CONDUCTIVE FILM, DISPLAY DEVICE PROVIDED WITH SAME, AND METHOD FOR EVALUATING CONDUCTIVE FILM

• US 20150342034A1
• Filed: 08/03/2015
• Published: 11/26/2015
• Est. Priority Date: 02/05/2013
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: IWAMI, Kazuchika
• Granted Patent: US 9,832,862 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H05K 1/0274 Optical details, e.g. printed circuits comprising integral optical means H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42
• CPC Class Codes: H05K 1/0296 Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18
• CPC Class Codes: H05K 9/0096 for television displays, e.g. plasma display panel

Abstract

The conductive film includes a transparent substrate and a conductive portion having a wiring pattern, in which when the wiring pattern is observed from at least one visual point, with respect to frequencies and intensities of moires which are calculated respectively from peak frequencies and peak intensities of predetermined data_and peak frequencies and peak intensities of another predetermined data, an evaluation index of moire, which is calculated from evaluation values of moires obtained by applying visual response characteristics of a human being to the intensities of the moires according to an observation distance at the frequencies of the respective moires that are equal to or lower than the maximum frequency of moire specified according to display resolution of the display unit, is equal to or less than a predetermined value.

Claims

1. A conductive film installed on a display unit of a display device, comprising:

a transparent substrate; and

a conductive portion which is formed on at least one surface of the transparent substrate and is composed of a plurality of thin metal wires,

wherein the conductive portion has a wiring pattern which is formed of the plurality of thin metal wires in a form of a mesh and in which a plurality of openings are arranged,

wherein the wiring pattern is superimposed on a pixel array pattern of the display unit, and

wherein when the wiring pattern is observed from at least one visual point, with respect to frequencies and intensities of moires which are calculated respectively from peak frequencies and peak intensities of a plurality of spectral peaks of two-dimensional Fourier spectra of transmittance image data of the wiring pattern and peak frequencies and peak intensities of a plurality of spectral peaks of two-dimensional Fourier spectra of transmittance image data of the pixel array pattern, an evaluation index of moire, which is calculated from evaluation values of moires obtained by applying visual response characteristics of a human being to the intensities of the moires according to an observation distance at the frequencies of the respective moires that are equal to or lower than the maximum frequency of moire specified according to display resolution of the display unit, is equal to or less than a predetermined value.

2. The conductive film according to claim 1,

wherein the predetermined value is −

1.75, and

the evaluation index is equal to or less than −

1.75 expressed in terms of a common logarithm.

3. The conductive film according to claim 2,

wherein the evaluation index is equal to or less than −

1.89 expressed in terms of the common logarithm.

4. The conductive film according to claim 1,

wherein provided that a display pitch of the display unit is p (μ

m), the maximum frequency of the moire is 1,000/(2p).

5. The conductive film according to claim 1,

wherein the evaluation values of moires are obtained by performing weighting on the frequencies and intensities of moires by convolution integral using a visual transfer function according to the observation distance as the visual response characteristics.

6. The conductive film according to claim 5,

wherein the visual transfer function is a visual sensitivity function S(u) determined by the following Equation (1),

7. The conductive film according to claim 1,

wherein the evaluation index of moire is calculated for a single frequency of the moire by using the worst evaluation value among the plurality of evaluation values of moires having undergone weighting according to the observation distance.

8. The conductive film according to claim 7,

wherein the evaluation index of moire is a sum obtained by summing up the worst evaluation values, each of which is selected for the single frequency of the moire, for all of the frequencies of the moires.

9. The conductive film according to claim 1,

wherein the frequencies of moires are obtained as a difference between the peak frequencies of the wiring pattern and the peak frequencies of the pixel array pattern, and the intensities of moires are obtained as a product of the peak intensities of the wiring pattern and the peak intensities of the pixel array pattern.

10. The conductive film according to claim 1,

wherein moire selected to apply the visual response characteristics has the intensity of moire of equal to or higher than −

4 and has a frequency equal to or lower than the maximum frequency.

11. The conductive film according to claim 1,

wherein the peak intensity is a sum of intensities in a plurality of pixels in a vicinity of a peak position of each of the plurality of spectral peaks.

12. The conductive film according to claim 11,

wherein the peak intensities are a sum of intensities of top 5 pixels ranked high in terms of intensity among 7×

7 pixels in a vicinity of the peak position.

13. The conductive film according to claim 1,

wherein the peak intensities are standardized by using the transmittance image data of the wiring pattern and the pixel array pattern.

14. The conductive film according to claim 1,

wherein the pixel array pattern is a black matrix pattern.

15. The conductive film according to claim 1,

wherein when peak intensity distribution of the plurality of spectral peaks of the two-dimensional Fourier spectra of the pixel array pattern is symmetrical, the wiring pattern has a symmetrical pattern shape.

16. The conductive film according to claim 1,

wherein when peak intensity distribution of the plurality of spectral peaks of the two-dimensional Fourier spectra of the pixel array pattern is asymmetrical, the wiring pattern has an asymmetrical pattern shape.

17. A display device comprising:

a display unit; and

the conductive film according to claim 1 that is installed on the display unit.

18. A method for evaluating a conductive film that is installed on a display unit of a display device and has a wiring pattern which is formed of a plurality of thin metal wires in a form of a mesh and in which a plurality of openings are arranged, the method comprising steps of:

obtaining transmittance image data of the wiring pattern and transmittance image data of a pixel array pattern of the display unit on which the wiring pattern is superimposed;

calculating peak frequencies and peak intensities of a plurality of spectral peaks of two-dimensional Fourier spectra of the transmittance image data of the wiring pattern and calculating peak frequencies and peak intensities of a plurality of spectral peaks of two-dimensional Fourier spectra of the transmittance image data of the pixel array pattern by performing two-dimensional Fourier transform on the transmittance image data of the wiring pattern and the transmittance image data of the pixel array pattern;

calculating frequencies and intensities of moires from the peak frequencies and peak intensities of the wiring pattern calculated as above and the peak frequencies and peak intensities of the pixel array pattern calculated as above;

selecting moire having a frequency equal to or lower than the maximum frequency of moire specified according to display resolution of the display unit, from among the moires having the frequencies and the intensities calculated as above;

obtaining evaluation values of moires by applying visual response characteristics of a human being to the intensities of moires according to an observation distance at the frequencies of the respective moires selected as above;

calculating an evaluation index of moire from a plurality of the evaluation values of moires obtained as above; and

evaluating a conductive film in which the evaluation index of moire calculated as above is equal to or less than a predetermined value.