JP4978225B2 - Display device - Google Patents

Description

  The present invention relates to a display device including a backlight unit that illuminates from the back side a liquid crystal panel on which a display element having a display pattern defined according to transmission / non-transmission or transparent / scattering states in pixel units is arranged. About.

  In recent years, liquid crystal display devices using a liquid crystal panel made of TFT or STN are being commercialized mainly for color notebook PCs (personal computers) in the OA field.

  Conventionally, this type of display device employs a so-called backlight method in which a light source is disposed on the back side (counter-viewer side) of a liquid crystal panel and the liquid crystal panel is illuminated with light from the light source. Yes.

  The backlight unit employed in this type of backlight system is roughly divided into a light source lamp such as a cold cathode fluorescent lamp (CCFT), and a side end portion of a flat light guide plate made of acrylic resin having excellent light transmittance. There are a “light guide plate light guide method” (so-called edge light method) in which light from the light source lamp is multiply reflected within the light guide plate, and a “direct type method” without using the light guide plate.

  As a liquid crystal display device on which a light guide plate light guide type backlight unit is mounted, for example, one having a structure as shown in FIG. 8 is generally known.

  This is provided with a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 at the top, and a light guide plate 79 made of a transparent base material such as a substantially rectangular plate-like PMMA (polymethyl methacrylate) or acrylic on the lower surface side. And a diffusion film (diffusion layer) 78 is provided on the upper surface (light exit surface) of the light guide plate.

  Further, on the lower surface of the light guide plate 79, a scattering reflection pattern portion for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 72 is provided by printing or the like ( A reflection film (reflection layer) 77 is provided below the scattering reflection pattern portion.

The light guide plate 79 has a light source lamp 76 attached to the side end thereof, and further covers the back side of the light source lamp 76 so that the light from the light source lamp 76 can be efficiently incident on the light guide plate 79. Thus, a high-reflectance lamp reflector 81 is provided. The scattering reflection pattern portion is a mixture of white titanium dioxide (TiO ₂ ) powder mixed in a solution such as a transparent adhesive, printed in a predetermined pattern, for example, a dot pattern, dried, and formed. This is a method for imparting directivity to the light incident on the light guide plate 79 and guiding it to the light exit surface side, and to increase the luminance.

  Furthermore, recently, in order to improve the light utilization efficiency and increase the brightness, as shown in FIG. 9, a prism film (prism layer) having a light condensing function between the diffusion film 78 and the liquid crystal panel 72 is used. ) 74 and 75 are proposed. The prism films 74 and 75 are configured to collect the light emitted from the light exit surface of the light guide plate 79 and diffused by the diffusion film 78 on the effective display area of the liquid crystal panel 72 with high efficiency.

  However, in these methods illustrated in FIGS. 8 and 9, the control of the visual field range is left only to the diffusibility of the diffusion film 78, which is difficult to control, the central part in the diffusion direction is bright, and the peripheral part is The characteristic that becomes darker as you go is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced.

  Furthermore, in the method using the prism film illustrated in FIG. 9, two prism films are required, which not only greatly reduces the amount of light due to the absorption of the film but also increases the cost due to the increase in the number of members. It was also.

  On the other hand, the direct type is used for a display device such as a large liquid crystal TV in which it is difficult to use a light guide plate.

  As a direct liquid crystal display device, a configuration illustrated in FIG. 10 is generally known. In this, a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 is provided on the upper side, and a row of light sources 51 made of fluorescent tubes or the like is disposed on the lower surface side thereof. An optical sheet such as a diffusion film (diffusion layer) 82 is provided on the emission surface.

  Furthermore, recently, a prism film (prism layer) having a light condensing function is provided between the diffusion film 82 and the liquid crystal panel 72 as in the case of FIG. ) Is proposed.

  The prism film collects light emitted from the light source 51 and diffused by an optical sheet such as the diffusion film 82 on the effective display area of the liquid crystal panel 72 with high efficiency. In order to efficiently use the light from the light source 51 as illumination light, a reflector 52 is disposed on the back surface of the light source 51.

  However, even in the configuration illustrated in FIG. 10, the control of the visual field range is left only to the diffusibility of the diffusion film 82, and the control is difficult, and the characteristic is that the central part in the diffusion direction is bright and becomes darker toward the peripheral part. Is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced. Furthermore, in the method using a prism film, since the number of prism films is two, not only the light quantity is greatly reduced due to absorption of the film, but also the cost is increased due to an increase in the number of members.

  Further, if the interval between the light sources 51 is too wide, uneven brightness tends to occur on the screen, and the number of the light sources 51 cannot be reduced, leading to an increase in power consumption and an increase in cost.

  By the way, in such a liquid crystal display device, light weight, low power consumption, and high brightness are strongly demanded as market needs, and accordingly, the backlight unit mounted on the liquid crystal display device is also light weight, low power consumption. Power and high brightness are required.

  In particular, in color liquid crystal type display devices that have recently made remarkable progress, the panel transmittance of the liquid crystal panel is much lower than that of a monochrome-compatible liquid crystal panel, and therefore the brightness of the backlight unit can be improved. It is essential to obtain low power consumption.

  However, with the conventional configuration as described above, it is difficult to say that the demand for high luminance and low power consumption is sufficiently met today, as liquid crystal type display devices are further reduced in thickness. The development of a backlight unit capable of realizing a liquid crystal type display device with low price, high brightness, high display quality, and low power consumption is awaited.

  In view of the above situation, for example, as disclosed in Patent Document 1, the present applicant includes a liquid crystal panel and light source means for illuminating light from the back side of the liquid crystal panel, and the light source means includes light from the light source. A liquid crystal display device has been proposed in which a lens layer for guiding the liquid crystal panel to the liquid crystal panel is provided and a light-shielding portion having an opening in the vicinity of the focal plane of the lens layer.

  In Patent Document 1, as shown in FIGS. 1 to 3 of the same document, a configuration in which a lens sheet having a light shielding portion is disposed between a liquid crystal panel and a backlight unit is disclosed. 1 to 3, the lens sheet is provided on the liquid crystal panel side, and has a concavo-convex shape formed of a plurality of unit lenses regularly arranged at equal pitches in each of the X direction and the Y direction. Have.

  The function and effect obtained by interposing the lens sheet having the above-described configuration is that the diffusibility of the light emitted from the light guide plate is modulated by the function of the unit lens corresponding to the opening in a one-to-one relationship, and the direction toward the liquid crystal panel is changed. It is in the point which can be made to inject uniformly.

In addition, by forming a light-shielding portion having an opening at a specific location, it becomes possible to selectively increase the amount of light incident on the display element of the liquid crystal panel, improving the use efficiency of the backlight, and the opening It is possible to control the viewing area of the display light by controlling the shape.
JP 2000-284268 A Japanese Patent No. 3381570 JP 2006-106197 A

  As described above, the display device that illuminates the liquid crystal panel with the lens sheet as shown in Patent Document 1 can selectively increase the amount of light incident on the display element of the liquid crystal panel, and the shape of the opening. By controlling the display, the viewing zone of the display light can be controlled. However, such a display device may cause moire.

  Moire is a beat phenomenon of two spatial frequencies that occur in accordance with the shift in period due to the overlap of periodicity. Moire itself also has a period, and this period is determined by a combination of the original periods. As described above, in the lens sheet shown in Patent Document 1, the unit lenses are periodically arranged along the X direction and the Y direction. Similarly, in the liquid crystal panel, display elements are periodically arranged along the X direction and the Y direction. Therefore, under certain conditions, moire occurs due to superposition of the arrangement periodicity of the unit lenses in such a lens sheet and the arrangement periodicity of the display elements in the liquid crystal panel, and the quality of the image displayed from the display device There is a problem that decreases.

  The present invention has been made in view of such circumstances, and even when a lens sheet in which unit lenses are regularly arranged is arranged between a liquid crystal panel and a light source, moiré is generated. An object of the present invention is to provide a display device that can prevent the image quality and realize a good image quality.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the invention of claim 1 includes a light source, a liquid crystal panel in which a plurality of display elements that define a display pattern of a display image in units of pixels are regularly arranged along the X direction and the Y direction, and a light source. And an optical sheet that supplies the light to the liquid crystal panel. Here, the optical sheet is provided with a light scattering layer that scatters light from the light source incident from the incident surface side to the exit surface side that is the non-incident surface side, and one surface on the exit surface side of the light scattering layer. A non-light-scattering layer provided between a plurality of light-reflecting portions that reflect light scattered by the light-scattering layer toward the light-scattering layer and two adjacent light-reflecting portions. And a plurality of light transmission parts made of, for example, an air layer that is transmitted to the side. The optical sheet further includes a lens unit in which a plurality of unit convex cylindrical lenses are regularly arranged in parallel along the Y direction on the liquid crystal panel side, and a surface opposite to the lens unit, and is transmitted by the light transmitting unit. A lenticular sheet having a non-lens surface on which incident light is incident.

  Each of the plurality of light transmitting portions corresponds to each of the plurality of unit convex cylindrical lenses in a ratio of 1: 1, and is provided so as to include a perpendicular to the non-lens surface from the vertex of the corresponding unit convex cylindrical lens, Each of the plurality of light reflecting portions is arranged along the X direction which is the longitudinal direction of each unit convex cylindrical lens so as to form a convex portion with respect to the non-lens surface, and is incident on the lenticular sheet from the non-lens surface. The supplied light is controlled by each unit convex cylindrical lens and supplied to the liquid crystal panel. Further, the arrangement pitch Py along the Y direction of the unit convex cylindrical lens and the arrangement pitch Gy along the Y direction of the display element are such that n is an integer of 3 or more, and Py / Gy = 1 / (n + 0. The relationship of Py / Gy ≦ 1 / (n + 0.213) excluding 5) is established.

  According to the display device of the present invention, even when a lens sheet in which unit lenses are regularly arranged is arranged between the liquid crystal panel and the light source, the occurrence of moire is prevented, and thus good. It is possible to realize a high image quality.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing an example of a display device according to an embodiment of the present invention.

  That is, the display device according to the embodiment of the present invention includes a plurality of cylindrical light sources 21 housed in the lamp house 20, a liquid crystal panel 30 sandwiched between the polarizing plates 31 and 32, and the light sources 21. And an optical sheet 10 for supplying the light H to the liquid crystal panel 30.

  As shown in the plan view of FIG. 2, the liquid crystal panel 30 includes a plurality of display elements 30a that define a display pattern of a display image in units of pixels at an arrangement pitch Gx along the X direction and an arrangement pitch along the Y direction. It is arranged regularly by Gy. Preferably, the arrangement pitch Gx and the arrangement pitch Gy are equal (Gx = Gy).

  FIG. 3 is a perspective view illustrating a configuration example of the optical sheet 10.

  The optical sheet 10 includes a light scattering layer 13 that scatters the light H incident from the incident surface 11 to the exit surface 12 side, which is the non-incident surface side. As is well known in the art, the light scattering layer 13 includes a transparent resin such as polycarbonate, polystyrene, or MS resin, a filler containing a filler, or the exit surface 12 side. It is processed into a mat. The particle size of the filler is described in, for example, Japanese Patent No. 338570 (Patent Document 2). In addition, one surface is provided on the emission surface 12 side, and a plurality of light reflecting portions 14 that reflect light scattered by the light scattering layer 13 to the light scattering layer 13 side are provided. Furthermore, a plurality of light transmitting portions 15 formed of, for example, an air layer, are provided between two adjacent light reflecting portions 14 and transmit light scattered by the light scattering layer 13 to the lenticular sheet 17 on the non-light scattering layer side. It has. Furthermore, a lens unit in which a plurality of unit convex cylindrical lenses 16 are arranged in parallel on the liquid crystal panel 30 side and a surface 19 on the side opposite to the lens unit, and the light transmitted by the light transmitting unit 15 is incident thereon. A lenticular sheet 17 having a lens surface 19 is provided.

  The plurality of unit convex cylindrical lenses 16 are, for example, lenticular lenses, and the lenticular sheet 17 is made of PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), etc. It is formed by an extrusion molding method, an injection molding method, or a hot press molding method well known in the art. Alternatively, by an ultraviolet curing molding method in which PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethyl methacrylate), PE (polyethylene), etc. are used as a base material, and an ultraviolet curing resin is disposed thereon. Form.

  Each of the plurality of light transmitting portions 15 corresponds to each of the plurality of unit convex cylindrical lenses 16 in a 1: 1 manner, and includes a perpendicular V from the vertex T of the corresponding unit convex cylindrical lens 16 to the non-lens surface 19. Each of the plurality of light reflecting portions 14 is formed using a printing method, a transfer method, or a photolithography method well known in the technical field, and forms a convex portion with respect to the non-lens surface 19. Thus, the unit convex cylindrical lenses 16 are arranged along the longitudinal direction X (the front-rear direction in FIG. 1 and the X direction in FIG. 3). The adhesive layer 18 adheres the light reflecting portions 14 and the light scattering layer 13.

  Thereby, as shown in the perspective view of the optical sheet 10 shown in FIG. 3 and the plan view of the light reflecting portion 14 shown in FIG. 4, the light along the arrangement direction Y in which the plurality of unit convex cylindrical lenses 16 are arranged in parallel. The reflection portions 14 and the light transmission portions 15 are alternately arranged in a stripe shape.

  According to the optical sheet 10 having such a configuration, the light H from the light source 21 is scattered by the light scattering layer 13 as described in, for example, JP-A-2006-106197 (Patent Document 3). Only light with a narrowed angle can be incident on the unit convex cylindrical lens 16, and light that cannot be incident on the unit convex cylindrical lens 16 can be reused without being wasted. Therefore, it is possible to supply the liquid crystal panel 30 by controlling the diffusion range while improving the utilization efficiency of the light from the light source 21. From the viewpoint of preventing moire of an image displayed from the liquid crystal panel 30, the arrangement pitch Py along the Y direction, which is the arrangement direction of the unit convex cylindrical lenses 16, is the same as the arrangement pitch Gy along the Y direction of the display element 30a. There is a relationship of Py / Gy ≦ 1 / (n + 0.213). However, except for the case of Py / Gy = 1 / (n + 0.5), n is an integer of 3 or more.

  The reason for this will be described with reference to FIG. FIG. 5 shows Py / Gy on the X axis and Moire wavelength / Gy on the Y axis. As can be seen from FIG. 5, moiré occurs at a specific value of Py / Gy. In particular, when Py / Gy = 1, a moiré with a significant period is generated. Further, when the relationship is Py / Gy = 1/2, 1/3,... Or when Py / Gy = 1 / (N + 0.5) (N is an integer), the cycle is large. If moiré occurs and, conversely, Py / Gy = 1 / N and Py / Gy = 1 / (N + 0.5) or Py / Gy = N and Py / Gy = (N + 0.5) become weak. Further, as the value of N increases, the moire density decreases, and when N is 3 or more, an image having an image quality having no practical problem can be obtained from the liquid crystal panel 30. On the other hand, from the viewpoint of image resolution, it is preferable that the arrangement pitch Py of the unit convex cylindrical lens 16 is smaller than the arrangement pitch Gy of the display element 30a.

However, even when Py / Gy = 1 / N and Py / Gy = 1 / (N + 0.5) or Py / Gy = N and Py / Gy = (N + 0.5) Experiments have confirmed that, for example, when Py / Gy = 1 / (N + 1), a strong moire occurs, resulting in a non-negligible deterioration in image quality. These results are shown in Table 1. Table 1 shows various Py obtained by fixing the arrangement pitch Gy of the display pixels 30a of the liquid crystal panel 30 to 490 μm (1 μm = 1 × 10 ⁻⁶ m) and changing the arrangement pitch Py of the unit convex cylindrical lens 16. 4 is a table summarizing evaluation results of image quality of images displayed from the liquid crystal panel 30 in / Gy.

  From Table 1, the moire is maximized when the arrangement pitch Py of the unit convex cylindrical lenses 16 is 490 × 1.1 = 539 μm and when 490 / 1.1 = 445.5 μm. It can be seen that selection of the arrangement pitch Py in the range of ˜539 μm is not preferable.

  Further, in the case of Py = 404 μm and Py = 226 μm, no noticeable moire was generated in the former, and noticeable moire was generated in the latter. In the former case, Py / Gy = 404/490 = 1 / 1.213 = 1 / (1 + 0.213), and in the latter case, Py / Gy = 226/490 = 1 / 2.168 = 1 / (2 + 0.168). From this, it is estimated that the value at which the occurrence of moire is not confirmed is present in the range of 0.168 to 0.213 after the decimal point of the denominator.

  From the above, in the display device according to the embodiment of the present invention, although Py / Gy <1 / n (where n is an integer of 3 or more), 1 / (n + 0.213) <Py / Gy < 1 / n and Py / Gy = 1 / (n + 0.5) are excluded. In Table 1, when n = 3, condition (1) corresponds to Py / Gy <1 / n, and condition (2) corresponds to 1 / (n + 0.213) <Py / Gy <1 / n. Condition (3) corresponds to Py / Gy = 1 / (n + 0.5). Condition (4) is included in the range of Py / Gy in the display device according to the embodiment of the present invention. That is, in the display device according to the embodiment of the present invention, n is an integer equal to or greater than 3, and a range of Py / Gy ≦ 1 / (n + 0.213) excluding Py / Gy = 1 / (n + 0.5). The arrangement pitch Py and the arrangement pitch Gy are set so that As shown in Table 1, in the condition (2) and the condition (3), a result that a conspicuous moire is generated in the image displayed from the liquid crystal panel 30 was obtained. However, in the condition (4), the liquid crystal panel 30 The displayed image did not generate a noticeable moire, and an image with good image quality having no practical problem was obtained.

  As described above, in the display device according to the embodiment of the present invention, the optical sheet 10 in which the plurality of unit convex cylindrical lenses 16 are regularly arranged is disposed between the liquid crystal panel 30 and the light source 21. Even in this case, it is possible to prevent the occurrence of moire and thus to realize a good image quality.

  As a result, it is possible to selectively increase the amount of light incident on the display element 30a of the liquid crystal panel 30 and to realize a good image quality while controlling the viewing area of the display light and without causing moire. Become.

  6A to 6C show various types of pixel arrangement of the color filter for the liquid crystal panel 30. FIG. In the case of information equipment that requires high definition, a stripe arrangement as shown in FIG. 6A is preferably used. In this case, a Y interference filter layer portion 110Ya is provided below the R and G colored filter layer portions 120Ra and 120Ga.

  On the other hand, the Y interference filter layer portion 110Ya is not provided under the striped B color filter layer portion 120Ba which is an example of the B color filter layer portion 120B.

  Further, when the color filter of the present invention is used for color display of a moving image that does not require much definition, a mosaic (diagonal) arrangement as shown in FIG. 6B, or as shown in FIG. 6C. A delta (triangle) arrangement is preferably used.

  In the case of the mosaic arrangement shown in FIG. 6B, a Y interference filter layer portion 110Yb is provided below the mosaic-like colored filter layer portions 120Rb and 120Gb for R, and a colored filter layer portion for B The Y interference filter layer portion 110Yb is not provided under the mosaic colored B filter layer portion 120Bb that is an example of 120B.

  In the case of the delta arrangement shown in FIG. 6C, a Y interference filter layer portion 110Yc is provided below the delta colored filter layer portions 120Rc and 120Gc for R and G, The Y interference filter layer portion 110Yc is not provided below the delta B colored filter layer portion 120Bc, which is an example of the colored filter layer portion 120B.

  FIG. 7 shows a modification of the stripe arrangement of FIG. 6A, in which a stripe is divided in the vertical direction in the figure and one pixel is divided into one set of R, G, and B that are adjacent in the horizontal direction in the figure. 40 is an enlarged photograph showing a method of expressing 40.

  As is clear from FIG. 7, when the boundary width for dividing the stripe in the vertical direction is wide, the periodicity of the frame of the pixel 40 like a thick black shadow is most clearly visible, and the liquid crystal panel 30 It is easily estimated that the occurrence of moiré between the unit cylindrical lens 16 of the optical sheet 10 disposed on the back surface (the light source 21 side) of the lens becomes remarkable.

  When the color filter has the pixel arrangement shown in FIG. 7, the occurrence of moire due to the periodicity in the vertical direction that occurs with the optical sheet 10 increases, but the pitch Py of the unit cylindrical lenses 16 of the optical sheet 10 In addition to control, it is also effective in eliminating moire to make the valley portion of the boundary of the unit cylindrical lens 16 non-sharp so that the boundary line (ridge line) of the unit cylindrical lens 16 is not conspicuous.

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The side view which shows an example of the backlight unit which concerns on embodiment of this invention. The top view which shows an example of display element arrangement | positioning in a liquid crystal panel. The perspective view which shows the structural example of an optical sheet. The top view which shows the example of arrangement | positioning of a light reflection part. The characteristic view which shows the relationship between pitch ratio and a moire wavelength. The conceptual diagram which shows the pixel arrangement | sequence type of the color filter for liquid crystal panels. The conceptual diagram which shows the modification of the stripe arrangement | sequence of Fig.6 (a). Explanatory drawing which shows the structural example of the liquid crystal display device by a prior art. Explanatory drawing which shows the structural example of the liquid crystal display device by a prior art. Explanatory drawing which shows the structural example of the liquid crystal display device by a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical sheet, 11 ... Incident surface, 12 ... Output surface, 13 ... Light scattering layer, 14 ... Light reflection part, 15 ... Light transmission part, 16 ... Unit convex cylindrical lens, 17 ... Lenticular sheet, 18 ... Adhesion layer, DESCRIPTION OF SYMBOLS 19 ... Non-lens surface, 20 ... Lamp house, 21 ... Light source, 30 ... Liquid crystal panel, 30a ... Display element, 31, 32 ... Polarizing plate, 40 ... Pixel, 51 ... Light source, 52 ... Reflector, 71, 73 ... Polarizing plate 72 ... Liquid crystal panel, 74,75 ... Prism film, 76 ... Light source lamp, 77 ... Reflection film, 78 ... Diffusion film, 79 ... Light guide plate, 81 ... Lamp reflector, 82 ... Diffusion film

Claims (1)

A light source, a liquid crystal panel in which a plurality of display elements defining a display pattern of a display image in pixel units are regularly arranged along the X direction and the Y direction, and light from the light source is supplied to the liquid crystal panel A display device comprising: an optical sheet,
The optical sheet is
A light scattering layer that scatters light from the light source incident from the incident surface side to the exit surface side that is the non-incident surface side;
One surface is provided on the exit surface side of the light scattering layer, and a plurality of light reflecting portions that reflect the light scattered by the light scattering layer to the light scattering layer side,
A plurality of light transmitting portions provided between the two adjacent light reflecting portions and transmitting light scattered by the light scattering layer to the non-light scattering layer side;
A plurality of unit convex cylindrical lenses are regularly arranged in parallel along the Y direction on the liquid crystal panel side, and a surface opposite to the lens unit, and is transmitted by the light transmitting unit. A lenticular sheet having a non-lens surface on which light is incident,
Each of the plurality of light transmission portions corresponds to each of the plurality of unit convex cylindrical lenses in a ratio of 1: 1, and is provided so as to include a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface. Each of the plurality of light reflecting portions is disposed along the X direction which is a longitudinal direction of each unit convex cylindrical lens so as to form a convex portion with respect to the non-lens surface, and the non-lens The light incident on the lenticular sheet from the surface is controlled by the unit convex cylindrical lenses and supplied to the liquid crystal panel, and the arrangement pitch Py along the Y direction of the unit convex cylindrical lenses, and the display element The arrangement pitch Gy along the Y direction is such that n is an integer of 3 or more, and Py / Gy = 1 / (n + 0.5) Display the relationship except the Py / Gy ≦ 1 / (n + 0.213) is characterized in that as established.

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