Abstract:
To provide a jig for flexible optical measurement that enables at all times a measurement position to be measured from the normal direction when performing any measurement of a flexible optical display panel with any given curvature. A jig for flexible optical measurement comprises a holding member which has a prescribed curvature that allows it to hold a flexible optical display panel with any given curvature, and a base member which has the same curvature as the holding member in order to shift the holding member and is used to shift the holding member. The holding member can be shifted using the base member, and when performing any measurement by shifting the flexible optical display panel and measuring, it is possible to measure the measurement position from the normal direction.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a jig for flexible optical measurement which makes it possible to measure optical characteristics of a flexible optical display panel with an arbitrary curvature. 
       BACKGROUND ART 
       [0002]    Recently, the digital signage has been attracting attention, and flexible optical display panels that can be placed in any shape are being developed. It is necessary to measure optical characteristics of these flexible optical display panels. Conventionally, optical characteristics of a display part of a display device are measured by measuring physical quantities such as luminance and chromaticity of the display part in the manufacturing process of the display device (Patent Literature 1). 
       CITATION LIST 
     Patent Literature 
       [0003]    Patent Literature 1: JP 2010-91509 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    However, conventional optical measurement devices have structures designed on the assumption of measuring flat panels. Accordingly, when a flexible optical display panel is measured in a bent state, such problems occur that the focal point differs between an end portion and the middle portion to cause changes in the diameter of the measuring light spot, and that the display panel has to be evaluated from an oblique direction with respect to a plane to be measured. Consequently, accurate measured values cannot be obtained. 
         [0005]    The present invention has been made considering these situations, and aims at providing a jig for flexible optical measurement that makes it possible, in any measurement of a flexible optical display panel with an arbitrary curvature, to perform measurement always from a normal direction to a measurement position. 
       Solution to Problem 
       [0006]    To solve the above-described problems and to achieve the above-mentioned aim, the present invention is configured as follows. 
         [0007]    An invention described in claim  1  is a jig for flexible optical measurement, including: a holding member having such a specified curvature that can hold a flexible optical display panel with an arbitrary curvature; and a base member for allowing the holding member to move and having the same curvature as that of the holding member to allow the holding member to move, wherein the holding member is movable by the base member so that measurement is possible from a normal direction to a measurement position in any measurement in which the flexible optical display panel is moved and measured. 
         [0008]    An invention described in claim  2  is the jig for flexible optical measurement according to claim  1 , wherein the holding member is a plate-like member having a surface with a specified curvature, and includes: a holding portion capable of holding the flexible optical display panel on the surface with the specified curvature; an opening formed on the holding portion to perform optical measurement; and slide portions provided at both ends of the holding portion to allow the holding portion to move relative to the base member. 
         [0009]    An invention described in claim  3  is the jig for flexible optical measurement according to claim  1 , wherein the base member includes: a base portion to enable the base member to be placed; an opening formed on the base portion to perform optical measurement; and a guide portion provided on the base portion to allow the holding member to move. 
         [0010]    An invention described in claim  4  is the jig for flexible optical measurement according to claim  1 , wherein the base member includes: a scale that indicates a moving amount of the holding member; and a measurement mark that indicates a measurement position of the flexible optical display panel. 
         [0011]    An invention described in claim  5  is the jig for flexible optical measurement according to claim  1 , wherein the base member includes a fastening member that fastens the holding member to fix the flexible optical display panel in a measurement position. 
       Advantageous Effects of Invention 
       [0012]    With the configurations as described above, the present invention has the following advantageous effects. 
         [0013]    According to the invention as described in each of claims  1  to  5 , the base member has the same curvature as that of the holding member, and allows the holding member to move. Since the holding member is allowed to move by the base member, in any measurement in which a flexible optical display panel is moved and measured, it is possible to perform measurement from a normal direction to a measurement position. Accordingly, accurate measured values can be obtained without causing such problems that the focal point changes to cause changes in the diameter of the measuring light spot and that the display panel is evaluated from an oblique direction with respect to a plane to be measured. As a result, flexible optical display panels can be evaluated accurately. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a jig for flexible optical measurement. 
           [0015]      FIG. 2  is a perspective view of a holding member. 
           [0016]      FIG. 3  is a perspective view showing a state in which a flexible optical display panel is fixed to the holding member. 
           [0017]      FIG. 4  is a perspective view of a base member. 
           [0018]      FIGS. 5(   a ) and  5 ( b ) are sectional views each showing a position of allocating a fastening member. 
           [0019]      FIG. 6  is a diagram showing a positional relation of a jig for flexible optical measurement and an optical measurement device during measurement. 
           [0020]      FIGS. 7(   a ) to  7 ( c ) are conceptual diagrams of optical measurement. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]    Hereinafter, an embodiment of a jig for flexible optical measurement of the present invention will be described. It should be understood that this embodiment is a best mode of the present invention, and that the present invention is not limited to this embodiment. 
       (Structure of a Jig for Flexible Optical Measurement) 
       [0022]      FIG. 1  is a perspective view of a jig for flexible optical measurement.  FIG. 2  is a perspective view of a holding member.  FIG. 3  is a perspective view showing a state in which a flexible optical display panel is fixed to the holding member.  FIG. 4  is a perspective view of a base member.  FIGS. 5(   a ) and  5 ( b ) are sectional views each showing a position of allocating a fastening member. 
         [0023]    A jig for flexible optical measurement  1  of this embodiment is used in a process of manufacturing a flexible optical display panel  2  to measure optical characteristics of a display portion of the flexible optical display panel  2  such as luminance, chromaticity and cell gap. This jig for flexible optical measurement  1  is configured by a holding member  10  having such a specified curvature that can hold a flexible optical display panel  2  with an arbitrary curvature, and a base member  20  for allowing the holding member  10  to move and having the same curvature as that of the holding member  10  to allow the holding member  10  to move. The holding member  10  is movable by the base member  20  so that measurement is possible from a normal direction to a measurement position in any measurement of the flexible optical display panel  2 . 
         [0024]    The holding member  10  is a plate-like member having a surface with a specified curvature. The holding member  10  has a holding portion  11  capable of holding the flexible optical display panel  2  on the surface with the specified curvature, an opening  12  formed on the holding portion  11  to perform optical measurement, and slide portions  13  at both ends of the holding portion  11  to allow the holding portion  11  to move relative to the base member  20 . 
         [0025]    The holding member  10  has a thickness t and a radius of curvature R, and fixes the flexible optical display panel  2  on the convex surface with the radius of curvature R of the holding portion  11 . The flexible optical display panel  2  may be fixed so as not to affect the display area of the flexible optical display panel  2  and so as to prevent the flexible optical display panel  2  and the holding member  10  from shifting in position from each other during handling. 
         [0026]    For example, the fixing method may be a method in which the holding member  10  and the flexible optical display panel  2  are provided with screw holes and fastened by fastening means, a method in which the outer periphery or only an end in the bent direction of the flexible optical display panel  2  is fixed with a metal fitting or a plastic plate, or a method in which the flexible optical display panel  2  is simply adhered to the holding member  10  with a strong adhesive tape. Although the flexible optical display panel  2  is fixed with a strong adhesive tape  19  in this embodiment, the fixing method used in the present invention is not limited to this method. 
         [0027]    The holding member  10  includes one or plural openings  12  on the holding portion  11 . The size of each opening and the number of the openings  12  may be determined depending on the measuring light spot diameter and the measurement position of the flexible optical display panel  2 , and thus may be arbitrary. 
         [0028]    The base member  20  includes a base portion  21  to enable the base member to be placed, an opening  22  formed on the base portion to perform optical measurement, and guide portions  23  provided on the base portion  21  to allow the holding member  10  to move. At the guide portions  23 , guide grooves  24  are provided to allow the slide portions  13  of the holding member  10  to be movable. Each of the guide grooves  24  has the same radius of curvature R as that of the holding member  10  to allow the support portions  13  of the holding member  10  to be movable. 
         [0029]    Each of the guide portions  23  of the base member  20  has a scale  25  that indicates a moving amount of the holding member  10 , and a measurement mark  26  that indicates a measurement position of the flexible optical display panel  2 . Since the scale  25  and the measurement mark  26  are formed on the guide grooves  24  of the guide portions  23 , the holding member  10  is molded by a transparent resin. However, when the scale  25  and the measurement mark  26  are formed on the side surfaces of the guide portions  23  along the guide grooves  24 , the holding member  10  may not be limited to a transparent resin. In the manner as described above, the scale  25  and the measurement mark  26  are formed so as to be easily visible from the outside. 
         [0030]    Also, the base member  20  includes a fastening member  27  that fastens the holding member  10  to fix the flexible optical display panel  2  in the measurement position. The fastening member  27  is formed by a fastening screw, and may have either a structure in which the fastening screw fastens to fix an end portion on the front surface of the holding member  10  located in a guide groove  24  from the upper end of a guide portion  23  as shown in  FIG. 5(   a ) or a structure in which the fastening screw fastens to fix a side surface of the holding member  10  located in the guide groove  24  from the outside of the guide portion  23  as shown in  FIG. 5(   b ). 
         [0031]    The base member  20  may have a size determined to a certain extent depending on the size of the holding member  10 , but it may not necessarily be formed to be in proportion to the size of the holding member  10 . The base member  20  includes the fastening member  27  to fix the holding member  10  to the base member  20 , so that the measurement can be adequately performed by fastening the fastening member  27  in the measurement position of the flexible optical display panel  2 . 
         [0032]    The measurement mark  26  is at the lowest position D 2  of the height D 1  of each of the guide grooves  24 . Further, each of the guide portions  23  includes the scale  25  made of marks put at constant intervals on the surface with the radius of curvature R. By matching the measurement mark  26  with a position desired to be measured of the flexible optical display panel  2  and moving the holding member  10 , it is possible to perform measurement from the normal direction to the measurement position in any measurement. 
         [0033]    Also, the scale  25  indicates a moving amount of the holding member  10 . Accordingly, it is possible to change the measurement position of the flexible optical display panel  2  by moving the holding member  10  based on the scale  25 . By using the scale  25 , reproducibility of repeated measurements is improved. 
         [0000]    (Optical Measurement using the Jig for Flexible Optical Measurement) 
         [0034]    Next, an optical measurement using the jig for flexible optical measurement will be described based on  FIG. 6 .  FIG. 6  is a diagram showing a positional relation between the jig for flexible optical measurement and an optical measurement device during measurement. 
         [0035]    This optical measurement device  50  includes a light emitting unit  51  and a light receiving unit  52 , and is used in a process of manufacturing the flexible optical display panel  2  to measure optical characteristics of the display portion of the flexible optical display panel  2  by measuring physical quantity of such as luminance and chromaticity of the display portion of the flexible optical display panel  2 . The measurement of the optical characteristics is performed by applying a light from the light emitting unit  51  to the display portion of the flexible optical display panel  2 , and receiving a light by the light receiving unit  52 . 
         [0036]    To perform a measurement using the optical measurement device  50 , the jig for flexible optical measurement  1  is set on a light ray S so that a line K connecting the measurement marks  26  on the opposing guide portions  23  matches with a portion to be measured of the flexible optical display panel  2 . The position of the flexible optical display panel  2  located at the intersection of the light ray S of the optical measurement device  50  and the line K corresponds to a position at which the flexible optical display panel  2  is measured from a normal direction to a portion to be measured. In this measurement of optical characteristics, measurement from the normal direction to the measurement position is made possible in any measurement by moving the holding member  10  of the jig for flexible optical measurement  1  by the base member  20 . The flexible optical display panel  2  is moved in such a manner that the holding member  10  is moved based on the scale  25  to change the measurement position of the flexible optical display panel  2 . 
         [0037]    As shown in conceptual diagrams of optical measurement in  FIGS. 7(   a ) to  7 ( c ), according to this embodiment, optical measurement of a flexible optical display panel  2  with an arbitrary curvature is performed by the optical measurement device  50  by using the jig for flexible optical measurement  1 . This optical measurement device  50  performs measurement by matching the normal direction at a measurement point A 1  of the flexible optical display panel  2  with the light ray S of the optical measurement device  50  ( FIG. 7(   a )). In this state, the thickness of the flexible optical display panel  2  at the measurement point A 1  is D 1 , which is the thickness in the normal direction matched with the light ray S. In order to change the measurement position of the flexible optical display panel  2 , the flexible optical display panel  2  is moved by the jig for flexible optical measurement  1  to perform measurement at a measurement point A 2  ( FIG. 7(   b )). At this measurement point A 2  also, the normal direction of the flexible optical display panel  2  matches with the light ray S of the optical measurement device  50 , so that the thickness of the flexible optical display panel  2  is D 1 , which is the thickness in the normal direction. As described above, in any measurement in which the measurement position of the flexible optical display panel  2  is changed, the thickness of the flexible optical display panel  2  at any measurement point is always the thickness D 1  in the normal direction, so that a measurement portion of the flexible optical display panel  2  can be evaluated from the normal direction. 
         [0038]    In the comparative example in which the jig for flexible optical measurement  1  is not used, measurement is performed without matching the normal direction at the measurement point A 2  of the flexible optical display panel  2  with the light ray S of the optical measurement device  50 . In this case, the thickness of the flexible optical display panel  2  at the measurement point A 2  becomes D 2  longer than D 1 . As described above, in the comparative example, in which measurement is performed without using the jig for optical flexible measurement  1 , measurement must be performed under the condition that the thickness is shifted from that in the normal direction. 
         [0039]    As described above, according to this embodiment, in any measurement in which the measurement position of the flexible optical display panel  2  with an arbitrary curvature is changed, measurement is performed from the normal direction to the flexible optical display panel  2 . Accordingly, accurate measured values can be obtained without causing such problems that the focal point changes to cause changes in the diameter of the measuring light spot, and that the display panel is evaluated from an oblique direction with respect to a plane to be measured. As a result, the flexible optical display panel can be evaluated accurately. 
         [0040]    In case of measuring a voltage-transmittance, for example, a specified voltage is applied to the flexible optical display panel  2 , and a luminance at that time is measured. Unless the measurement is performed from the normal direction to the flexible optical display panel  2 , the distance the light ray passes through the flexible optical display panel  2  becomes longer, so that accurate values of luminance cannot be obtained. 
         [0041]    Also, in case of measuring the cell gap, for example, the cell gap can be measured by applying a linearly-polarized specific light ray to the flexible optical display panel  2 , and measuring changes in the phase. Unless the measurement is performed from the normal direction to the flexible optical display panel  2 , the distance the light ray passes through the flexible optical display panel  2  becomes longer, so that the changes in the phase cannot accurately be measured. 
         [0042]    Also, since the holding member  10  of the jig for flexible optical measurement  1  has a certain curvature, it is possible to bend the flexible optical display panel  2  uniformly by simply placing it along the holding member  10 . Also, when the holding member  10  is made of a material having a high resistance to heat and a high resistance to humidity, the flexible optical display panel  2  can be put into a reliability test in the state being fixed to the holding member  10 , so that characteristics of the curved-surface flexible optical display panel  2  can be easily evaluated. Further, the jig for flexible optical measurement  1  can be installed either transversely or vertically, so that it can be mounted to various types of optical measurement devices. 
       INDUSTRIAL APPLICABILITY 
       [0043]    The present invention is applicable to a jig for flexible optical measurement that can measure optical characteristics of a flexible optical display panel with an arbitrary curvature, and makes it possible, in any measurement position of the flexible optical display panel with an arbitrary curvature, to always perform measurement from a normal direction to a measurement position. 
       REFERENCE SIGNS LIST 
       [0044]      1  jig for flexible optical measurement 
         [0045]      2  flexible optical display panel 
         [0046]      10  holding member 
         [0047]      11  holding portion 
         [0048]      12  opening 
         [0049]      13  slide portion 
         [0050]      20  base member 
         [0051]      21  base portion 
         [0052]      22  opening 
         [0053]      23  guide portion 
         [0054]      24  guide groove 
         [0055]      25  scale 
         [0056]      26  measurement mark 
         [0057]      27  fastening member