JP6274568B2 - Display device - Google Patents

Description

  The present invention relates to a display device including a light control sheet, and more particularly to a display device that can ensure design and harmony with the surroundings without impairing display image quality.

  In Patent Document 1, a functional liquid crystal film that can be electrically switched between transmission and non-transmission is applied to a display device for the purpose of achieving harmony with the surrounding environment when not driven. The device disclosed in Patent Document 1 includes a housing, a display unit supported by the housing, and a concealing member. Of these, the concealing member includes a functional liquid crystal film. In the device disclosed in Patent Document 1, the display unit can be concealed by making the functional liquid crystal film opaque. Therefore, it is possible to effectively prevent the display unit from greatly losing harmony with the surroundings.

WO2010 / 113739A1

  However, in the device disclosed in Patent Document 1, the concealing member including the functional liquid crystal film is disposed away from the display unit by the housing. In such a device, an air layer is formed between the concealing member and the display unit, which causes a double image (ghost) problem and a decrease in contrast due to external light reflection.

  The present invention has been made in consideration of the above points, and an object of the present invention is to provide a display device that can improve the design and harmony with the surroundings without impairing the display image quality.

A display device according to the present invention comprises:
An image forming apparatus having an image forming surface;
A front plate disposed in contact with or in contact with the image forming surface of the image forming apparatus,
The front plate includes a light control sheet capable of switching between a high haze state and a low haze state.

  In the display device according to the present invention, the light control sheet may be in a high haze state when a voltage is not applied and may be in a low haze state when a voltage is applied.

  In the display device according to the present invention, the front plate may include a plurality of light control sheets.

  In the display device according to the present invention, the light control sheet includes a polymer network made of a resin formed in a three-dimensional network, liquid crystal molecules and dichroic dyes located in voids formed inside the polymer network. You may make it have.

  In the display device according to the present invention, the image forming surface of the image forming apparatus may be a curved surface, and the light control sheet may be bent.

In the display device according to the present invention,
The image forming apparatus includes a light receiving unit that receives an external signal,
The light control sheet is positioned facing the image forming surface and is switchable between a high haze state and a low haze state, and is positioned facing the light receiving unit and can transmit the external signal. And a light receiving area,
The light control sheet may be unable to be switched to the high haze state in the light receiving region.

  ADVANTAGE OF THE INVENTION According to this invention, harmony with the designability of a display apparatus and the circumference | surroundings can be ensured, without impairing display image quality.

FIG. 1 is a view for explaining an embodiment of the present invention, and is a view showing a longitudinal sectional view of a display device. FIG. 2 is a plan view of the display device of FIG. FIG. 3 is a cross-sectional view illustrating an example of a light control sheet that can be incorporated in the display device of FIG. 1, and illustrates the light control sheet in a state where no voltage is applied. FIG. 4 is a cross-sectional view showing the light control sheet of FIG. 3 in a state where a voltage is applied. FIG. 5 is a cross-sectional view showing another example of the light control sheet that can be incorporated in the display device of FIG. 1, and is a view showing the light control sheet in a state where no voltage is applied. 6 is a cross-sectional view showing the light control sheet of FIG. 5 in a state where a voltage is applied. FIG. 7 is a diagram showing a cross section of the display device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  1 to 7 are diagrams for explaining an embodiment of a display device according to the present invention. Among these, FIG.1 and FIG.2 is a longitudinal cross-sectional view or top view which respectively show a display apparatus. 3 and 4 are longitudinal sectional views showing an example of a light distribution sheet that can be incorporated into the display device, and FIGS. 5 and 6 are longitudinal sectional views showing another example of the light distribution sheet that can be incorporated into the display device. FIG. FIG. 7 is a cross-sectional view showing the display device in a region where the light receiving unit of the image forming apparatus is provided.

  In the present specification, the terms “sheet”, “film”, and “plate” are not distinguished from each other only based on the difference in names. For example, “sheet” is a concept that includes a member that can be called a film or a plate. Therefore, “light distribution sheet” is only a difference in name from a member called “light distribution film” or “light distribution plate”. Cannot be distinguished.

  In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  As shown in FIG. 1, the display device 10 includes an image forming device 20 having an image forming surface 20 a and a front plate 30 laminated on the image forming device 20. The front plate 30 includes a light control sheet 40 capable of switching between a high haze state and a low haze state. In addition, the display apparatus 10 shown by FIG. 1 is arrange | positioned in the recessed part 5a formed in the wall 5 as an example. The display surface 10a of the display device 10 is aligned with the wall surface. As will be described in detail below, the display device 10 described here is devised so that it can be given design characteristics and harmony with the surroundings without impairing the display image quality. Hereinafter, each component of the display device 10 will be described.

  The image forming apparatus (display device main body) 20 is a means for forming a still image or a moving image that can be observed by an observer. The image forming apparatus 20 displays the formed image on the image forming surface 20a. The image forming apparatus 20 is not particularly limited, and various devices known by names such as display devices can be used. As an example, a liquid crystal display device, a cathode ray tube display device (CRT), a plasma display, an electroluminescence display (ELD), a field emission display (FED), or the like can be used as the image forming apparatus 20.

  The illustrated image forming apparatus 20 includes a housing 22, a display panel 25 held by the housing 22, and a control circuit (not shown). The display panel 25 is configured according to the type of the image forming apparatus 20, and includes, for example, a liquid crystal display panel, a plasma display panel, an electroluminescence display panel, or the like. The display panel 25 forms the image forming surface 20a of the image forming apparatus 20 with the surface on the viewer side.

  The illustrated image forming apparatus 20 includes a light receiving unit 28 that receives an external signal. The external signal is typically an operation signal transmitted from a remote operation device called a remote controller or the like. The external signal is formed by light having a wavelength in the infrared band, for example. The external signal received by the light receiving unit 28 is processed by a control circuit (not shown), and the operation of the display panel 25 is realized. For example, when the light receiving unit 28 receives an external signal, the power of the image forming apparatus 20 is turned on and off, and the volume is increased or decreased. When the image forming apparatus 20 functions as a television receiver, the channel is changed. Etc. are also implemented.

  Next, the front plate 30 will be described. The front plate 30 is joined to the display surface 20a of the image forming apparatus 20 or arranged in contact, particularly in surface contact. In the illustrated example, the front plate 30 is bonded to the observer side surface of the image forming apparatus 20 including the image forming surface 20 a via the bonding layer 15. That is, the bonding layer 15 is in surface contact with the front plate 30 and the image forming apparatus 20 between the front plate 30 and the image forming apparatus 20 to bond them together.

  As the bonding layer 15, various adhesive layers and adhesive layers can be used. However, when the refractive index difference between the bonding layer 15 and the front plate 30 or the image forming apparatus 20 increases, image light from the image forming apparatus 20 is reflected or external light incident on the display device 10 is reflected. Or In this case, problems such as dark images and low contrast occur. Therefore, it is preferable that the bonding layer 15 is appropriately selected so that the difference in refractive index between adjacent portions is small.

  The front plate 30 further includes a functional layer 32 bonded to the light control sheet 40 in addition to the light control sheet 40 capable of switching between a high haze state and a low haze state. The functional layer 32 is a layer intended to perform some function. As an example, a hard coat property, an antireflection property, an antistatic property, an antifouling property, or a layer that exhibits these two or more functions can be given. The number of functional layers included in the front plate 30 can be any number greater than or equal to one.

  Next, the light control sheet 40 will be further described in detail. The light control sheet 40 is a sheet-like member in which the haze value [%] changes. Haze can be measured by a method based on JIS K7136 using a haze meter (manufactured by Murakami Color Research Laboratory, product number: HM-150).

  The light control sheet 40 may be formed using various sheet-like members whose haze values change. However, in the display device 10 described here, the light control sheet 40 is intended to conceal the image forming apparatus 20 in a high haze state, that is, to obscure the presence of the image forming apparatus 20. Therefore, it is preferable that the haze value of the light control sheet 40 in a high haze state is 90% or more. On the other hand, the light control sheet 40 is intended not to impair the visibility of the image formed by the image forming apparatus 20 in the low haze state. Therefore, the haze value of the light control sheet 40 in the low haze state is preferably 10% or less.

  An example of the light control sheet 40 that enables switching of the haze value is a sheet-like member whose haze value changes depending on whether or not a voltage is applied. 3 to 6 exemplify a polymer network type liquid crystal (PNLC) as a light control sheet capable of switching between a high haze state and a low haze state according to the presence or absence of voltage application. Among them, the light control sheet 40 shown in FIGS. 3 and 4 is a type called a normal type, and the light control sheet 40 shown in FIGS. 5 and 6 is a type called a reverse type.

  The normal type light control sheet 40 shown in FIGS. 3 and 4 is disposed between a pair of base materials 41, 42, and a first base material 41 and a second base material 42 disposed to face each other, and A first electrode 43 and a second electrode 44 respectively stacked on the corresponding base materials 41 and 42; and a polymer network 48 and a liquid crystal material 49 disposed between the pair of electrodes 43 and 44, respectively. Yes. The pair of base materials 41 and 42 has visible light permeability, and allows an image formed by the image forming apparatus 20 to be visually recognized. For the same reason, the pair of electrodes 43 and 44 also has visible light transparency. The pair of base materials 41 and 42 can be formed using, for example, transparent glass or a resin film. The pair of electrodes 43 and 44 can be formed using a transparent conductive material such as indium tin oxide.

  On the other hand, the reverse type light control sheet 40 shown in FIGS. 5 and 6 further includes a pair of alignment films 45 and 46 disposed between the pair of electrodes 43 and 44. The first alignment film 45 is stacked on the first electrode 43, and the second alignment film 46 is stacked on the second electrode 44. The polymer network 48 and the liquid crystal material 49 are disposed between the pair of alignment films 45 and 46. The alignment films 45 and 46 are so-called vertical alignment films, and align the liquid crystal molecules so that the longitudinal direction of the liquid crystal molecules is along the normal direction of the alignment films 45 and 46.

  The polymer network 48 is formed in a three-dimensional network shape, in other words, a sponge shape. The polymer network 48 has a number of voids formed therein. A liquid crystal material 49 is provided in the gap. The polymer network 48 is formed from a cured product of a resin material. On the other hand, the liquid crystal material 49 is a liquid material containing liquid crystal molecules 50 having a longitudinal direction. The liquid crystal molecule 50 has a refractive index anisotropy corresponding to its shape. That is, the refractive index in the direction orthogonal to the longitudinal direction of the liquid crystal molecules 50 is different from the refractive index in the direction parallel to the longitudinal direction of the liquid crystal molecules 50.

  As an example, in the light control sheet 40 shown in FIGS. 3 to 6, the refractive index of the liquid crystal molecules 50 and the refractive index of the polymer network 48 in the state where the liquid crystal molecules 50 are aligned (FIGS. 4 and 5). Is complete. In this state, the light incident on the light control sheet 40 can pass through the light control sheet 40 without greatly bending the traveling direction. That is, in the state where the liquid crystal molecules 50 are aligned, the light control sheet 40 is in a low haze state. In this state, the light control sheet 40 is in a transparent state, and the image forming apparatus 20 can be observed through the light control sheet 40.

  On the other hand, in the light control sheet 40 shown in FIGS. 3 to 6, in the state where the liquid crystal molecules 50 of the liquid crystal material 49 are not aligned (FIGS. 3 and 6), the orientation of the liquid crystal molecules 50 in the longitudinal direction is Depending on the polymer network 48 located in the vicinity of the liquid crystal molecules 50, it becomes irregular. In this state, the light incident on the light control sheet 40 is greatly bent in the traveling direction and diffused. That is, in the state where the liquid crystal molecules 50 are not aligned, the light control sheet 40 is in a high haze state. At this time, the light control sheet 40 becomes clouded, and the image forming apparatus 20 is concealed by the light control sheet 40.

  In the normal type light control sheet 40 shown in FIGS. 3 and 4, positive type liquid crystal molecules 50 are used. In the state where the switch 18 shown in FIG. 3 is opened (cut state), the orientation of the liquid crystal molecules 50 is irregular. Therefore, the normal type light control sheet 40 can be clouded and conceal the image forming apparatus 20 in a state where an electric field is not applied. On the other hand, as shown in FIG. 4, the liquid crystal molecules 50 are aligned when the switch 18 is closed (entered). Therefore, the normal type light control sheet 40 becomes transparent when a voltage is applied, and the observer can view the image formed on the image forming surface 20a of the image forming apparatus 20 via the transparent light control sheet 40. Can be observed.

  In the reverse type light control sheet 40 shown in FIGS. 5 and 6, negative liquid crystal molecules 50 are used. In the state in which the switch 18 shown in FIG. 5 is opened (cut state), the liquid crystal molecules 50 are vertically aligned by the alignment action of the pair of alignment films 45 and 46. Therefore, the reverse type light control sheet 40 becomes transparent when no voltage is applied, and the observer is formed on the image forming surface 20 a of the image forming apparatus 20 via the transparent light control sheet 40. The image can be observed. On the other hand, as shown in FIG. 6, in the state in which the switch 18 is closed (entered state), the orientation of the negative liquid crystal molecules 50 is irregular. Therefore, the reverse type light control sheet 40 can be clouded and conceal the image forming apparatus 20 in a state where an electric field is applied.

  The on / off of the switch 18 that controls the voltage application of the pair of electrodes 43 and 44 may be interlocked with the on / off of the power supply of the image forming apparatus 20. According to such control, while the image forming apparatus 20 is turned on and the image forming apparatus 20 forms an image on the image forming surface 20a, the light control sheet 40 is maintained in a low haze state, and the light control is performed. An image can be observed through the sheet 40. On the other hand, while the image forming apparatus 20 is turned off and image formation is stopped by the image forming apparatus 20, the light control sheet 40 is maintained in a high haze state, and the presence of the image forming apparatus 20 is noticeable. Can be eliminated.

  By the way, the liquid crystal material 49 may have a dichroic dye. Similar to the liquid crystal molecules 50, the dichroic dye has a longitudinal direction and changes its direction according to the presence or absence of voltage application. And a dichroic pigment | dye comes to have a color according to the direction. For this reason, the light control sheet 40 is maintained colorless and transparent in the low haze state, and on the other hand, in the high haze state, the light control sheet 40 can exhibit concealability while having a predetermined color rather than mere white turbidity. Here, the predetermined color can be the same as the surrounding color where the display device 10 is installed, that is, the color of the wall 5 in the illustrated example. According to this example, the display device 10 can be arranged without destroying the color tone of the surrounding environment. That is, the display device 10 can be arranged while maintaining harmony with the surroundings. As such a dichroic dye, various well-known things as disclosed in, for example, JP-A-2007-009120 and JP-A-2011-246411 can be used.

  The light control sheet 40 as described above is a liquid state of an uncured resin composition that forms a polymer network 48 between the pair of base materials 41 and 42, the electrodes 43 and 44, and the alignment films 45 and 46. The liquid crystal material 49 is disposed. From this state, the uncured resin composition is cured. By adjusting the curing speed at this time, the resin composition and the liquid crystal material 49 are each aggregated to some extent. As a result, the liquid crystal material 49 is distributed to some extent, while a three-dimensional network (sponge-like) polymer network 48 is formed. In addition, the resin composition which makes the polymer network 48 can be made into the photocurable resin hardened | cured by irradiating light as an example. When a photocurable resin is used, the dispersion of the liquid crystal material 49 can be adjusted by adjusting the amount of light irradiated by the resin composition.

  Incidentally, the illustrated light control sheet 40 is not limited to the light control region 40a capable of switching between a high haze state and a low haze state as described with reference to FIGS. It also has a possible light receiving area 40b. As shown in FIG. 2, the light receiving region 40 b is located facing the light receiving unit 28 of the image forming apparatus 20. On the other hand, the light control region 40 a is provided at a position facing the entire region of the image forming apparatus 20 other than the vicinity of the light receiving unit 28.

  The light receiving unit 28 is formed of a material that can transmit an external signal received by the light receiving unit 28. Therefore, even when the light control sheet 40 is maintained in a high haze state in the light receiving region 40b, the external signal is incident on the light receiving unit 28 of the image forming apparatus 20 without disturbing the optical path by the light control sheet 40. be able to.

  The light control sheet 40 shown in FIG. 7 includes a pair of base materials 41 and 42 and electrodes 43 and 44, and a polymer network 48 and a liquid crystal material 49 that can be formed by the above-described method. It is obtained by sealing the hollowed portion with a resin material made of a material capable of transmitting an external signal. In the case where the liquid crystal material 49 includes a dichroic dye, it is preferable to form the light receiving region 40b in the same color as the light control region 40a in the high haze state. In the high haze state where the image forming apparatus 20 is concealed, the light control sheet 40 can have the same color as the surrounding environment over the entire region.

  Next, the operation of the display device 10 as described above will be described.

  First, when the image forming apparatus 20 is not forming an image, that is, when the observer is not observing the display device 10, the light control sheet 40 is kept in a high haze state. In the high haze state, since the light control sheet 40 scatters the transmitted light, the image forming apparatus 20 is hardly observed through the light control sheet 40. In particular, in the illustrated example, the light control sheet 40 covers the entire surface of the image forming apparatus 20. Therefore, it is possible to effectively prevent the design and color tone of the entire room from being destroyed by the image forming apparatus 20 while the display device 10 is disposed in the room, for example. That is, the display device 10 can be arranged while harmonizing with the surrounding environment where the display device 10 should be installed.

  When the light control sheet 40 adopts the normal type haze switching method in the light control region 40a, the image forming apparatus 20 is concealed in a state where no voltage is applied. That is, the image forming apparatus 20 can be concealed without using power. Therefore, when the non-use time is longer than the use time as in a normal display device, from the viewpoint of reducing power consumption, when a voltage is applied, the state becomes a low haze state and no voltage is applied. In this case, it is preferable to adopt a normal type haze switching method that results in a high haze state.

  Next, when observing an image on the display device 10, the display device 10 is driven using, for example, a remote control device (remote control). The light receiving unit 28 of the image forming apparatus 20 that receives an operation signal from the remote control device is covered with a light control sheet 40 of the front plate 30 as in the other areas of the image forming apparatus 20. However, the light control sheet 40 has a light receiving region 40 b at a position facing the light receiving unit 28. The light receiving region 40b does not change the haze value according to the presence or absence of voltage application. Accordingly, even when the light control sheet 40 is concealing the image forming apparatus 20 in the light control region 40 a, the light receiving unit 28 of the image forming apparatus 20 operates the image forming apparatus 20 via the light control sheet 40. For this reason, it is possible to stably and reliably receive an external signal.

  When the image forming apparatus 20 forms an image on the image forming surface 20a, the light control sheet 40 of the image forming apparatus 20 is kept in a low haze state. As a result, the observer can observe the image formed by the image forming apparatus 20 via the transparent light control sheet 40.

  Incidentally, in the device disclosed in Patent Document 1 (WO2010 / 113739A1), an air layer is formed between the concealing member and the display unit. Therefore, part of the image light from the display unit is reflected at the interface between the air layer and the concealing member. Part of this reflected light is then reflected at the interface between the air layer and the display unit, and changes its direction to the viewer. The observer visually recognizes the image light reflected twice as the same image at a position different from the image visually recognized by the normal image light. A phenomenon in which the same image is observed at a slightly deviated position is called a double image or a ghost, and it is assumed that the display quality of the display device is significantly deteriorated.

  In addition, when an air layer is formed between the concealing member and the display unit, when most of the ambient light (for example, illumination light) in the region where the display device 10 is disposed enters the display device 10, The light is reflected at the interface between the masking member and the air layer, or at the interface between the air layer and the display unit. Such external light reflection causes a decrease in contrast of the display image.

  On the other hand, in the display device 10 of the present embodiment, the front plate 30 including the light control sheet 40 is disposed in contact with or in contact with the image forming surface 20 a of the image forming device 20. That is, no air layer is formed between the front plate 30 and the image forming surface 20 a of the image forming apparatus 20. Therefore, in the present embodiment, the front plate 30 including the light control sheet 40 is disposed without impairing the image quality of the image displayed by the display device 10. For this reason, while suppressing deterioration of display image quality, the harmony between the surrounding environment in which the display device 10 is disposed and the display device 10 is ensured without impairing the design of the surrounding environment in which the display device 10 is disposed. It becomes possible.

  As mentioned above, although this invention was demonstrated based on one embodiment illustrated, this invention is not limited to these embodiment, In addition, it can implement in a various aspect.

  For example, in the above-described embodiment, the front plate 30 has an example having one light control sheet 40. However, the present invention is not limited to this, and the front plate 30 has two or more light control sheets 40. May be. By providing the plurality of light control sheets 40, the concealability in the high haze state can be significantly improved. On the other hand, when using a plurality of light control sheets 40, it is not necessary to increase the voltage at the time of switching the haze state as compared with the case where one thick light control sheet is used. Therefore, the display device 10 that can exhibit the above-described excellent operational effects can be used with low voltage and safe and excellent handling properties.

  Further, the image forming surface 20a of the image forming apparatus 20 may be a curved surface. As a typical example, when the image forming apparatus 20 is an electroluminescence display, not only the image forming surface 20a but also the image forming apparatus 20 itself can be curved. On the other hand, when the pair of base materials 41 and 42 of the light control sheet 40 is formed of a resin film, the light control sheet 40 has flexibility. Accordingly, the front plate 30 including the light control sheet 40 is curvedly arranged on the image forming surface 20a of the image forming apparatus 20 in a state where the curved surface of the image forming apparatus 20 is bonded or surface-contacted. It becomes possible to do. In such a display device 10, the display surface 10a is also curved. Therefore, the display device 10 having the curved display surface 10a is disposed on a curved wall or column, or is embedded in the curved wall or column so that the surface of the wall or column and the display surface 10a are flush with each other. Can be arranged as follows. Therefore, according to such a display device 10, it is possible to improve the design of the display device 10, and to improve the texture of the area where the display device 10 is arranged to give a high-class feeling. .

  Note that in the device disclosed in Patent Document 1 (WO2010 / 113739A1), the concealing member is supported by the casing apart from the display unit. In this device, if the display surface of the display unit and the concealing member are curved, it is difficult to keep the spacing between the display surface of the display unit and the concealing member uniform in each region on the display surface. When in-plane variation occurs in the separation distance between the display surface of the display unit and the concealing member, the image observed by the observer is different from the image displayed on the display unit.

  In addition, although the some modification with respect to embodiment mentioned above was demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

5 Wall 5a Recess 10 Display device 101 Display surface 15 Bonding layer 17 Power supply 18 Switch 20 Image forming device 201 Image forming surface 22 Housing 25 Display panel 28 Light receiving unit 30 Front plate 32 Functional layer 40 Light control sheet 401 Light control region 402 Light reception Region 41 First substrate 42 Second substrate 43 First electrode 44 Second electrode 45 First alignment film 46 Second alignment film 48 Polymer network 49 Liquid crystal material 50 Liquid crystal molecule

Claims (5)

An image forming apparatus having an image forming surface;
A front plate disposed in contact with or in contact with the image forming surface of the image forming apparatus,
The front plate includes a light control sheet capable of switching between a high haze state and a low haze state ,
The image forming apparatus includes a light receiving unit that receives an external signal,
The light control sheet is positioned facing the image forming surface and is switchable between a high haze state and a low haze state, and is positioned facing the light receiving unit and can transmit the external signal. And a light receiving area,
The said light control sheet | seat is a display apparatus which cannot switch to the said high haze state in the said light reception area | region, and has the same color as the said light control area | region in the said high haze state .   The display device according to claim 1, wherein the light control sheet is in a high haze state when no voltage is applied and is in a low haze state when a voltage is applied.   The display device according to claim 1, wherein the front plate includes a plurality of light control sheets.   The light control sheet includes a polymer network made of a resin formed in a three-dimensional network, and liquid crystal molecules and dichroic dyes located in voids formed inside the polymer network. The display apparatus as described in any one of 1-3. The image forming surface of the image forming apparatus is a curved surface,
The display device according to claim 1, wherein the light control sheet is bent.

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