut can be expanded compared to the comparative example, that is, the range of colors represented by the second light L20 can be expanded.

(Embodiment 3)
Next, a display device 1 according to a third embodiment will be described with reference to Fig. 13. Fig. 13 is a schematic diagram showing the configurations of the display device 1 and a projection device 400 according to the present embodiment.

Embodiment 3 differs from embodiment 1 in that the first light source is a light source provided in the projection device 400.

The projection device 400 is a projector, but is not limited to this and may be, for example, a floodlight. The projection device 400 is a device that projects an image onto the optical adjustment sheet 10 provided in the display device 1. More specifically, the first light L10 emitted by the first light source provided in the projection device 400 is light that projects an image (hereinafter, the first image). In this case, the optical adjustment sheet 10 can be said to be a screen for the projection device 400.

In this embodiment, the first image projected by the first light L10 is different from the image displayed by the second light L20 emitted by the display surface unit 2 (hereinafter, the second image), but they may be the same. Specifically, the first image is an image that highlights the second image toward the circle surrounded by the dashed line shown in the second image so as to make it stand out.

In addition, in FIG. 13, the first image is projected only onto a part of the optical adjustment sheet 10 (i.e., within the circle surrounded by the dashed line), but the first image may be projected onto the entire optical adjustment sheet 10. For example, if the first image is the same as the second image and is projected onto the entire optical adjustment sheet 10, that is, the images are superimposed, the second image can be made more noticeable. Furthermore, in this case, the light (yellow light) in the wavelength region reflected by the optical adjustment sheet 10 out of the second light L20 is not visible to the user U, but the light (yellow light) in the wavelength region reflected by the optical adjustment sheet 10 out of the first light L10 is visible to the user U. In other words, the light (yellow light) in the missing wavelength region of the second image can be supplemented by the first image, so that the second image can be expressed more vividly.

In summary, in the display device 1c according to this embodiment, it is possible to make the second image displayed by the second light L20 stand out more. In other words, it is possible to enhance the eye-catching effect of the display device 1.

(Other embodiments)
Although the display device and the like according to the present invention have been described above based on the respective embodiments, the present invention is not limited to these respective embodiments. As long as they do not deviate from the gist of the present invention, various modifications conceived by those skilled in the art to the embodiments and other forms constructed by combining some of the components in each embodiment are also included in the scope of the present invention.

For example, the second light source may have a light emitting diode that emits blue light, a light emitting diode that emits green light, and a light emitting diode that emits red light. In this case, the second light L20 is light that includes blue light, green light, and red light. In this case, the display device may or may not have a color filter.

In addition, in each of the above embodiments, one optical adjustment sheet has one colloidal crystal film, but this is not limited to this. For example, one optical adjustment sheet may have multiple colloidal crystal films stacked together. In this case, one optical adjustment sheet may have the same number of reflection peaks as the number of colloidal crystal films.

In the above embodiment, the second light L20 includes three colors of light, i.e., has three emission peaks in the emission spectrum, but is not limited to this. For example, the second light L20 may include four or more colors of light, i.e., has four or more emission peaks in the emission spectrum.

The display devices 1, 101, and 201 are not limited to liquid crystal monitors. They may be cathode ray tube monitors, plasma monitors, organic electroluminescence monitors, etc. Also, quantum dot semiconductors that emit fluorescence may be used as phosphors.

Furthermore, the above embodiment may be modified, substituted, added, omitted, etc. in various ways within the scope of the claims or their equivalents.

Reference Signs List 1 Display device 2 Display surface portion 10 Optical adjustment sheet 11 First surface 12 Second surface 30 Colloidal crystal film 300 First light source L10 First light L20 Second light w Reflection peak half-width λ1 First emission peak wavelength λ2 Second emission peak wavelength λ3 Third emission peak wavelength λr Reflection peak wavelength

Claims (9)

A display device illuminated by a first light emitted from a first light source,
a display surface emitting a second light for displaying an image;
an optical adjustment sheet provided to cover the display screen portion, the optical adjustment sheet having a first surface on which the first light is incident and a second surface facing away from the first surface on which the second light is incident, the optical adjustment sheet reflecting light in a predetermined wavelength region among the first light and the second light;
Equipped with
the second light has a plurality of emission peak wavelengths,
In the reflection spectrum of the optical adjustment sheet,
a first condition is that a reflection peak wavelength is located between two adjacent emission peak wavelengths among the plurality of emission peak wavelengths, and a reflection peak half-width is equal to or smaller than a difference between the two adjacent emission peak wavelengths;
a second condition being that the reflection peak wavelength is located between the shortest emission peak wavelength among the plurality of emission peak wavelengths and 380 nm, and the reflection peak half-width is equal to or smaller than the difference between the shortest emission peak wavelength and 380 nm;
When a third condition is that the reflection peak wavelength is located between the longest emission peak wavelength among the plurality of emission peak wavelengths and 780 nm, and the reflection peak half width is equal to or smaller than the difference between the longest emission peak wavelength and 780 nm,
the reflection spectrum satisfies at least one of the first condition, the second condition, and the third condition. A plurality of the optical adjustment sheets are provided,
The display device according to claim 1 , wherein the reflection peak wavelengths of the plurality of optical adjusting sheets are different from each other. the plurality of emission peak wavelengths include a first emission peak wavelength, a second emission peak wavelength adjacent to the first emission peak wavelength and longer than the first emission peak wavelength, and a third emission peak wavelength adjacent to the second emission peak wavelength and longer than the second emission peak wavelength,
In the reflection spectrum of one of the plurality of optical adjusting sheets, the reflection peak wavelength is located between the first emission peak wavelength and the second emission peak wavelength, and the reflection peak half width is equal to or less than the difference between the first emission peak wavelength and the second emission peak wavelength,
The display device of claim 2, wherein in the reflection spectrum of another optical adjustment sheet among the plurality of optical adjustment sheets, the reflection peak wavelength is located between the second emission peak wavelength and the third emission peak wavelength, and the reflection peak half-width is less than or equal to the difference between the second emission peak wavelength and the third emission peak wavelength. The display device according to claim 2 , wherein the plurality of optical adjusting sheets are laminated. The display device according to any one of claims 1 to 4, wherein the optical adjustment sheet has a colloidal crystal film. The display device according to any one of claims 1 to 5, wherein the optical adjustment sheet has a dielectric multilayer film. 7. The display device according to claim 1, wherein the second light source of the display screen portion has a light-emitting body utilizing cathode luminescence or plasma discharge, a cold cathode fluorescent lamp, a light-emitting diode, a laser diode, or an organic light-emitting diode. The display device according to claim 1 , wherein the first light source is a light source included in a projection device. An optical adjustment sheet,
a first surface on which a first light emitted from a first light source is incident;
a second surface facing away from the first surface and receiving second light emitted from a second light source provided in the display device;
Equipped with
The display device is provided so as to cover a display surface portion of the display device.
Reflecting light in a predetermined wavelength range of the first light and the second light,
the second light is light for displaying a moving image on the display surface, and has a plurality of emission peak wavelengths when incident on the second surface;
In the reflection spectrum of the optical adjustment sheet,
a first condition is that a reflection peak wavelength is located between two adjacent emission peak wavelengths among the plurality of emission peak wavelengths, and a reflection peak half-width is equal to or smaller than a difference between the two adjacent emission peak wavelengths;
a second condition being that the reflection peak wavelength is located between the shortest emission peak wavelength among the plurality of emission peak wavelengths and 380 nm, and the reflection peak half-width is equal to or smaller than the difference between the shortest emission peak wavelength and 380 nm;
When a third condition is that the reflection peak wavelength is located between the longest emission peak wavelength among the plurality of emission peak wavelengths and 780 nm, and the reflection peak half width is equal to or smaller than the difference between the longest emission peak wavelength and 780 nm,
the reflection spectrum satisfies at least one of the first condition, the second condition, and the third condition.

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