JP6019698B2 - Pattern light emitting display device - Google Patents

Description

  The present invention relates to a design light-emitting display device, and in particular, an organic electroluminescence element plate is used as a light-emitting light source, and visibility is not only during daytime direct light and at night, but also in backlight that receives direct sunlight from the back of the daytime design. The present invention relates to an excellent pattern light emitting display device.

  Conventionally, two methods are mainly used as a symbol display method used for road signs and the like, and one method is a non-illuminated symbol display device. In this method, the visibility of the symbol during the daytime is ensured by the direct sunlight and diffused skylight, scattered light emission or absorption by secondary scattered light from buildings, road surfaces, trees, etc. To do. On the other hand, at night, it is a method of obtaining visibility and attractiveness by illuminating with diffused light from street lights and buildings, vehicle headlight light, or external illumination means.

  When such an unilluminated pattern display device is applied to a road sign, a pattern is formed on the white reflective sheet of the sign substrate by a transparent colored ink, a non-transparent colored ink, or a combination of a colored reflective sheet and a colored non-reflective sheet. In the daytime, the direct sunlight and diffuse sky light that directly acts on the pattern surface, and the scattered light emission or absorption of the pattern surface by secondary scattered light provides visibility and attractiveness. Visibility and attractiveness are obtained by the recursive reflected light by the headlight light of the above.

  Other methods include a symbol light-emitting display device (internal illumination symbol display device) having a lighting member inside the display device, and in the daytime, the symbol is the same as the above-described non-illuminated symbol display device. In the nighttime, the light emitting part (illumination member) provided in the interior is turned on to illuminate the symbol so as to be visually recognized. For example, a fluorescent lamp, an LED, a light emitting diode, or the like is used as the illumination member provided inside.

  On the other hand, as other characteristics required for the symbol light-emitting display device, it is important to improve the discrimination and visibility of the symbol when the sun goes down from the back side of the symbol display board and the backlight is in the backlit state.

  As a method for improving the visibility in such a backlight environment, for example, a method having a large number of holes in the graphic portion of the sign plate as disclosed in Japanese Patent No. 3626602 is disclosed. However, after making many holes in the graphic part of the plate material (for example, aluminum plate), the reflective sheet is laminated, and the holes are manually made only in the part corresponding to the hole in the reflective sheet. Therefore, it takes a lot of work to manufacture, and in addition, there is a drawback that the outline of the figure becomes unclear when viewed from the driver during backlighting.

  As another method, for example, as disclosed in Japanese Patent No. 3468506, a transparent reinforced plastic plate is provided on the surface side of the frame, and a reflective material such as a base material and a reflective material such as letters are used on this surface. And a method in which the display unit is configured. In this method, a translucent milky white reinforced plastic plate is provided on the back of the frame, and when sunlight is received from the back side of the road sign, a part of the sunlight passes through the display part through the translucent plastic plate. In this way, the label portion can be clearly seen even in backlight.

  In addition, a technique for appropriately diffusing light from a light source using, for example, a light diffusing glass fiber sheet in an illumination device is disclosed in Japanese Patent Application Laid-Open No. 2001-55646, and includes, for example, a polyester fiber layer. A technique for applying a display body made of a reflective material such as arbitrary characters and symbols to such a display surface base material using a display base material of a fiber sheet and a light scattering particle mixed plate that partially transmits reverse light is disclosed in Japanese Patent Application Laid-Open No. 2002-2002. No. 317411.

  However, these proposed sign means have illumination means inside, especially like large road signs, in addition to the visibility of signs by natural light in the daytime and the visibility of signs by the internal illumination means at night, It was difficult to improve the visibility at the same time of backlighting. In addition, it has been difficult to reduce the weight of the device in a large road sign or the like and relatively increase the strength.

  To solve the above problem, the vertical and horizontal surfaces of the transparent light plane opposite to the incident light surface of the transparent flat plate are used to uniformly emit high-intensity light on the reverse surface of the incident light surface of the direct sunlight and diffuse sky light received on the back of the pattern. In addition, a high-luminance symbol light-emitting display device including a surface light-emitting plate in which a transparent plano-convex lens group is integrally formed of glass is disclosed (for example, see Patent Document 1). According to the method described in Patent Document 1, it is said that the visibility and attractiveness of a symbol can be improved even when the direct sunlight received on the back of the symbol and the diffuse sky light are backlit and at night. Further, the structure of the internal illumination type sign, which has a sign body and a frame body made of an aluminum frame material, and vertical and horizontal reinforcing members provided on the sign body, and a display made of a fiber sheet on the front surface of the frame body It has a base material, and has a light-transmitting back plate made of a fiber sheet similar to the display base material on the back surface of the sign body, and a large number of internal lighting devices are provided in the lateral reinforcing material inside the sign body In addition, there is disclosed an internal illumination type sign that allows the reverse light to pass through the back plate and the fiber sheet of the display base material when the sunlight against the sign is backlit (see, for example, Patent Document 2). According to the method described in Patent Document 2, it is said that an internal illumination type sign that can sufficiently protect the backlight of the internal illumination type and can make the visibility of the sign uniform in addition to being light and durable. In addition, it has a back plate in which the first reflective sheet is laminated on the surface of the first metal plate, and the back plate has a large number of holes penetrating through the entire surface, and a display unit for characters, figures, symbols, etc. Has been disclosed by a laser processing and a road sign provided with a front plate in which a second reflective sheet is laminated on the surface of a second metal plate (see, for example, Patent Document 3). According to the method described in Patent Document 3, it is said that a road sign with good visibility of the display unit can be easily manufactured even in backlight.

  However, any of these disclosed methods has a complicated structure and a large number of parts, so it takes time to assemble the design light emitting display device, it is troublesome to repair, and the mass is increased. Was inconvenient. Furthermore, the method described in Patent Document 3 does not have an illumination member inside, and thus visibility at night is insufficient.

  On the other hand, even in a design light emitting display device equipped with an illumination member inside the display device, as a countermeasure against backlighting, a transparent plastic plate is applied to the back member or a method of opening a large number of holes, etc., so that light is transmitted from the back surface. Even if it is set as the structure which improves property, since the illumination member itself provided in the inside is not provided with sufficient light transmittance, it is the present condition that sufficient label | marker visibility cannot be obtained at the time of backlight.

  Therefore, in all conditions of daytime direct light, nighttime, and daylight backlight, excellent visibility and attractiveness can be exhibited, and the structure of the symbol light emitting display device that is simple and easy to assemble Development is anxious.

JP 7-279131 A JP 2010-112029 A JP 2011-157777 A

  The present invention has been made in view of the above problems, and its solution is to exhibit excellent visibility and attractiveness under all conditions of daytime daylight, nighttime, and daylight backlighting. It is possible to provide a light-emission display device that is simple in structure, easy to assemble and maintain, and lightweight.

  As a result of intensive studies in view of the above problems, the inventor is a pattern light emitting display device having a light-transmitting pattern plate, an organic electroluminescence element plate, and a light-transmitting back plate in this configuration order. As a result of imparting high light transmittance as an organic electroluminescence element plate, the above problems have been solved.

  That is, the said subject of this invention is solved by the following means.

1. A light-emitting display device having a light-transmitting pattern plate, an organic electroluminescence element plate disposed on the back side of the pattern plate, and a light-transmitting back plate disposed on the back side of the organic electroluminescence element plate a is, organic electroluminescent element plate, light transmittance T _C at a wavelength 550nm in a non-light emitting state is 65% or more, and among the light emitted from the organic electroluminescence element plate, the symbol The amount of light A reaching the surface side C of the organic electroluminescence element plate in contact with the plate is 1.1 times or more of the amount of light B reaching the surface side D of the organic electroluminescence element plate in contact with the back plate A symbol light emitting display device characterized by being.

  2. The organic electroluminescence element plate has a pair of surface electrodes on the substrate and at least one organic light emitting layer between the pair of surface electrodes, and at least one of the pair of surface electrodes. 2. The pattern light emitting display device according to item 1, wherein the electrode is a thin film silver electrode having a thickness in the range of 4.0 to 10 nm.

  By the above means of the present invention, the visibility and attractiveness of the pattern during daytime direct light and nighttime, and the excellent visibility and attractiveness at the time of backlight receiving direct sunlight from the back of the daytime pattern light emitting display device are expressed. In addition, because of its simple configuration, it is possible to provide a lightweight design light emitting display device that is easy to assemble and maintain and that is lightweight.

  It is presumed that the above problem can be solved by the configuration defined in the present invention for the following reason.

  Conventionally, various studies have been made on symbol display devices with the aim of improving display performance (visibility) under the conditions of a) daylighting, b) nighttime, and c) daylighting. However, in all of the situations (i) to (c), the desired visibility was not achieved. In particular, in the case of a symbol light emitting display device in which an illumination member is incorporated in the symbol display device in order to enhance nighttime visibility, as described above, due to the low transmittance of the incorporated illumination member, c) during daylight backlighting The visibility of was very insufficient.

The present inventor examined the characteristics of the illumination member incorporated in the design light emitting display device, in particular, the illumination member that does not impair the transmittance of light incident from the back surface (especially evening sun) in the backlight. As a result, an organic electroluminescence element plate (hereinafter also referred to as an organic EL element plate), which can be designed with a very thin film structure, can emit light with low energy, has excellent durability, and can be easily incorporated, specifically. By applying an organic electroluminescence element plate having a high light transmittance having a light transmittance _TC of 65% or more at a wavelength of 550 nm, b) visibility during normal daytime direct light, and b) Increasing visibility at night using the light emission of organic electroluminescence elements and c) Incident from the back by organic electroluminescence elements with high transparency It is possible to realize excellent visibility at the same time without backlighting, and without disturbing the passage of light rays (especially the western sun) in the symbol light emitting display device.

The perspective view which shows an example of a structure of the design light emission display apparatus of this invention. The schematic exploded view which shows an example of arrangement | positioning of each member which comprises the design light emission display apparatus of this invention Schematic showing the behavior of each beam during (a) daytime direct light, (b) nighttime and (c) backlit Schematic sectional view showing an example of the configuration of the organic electroluminescence element plate according to the present invention Schematic sectional view showing an example of the configuration of the design light emitting display device of the present invention

The design light emitting display device of the present invention includes a light transmissive design plate, an organic electroluminescence element plate arranged on the back side of the design plate, and a light transmissive design arranged on the back side of the organic electroluminescence element plate. a symbol light emitting display device having a back plate, organic electroluminescent element plate, light transmittance T _C at a wavelength 550nm in a non-light emitting state is 65% or more, and from the organic electroluminescence element plate Of the emitted light, the amount of light A reaching the surface side C of the organic electroluminescence element plate in contact with the pattern plate reaches the surface side D of the organic electroluminescence element plate in contact with the back plate It is characterized by being 1.1 times or more of the amount of light B, and the visibility and attractiveness of the pattern during daylighting and nighttime, It is possible to realize a light-weight symbolic light-emitting display device that is easy to assemble and maintain and has a simple structure because it has excellent visibility and attractiveness during backlighting that receives direct sunlight from the back of the light display device. . This feature is a technical feature common to the inventions according to claims 1 and 2 .

As an embodiment of the present invention, the light transmittance T _C at a wavelength 550nm in a non-emission state defined in the present invention, from the viewpoint of realizing the organic electroluminescent element plate 65% or more, the organic electroluminescence element plate A pair of surface electrodes and at least one organic light emitting layer between the pair of surface electrodes, and at least one of the pair of surface electrodes has a thickness of 4 It is a preferable aspect that it is a thin film silver electrode which exists in the range of 0.0-10 nm. Further, the organic electroluminescence element plate has a configuration in which the light amount A of light reaching the surface side in contact with the symbol plate is higher than the light amount B of light reaching the surface side in contact with the back plate. It is preferable from the viewpoint that the desired effect can be expressed more.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in this invention is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Configuration of Symbol Light-Emitting Display Device >>
The configuration of the design light emitting display device of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of the configuration of the symbol light emitting display device of the present invention, and FIG. 2 is a schematic exploded view showing an example of the arrangement of each member constituting the symbol light emitting display device of the present invention.

  1 and 2, the symbol light emitting display device 1 has, from the symbol display surface side, I) a symbol plate 2 having light transmittance, II) an organic EL element plate 6 that is a light emitting material, and III) light transmittance. It is comprised from the backplate 8 which has. Each component of I) to III) is configured by combining in this order as shown in the figure, and then the peripheral portion thereof is fixed by the housing portion 9 and the housing portion 10 so that the design light emitting display device 1 is formed. Forming.

  The light-transmitting pattern board 2 is printed on a transparent surface board 3 with a colored transparent background 4 and a transparent pattern 5 for displaying road signs and the like.

  The organic EL element plate 6 described later in detail forms a surface light emitter by combining a plurality of single organic EL element units 6U (in FIG. 2, nine organic EL element units 6U are used). Electricity is supplied from an external power source to the organic EL element plate 6 through an outlet 7, and each organic EL element unit 6A is driven to emit light.

  The organic EL element plate 6 according to the present invention is a light-emitting member that is an extremely thin film and has a sealed structure. The design light-emitting display device 1 can be designed compactly and exhibits excellent durability.

(Light transmission characteristics)
In the pattern light emitting display device 1 of the present invention, by controlling the light transmittance of each of the light-transmitting pattern plate 2, the organic EL element plate 6, and the light-transmitting back plate 8, it is daytime. Needless to say, the visibility at night and the visibility at night, it is a feature that the visibility at the time of backlight is remarkably improved.

  Having light transmittance in the present invention means that the light transmittance when measured at a wavelength of 550 nm (hereinafter also simply referred to as light transmittance) is 30% or more. The optimum range of transmittance varies. The light transmittance referred to in the present invention can be obtained by measuring with a spectrophotometer (for example, U-3300 manufactured by Hitachi, Ltd.) with light having a wavelength maximum of 550 nm.

In symbol-emitting display device 1 of the present invention, the light transmittance T _C at a wavelength 550nm in a non-emission state of the organic EL element plate 6 according to the present invention is characterized in that at least 65%. By imparting this light transmittance characteristic to the organic EL element plate 6, excellent visibility is exhibited in the daytime when backlighting receives direct sunlight from the back surface of the design light emitting display device 1. Furthermore, the organic EL element plate 6 according to the present invention preferably has a light transmittance of 70% or more, and more preferably in the range of 70 to 90%.

Further, as the light transmittance T _A of the transparent surface plate 3 constituting the pattern plate 2 _(shown in Figure 5), it is preferably in the range 40-55%. Further, the light transmittance T _B (shown in FIG. 5) of the back plate 8 is preferably in the range of 35 to 55%. The technical reason for setting the above-described light transmittance range of each component will be described later.

Further, in the present invention, the light transmittance of the transparent faceplate 3 symbols plate 2 T _{A (%),} the light transmittance T _B of the back plate 8 _(the percent), a combination that satisfies the relationship of TB ≦ TA It is preferable from the viewpoint that the light emission of the organic EL element plate 6 sandwiched therebetween can be used more effectively with respect to the symbol plate 2 side.

In the present invention, the total light transmittance _{T (T A × T B ×} T C) of the total material constituting the pattern light emitting display device 1, the T _A background 4 and figures 5 on pattern plate 2 Print It is preferable that it is 15 to 30% of range when it measures by 3 parts of transparent surface plates which are not made. Even the total light transmittance of the entire symbol light emitting display device _{1 T (T A × T B} × T C) is a case showing the same value, the light transmittance in the non-emission state of the organic EL element plate 6 T The effect of the present invention can be exhibited only in the configuration of the present invention that satisfies the condition that _C is 65% or more.

As an example of the symbol light emitting display device 1 of the present invention, as shown in FIG. 1 and FIG. 2, a configuration having the symbol plate 2 on one side of the symbol light emitting display device 1 is shown. It can also be set as the double-sided symbol display type light emission display apparatus which has these. In this case, the light transmittance T _A of the transparent surface plate 3 of the pattern plate 2 and the light transmittance T _B of the back plate 8 are preferably in a relationship of T _B = T _A. In addition, in the double-sided symbol display type light-emitting display device, each symbol surface is arranged in the east-west direction, and the positional relationship between the viewer and the symbol light-emitting display device is when the sun is backlit and when the sunset is backlit. In any of the situations, excellent visibility can be expressed.

(Ray state in each situation)
FIG. 3 is a schematic diagram showing the behavior of each light beam during (a) daytime direct light, (b) nighttime, and (c) daytime backlight.

(A) of FIG. 3 is a diagram showing the visibility of the status and pattern light emitting display device of the incident light in the daytime frontlit S _1, from the front of the symbol light emitting display device in daytime, sunlight strikes such order In the light environment, the built-in organic EL element plate 6A does not emit light, and the pattern 4 is visually recognized mainly by reflected sunlight La1 and La2 of sunlight irradiated from the front.

  FIG. 3B is a diagram showing the state of visual recognition of the symbol light emitting display device at night. At night, the built-in organic EL element plate 6B exhibits a light emission state, and the light emission Lb1 and Lb2 The symbol 4 is visually recognized. Although not shown in the figure, at night, in addition, there may be a visual effect due to the reflected light from the headlights and street lights of the car, external lighting installed outside the symbol light emitting display device, etc. is there.

(C) in FIG. 3 is a diagram showing the visibility of the status and pattern light emitting display device of the incident light in the daytime backlit S _2, from the back of the pattern light emitting display device in the daytime, sunlight (backlit) Lc3 hits In such a backlit environment, the built-in organic EL element plate 6A does not emit light, and the pattern 4 is visually recognized by reflected light La1 and La2 due to light incident from the front as in FIG. To do. In addition, the backlight Lc3 received from the back side of the design light emitting display device passes through the transparent back plate 8, the organic EL element plate 6A and the design plate 2 to reach the surface portion, thereby allowing the design to reach the surface portion even under backlight conditions. The visibility of the pattern 4 of the light emitting display device can be dramatically improved.

  That is, the symbol light emitting display device having the configuration defined in the present invention realizes excellent symbol visibility even in different situations such as (a) daytime direct light, (b) nighttime, and (c) daylight backlight. We were able to.

<< Pattern board >>
The pattern board 2 according to the present invention has a light-transmitting transparent surface plate 3 and a light-transmitting paint, using a light-transmitting paint, and a transparent background 4 for displaying road signs and the like. The design 5 is displayed, and the design is not only visually recognized by reflection of sunlight or illumination light, but also by the light emission of the built-in organic EL element plate 6 and the background 4 portion and the design 5 portion. It is also visually recognized by the difference in transmittance and color. The symbol 5 is applied from advertising and advertising characters and images to displays, signs, and information boards for public use. Therefore, the light-transmitting transparent surface plate 3 preferably exhibits white or milky white.

  The material of the transparent surface plate 3 constituting the symbol plate 2 according to the present invention is not particularly limited as long as it is a material having optical transparency, but in addition to the optical transparency, durability as a symbol light emitting display device. Considering the properties, for example, polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), polyethylene naphthalate resin (PEN resin), polypropylene naphthalate resin, polycarbonate resin, polyphenylene oxide resin, polyurethane resin, acrylic resin , Acryl-urethane resin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) and other fluororesins, melamine resin, acrylonitrile / butadiene / styrene copolymer resin (ABS resin) and the like, and these resins Resin Command resins, polymer alloys and the like. Among these, acrylic resins and acrylic-urethane resins are particularly preferable.

  Moreover, in the transparent surface board 3 which concerns on this invention, as a method of adjusting to desired light transmittance, when shape | molding the transparent surface board 3, a coloring agent (for example, white pigment etc.) is suitably used with respect to the resin raw material. It can be adjusted by adding.

  Moreover, as a method of providing the background 4 and the pattern 5 on the transparent surface plate 3 according to the present invention, a gravure printing method, an offset printing method, a silk screen printing method, and a transfer sheet are used using a printing ink or paint. A desired pattern or the like can be formed by using a conventionally known wet printing method such as a transfer printing method, sublimation transfer printing method, and ink jet printing method.

  Moreover, after coloring resin which can be used for the said transparent surface board 3 with a dye or a pigment, the thin resin board is shape | molded and what was cut out in the shape of a pattern is given on the transparent surface board 3 It is also possible to do it.

In the present invention, as described above, the light transmittance T _A (%) of the transparent surface plate 3 constituting the symbol plate 2 is preferably in the range of 40 to 55%. If the light transmittance T _A (%) of the transparent surface plate 3 is 40% or more, the light emission of the built-in organic EL element plate 6 can be used efficiently, and the effect of visibility in backlighting is obtained. It can be fully demonstrated. Moreover, if the light transmittance T _A (%) of the transparent surface plate 3 is 55% or less, it is possible to ensure visibility due to, for example, sunlight during daylighting or reflection of illumination light at night.

《Organic electroluminescence element plate》
(Configuration of organic EL element plate)
The organic EL element plate according to the present invention, in the non-emission state, the light transmittance T _C at a wavelength of 550nm, characterized in that at least 65%. Further, the organic EL element plate has a pair of surface electrodes on the substrate and at least one organic light emitting layer between the pair of surface electrodes, and at least one of the pair of surface electrodes. It is a preferable aspect that the electrode is composed of a thin film silver electrode having a thickness in the range of 4.0 to 10 nm.

The light transmittance of the organic EL element plate according to the present invention in a non-light-emitting state refers to a substrate constituting the organic EL element plate, a pair of surface electrodes, an organic functional layer including an organic light emitting layer, and a wavelength of 550 nm of the entire sealing layer. In order to achieve this, the light transmittance of each of these components is high, and in particular, surface electrodes that are usually low in light transmittance are designed with higher light transmittance. be, namely an anode, a cathode, all of the intermediate electrode which is provided if necessary, light transmittance is high, becomes an important requirement for achieving a light transmittance T _C defined in the present invention . In addition, when laminating an organic functional layer such as an organic light emitting layer, it is also preferable to devise so as to increase the light transmittance.

As the substrate and the sealing layer constituting the organic EL element plate, it is preferable to use a substrate having a high light transmittance such as glass, quartz, or a plastic film. By increasing the optical transparency of the components of the organic EL element plate, but the light transmittance T _C becomes possible to 65% or more, further, the range of light transmittance T _C of 70% to 90% It is preferable to design within.

The light transmittance T _C in the present invention refers to a transmittance when the wavelength maximum was measured with light of 550 nm. Light transmittance T _C ordinary spectrophotometer (e.g., such as manufactured by Hitachi U-3300) can be readily determined using.

  The main structure of the organic EL element plate has a pair of surface electrodes (anode and cathode) on the substrate, and an organic functional layer including an organic light emitting layer between the surface electrodes. Usually, from the anode side, there are a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, etc., but the number of layers may be reduced as a composite layer depending on the characteristics of the material used. Further, a new functional layer may be added. For the configuration of the organic EL element plate, “Organic EL Handbook” (supervision: Tetsuo Tsutsui; published by Realize Science and Technology Center) is referred to.

  FIG. 4 is a schematic cross-sectional view showing an example of the configuration of the organic EL element plate according to the present invention.

  In FIG. 4, an organic EL element plate 6 is provided with a transparent electrode 12 as an anode, for example, on a support substrate 11 made of a light-transmitting plastic film or glass, on which an organic functional layer unit C is provided. Is formed. In addition to the organic light emitting layer 14, the organic functional layer unit C is composed of organic functional layers 13, 15 such as a hole transport layer, a hole blocking layer, and an electron transport layer. On this organic functional layer unit C, for example, the transparent electrode 16 is provided as a cathode, and finally a sealing member (sealing layer) is provided as the outermost layer.

  In the conventional organic EL element plate, for example, an indium-tin composite oxide (hereinafter abbreviated as ITO) having a certain degree of light transmittance has been used as the transparent electrode 12 configured as an anode. On the other hand, a metal vapor deposition film such as aluminum is used as the transparent electrode 16 which is a cathode. However, these cathode materials have poor light transmittance, and the organic EL element plate having such a structure has a light transmittance. Is 60% or less, which is not preferable as a constituent member of an organic EL element plate applied to a design light emitting display device.

In the present invention, either one of the transparent electrode 12 or the transparent electrode 16 shown in FIG. 4, preferably both transparent electrodes, is made of a member having extremely excellent light transmittance, more specifically, a thickness of 4.0 to 10 nm. by a thin film silver electrode which is within the range, the light transmittance T _C at a wavelength of 550nm is able to realize an organic EL element plate that becomes 65% or more, and enables the application to design a light-emitting display device Is.

  FIG. 5 is a cross-sectional view showing a configuration of a design light emitting display device including the organic EL element plate according to the present invention.

5, the left side of the drawing is a follow light side S _1, the right side is the backlight side S _2. Symbol light emitting display device 1, from front light side S _1, symbol plate 2, the organic EL element plate 6 is constructed in the order of the back plate 8. In such a configuration, the organic EL element plate 6 has a transparent electrode 16 as a cathode disposed on the pattern plate 2 side.

In such a configuration, among the light emitted from the organic EL element plate 6, the amount of light A reaching the surface side C of the organic electroluminescence element plate 6 in contact with the pattern plate 2 is in contact with the back plate 8. One characteristic is that the amount of light B reaching the surface side D of the element plate 6 is 1.1 times or more , more preferably 1.1 to 3.0 times, and still more preferably 1.2. It is the range of -2.0 times.

  The above configuration is preferable because light emission can be used effectively and driving power can be reduced.

  The layer structure of the organic E1L element plate shown in FIGS. 4 and 5 is merely a preferred specific example, and the present invention is not limited to these. For example, the configuration of the organic EL element plate according to the present invention may have the following layer structures (i) to (v).

(I) Support substrate / anode / light emitting layer / electron transport layer / cathode / sealing adhesive / sealing member (ii) Support substrate / anode / hole transport layer / light emitting layer / electron transport layer / cathode / sealing Adhesive / sealing member (iii) support substrate / anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode / sealing adhesive / sealing member (iv) support substrate / anode / Hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode / sealing adhesive / sealing member (v) support substrate / anode / anode buffer layer / hole transport layer / Light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode / sealing adhesive / sealing member [organic functional layer of organic EL element plate]
Next, each component of the organic EL element plate according to the present invention will be described.

(1) Injection layer: hole injection layer, electron injection layer In the organic EL element plate according to the present invention, the injection layer can be provided as necessary. The injection layer includes an electron injection layer and a hole injection layer, and may be present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above.

  The injection layer referred to in the present invention is a layer provided between the electrode and the organic functional layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. The details are described in Chapter 2, “Electrode Material” (pages 123 to 166) of the second edition of “S. Co., Ltd.”, and there are a hole injection layer and an electron injection layer.

  Details of the hole injection layer are described in, for example, JP-A-9-45479, JP-A-9-260062, and JP-A-8-288069. Examples of the hole injection material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives. Derivatives, polymers containing silazane derivatives and the like, aniline copolymers, polyarylalkane derivatives, or conductive polymers are preferable, and polythiophene derivatives, polyaniline derivatives, and polypyrrole derivatives are more preferable. It is a polythiophene derivative.

  In the organic EL element plate according to the present invention, the electron injection layer may or may not be provided. Details of the electron injection layer applicable in the present invention are described in, for example, JP-A-6-325871, 9-17574, 10-74586, and the like. Metal buffer layer typified by strontium or aluminum, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide Etc. In the present invention, the buffer layer (injection layer) is desirably a very thin film, and potassium fluoride and sodium fluoride are preferable. The film thickness is about 0.1 nm to 5 μm, preferably 0.1 to 100 nm, more preferably 0.5 to 10 nm, and most preferably 0.5 to 4 nm.

(2) Hole transport layer As the hole transport material constituting the hole transport layer according to the present invention, the same compounds as those applied in the hole injection layer can be used. It is preferable to use a compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  In the present invention, the hole transport layer can be formed by coating and drying using a wet coating method (for example, a spin coating method, a casting method, a printing method including an inkjet method, or the like). As another method for forming the hole transport layer, the hole transport material is formed by thinning it by a known method such as a vacuum vapor deposition method or a Langmuir-Blodgett method (LB method). be able to.

(3) Electron Transport Layer The electron transport layer according to the present invention is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer may be a single layer or a plurality of layers. For example, it can be used as a hole block layer / electron transport layer combination.

  When the electron transport layer is a single layer or a plurality of layers, it is injected from the cathode as an electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the light emitting layer on the cathode side. As long as it has a function of transmitting electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, fluorene derivatives, carbazole derivatives, azacarbazole Examples thereof include metal complexes such as derivatives, oxadiazole derivatives, triazole derivatives, silole derivatives, pyridine derivatives, pyrimidine derivatives, and 8-quinolinol derivatives.

(4) Light-emitting layer The light-emitting layer constituting the organic EL element plate according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode or the electron transport layer and the hole transport layer, The portion that emits light may be within the layer of the light emitting layer or at the interface between the light emitting layer and the adjacent layer.

  The light emitting layer is mainly composed of a dopant compound and a host compound. The material for forming the light emitting layer according to the present invention is a low molecular weight organic compound, and the low molecular weight compound in the present invention is defined as a compound having a molecular weight of 1500 or less.

  Hereinafter, each of the host compound and the dopant compound will be described.

<4.1> Host compound As the host compound contained in the light emitting layer of the organic EL device plate according to the present invention, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C) of less than 0.1 is preferable. . More preferably, the phosphorescence quantum yield is less than 0.01. Further, the non-light emitting organic material may contain a host compound.

  Different types of luminescent colors can be obtained by using a plurality of known host compounds and luminescent materials described later, and by mixing these, any luminescent color, for example, white luminescence can be expressed. it can.

  Specific examples of known host compounds include compounds described in the following documents. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

<4.2> Luminescent Material As the luminescent material (luminescent dopant) according to the present invention, a fluorescent compound, a phosphorescent luminescent material (also referred to as a phosphorescent compound, a phosphorescent compound, a phosphorescent dopant compound, etc.). However, a phosphorescent dopant compound is preferable.

  The phosphorescent light-emitting material can be appropriately selected from known materials used for the light-emitting layer of the organic EL element plate, but is preferably a complex system containing a group 8-10 metal in the periodic table of elements. Compounds, more preferably iridium compounds, osmium compounds, platinum compounds (platinum complex compounds), rare earth complexes, and most preferred are iridium compounds.

(5) Transparent electrode In the organic EL element plate according to the present invention, it is important to apply a surface electrode (transparent electrode) having a high light transmittance in order to set the light transmittance _TC to 65% or more. As the surface electrode having high light transmittance, what is generally known as a transparent electrode can be used. Examples include metal oxide electrodes such as indium-tin composite oxide (ITO) and indium zinc oxide (IZO), conductive polymer electrodes such as polythiophene and polyaniline, and metal thin film electrodes such as silver thin films and copper thin films. as the light transmittance T _C of one transparent electrode, preferably achieved by designing such that 80% or more.

  On the other hand, the transparent electrode is required to have high conductivity. Many conventional transparent electrodes have insufficient conductivity when formed thin in order to increase the light transmittance. In the present invention, it is preferable to use a thin-film silver electrode described below as a transparent electrode having high light transmittance and high conductivity.

  The transparent electrode according to the present invention preferably has a surface resistivity of 0.3 to 200 Ω / □, more preferably 0.5 to 100 Ω / □, and 1 to 50 Ω / □. A range of □ is particularly preferable. The surface specific resistance can be measured based on, for example, JIS K6911, ASTM D257, etc., and can be easily measured using a commercially available surface resistivity meter.

<Thin film silver electrode>
The thin film silver electrode is a layer formed using silver or an alloy containing silver as a main component. As a method for forming such a thin film silver electrode layer, a method using a wet process such as a coating method, an ink jet method, a coating method, a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, etc. And a method using a dry process such as Of these, the vapor deposition method is preferably applied. If necessary, high-temperature annealing treatment may be performed after film formation.

  Alloys mainly composed of silver (Ag) constituting the thin film silver electrode layer include silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), silver indium (AgIn), and the like. Is mentioned. These layers of silver or an alloy containing silver as a main component may be divided into a plurality of layers as necessary.

  Furthermore, since this thin film silver electrode layer has a film thickness in the range of 4 to 10 nm, it has a high light transmittance and can secure conductivity, so that it can be effectively applied to an organic EL element plate. In the present invention, it is preferably in the range of 4 to 9 nm. If the film thickness is 10 nm or less, light absorption or reflection can be suppressed, and a desired transmittance as a transparent electrode can be obtained. Moreover, if the film thickness is 4 nm or more, sufficient conductivity can be obtained, and a continuous thin film can be stably formed. In the present invention, at least one of the surface electrodes of the organic EL element plate, that is, the anode, the cathode, and the intermediate electrode provided as necessary is preferably a thin film silver electrode, and all the electrodes are thin film silver electrodes. Is more preferable.

  In the thin film silver electrode layer, it is preferable to form silver or an alloy containing silver as a main component on the base layer having a compound containing a nitrogen atom by the above method. The silver atoms constituting the electrode layer interact with the compound containing nitrogen atoms constituting the underlayer, the diffusion distance of silver atoms on the underlayer surface is reduced, and aggregation of silver is suppressed. Therefore, in general, a silver thin film that is easily isolated in an island shape by film growth of a nuclear growth type (Volume-Weber: VW type) is a single-layer growth type (Frank-van der Merwe: FW type) film growth. As a result, a film is formed. Accordingly, an electrode layer having a uniform film thickness can be obtained even though the film thickness is small. As a result, it is possible to obtain a transparent electrode in which conductivity is ensured while maintaining a high light transmittance with a thinner film thickness.

(6) Support Substrate As a support substrate that can be used for the organic EL element plate according to the present invention, a transparent support substrate such as glass or plastic is used. Examples of the transparent support substrate used include glass, quartz, and a transparent resin film.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, arton (trade name, manufactured by JSR) or appel (trade name, manufactured by Mitsui Chemicals) Resin etc. are mentioned.

《Back plate》
In the design light emitting display device of the present invention, it is one of the structural features to have a light-transmitting back plate. The light transmittance of the back plate, a hole to the light non-transparent back plate, and designed to be fixed in the aperture ratio, may also be but obtained by the desired optical transparency T _{B (%)} It is preferable that the light-transmitting material is molded into a uniform plate shape since the transmitted light is uniformly introduced into the pattern plate. Since the back plate is required to have a function of protecting the highly precise organic EL element plate according to the present invention together with the pattern plate according to the present invention, those having excellent weather resistance and durability are preferable.

  The material constituting the back plate 8 according to the present invention is not particularly limited as long as it is a material having light transmissivity, but in addition to the light transmissivity, considering the durability as a symbol light emitting display device, For example, polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), polyethylene naphthalate resin (PEN resin), polypropylene naphthalate resin, polycarbonate resin, polyphenylene oxide resin, polyurethane resin, acrylic resin, acrylic-urethane resin , Fluorine resins such as tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), melamine resin, acrylonitrile / butadiene / styrene copolymer resin (ABS resin), and blend resins of resins selected from these resins The Maaroi, and the like. Among these, acrylic resins and acrylic-urethane resins are particularly preferable.

  Further, in the back plate according to the present invention, as a method of adjusting to a desired light transmittance, a colorant (for example, a white pigment) is appropriately added to the resin raw material when forming the back plate. can do.

  Moreover, a background and a pattern can be provided on the back plate according to the present invention as necessary as described above. As a method for providing these symbols and the like, the same method as described for the symbol board can be applied.

The light transmittance T _B of the light-transmitting of the back plate according to the present invention, it is preferable that the light transmittance measured at a wavelength of 550nm is in the range 35 to 55%. If the light transmittance is 35% or more, the effect of improving the visibility in backlighting, which is the object of the present invention, can be exhibited, and if it is 55% or less, the organic EL element plate emits light at night. In this case, the efficiency of reflecting and using the light emitted to the back plate side by the back plate can be sufficiently exhibited. In addition, the light-transmitting back plate has an effect of transmitting part of sunlight during backlighting and improving the visibility of the symbol, but if the light transmittance during backlighting is excessively high, the symbol visibility is too high. May be reduced.

  Since the light-transmitting back plate according to the present invention contributes to the visibility of the pattern by utilizing the transmitted light, it is preferable to exhibit white or milky white.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

<< Preparation of organic EL element board >>
[Preparation of organic EL element plate 101]
(Formation of anode)
An ITO electrode (anode) was formed on a transparent non-alkali glass substrate having a thickness of 0.7 mm by sputtering with ITO under the condition of a thickness of 100 nm.

(Formation of organic functional layer unit)
The support substrate provided with the ITO layer was washed and dried, and the following layers were sequentially formed using a commercially available vacuum deposition apparatus.

<Formation of hole injection layer and hole transport layer>
A hole injection layer / hole transport layer was formed by depositing α-NPD at a deposition rate of 0.1 to 0.2 nm / second on the ITO layer to a film thickness of 20 nm.

<Formation of light emitting layer>
Next, the light-emitting host compound 1 and the light-emitting dopant 1 were adjusted so that the deposition rate was light-emitting host compound 1: light-emitting dopant 1 = 100: 6, and a light-emitting layer having a thickness of 30 nm was provided.

<Formation of hole blocking layer>
Next, a hole blocking layer was provided so that the film thickness was 10 nm at a deposition rate of 0.1 to 0.2 nm / second with BAlq.

<Formation of electron transport layer>
Next, the nitrogen-containing compound 1 and potassium fluoride were adjusted so that the deposition rate was nitrogen-containing compound 1: potassium fluoride = 75: 25, and an electron transport layer having a thickness of 30 nm was provided.

<Formation of electron injection layer>
Furthermore, lithium fluoride was provided with an electron injection layer having a thickness of 1 nm at a deposition rate of 0.01 to 0.02 nm / second.

(Formation of cathode)
A light-transmitting cathode was provided so that the film thickness was 150 nm while adjusting the ITO at a film formation rate of 0.3 to 0.5 nm / second.

(Sealing of organic EL element plate)
Finally, the organic EL element obtained above is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is used as a sealing material around the periphery. ) Was applied to a support substrate of the organic EL element, and UV light was irradiated from the glass substrate side to be cured and sealed to obtain an organic EL element plate 101.

[Preparation of organic EL element plate 102]
In the organic EL element plate 101, the substrate formed up to the electron injection layer was fixed to a substrate holder of a commercially available vacuum deposition apparatus and attached to a vacuum chamber of the vacuum deposition apparatus. Moreover, silver (Ag) was put into the resistance heating boat made from tungsten, and it attached in the said vacuum chamber. Next, after depressurizing the vacuum tank to 4 × 10 ⁻⁴ Pa, the resistance heating boat is energized and heated, and the thickness is made of silver while controlling the deposition rate at 0.1 to 0.2 nm / second. An organic EL element plate 102 was produced in the same manner except that a light-transmitting cathode having a thickness of 10 nm was formed.

[Preparation of organic EL element plate 103]
In the production of the organic EL element plate 102, an organic EL element 103 was produced in the same manner except that the base layer, the anode and the cathode were formed as follows.

<Formation of underlayer>
A transparent non-alkali glass substrate having a thickness of 0.7 mm was attached to a vacuum chamber of a vacuum evaporation apparatus. Next, an underlying layer was formed so as to have a film thickness of 25 nm while controlling the following TPD at a deposition rate of 0.1 to 0.2 nm / second.

<Formation of anode>
On the ground layer, silver (Ag) is put in a resistance heating boat made of tungsten, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, the resistance heating boat is energized and heated, and the deposition rate is 0.1 to 0. A light-transmitting anode made of silver and having a thickness of 10 nm was formed while controlling under the condition of 2 nm / second. <Formation of cathode>
From the hole injection layer to the electron injection layer, after film formation was performed in the same manner as the organic EL element 101, silver (Ag) was placed in a resistance heating boat made of tungsten, and the vacuum chamber was decompressed to 4 × 10 ⁻⁴ Pa. A resistance heating boat was energized and heated, and a light-transmitting cathode made of silver and having a thickness of 8 nm was formed while controlling the deposition rate at 0.1 to 0.2 nm / second. [Organic EL element plate 104 Production)
In the production of the organic EL element plate 103, an organic EL element 104 plate was produced in the same manner except that the film thickness of the silver layer of the anode was 8 nm and the film thickness of the silver layer of the cathode was 5 nm.

(Measurement of light transmittance of each organic EL element plate)
The organic EL element plate 101 to 104 were prepared, using a spectrophotometer (manufactured by Hitachi Ltd. U-3300), it was measured the light transmittance _{T C} in the spectral wavelength of 550 nm.

Measurements showed that the light transmittance of the organic EL element plate 101 _{T C} is 57%, the light transmittance of the organic EL element plate 102 _{T C} 65%, the light transmittance of the organic EL element plate 103 _{T C} is 73%, the organic light transmittance _{T C} of the EL element plate 104 was 86%.

(Measurement of the amount of light emitted from each organic EL element plate)
About the produced organic EL element plates 101 to 104, the light amount A of light reaching the surface side C in contact with the design plate and the light amount B of light reaching the surface side D in contact with the back plate were measured according to known methods. As a result, in all the organic EL element plates, the light amount A was in the range of 1.2 times to 1.4 times the light amount B.

<< Preparation of design board >>
As the substrate of the pattern plate, a thickness of 3.0 mm, the light transmittance _{T A} at opalescent spectral wavelength 550nm is 43%, 46%, 52%, was prepared 57% of the acrylic plate.

  The design of the road sign as shown in FIG.1 and FIG.2 was printed on the design board with the light transmissive ink.

《Preparation of back plate》
As the back plate, acrylic plates having a thickness of 3.0 mm, milky white, and light transmittance at a spectral wavelength of 550 nm of 40%, 43%, 46%, and 52% were prepared.

<< Production of design light emitting display device >>
With the configuration shown in FIG. 1 and FIG. 2, the symbol light emitting display devices 1 to 14 were manufactured using the symbol plate, the organic EL element plate, and the back plate in the combinations shown in Table 1.

  The organic EL element plate was arranged so that the cathode side was located on the side of the figure side plate.

<< Evaluation of design light emitting display device >>
About the produced said symbol light emission display apparatuses 1-14, the visibility in the daytime outdoors, the visibility at the time of light emission at night, and the visibility at the time of backlighting in the daytime were evaluated.

(Evaluation of visibility outdoors during the day)
Each symbol light-emitting display device is installed at a height of 5 m, and a visibility evaluator stands 10 m in front of the symbol light-emitting display device, at 45 ° from the display plate installation point of the line connecting the display plate installation point and the evaluator's point. Then, the sun was placed at an elevation angle of 60 ° from the display board installation point, and the visibility was subjected to sensory evaluation in accordance with the following evaluation criteria at the time of fine weather and the time of cloudy weather (cloud amount 10).

(Visibility when emitting light at night)
A design light-emitting display device is installed in a completely dark room at a height of 5 m, a visibility evaluator stands 10 m in front of the design light-emitting display device, energizes the organic EL element to emit light, and is visible according to the following evaluation criteria. Sensory evaluation.

(Visibility during daylight backlighting)
The design light-emitting display device is installed at a height of 5 m, and a visibility evaluator stands 10 m in front of the design light-emitting display device so that the elevation angle from the visibility evaluator is 30 ° and the sun appears on the design light-emitting display device. And the sensory evaluation of the visibility under backlighting was performed according to the following evaluation criteria.

(Visibility sensory evaluation criteria)
Visual observation was performed with a total of 10 monitors of 6 males and 4 females, evaluation was performed according to the following criteria, and the average value of the ranks was obtained.

◎: Visibility is very good ○: Visibility is good and there is no problem △: Visibility is inferior quality ×: Visibility is extremely inferior quality Table 1 shows the results obtained as described above. .

Table 1 As apparent from the results described in the, symbol light emitting display device of the present invention where the light transmittance T _C is equipped with the organic EL element plate is 65% or more at a wavelength of 550nm in a non-emission state specified in the present invention Compared with the comparative example, it can be seen that excellent visibility is exhibited under all conditions of (a) daytime direct light, (b) nighttime, and (c) daylight backlight.

DESCRIPTION OF SYMBOLS 1 Pattern light emission display apparatus 2 Pattern board 3 Transparent surface board 4 Background 5 Pattern 6, 6A, 6B Organic EL element board 6U Organic EL element unit 7 Outlet 8 Back plate 9, 10 Housing | casing part 11 Support substrate 12 Transparent electrode (anode)
13, 15 Organic functional layer 14 Organic light emitting layer 16 Transparent electrode (cathode)
17 Sealing member La1, La2, Lb1, Lb2, Lc1, Lc2 Reflected light Lc3 Transmitted light S1 Forward light S2 Backlight

Claims (2)

A light-emitting display device having a light-transmitting pattern plate, an organic electroluminescence element plate disposed on the back side of the pattern plate, and a light-transmitting back plate disposed on the back side of the organic electroluminescence element plate a is, organic electroluminescent element plate, light transmittance T _C at a wavelength 550nm in a non-light emitting state is 65% or more, and among the light emitted from the organic electroluminescence element plate, the symbol The amount of light A reaching the surface side C of the organic electroluminescence element plate in contact with the plate is 1.1 times or more of the amount of light B reaching the surface side D of the organic electroluminescence element plate in contact with the back plate A symbol light emitting display device characterized by being.   The organic electroluminescence element plate has a pair of surface electrodes on the substrate and at least one organic light emitting layer between the pair of surface electrodes, and the thickness of at least one electrode of the pair of surface electrodes Is a thin film silver electrode in a range of 4.0 to 10 nm.

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