JP2006308859A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of suppressing light deteriorating coloration of a resin in a phosphor sections by photodegradation. <P>SOLUTION: Amorphous cycloolefin polymers are incorporated in the phosphor sections 3R, 3G, and 3B of the display device 1 equipped with a light source 2 emitting a ultraviolet or visible light and the phosphor sections 3R, 3G, and 3B containing phosphors absorbing the light emitted by the light source 2 to emit visible light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly to a display device using fluorescence.

In recent years, flat display devices such as liquid crystal display devices and plasma display devices have been rapidly spread. Compared with conventional CRT (Cold Cathode Tube) displays, flat display devices have a thin and light feature, and in the field of large display devices, most display devices are flat. Among them, liquid crystal display devices are widespread.
Also, the flat type is rapidly spreading in the field of medium-sized display devices, and the liquid crystal display device is particularly widespread among the flat types.

  However, since the current liquid crystal display device controls the light of the backlight by the liquid crystal light shutter, the passage angle of the backlight light is limited, and the viewing angle of the passed light is extremely limited, depending on the viewing angle There was a viewing angle problem that black and white contrast was reduced and inverted. In order to solve the viewing angle problem, for example, a pixel division method in which the divided pixels have different voltage-transmittance characteristics, a method using an optical compensator, and the like have been proposed. However, these methods have led to an increase in manufacturing costs and member costs, and have hindered the spread of liquid crystal display devices.

  For colorization, a conventional display device uses a micro color filter in which color filters are arranged in red, green, and blue pixels. However, since the micro color filter is expensive, this also hinders the spread of liquid crystal display devices.

  On the other hand, a self-luminous display device represented by a CRT display, a plasma display device, an electroluminescence display or the like does not have a viewing angle problem as seen in a liquid crystal display device. However, since the CRT display is heavy and large, a wide installation place is required. In addition, since the plasma display device needs to use a high voltage for driving, it requires a special circuit and becomes expensive. Further, since the plasma display device generates plasma, the size of each pixel cannot be reduced so much that it is difficult to achieve high definition particularly in a medium-sized display device. In addition, the electroluminescence display has problems in environmental resistance characteristics and lifetime.

  Therefore, the luminance is adjusted by adjusting the amount of transmitted light by an electro-optic element using liquid crystal having excellent life and durability, and three primary color phosphor parts are provided in a shape corresponding to each pixel, and the wavelength is from 380 nm to 420 nm. There has been proposed a fluorescent self-luminous liquid crystal display device that excites a phosphor portion using a backlight having a main light emitting region in the wavelength region to emit light (Patent Documents 1 and 2).

JP-A-8-62602 JP 2004-348096 A

In the conventional display devices as described in Patent Documents 1 and 2, the phosphor portion is usually formed by dispersing the phosphor in a binder such as a resin. However, in that case, when the phosphor part is excited with ultraviolet or visible light, particularly light in a wavelength region of 350 to 500 nm, there is a problem that the resin constituting the phosphor part is easily deteriorated and colored.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device capable of suppressing light deterioration coloring of a resin contained in a phosphor portion.

  The inventors of the present invention have made extensive studies to solve the above problems, and as a result, even when the amorphous cycloolefin polymer is irradiated with ultraviolet or visible light, particularly in the wavelength region of 350 nm to 500 nm, it is photodegraded and colored. It was found that the excitation light and fluorescence of the phosphor can be transmitted satisfactorily. Furthermore, the inventors have also found that amorphous cycloolefin polymers have a very low water content and can prevent deterioration of phosphors that are generally sensitive to moisture. From these findings, the inventors of the present invention can suppress the photodegradation coloring of the resin contained in the phosphor part by using the amorphous cycloolefin polymer in the phosphor part of the display device. As a result, the present invention has been completed.

  That is, the gist of the present invention is a light source that emits light having a main emission peak wavelength in the ultraviolet region or the visible region, and a phosphor part that contains a phosphor that absorbs light emitted from the light source and emits visible light. And the phosphor part contains an amorphous cycloolefin polymer. (Claim 1)

  At this time, the amorphous cycloolefin polymer preferably has a total light transmittance of 85% or more at a thickness of 3 mm (claim 2).

  Further, the saturated water absorption of the amorphous cycloolefin polymer is preferably 1% by weight or less (Claim 3).

  Furthermore, it is preferable that the glass transition temperature of the amorphous cycloolefin polymer is 100 ° C. or higher.

  According to the display device of the present invention, the photodegradation coloring of the resin contained in the phosphor portion can be suppressed. Moreover, since the moisture content of the resin is low, it is possible to appropriately suppress the deterioration of the phosphor.

  Hereinafter, the present invention will be described in detail with reference to embodiments. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention. .

  The display device of the present invention is a display device that includes a light source that emits ultraviolet or visible light, and a phosphor portion that contains a phosphor that emits visible light by absorbing light emitted from the light source. In the display device of the present invention, the phosphor portion contains an amorphous cycloolefin polymer.

[I. Amorphous cycloolefin polymer]
First, an amorphous cycloolefin polymer (hereinafter referred to as “amorphous cycloolefin polymer according to the present invention”) used in the display device of the present invention will be described.
Any amorphous cycloolefin polymer according to the present invention can be used as long as the effects of the present invention are not significantly impaired.

The amorphous cycloolefin polymer according to the present invention is an amorphous polymer composed of a bond unit having an aliphatic ring.
The number of carbons in the aliphatic ring of the amorphous cycloolefin polymer according to the present invention is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 4 or more, preferably 5 or more, and usually 10 or less, preferably Is 8 or less. Below the lower limit of this range, it may be too rigid, and above the upper limit, it may be too flexible.

  Furthermore, the bond unit having the above aliphatic ring may constitute a bond unit by substituting an optional substituent on the aliphatic ring. Examples of the substituent include an alkyl group, an aryl group, and an alkylenearyl group. In addition, carbon number of these substituents is 1-8 normally, The carbon chain may be linear, may be branched, and may be cyclic.

  Furthermore, the amorphous cycloolefin polymer according to the present invention may have a bond unit having no aliphatic ring as a constituent unit in addition to the bond unit having an aliphatic ring. There is no restriction | limiting in the bond unit which does not have an aliphatic ring, unless the effect of this invention is impaired remarkably. Therefore, the amorphous cycloolefin polymer according to the present invention may be copolymerized with, for example, conjugated dienes, various substituted vinyl compounds, α-olefins and the like in addition to the above-described aliphatic bond units. . However, even in this case, it is desirable that the bond unit having an aliphatic ring is contained in an amount of 50% by mass or more. This is because if the amount of the linking unit having an aliphatic ring is too small, the amorphous cycloolefin polymer according to the present invention may deteriorate light resistance and heat resistance, and the object of the present invention may not be sufficiently achieved.

  Furthermore, the amorphous cycloolefin polymer according to the present invention is amorphous. If there is crystallinity, reflection and refraction at the crystal interface occur, and when used in the display device of the present invention, there is a risk of lowering transparency, which is not preferable. The amorphous cycloolefin polymer according to the present invention can be confirmed to be amorphous by an X-ray diffraction method.

  The amorphous cycloolefin polymer according to the present invention desirably has a total light transmittance at a thickness of 3 mm of usually 85% or more, preferably 88% or more, more preferably 90% or more. Thereby, brighter fluorescent emission can be obtained. The total light transmittance can be measured by a test method defined in JIS K 7361-1.

  Further, in this connection, the amorphous cycloolefin polymer according to the present invention preferably has substantially no absorption in the ultraviolet region and the visible region, particularly in the wavelength region of 350 nm to 500 nm. “Substantially no absorption” means that the transmittance of light having the above wavelength is 85% or more at a thickness of 3 mm. Thereby, the advantage that there is very little light degradation can be acquired.

  The amorphous cycloolefin polymer according to the present invention desirably has a saturated water absorption of usually 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.1% by weight or less. Thereby, the advantage that deterioration of a fluorescent substance can be suppressed can be acquired. The saturated water absorption can be measured by a test method defined in ASTM (American Society for Testing and Materials) D570.

  Furthermore, the amorphous cycloolefin polymer according to the present invention desirably has a glass transition temperature of usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 140 ° C. or higher. Thereby, the advantage of being excellent in stability at high temperatures can be obtained. The glass transition temperature can be measured by a method defined in JIS K7121.

  The amorphous cycloolefin polymer according to the present invention desirably has a hydrogenation rate of usually 60% or more, preferably 80% or more, more preferably 95% or more. This is because if there are many remaining unsaturated bonds and aromatic rings, the light resistance and heat resistance of the amorphous cycloolefin polymer according to the present invention may be lowered. The hydrogenation rate can be measured by quantifying hydrogen on unsaturated carbon and hydrogen on saturated carbon by nuclear magnetic resonance (NMR).

Furthermore, in the amorphous cycloolefin polymer according to the present invention, the aliphatic ring may be in the side chain or in the main chain.
Moreover, the amorphous cycloolefin polymer concerning this invention may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Examples of the structure of the amorphous cycloolefin polymer according to the present invention include those represented by the following formulas (1) and (2).

In the formula (1), n represents an arbitrary natural number, and R ¹ and R ² each independently represents an arbitrary substituent.
In the formula (2), m and n each independently represent an arbitrary natural number, and R ³ , R ⁴ and R ⁵ each independently represent an arbitrary substituent.
Specific examples of R ^{1 to} R ⁵ include the same as those described above as the substituent of the aliphatic ring.

In addition, examples of the amorphous cycloolefin polymer according to the present invention include vinyl aromatic compounds such as styrene, α-methylstyrene, p-methylstyrene, vinylnaphthalene and the like, in which the aliphatic ring is in the side chain. Examples thereof include aromatic ring hydrogenated polymers.
On the other hand, examples of those having an aliphatic ring in the main chain include hydrogenated cyclohexadiene polymers, hydrogenated norbornene polymers, and copolymers of α-olefin and norbornene.

  Further, as specific products, ZEONEX (Nippon Zeon Corporation; registered trademark), ZEONOR (Nippon Zeon Corporation; registered trademark), Arton (JSR Corporation; registered trademark), Apel (Mitsui Chemicals; registered trademark) and the like can be mentioned. It is done.

  The amorphous cycloolefin polymer according to the present invention does not deteriorate and color even when irradiated with light having a wavelength in the ultraviolet region or visible region. In particular, it is excellent in resistance to light deterioration coloring when irradiated with light having a wavelength of 350 nm to 500 nm. Therefore, if the amorphous cycloolefin polymer according to the present invention is used as a binder in the phosphor portion of the display device, the photodegradation coloring of the binder can be suppressed. As a result, it is possible to obtain advantages such as preventing changes in the color of the image displayed on the display device with time and preventing the luminance of the pixels from decreasing with time.

Furthermore, it is possible to suppress the deterioration of the phosphor contained in the phosphor portion of the display device. In a display device using a conventional phosphor, one of the main causes of phosphor degradation is that the phosphor and the phosphor react with each other over a long period of time and the phosphor is denatured. there were. This is presumably due to the use of a non-aromatic thermosetting epoxy resin as a binder in the conventional phosphor portion. That is, a non-aromatic thermosetting epoxy resin has been widely used as a binder of a phosphor part because it is excellent in light resistance and heat resistance, but since it condenses with a curing agent, During the formation, a hydroxyl group is inevitably generated after curing. As a result, since the epoxy resin itself has a polar structure, it is easy to absorb water from the atmosphere, and the water concentration in the phosphor portion tends to increase. Therefore, the phosphor deteriorated due to the reaction of this water with the phosphor.
On the other hand, since the amorphous cycloolefin polymer according to the present invention does not contain water or contains less water, the amorphous cycloolefin polymer according to the present invention is used as a binder for the phosphor part. It becomes possible to suppress deterioration of the phosphor as compared with the conventional case.

[II. Display device]
Hereinafter, embodiments of a display device of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[First Embodiment]
FIG. 1 is an exploded sectional view schematically showing a main part of a display device as a first embodiment of the present invention. In the display device shown in FIG. 1, it is assumed that the observer sees an image displayed on the display device from the right side in the figure.

The display device 1 according to the present embodiment includes a light source 2 and phosphor portions 3R, 3G, and 3B that contain a phosphor that absorbs light emitted from the light source 2 and emits visible light. The display device 1 includes a frame 4, a polarizer 5, an optical shutter 6, and an analyzer 7.
Hereinafter, each member will be described.

[1. flame]
The frame 4 is a base portion that holds members such as the light source 2 constituting the display device 1, and the shape thereof is arbitrary.
The material of the frame 4 is also arbitrary. For example, an appropriate material such as an inorganic material such as metal, alloy, glass, or carbon, or an organic material such as synthetic resin can be used.

  However, from the viewpoint of effectively using the excitation light emitted from the light source 2 and improving the light emission efficiency of the display device 1, the surface of the frame 4 on which the excitation light emitted from the light source 2 hits is reflected by the reflected light. The rate is preferably increased. Therefore, it is preferable that at least the surface that is exposed to light is formed of a material having high reflectance. Specific examples include forming the entire frame 4 or the surface of the frame 4 with a material (such as an injection molding resin) containing a material having a high reflectance such as glass fiber, alumina powder, and titania powder.

The specific method for increasing the reflectance of the surface of the frame 4 is arbitrary. In addition to selecting the material of the frame 4 itself as described above, for example, a metal having a high reflectance such as silver, platinum, and aluminum, The light reflectance can be increased by plating or vapor deposition with an alloy.
The part that increases the reflectivity may be the whole or a part of the frame 4, but usually the reflectivity of the entire surface of the part that is irradiated with the excitation light emitted from the light source 2 is increased. It is desirable.

  In addition, the frame 4 is usually provided with electrodes, terminals and the like for supplying power to the light source 2. At this time, the means for connecting the electrode or terminal and the light source 2 is arbitrary. For example, the light source 2 and the electrode or terminal can be connected by wire bonding to supply power. There is no restriction | limiting in the wire to be used, A raw material, a dimension, etc. are arbitrary. For example, a metal such as gold or aluminum can be used as the material of the wire, and the thickness can be usually 20 μm to 40 μm, but the wire is not limited to this.

Another example of a method for supplying power to the light source 2 is a method for supplying power to the light source 2 by flip chip mounting using bumps.
Further, when power is supplied to the light source 2, solder may be used. Since the solder exhibits excellent heat dissipation, a large current type light emitting diode (hereinafter referred to as “LED”) or a laser diode (hereinafter referred to as “LD”) or the like where heat dissipation is important is used as the light source 2. This is because the heat dissipation of the display device 1 can be improved. The type of solder is arbitrary, but, for example, AuSn, AgSn, or the like can be used.

In addition to connecting to electrodes and terminals and using the power supply path, the solder may be used simply to install the light source 2 on the frame 4.
Further, when the light source 2 is attached to the frame 4 by means other than solder, for example, an adhesive such as an epoxy resin, an imide resin, or an acrylic resin may be used. In this case, by using a paste in which conductive fillers such as silver particles and carbon particles are mixed into the adhesive, the adhesive can be energized to supply power to the light source 2 as in the case of using solder. It is also possible to do so. Furthermore, it is preferable to mix these conductive fillers because heat dissipation is improved.

  In the present embodiment, it is assumed that a flat frame 4 having a high surface reflectance is used, and a terminal (not shown) for supplying power to the light source 2 is provided on the surface. In addition, it is assumed that power is supplied to the terminal from a power source (not shown).

[2. light source]
The light source 2 emits excitation light that excites the phosphors contained in the phosphor portions 3R, 3G, and 3B. Further, it is possible to allow the observer of the display device 1 to see the light itself emitted from the light source 2, and in this case, the light emitted from the light source 2 is also the light itself emitted from the pixels.

  As long as the wavelength of the light emitted from the light source 2 can excite the phosphors in the phosphor portions 3R, 3G, and 3B, light in the ultraviolet region or the visible region can be arbitrarily used. When the desirable range of the wavelength of the excitation light is given, the main emission peak wavelength is usually 350 nm or more, preferably 380 nm or more, more preferably 390 nm or more, and usually 500 nm or less, preferably 480 nm or less, more preferably 470 nm or less. . If the lower limit of this range is exceeded, the liquid crystal substance itself may be destroyed by light (in this case, ultraviolet light) emitted from the light source 2 when a liquid crystal light shutter is used as the light shutter 6. On the other hand, if the upper limit of the above range is exceeded, the luminous efficiency of the phosphor is lowered, and the luminance of the pixel may be lowered or the color reproduction range may be narrowed.

  When the wavelength of the excitation light emitted from the light source 2 is in the visible region, the light emitted from the light source 2 may be used as it is for image display. In this case, the light shutter 6 adjusts the amount of light emitted from the light source 2 so that the luminance of the pixel using the light emitted from the light source 2 is adjusted. For example, when the light source 2 emits blue light having a wavelength of 450 nm to 470 nm, the blue light can be used as light emitted from the pixels of the display device 1 as it is. However, in this case, since it is not necessary to perform wavelength conversion using a phosphor, there is no need for a phosphor portion corresponding to the blue pixel.

  Examples of the light source 2 include an LED, a fluorescent lamp, an edge-emitting or surface-emitting LD, and an electroluminescence element. Of these, LEDs and fluorescent lamps are usually preferred. Furthermore, fluorescent lamps can use cold cathode tubes and hot cathode tubes that have been used in the past, but when white light is used, other colors are mixed into the blue, green, and red light emitting areas. It is desirable to extract only the near-ultraviolet region in white light using a filter or the like. In particular, it is particularly preferable to use a fluorescent lamp coated only with a near-ultraviolet phosphor to reduce power consumption.

As phosphors used in the fluorescent lamp, SrMgP ₂ O ₇ : Eu (emission wavelength 394 nm), Sr ₃ (PO ₄ ) ₂ : Eu (emission wavelength 408 nm), (Sr, Ba) Al ₂ Si ₂ O ₈ : Eu ( Emission wavelength 400 nm), Y ₂ Si ₂ O ₇ : Ce (emission wavelength 385 nm), ZnGa ₂ O ₄ : Li, Ti (emission wavelength 380 nm), YTaO ₄ : Nb (emission wavelength 400 nm), CaWO ₄ (emission wavelength 410 nm) BaFX: Eu (X is halogen, emission wavelength 380 nm), (Sr, Ca) O.2B ₂ O ₃ : Eu (emission wavelength 380 to 450 nm), SrAl ₁₂ O ₁₄ : Eu (emission wavelength 400 nm), and Y ₂ Examples thereof include SiO ₅ : Ce (emission wavelength: 400 nm). In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  On the other hand, as LEDs, high-intensity near-ultraviolet inorganic semiconductor LEDs can be obtained recently, and therefore backlights using these light sources can be used. In particular, near-ultraviolet emitting inorganic semiconductor LEDs can be suitably used because they can selectively emit light in a wavelength region preferable for the present invention. For example, a known single or multiple quantum well structure blue LED using InGaN as the light emitting layer, or a known single or multiple quantum well structure near ultraviolet LED using AlInGaN, GaN or AlGaN as the light emitting layer is preferable.

  Furthermore, the light emitted from the light source 2 is directly incident on the phosphor portions 3R, 3G, and 3B, and is converted into planar light emission using a light guide plate and a light diffusing plate, and the phosphor portions 3R, 3G, and 3B. Alternatively, the light may be incident on the phosphor portions 3R, 3G, and 3B after the reflection plate is installed and reflected once. If a reflector is provided on the back surface of the light source 2 (on the side opposite to the optical shutter 6) as in the case of using a frame 4 having a high reflectance, the utilization efficiency of light emitted from the light source 2 can be improved. Can be increased.

The conversion mechanism that converts the light emitted from the light source 2 into planar light emission is arbitrary, for example, a light guide plate such as a quartz plate, a glass plate, an acrylic plate, a reflection mechanism such as an Al sheet, various metal deposition films, A light diffusing mechanism such as a pattern using a TiO ₂ compound, a light diffusing sheet, or a light diffusing prism may be used alone or preferably in combination. In particular, a conversion mechanism that converts the light into planar light by converting the light source 2 into a surface light emitter using a light guide plate, a reflection plate, a diffusion plate, or the like is preferably used in this embodiment. Further, for example, a conversion mechanism used for a liquid crystal display device or the like can also be suitably used.

  Furthermore, when the light source 2 is installed on the frame 4, there is no limitation on the installation means, and any known means can be used. Therefore, as described above, for example, the light source 2 can be installed on the frame 4 using solder or the like.

  In the present embodiment, a surface light emitter that emits near-ultraviolet light in a planar manner is used as the light source 2. Further, it is assumed that the power supply to the light source 2 is performed by electrically connecting the terminals on the frame 4 and the electrodes of the light source 2 using an interconnection circuit, wires, or the like.

[3. Polarizer]
A polarizer 5 is preferably provided in front of the light source 2 (right side in the drawing), specifically between the light source 2 and the optical shutter 6. The polarizer 5 is provided to select only light in a predetermined direction from light emitted from the light source 2. Also in the present embodiment, it is assumed that the polarizer 5 is installed between the light source 2 and the optical shutter 6.

[4. Light shutter]
In the present embodiment, the optical shutter 6 transmits irradiated light by adjusting the amount of light. Specifically, this is a member that adjusts the amount of light for each pixel and transmits the light irradiated on the back surface to the front corresponding to the image to be displayed. In the case of the present embodiment, the optical shutter 6 adjusts the amount of light emitted from the light source 2 to the phosphor portions 3R, 3G, 3B for each pixel and transmits the light forward. In addition, also when using the light (blue light etc.) which the light source 2 emitted as it is as the light of a pixel, it is comprised so that the light quantity of the light which the light source 2 emitted may be adjusted and permeate | transmitted ahead.

  More specifically, when the display device 1 is configured as a multi-color or full-color display, two or more types of the phosphors described above are independently defined as light wavelength conversion mechanisms (that is, the phosphor portions 3R, 3G, 3B). In the present embodiment, the light amounts of the excitation light applied to the phosphor portions 3R, 3G, and 3B are adjusted by the optical shutter 6 to adjust the light amounts of the light emitted from the phosphor portions 3R, 3G, and 3B. The apparatus 1 can display a desired image with multicolor light emission.

  Some types of the optical shutter 6 can adjust the light amount only for light in a specific wavelength region. Therefore, as the optical shutter 6, an optical shutter capable of switching light by adjusting the amount of light in the wavelength region of light emitted from the light source 2 is used. Depending on the configuration of the display device 1, the light emitted from the phosphor portions 3R, 3G, 3B instead of the light from the light source 2 may be adjusted by the optical shutter 6. In this case, the phosphor portion is adjusted. In the light wavelength region emitted from 3R, 3G, 3B, a light capable of switching light by adjusting the amount of light is used. Usually, the center wavelength of the light emitted from the light source 2 and the light emitted from the phosphor portions 3R, 3G, 3B is usually 350 nm or more, and usually 780 nm or less, preferably 420 nm or less. It is desirable to be able to adjust the amount of light.

  Further, the mechanism of the optical shutter 6 is usually composed of an assembly of a plurality of pixels (pixels). However, the number and size of pixels and the arrangement method vary depending on the screen size, display method, application, etc., and are not particularly limited to constant values. Therefore, there is no limitation on the size of the pixel of the optical shutter 6, and it is arbitrary as long as the effect of the present invention is not significantly impaired.

  For example, in a normal display application, the size of one pixel is preferably 500 μm square or less. Furthermore, as a suitable pixel size, it is more preferable that the number of pixels is about 640 × 3 × 480 and the single pixel size is about 100 × 300 μm as a value of a liquid crystal display currently in practical use.

Further, the quantity and size of the optical shutter 6 itself are not limited and are arbitrary as long as the effects of the present invention are not significantly impaired. For example, the thickness of the optical shutter 6 is usually 5 cm or less, and preferably 1 cm or less in consideration of reduction in thickness and weight.
When the display device 1 is a flat display device, an optical shutter 6 that changes the light transmittance of the pixel to an arbitrary value by electrical control is preferably used in order to enable gradation display. Can do. The higher the absolute value of the light transmittance, the contrast of the change and the speed response, the better.

  Examples of optical shutters 6 that satisfy these requirements are TFT (Thin Film Transistor), STN (Super Twisted Nematic liquid crystal), ferroelectric, antiferroelectric, guest host using dichroic dye, polymer dispersion type A transmissive liquid crystal optical shutter such as a certain PDN (Polymer Dispersed Network) system; tungsten oxide, iridium oxide, Prussian blue, viologen derivative, TTF-polystyrene, rare earth metal-diphthalocyanine complex, polythiophene, electrochromic represented by polyaniline, Examples include chemical chromic. Among them, a liquid crystal optical shutter is preferably used because it is thin, lightweight, and has low power consumption, has practical durability, and can increase the density of segments. Among these, a liquid crystal optical shutter using a TFT active matrix drive or a PDN method is particularly desirable. The reason is that the active matrix using twisted nematic liquid crystal does not cause high-speed response and crosstalk corresponding to moving images, and the PDN method does not require the polarizer 7, so the light source 2 and the phosphor portions 3R, 3G, This is because light emission from 3B is small and light emission with high luminance becomes possible.

  Further, the display device 1 is usually provided with a control unit (not shown) that controls the optical shutter 6 so as to adjust the amount of light for each pixel in accordance with the image displayed on the display device 1. The optical shutter 6 adjusts the amount of visible light emitted from each pixel in accordance with the control of the control unit, whereby a desired image is displayed on the display device 1.

By adjusting the luminance of the pixels with the optical shutter 6, the display device 1 can further simplify the control circuit of the control unit. For example, when an LED is used as the light source 2 and the luminance of the pixel is adjusted by controlling the light emission intensity of the LED, the current-luminance characteristic of the LED changes with time, and therefore a control circuit that controls the image to be displayed. Was complicated.
On the other hand, if a light shutter 6 portion for adjusting the amount of light emitted from the light source 2 is provided as in the present embodiment and the luminance of the pixels is adjusted by the light shutter 6, light from a liquid crystal light shutter or the like can be obtained. Since most of the shutters are voltage controlled, the brightness can be adjusted with a simple control circuit.

  In the present embodiment, a liquid crystal optical shutter in which the back electrode 61, the liquid crystal layer 62, and the front electrode 63 are stacked in the above order is used as the optical shutter 6, and the optical shutter 6 is in front of the polarizer 5 (in the drawing). It is assumed that it is provided on the right). The back electrode 61 and the front electrode 63 are configured by transparent electrodes that do not absorb light used in the display device 1. In this liquid crystal light shutter, the molecular arrangement of the liquid crystal in the liquid crystal layer 62 is controlled by the voltage applied to the back electrode 61 and the front electrode 63. Adjustment is performed for each pixel (that is, for each of the phosphor portions 3R, 3G, and 3B).

[5. Analyzer]
In front of the optical shutter 6, an analyzer 7 is generally provided that receives light having a light amount adjusted through the optical shutter 6. The analyzer 7 is for selecting light having passed through the optical shutter 6 and having only a certain plane of polarization.
Also in the present embodiment, it is assumed that the analyzer 7 is provided in front of the optical shutter 6, specifically, between the optical shutter 6 and the phosphor portions 3R, 3G, 3B.

[6. Phosphor part]
The phosphor portions 3R, 3G, and 3B are portions containing a phosphor that absorbs excitation light emitted from the light source 2 and emits visible light for forming an image displayed on the display device 1. The phosphor portions 3R, 3G, and 3B are usually provided one by one corresponding to the pixels, and generate light that is emitted from the pixels of the display device 1. Therefore, in this embodiment, the observer recognizes an image by looking at the fluorescence emitted by the phosphor portions 3R, 3G, 3B.

There is no restriction | limiting in the fluorescent substance used in this embodiment, Arbitrary fluorescent substance can be used unless the effect of this invention is impaired remarkably.
Further, in the present embodiment, the phosphor is used by blending one type or two or more types of phosphors. The emission color of the phosphor is not particularly limited because there is an appropriate color depending on the application, but blue, green, and red phosphors with high color purity are preferably used when, for example, a full color display is manufactured. There are several methods for expressing the appropriate color. For convenience, the center wavelength of light emission, CIE chromaticity coordinates, and the like are used. In addition, when the light wavelength conversion mechanism is monochrome display or multicolor display, it preferably includes a phosphor that develops colors of purple, blue-violet, yellow-green, yellow, and orange. Further, two or more of these phosphors may be mixed to emit light with high color purity, or to emit intermediate color or white light.

Speaking of the central wavelength of light emission, for example, a specific wavelength range of fluorescence emitted by a phosphor emitting red fluorescence (hereinafter referred to as “red phosphor” as appropriate) is illustrated. The central wavelength is usually 370 nm or more, Preferably it is 380 nm or more, and usually 500 nm or less, preferably 480 nm or less.
Further, for example, when a specific wavelength range of fluorescence emitted by a phosphor emitting green fluorescence (hereinafter referred to as “green phosphor” as appropriate) is exemplified, the center wavelength is usually 490 nm or more, preferably 500 nm or more, Usually, it is 570 nm or less, preferably 550 nm or less.
Furthermore, for example, when a specific wavelength range of fluorescence emitted by a phosphor emitting blue fluorescence (hereinafter referred to as “blue phosphor” as appropriate) is exemplified, the center wavelength is usually 420 nm or more, preferably 440 nm or more, Usually, it is 480 nm or less, preferably 470 nm or less.

The composition of the phosphor is not particularly limited, but a metal oxide represented by Y ₂ O ₃ , Zn ₂ SiO _4, etc., which is a crystal matrix, phosphorus represented by Ca ₅ (PO ₄ ) ₃ Cl, etc. Acids and sulfides represented by ZnS, SrS, CaS, etc., ions of rare earth metals such as Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Ag A combination of metal ions such as Al, Mn, and Sb as an activator or coactivator is preferable.

Preferred examples of the crystal matrix include, for example, ZnS, Y ₂ O ₂ S, (Y, Gd) ₃ Al ₅ O ₁₂ , YAlO ₃ , BaAl ₂ Si ₂ O ₈ , Y ₃ Al ₅ O ₁₂ , Y ₂ SiO _5. , Zn ₂ SiO ₄ , Y ₂ O ₃ , BaMgAl ₁₀ O ₁₇ , BaAl ₁₂ O ₁₉ , (Ba, Sr, Mg) O · αAl ₂ O ₃ , (Y, Gd) BO ₃ , Y ₂ O ₃ , (Zn , Cd) S, SrGa ₂ S ₄ , SrS, SnO ₂ , Ca ₁₀ (PO ₄ ) ₆ (F, Cl) ₂ , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ , (Sr, Ca, Ba) , Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ , (La, Ce) PO ₄ , CeMgAl ₁₁ O ₁₉ , GdMgB ₅ O ₁₀ , Sr ₂ P ₂ O ₇ , Sr ₄ Al ₁₄ O ₂₅ , (Ba, Sr, Ca ) (Mg, Zn, Mn) Al ₁₀ O _{17 and the} like.

  However, the above-mentioned crystal matrix and activator or coactivator are not particularly limited in elemental composition, and can be partially replaced with elements of the same family, and the obtained phosphor absorbs ultraviolet rays and emits visible light. Those are preferred. Examples of phosphors that can be used are given below. However, the phosphors used in the display device 1 of the present embodiment are not limited to those exemplified below.

・ Red phosphor:
The red phosphor capable of emitting red light by ultraviolet irradiation is composed of, for example, broken particles having a red fracture surface and emits light in the red region (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu. The europium-activated alkaline earth silicon nitride-based phosphor represented, which is composed of growing particles having a substantially spherical shape as a regular crystal growth shape, emits light in the red region (Y, La, Gd, Lu) ₂ O ₂ Examples include europium-activated rare earth oxychalugenite-based phosphors represented by S: Eu.

  Furthermore, the oxynitride and / or acid containing at least one element selected from the group consisting of Ti, Zr, Hf, Nb, Ta, W, and Mo described in JP-A-2004-300247 A phosphor containing a sulfide and containing an oxynitride having an alpha sialon structure in which a part or all of the Al element is substituted with a Ga element can also be used in this embodiment. These are phosphors containing oxynitride and / or oxysulfide.

Other red phosphors include Y ₂ O ₂ S: Eu ³⁺ , (BaMg) ₂ SiO ₄ : Eu ³⁺ , (BaCaMg) ₅ (PO ₄ ) ₃ Cl: Eu ³⁺ , YVO ₄ : Eu. ³⁺ , CaS: Eu ³⁺ , YAlO ₃ : Eu ³⁺ , Ca ₂ Y ₈ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , (Y, Gd _{) 3 Al 5 O 12: Ce} 3+, (Ca, Sr) 2 Si 5 N 8: Eu, CaSiN 2: Eu, CaAlSiN 3; Eu, (Sr, Ca, Ba, Mg) 10 (PO 4) 6 Cl ₂ : Eu, Mn, (Ba ₃ Mg) Si ₂ O ₈ : Eu, Mn, etc. can also be used.

・ Green phosphor:
As a green phosphor capable of emitting green light by ultraviolet irradiation, for example, it is composed of fractured particles having a fracture surface, and emits light in a green region (Mg, Ca, Sr, Ba) represented by Si ₂ O ₂ N ₂ : Eu. Europium-activated alkaline earth silicon oxynitride-based phosphors, europium-activated alkaline earths represented by (Ba, Ca, Sr) ₂ SiO ₄ : Eu that are composed of fractured particles having a fracture surface Examples include magnesium silicate phosphors.

In addition, as the green phosphor, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al ₂ Si ₂ O ₈ : Eu ²⁺ , (BaMg) ) ₂ SiO ₄ : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ , Sr ₂ P ₂ O ₇ —Sr ₂ B ₂ O ₅ : Eu ²⁺ , (BaCaMg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu ²⁺ , Zr ₂ SiO ₄ , MgAl ₁₁ O ₁₉ : Ce ³⁺ , Tb ³⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Ca ₂ Y ₈ (SiO ₄ ) ₆ O ₂ : Tb ³⁺ , Y ₃ Al ₅ O ₁₂ : Tb ³⁺ , La ₃ Ga ₅ SiO ₁₄ : Tb ³⁺ , SrGa ₂ S ₄ : Eu ²⁺ , Tb ³⁺ , Sm ^{2 _{+, Y 3 (Al, Ga}} ) 5 O 12: Ce, Ca 3 Sc 2 Si 3 O 12: Ce, SrSi 2 O 2 N 2: Eu, BaMgAl 10 O 17: Eu, M , SrAl ₂ O _4: Eu can also be used like.

・ Blue phosphor:
As a blue phosphor capable of emitting blue light by ultraviolet irradiation, europium activated barium represented by BaMgAl ₁₀ O ₁₇ : Eu, which is composed of growing particles having a substantially hexagonal shape as a regular crystal growth shape, and emits light in a blue region. Magnesium aluminate-based phosphor, which is composed of growing particles having a substantially spherical shape as a regular crystal growth shape, emits light in the blue region, and is represented by (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ Cl: Eu Europium-activated calcium halophosphate-based phosphor, which is composed of grown particles having a cubic shape as a regular crystal growth shape, and emits light in the blue region (Ca, Sr, Ba) ₂ B ₅ O ₉ Cl: Eu Europium activated alkaline earth chloroborate phosphor, composed of fractured particles with fractured surface, blue green Performing emission band (Sr, Ca, Ba) Al 2 O 4: Eu or _{(Sr, Ca, Ba) 4} Al 14 O 25: europium-activated alkaline earth aluminate phosphors represented by Eu, and the like .

In addition, blue phosphors include Sr ₂ P ₂ O ₇ : Sn ⁴⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , SrGa ₂ S ₄ : Ce ³⁺ , CaGa ₂ S ₄ : Ce ³⁺ , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , BaAl ₂ Si ₂ O ₈ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Tb ³⁺ , Sm ²⁺ , (Ba, Sr, Ca) (Mg, Zn, Mn) Al ₁₀ O ₁₇ : Eu ²⁺ (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, etc. may be used. Is possible.

  In addition, the above-mentioned red phosphor, green phosphor, blue phosphor, and the like, which emit fluorescence of the color emitted from each pixel, may be used alone or in combination of two or more in any combination and ratio. You may use together.

Furthermore, a binder is used for the phosphor portions 3R, 3G, and 3B in order to protect the phosphor from external forces and moisture from the external environment. Specifically, the phosphor portions 3R, 3G, and 3B are configured by a molded body in which the phosphor is dispersed in a binder.
In the present embodiment, the amorphous cycloolefin polymer according to the present invention is used as the binder, and the phosphor portions 3R, 3G, and 3B are configured to contain the amorphous cycloolefin polymer according to the present invention.

  In addition, other binders can be used in combination with the amorphous cycloolefin polymer according to the present invention. As the binder that can be used in combination, known binders can be arbitrarily used, but it is usually preferable to use a colorless and transparent material in order to appropriately transmit fluorescence and excitation light.

  Specific examples of binders that can be used in combination include polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose polystyrene, styrene / maleic anhydride copolymer, styrene / acrylonitrile copolymer, polyvinyl. Chloride, cellulose acetate butyrate, cellulose propionate, poly α-naphthyl methacrylate, polyvinyl naphthalene, poly n-butyl methacrylate, tetrafluoroethylene / hexafluoropropylene copolymer, polycyclohexyl methacrylate, poly (4-methylpentene), Epoxy, polysulfone, polyetherketone, polyarylate, polyimide, polyetherimide, cyclic orange Fin polymers, polysiloxanes, benzocyclobutane polymers, water glass, silica, titanium oxide, and those with such a component epoxy resin. Among these, a resin having substantially no absorption at 350 nm to 500 nm is preferable, and a non-aromatic epoxy resin or a cyclic olefin polymer is particularly desirable.

  However, as described above, in order to obtain the effects of the present invention, among the binders used in the phosphor portions 3R, 3G, 3B, 50% by weight or more of the amorphous cycloolefin polymer according to the present invention is used. It is desirable to use it. In addition, these binders that can be used in combination may be used alone or in combination of two or more in any combination and ratio.

  In the phosphor portions 3R, 3G, 3B, the ratio of the binder in the phosphor portions 3R, 3G, 3B is arbitrary as long as the effects of the present invention are not significantly impaired. 5 parts by weight or more, preferably 10 parts by weight or more, and usually 95 parts by weight or less, preferably 90 parts by weight or less. If the lower limit of this range is not reached, the phosphor parts 3R, 3G, 3B may be fragile, and if the upper limit is exceeded, the emission intensity may be reduced.

  Moreover, you may make the fluorescent substance part 3R, 3G, 3B contain additives other than a binder and fluorescent substance. As an additive, for example, a diffusing agent may be added to further increase the viewing angle. Specific examples of the diffusing agent include barium titanate, titanium oxide, aluminum oxide, and silicon oxide. Moreover, as an additive, for example, an organic or inorganic coloring dye or coloring pigment can be contained for the purpose of cutting an undesired wavelength. In addition, these additives may be used individually by 1 type, respectively, and may use 2 or more types together by arbitrary combinations and ratios.

  Furthermore, the phosphor portions 3R, 3G, and 3B can be manufactured by any known method. For example, the phosphor portions 3R, 3G, and 3B are a mixture of a binder, a phosphor, and a solvent (coating liquid) in a mosaic shape, an array shape, or an interval corresponding to the pixels of the optical shutter 6 by screen printing. It can be formed on the transparent substrate 31 in a stripe shape.

  In addition, a block matrix layer 32 may be formed between the respective phosphor portions 3R, 3G, 3B for absorbing external light. The black matrix layer 32 may be formed on a transparent substrate 31 such as glass by a process of manufacturing a light absorption film made of carbon black using the photosensitive principle of a photosensitive resin. A mixture composed of a solvent may be laminated by screen printing.

  Further, the shape of the phosphor portions 3R, 3G, 3B is arbitrary. For example, when the display device 1 is set to multicolor display, phosphors that emit light of a predetermined color are arranged in the light emitting regions such as the phosphor portions 3R, 3G, and 3B in accordance with the pixel shape of the optical shutter mechanism. However, the shape of the phosphor portions 3R, 3G, and 3B includes a segment shape and a matrix shape necessary for information display. Among the matrix shapes, a stripe structure, a delta structure, and the like are given as preferable forms. be able to. Furthermore, in the case of monochrome display, in addition to the above-described shape, it is possible to apply a uniform phosphor.

  Furthermore, the dimensions of the phosphor portions 3R, 3G, 3B are also arbitrary. For example, the thickness is arbitrary as long as the effects of the present invention are not significantly impaired, but usually, it can be suitably used when the thickness is 1 cm or less. Furthermore, in a flat panel display that is required to be thin and light, it is more preferable that the thickness be 2 mm or less. Considering the balance with the emission rate of emitted light, it is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less.

  By the way, as described above, when visible light such as blue light is emitted from the light source 2, the visible light emitted from the light source 2 can be used as light emitted from the pixels. In that case, a phosphor portion that emits fluorescence of the same color as the light corresponding to the visible light is not essential. For example, when a blue light emitting LED is used as the light source 2, a phosphor portion including a blue phosphor is unnecessary. Therefore, if visible light emitted from the light source 2 is emitted outside the display device 1 by adjusting the amount of light by the optical shutter, it is not always necessary to use phosphors in all the pixels. However, even in such a case, the visible light emitted from the light source 2 is efficiently added to the binder to the visible light emitted from the light source 2 in order to efficiently emit or scatter the visible light to the outside, scatter the light, or cut light having an undesired wavelength. It is desirable to transmit the light transmitting portion containing the agent.

  In the present embodiment, a phosphor portion 3R in which a red phosphor is dispersed in a binder, a phosphor portion 3G in which a green phosphor is dispersed in a binder, and a phosphor portion 3B in which a blue phosphor is dispersed in a binder. Assume that they are provided on the transparent substrate 31 in an array corresponding to the red pixel, the green pixel, and the blue pixel, respectively. Further, the transparent substrate 31 provided with the phosphor portions 3R, 3G, and 3B is provided in front of the analyzer 7 (right side in the drawing) at a position facing the optical shutter 6. Furthermore, the amorphous cycloolefin polymer concerning this invention shall be used as a binder of fluorescent substance part 3R, 3G, 3B. Thus, the phosphor portion 3R receives light from the light source 2 and emits red light, the phosphor portion 3G receives light from the light source 2 and emits green light, and the phosphor portion 3B emits light from the light source 2. In response, it emits blue light. Further, it is assumed that the phosphor portions 3R, 3G, and 3B are partitioned by the black matrix layer 32, respectively.

[7. Action]
Since the display device 1 of the present embodiment is configured as described above, the light source 2 emits light with a predetermined intensity during use. Light emitted from the light source 2 is incident on the optical shutter 6 after the plane of polarization is aligned by the polarizer 5.

  The optical shutter 6 adjusts the amount of light incident from the back side for each pixel according to the image to be displayed under the control of a control unit (not shown), and transmits the light forward. Specifically, by controlling the voltage applied to the transparent electrodes 61 and 63, the orientation of the liquid crystal in the portion corresponding to each pixel is adjusted, and thereby, how much light is transmitted for each pixel. The light received on the back surface is transmitted forward while adjusting or adjusting.

The light that has passed through the optical shutter 6 enters the corresponding phosphor portions 3R, 3G, and 3B through the analyzer 7, respectively.
In the phosphor portion 3R, the red phosphor dispersed in the phosphor portion 3R absorbs incident light and emits red fluorescence. In the phosphor portion 3G, the green phosphor dispersed in the phosphor portion 3G absorbs incident light and emits green fluorescence. Further, in the phosphor portion 3B, the blue phosphor dispersed in the phosphor portion 3G absorbs incident light and emits blue fluorescence.

At this time, since the amount of incident light is adjusted for each pixel by the optical shutter 6 in accordance with the image to be formed, the amount of fluorescence (visible light) emitted from each phosphor portion 3R, 3G, 3B is also the pixel. Each image is adjusted to form a desired image.
The red, green, and blue fluorescence generated in this way is emitted to the outside (right side in the figure) of the display device 1 through the transparent substrate 31. An observer sees the light emitted from the surface of the transparent substrate 31 and recognizes the image.

Furthermore, by configuring as described above, the display device 1 of the present embodiment can suppress the photodegradation coloring of the binder contained in the phosphor portions 3R, 3G, and 3B. Therefore, it is possible to prevent the color and luminance of the image displayed on the display device 1 from deteriorating with time.
Furthermore, according to the display device of the present embodiment, the amount of water in the phosphor portions 3R, 3G, 3B can be reduced as compared with the conventional case, so that the phosphors in the phosphor portions 3R, 3G, 3B are deteriorated. It can also be suppressed.

  Also, according to the display device 1 of the present embodiment, unlike the conventional display device using a liquid crystal light shutter, it is possible to prevent the luminance of the pixel from being lowered or the color from being changed depending on the viewing angle. .

[Second Embodiment]
[1. Constitution]
FIG. 2 is an exploded cross-sectional view schematically showing the main part of a display device as a second embodiment of the present invention. In the display device shown in FIG. 2, it is assumed that the observer sees an image displayed on the display device from the right side in the figure. Further, in FIG. 2, parts indicated by the same reference numerals as in FIG. 1 represent the same parts as in FIG.

  In the display device 1 ′ of the present embodiment, the arrangement order of the constituent members is the order of the substrate 4, the light source 2, the phosphor portions 3 </ b> R, 3 </ b> G, 3 </ b> B, the polarizer 5, the optical shutter 6, and the analyzer 7 from the back side. In addition, the configuration is the same as that of the display device 1 described in the first embodiment except that a black matrix (not shown) is provided between the pixels of the optical shutter 6.

  It is preferable that a black region called a black matrix exists between the pixels of the optical shutter 6 in order to increase the contrast. The black matrix has a function of making a gap between pixels black and making an image easy to see. As a material of the black matrix, for example, chromium, carbon, or a resin in which carbon or other black substance is dispersed is used, but the material is not limited thereto. In this embodiment, since the observer sees the light transmitted through the optical shutter 6, this black matrix is provided in the optical shutter.

  Further, in the display device 1 ′ of the present embodiment, since the arrangement order of the constituent members is changed as described above, the optical shutter 6 changes the amount of light emitted from the phosphor portions 3R, 3G, 3B for each pixel. It is designed to transmit forward by adjusting to. That is, the light emitted from the light source 2 is incident on the phosphor portions 3R, 3G, 3B, and the light shutter 6 adjusts the amount of light emitted from the phosphors in the phosphor portions 3R, 3G, 3B for each pixel. In addition, a desired image can be displayed with multicolor light emission on the display device 1 by light that is transmitted forward and whose light amount is adjusted by the optical shutter 6.

  Therefore, in the first embodiment, the optical shutter 6 is one that can adjust the amount of light in the wavelength region of the light emitted from the light source 2, but in the present embodiment, the phosphor portions 3R, 3G. , 3B is used that can adjust the amount of light in the wavelength region of light emitted. Specifically, in the optical shutter 6 of the present embodiment, the molecular arrangement of the liquid crystal in the liquid crystal layer 62 is controlled by the voltage applied to the back electrode 61 and the front electrode 63, and each light irradiated to the back side by this molecular arrangement is controlled. The amount of light is adjusted for each pixel.

  Furthermore, in the present embodiment, the phosphor portions 3R, 3G, and 3B are each configured to contain the amorphous cycloolefin polymer according to the present invention as a binder, as in the first embodiment.

[2. Action]
Since the display device 1 ′ of the present embodiment is configured as described above, the light source 2 emits light with a predetermined intensity during use. The light emitted from the light source 2 is incident on the corresponding phosphor portions 3R, 3G, and 3B, respectively.

  In the phosphor portion 3R, the red phosphor dispersed in the phosphor portion 3R absorbs incident light and emits red fluorescence. In the phosphor portion 3G, the green phosphor dispersed in the phosphor portion 3G absorbs incident light and emits green fluorescence. Further, in the phosphor portion 3B, the blue phosphor dispersed in the phosphor portion 3B absorbs incident light and emits blue fluorescence.

The red, green, and blue fluorescence generated in this way is incident on the optical shutter 6 after the plane of polarization is aligned by the polarizer 5.
The optical shutter 6 adjusts the amount of red light, green light, and blue light incident from the back side according to the image to be displayed according to the control of a control unit (not shown) for each pixel, and transmits the light forward. . Specifically, by controlling the voltage applied to the transparent electrodes 61 and 63, the orientation of the liquid crystal in the portion corresponding to each pixel is adjusted, and thereby, how much light is transmitted for each pixel. The light received on the back surface is transmitted forward while adjusting or adjusting.

  The light passing through the optical shutter 6 is irradiated to the analyzer 7. At this time, the amount of fluorescent light emitted from the phosphor portions 3R, 3G, and 3B is adjusted for each pixel by the optical shutter 6, so that the fluorescent light applied to the analyzer 7 forms a desired image. . The observer then recognizes the image by looking at the light emitted from the surface of the analyzer 7.

Furthermore, by configuring as described above, the display device 1 ′ of the present embodiment can suppress the photodegradation coloring of the binder included in the phosphor portions 3R, 3G, and 3B. Therefore, it is possible to prevent the color and brightness of the image displayed on the display device 1 'from deteriorating with time.
Further, according to the display device 1 'of the present embodiment, since the water in the phosphor portions 3R, 3G, 3B can be reduced as compared with the conventional case, the phosphors in the phosphor portions 3R, 3G, 3B can be reduced. It is also possible to suppress deterioration.

Furthermore, according to the display device 1 ′ of the present embodiment, unlike the display device using the conventional liquid crystal light shutter, the influence of the afterglow characteristics of the phosphors in the phosphor portions 3R, 3G, and 3B is eliminated. Can do. The phosphor may emit fluorescence only for a predetermined time even after the light irradiation is stopped, and the time during which the fluorescence is emitted after the light irradiation is stopped is referred to as afterglow characteristics. Since afterglow characteristics differ depending on the phosphor, conventionally, a specific color tends to be emphasized in an image displayed on a display device, which has been a cause of high cost and complicated control. However, according to the display device 1 ′ of the present embodiment, it is possible to eliminate the influence of the afterglow characteristic and prevent a specific color of the image from being emphasized.
Furthermore, as in the first embodiment, the control circuit of the control unit can be simplified.

[9. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
For example, in the above embodiment, the case where an image is displayed using three kinds of light of red, green, and blue has been described. However, the image display is performed using light other than the above red, green, and blue. In addition, image display may be performed using two types or four or more types of light.

For example, in some pixels, the light emitted from the light source 2 may be directly used as the light of the pixel.
Further, in addition to transmitting through the phosphor portions 3R, 3G, 3B, a reflection type configuration in which the light emitted from the light source 2 is reflected by the phosphor portions 3R, 3G, 3B may be applied. Specifically, for example, in the configuration of the first embodiment, the display device 1 can be configured by installing the light source 2 in front of the phosphor portions 3R, 3G, and 3B.

  In addition to providing the optical shutter 6, the light source 2 is installed for each pixel, the intensity of light emitted from the light source 2 is controlled for each pixel by adjusting the amount of current supplied to each light source 2, and the luminance of the pixel. May be adjusted.

Further, the above-described members such as the light source 2, the phosphor portions 3R, 3G, and 3B, the frame 4, the polarizer 5, the optical shutter 6, and the analyzer 7 are used in any combination without departing from the gist of the present invention. be able to.
Further, the display devices 1 and 1 ′ may be used in combination with other constituent members. For example, you may make it employ | adopt a protective film as it describes in the 0039th paragraph or less of Unexamined-Japanese-Patent No. 2005-885066.

Furthermore, in addition to the above members, films with various functions such as antireflection layers, alignment films, retardation films, brightness enhancement films, reflection films, transflective films, and light diffusion films can be added or laminated. You may do it.
The film having these optical functions can be formed, for example, by the following method.

The layer having a function as a retardation film is subjected to, for example, a stretching process described in Japanese Patent No. 2841377, Japanese Patent No. 3094113, or a process described in Japanese Patent No. 3168850. Can be formed.
The layer having a function as a brightness enhancement film may be formed by, for example, forming fine holes by a method described in JP-A No. 2002-169025 or JP-A No. 2003-29030, or selective reflection. It can be formed by superposing two or more cholesteric liquid crystal layers having different center wavelengths.

Furthermore, the layer having a function as a reflective film or a transflective film can be formed using, for example, a metal thin film obtained by vapor deposition or sputtering.
The layer having a function as a diffusion film can be formed by coating the protective film with a resin solution containing fine particles.
Furthermore, the layer having a function as a retardation film or an optical compensation film can be formed by applying and aligning a liquid crystal compound such as a discotic liquid crystal compound or a nematic liquid crystal compound.

  The present invention can be arbitrarily used as a display device using a phosphor, and is particularly suitable for a display device capable of color display.

1 is an exploded cross-sectional view schematically showing a main part of a display device as a first embodiment of the present invention. It is a disassembled sectional view which shows typically the principal part of the display apparatus as 2nd Embodiment of this invention.

Explanation of symbols

1, 1 'Display device 2 Light source 3R, 3G, 3B Phosphor part 4 Substrate 5 Polarizer 6 Optical shutter 7 Analyzer 31 Transparent substrate 32 Black matrix 61, 63 Transparent electrode 62 Liquid crystal layer

Claims (4)

A light source that emits ultraviolet or visible light;
A display device comprising a phosphor portion containing a phosphor that absorbs light emitted from the light source and emits visible light,
The display device, wherein the phosphor part contains an amorphous cycloolefin polymer. The display device according to claim 1, wherein the total light transmittance of the amorphous cycloolefin polymer at a thickness of 3 mm is 85% or more. The display device according to claim 1 or 2, wherein the amorphous cycloolefin polymer has a saturated water absorption of 1% by weight or less. The display device according to claim 1, wherein the amorphous cycloolefin polymer has a glass transition temperature of 100 ° C. or higher.

Images