JP2014063248A - On-vehicle touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle touch panel capable of effectively preventing moire due to interference between pixel patterns of a transparent electrode and a display, even when the touch panel is formed in a curved surface.SOLUTION: An on-vehicle touch panel includes a liquid crystal display 12, and a transparent protective layer (transparent panel) 16 formed integrally with a transparent electrode 14 and having a predetermined curvature. The liquid crystal display 12 and transparent electrode 14 have a gap 13 formed therebetween. When an electrode gap of the transparent electrode 14 is P1, a pixel pitch of the liquid crystal display 12 is P2, and angle deviation between pixel patterns of the transparent electrode 14 and liquid crystal display 12 is α, α and P1 are set so that a pitch of moire R given by a predetermined expression becomes equal to or less than a threshold set on the basis of P2, so as to suppress the moire.

Description

  The present invention relates to a touch panel, and more particularly to an in-vehicle touch panel.

  Conventionally, touch panels have been used in various electronic devices. Usually, a touch panel is configured by adhering glass or the like on which a transparent electrode is formed on a liquid crystal display (LCD) via an adhesive and an insulating layer.

  The touch panel is generally flat. However, when an in-vehicle navigation system or the like is configured with a touch panel, the touch panel must be flat to match the curvature of the instrument panel in order to have a sense of unity with the instrument panel of the vehicle. Instead of a curved surface.

JP 2011-253263 A

  A transparent electrode such as ITO is configured by patterning into a predetermined shape, but the transparent electrode is not completely transparent and has some color, so it depends on the contrast difference from the part where the transparent electrode does not exist A pattern may be seen, and the merchantability as a touch panel will deteriorate. In particular, moire due to interference between the pattern of the transparent electrode and the pixel pattern of the liquid crystal display below becomes a problem.

  In order to prevent this, it is effective to reduce the gap between the transparent electrodes to a level where it cannot be visually observed and to make it closely contact with the liquid crystal display. In particular, since a gap is generated between the liquid crystal display and the transparent electrode, such a preventive measure cannot be adopted.

  On the other hand, if the gap between the transparent electrodes is narrower than the pixel pattern of the liquid crystal display, the two will not interfere with each other. However, if the transparent electrode is closer to the viewer, ie, the user than the pixels of the liquid crystal display, The lens effect can cause interference on the retina.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an in-vehicle touch panel that can effectively prevent moire from a pixel pattern of a display even when the touch panel is configured with a curved surface. There is.

  The present invention is an in-vehicle touch panel, comprising: a display; and a transparent panel laminated on the display and integrated with a transparent electrode and having a predetermined curvature, between the display and the transparent electrode. When a gap is formed, the electrode gap of the transparent electrode is P1, the pixel pitch of the display is P2, and the angle deviation between the electrode pattern of the transparent electrode and the pixel pattern of the display is α, it is defined by a predetermined formula The angular deviation α and the electrode gap P1 are set such that the moiré pitch R is equal to or less than a threshold value set based on the pixel pitch P2 of the display.

  In one embodiment of the invention, the threshold is equal to the pixel pitch P2 of the display.

  According to the present invention, the electrode gap P1 of the transparent electrode or the electrode gap P1 of the transparent electrode and the angle deviation α are set to an appropriate value or range to suppress moire and improve the merchantability or performance of the touch panel. it can. Further, according to the present invention, the processing conditions of the transparent electrode are clarified, so that the processing becomes easy and reliable.

It is a block diagram of a touch panel. It is explanatory drawing of a moire by the pitch shift of the pattern of a vertical direction. It is explanatory drawing of a moire by the angle shift | offset | difference of the pattern of a vertical direction. It is explanatory drawing which shows the positional relationship of a liquid crystal display, a transparent electrode, and eyes. It is explanatory drawing which shows the relationship between a pixel pattern and a transparent electrode pattern. It is explanatory drawing which shows the relationship between a pixel pattern in case there exists an angle shift | offset | difference, and a transparent electrode pattern. It is a table | surface figure which shows the relationship between the angle of a pixel pattern and a transparent electrode pattern, and moire. It is a graph which shows the relationship between the gap | interval of a transparent electrode, and a moire pitch. It is a top view which shows the transparent electrode pattern of embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments.

  In FIG. 1, the schematic block diagram of the vehicle-mounted touchscreen of this embodiment is shown. The touch panel includes a substrate 10, a liquid crystal display 12, a transparent electrode 14, and a transparent protective layer (transparent panel) 16.

  The liquid crystal display 12 includes red (R), green (G), and blue (B) pixels arranged in a horizontal direction and a vertical direction. The liquid crystal display 12 is used as, for example, a display screen of an in-vehicle navigation system.

  The transparent electrode 14 is made of, for example, ITO, and is formed by patterning so as to have a predetermined gap.

  The transparent protective layer (transparent panel) 16 is made of, for example, glass or resin, and the transparent electrode 14 and the transparent protective layer 16 are directly formed by sputtering or integrated by film insert molding or the like to form a curved surface as shown in the figure. Composed. The reason why the transparent protective layer 16 in which the transparent electrode 14 is integrated is a curved surface is that an instrument panel of a vehicle in which the touch panel is incorporated is configured by a curved surface and has a sense of unity with it. Therefore, the curvature of the transparent protective layer 16 in which the transparent electrode 14 is integrated is adjusted so as to have a predetermined curvature. Although an insulating layer is provided between the liquid crystal display 12 and the transparent electrode 14, it is omitted in the figure for convenience of explanation. Further, an index matching layer can be interposed between the transparent protective layer 16 and the transparent electrode 14, but this is not particularly necessary in the present embodiment. Furthermore, since the transparent protective layer 16 in which the transparent electrode 14 is integrated has a curved surface, a gap (or air layer) 13 is formed between the liquid crystal display 12 and the transparent electrode 14.

  In the liquid crystal display 12, a plurality of pixels are arranged in the horizontal direction and the vertical direction to calibrate the pixel pattern, and the transparent electrode 14 is also patterned.

  FIG. 2 shows moiré caused by a shift in the pitch of both patterns when attention is paid to the pattern of the liquid crystal display 12 and the pattern of the transparent electrode 14. In the figure, it is assumed that the liquid crystal display 12 exists on the back side of the paper surface and the transparent electrode 14 exists on the front side of the paper surface. This is a case where the vertical pattern pitch deviation between them is 90%, which is very small. Moire does not occur when the pitches of the two patterns are completely coincident with each other, but moire occurs due to interference due to a slight shift in the pitch, and the touchability of the touch panel is reduced. Of course, if the pitch deviation between the two patterns is increased, interference can be suppressed and moire can be reduced, but there is a limitation on the processing accuracy of the transparent electrode 14.

  FIG. 3 shows moiré caused by a shift in the angle of both patterns when attention is paid to the pattern of the liquid crystal display 12 and the pattern of the transparent electrode 14. In the figure, it is assumed that the liquid crystal display 12 exists on the back side of the paper surface and the transparent electrode 14 exists on the near side of the paper surface as in FIG. This is a case where the pitch of both patterns is equal and the angle deviation is 5 degrees and is minute. Moire occurs due to interference caused by a slight shift in the angle between the two patterns, and the merchantability of the touch panel similarly decreases.

  In addition, it is known that the deviation of the pattern angle is 90 degrees, that is, when the two patterns are orthogonal, there is no interference and no moire occurs. From this, the liquid crystal display 12 and the transparent electrode 14 are both in the vertical and horizontal directions. When there is a pattern, it can be seen that moire can be suppressed when the angle difference between the two patterns is around 45 degrees. In the present embodiment, under the general condition that both the pitch deviation and the angle deviation exist in the patterns of both the liquid crystal display 12 and the transparent electrode 14, the angle deviation is set to about 45 degrees and the pitch is changed. More specifically, in a situation where the pattern of the liquid crystal display 12 is given as a predetermined pattern, the moire is minimized by setting the electrode gap of the transparent electrode 14 to a specific value.

FIG. 4 schematically shows a positional relationship among the liquid crystal display 12, the transparent electrode 14, the user's eyeball (crystal lens) 100, and the user's retina 102. FIG. 5 shows the arrangement of the liquid crystal display 12 and the transparent electrode 14 as viewed from the user. In the liquid crystal display 12, R pixels, G pixels, and B pixels are arranged in a horizontal direction and a vertical direction, and the horizontal arrangement of R pixels, G pixels, and B pixels is shown in the drawing. On the other hand, if the pattern of the transparent electrode 14 exists in the same horizontal direction, the pattern of the liquid crystal display 12 and the pattern of the transparent electrode 14 exist in the same horizontal direction as shown in FIG. Moire occurs due to a shift in the pitch of the pattern. The distance between the user's retina 102 and the transparent electrode 14 is L1, the distance between the user's retina 102 and the liquid crystal display 12 is L2, the moire pitch is W, the pitch of the transparent electrode 14, that is, the electrode gap of the transparent electrode 14 is P1. When the pitch of the liquid crystal display 12 is P2,
W = P1 / P2 / (P1-P2)
Given in.

  From this equation, it can be seen that, assuming that the pitch P2 of the liquid crystal display 12 is given, the electrode gap P1 of the transparent electrode 14 is small, and the farther from the pitch of the liquid crystal display 12, the smaller the moire pitch. If the moiré pitch can be reduced to such an extent that it cannot be identified by the user's eyes, the influence of moire can be eliminated.

The relationship between the distance from the touch panel, the user's visual acuity, and the pattern pitch that can be identified is as follows.
<When distance is 300 mm>
0.125mm for sight 0.7
0.087mm for sight 1.0
0.044mm for sight 2.0
<When distance is 400 mm>
0.166mm for sight 0.7
0.116mm for sight 1.0
0.058mm for sight 2.0
<When distance is 500 mm>
0.208mm at sight 0.7
0.145mm for sight 1.0
0.073mm for sight 2.0
<For a distance of 600 mm>
0.249mm for sight 0.7
0.175mm for sight 1.0
0.087mm for sight 2.0

  However, the contrast is 100%. Therefore, for example, assuming that the distance from the touch panel is 600 mm while the user is sitting in the driver's seat of the vehicle and the average visual acuity of the user is 0.7, the moire pitch is set to 0.249 mm or less. The influence of moire can be suppressed.

で与えられる。ここで、図４に示す視野角をθとすると、
Ｐ１＝Ｌ１ｔａｎθ
Ｐ２＝Ｌ２ｔａｎθ
である。 On the other hand, FIG. 6 shows, more generally, an arrangement viewed from the user when not only the electrode gap of the pattern of the transparent electrode 14 but also the angle with respect to the pixel pattern of the liquid crystal display 12. If the angle deviation is α, the pitch of the moire is

Given in. Here, when the viewing angle shown in FIG.
P1 = L1 tan θ
P2 = L2tanθ
It is.

FIG. 7 is a table showing the moire pitch when the electrode gap P1 of the transparent electrode 14 is fixed to 0.075 mm, the pitch P2 of the liquid crystal display 12 is fixed to 0.08 mm, and the angle α is changed. When the angle α is 5 degrees, the moire pitch is 0.75549 mm, when it is 30 degrees, 0.158172 mm, when it is 40 degrees, 0.119707 mm when it is 50 degrees, and 0.096614 mm when it is 50 degrees, the angle α As the value increases, the moire pitch decreases. This is the case where the pattern of the liquid crystal display 12 and the pattern of the transparent electrode 14 are only in the horizontal direction. As described above, when there are patterns in both the vertical and horizontal directions, the angle deviation α is 45 degrees. The pitch of moire in the vertical and horizontal directions is the smallest. In order to evaluate the moire pitch in the horizontal direction and the vertical direction, for example, the pitch of the moire in the horizontal direction is Ri and the pitch of the moire in the vertical direction is Rj.
E = Ri + Rj
An evaluation function as follows may be used.

  The evaluation function is minimum when P1 and P2 are fixed and the angular deviation α is 45 degrees, but it is not necessarily 45 degrees, and may be in the vicinity of 45 degrees, that is, 45 degrees ± β. Here, β is a certain allowable range. For example, β can be set to 40 degrees to 50 degrees with 5 degrees.

  FIG. 8 shows the moire pitch when the angle deviation α is 1 degree, 20 degrees, and 40 degrees, the pitch P2 of the liquid crystal display 12 is fixed to 0.08 mm, and the electrode gap of the transparent electrode 14 is changed. Show.

  When α is 1 degree, the pitch of moire increases, but when α is 20 degrees, the electrode gap is 0.3 mm or less in the range of 0 mm to 0.4 mm, and when α is 40 degrees, the electrode gap Is further smaller at 0 mm to 0.4 mm and 0.2 mm or less.

  Therefore, assuming that the above standard, that is, the distance from the touch panel when the user is sitting in the driver's seat of the vehicle is 600 mm and the average visual acuity of the user is 0.7, the moire pitch is 0.249 mm. If the standard that the influence of moire can be suppressed is adopted if the following is set, the angle deviation α is set to 40 degrees, and the electrode gap of the transparent electrode 14 is set to about 0 mm to 0.4 mm. This standard can be satisfied, and the influence of moire can be suppressed to improve the merchantability of the touch panel.

  As described above, in the present embodiment, assuming that the pitch P of the liquid crystal display 12 is given, the angle deviation α and the electrode gap P1 of the transparent electrode 14 are adjusted, and the moire pitch R defined by Expression (1) is set. By setting the threshold value to be a predetermined threshold value, for example, 0.249 or less, the influence of moire is suppressed. The electrode gap of the transparent electrode 14 must be a certain value or more due to processing accuracy limitations. In the present embodiment, the allowable range of the electrode gap in the correlation with the angle deviation α based on the formula (1). Therefore, moire can be effectively suppressed without increasing the processing accuracy. In other words, the larger the electrode gap of the transparent electrode 14 is, the easier it is to process, but at the same time, the influence of moire increases, but in the present embodiment, the influence of moire is reliably suppressed based on Equation (1). As described above, the angle deviation α and the electrode gap P1 can be set to appropriate ranges. This means that the processing of the transparent electrode 14 is facilitated and the options for the processing method of the transparent electrode 14 are increased.

  In FIG. 9, an example of the pattern of the transparent electrode 14 in this embodiment is shown. Assuming that the pixels of the liquid crystal display 12 are arranged in the horizontal direction and the vertical direction in the figure, the transparent electrode 14 is patterned in a direction shifted by 45 degrees from the horizontal direction or the vertical direction. Further, the electrode gap P1 of the transparent electrode 14 is set to a value such that the moiré pitch R in the formula (1) is 0.249 mm or less, assuming that the angle deviation α is 45 degrees and the pitch P2 of the liquid crystal display 12 is 0.08 mm. .

  In this embodiment, as the threshold of the moire pitch, the distance from the touch panel is 600 mm when the user is sitting in the driver's seat of the vehicle, and the user's visual acuity is set to 0.7 and is set to 0.249 mm. This is an example, and other threshold values may be set. For example, when the user is sitting in the driver's seat of the vehicle and the distance to the touch panel is 400 mm, and the user's visual acuity is 1.0, the threshold is 0.116 mm. In this case, the angle deviation α and the electrode gap P1 may be set so that the moire pitch R in the formula (1) is 0.116 mm or less. The distance to the touch panel can be determined by the vehicle type on which the touch panel is mounted.

  In addition to determining the threshold of the moire pitch based on the distance between the user and the touch panel and the visual acuity of the user, the threshold can be determined based on the pitch of the liquid crystal display 12. That is, the pitch of the liquid crystal display 12 is given, and the influence of moire can be suppressed if it is set at least equal to or less than this pitch. If the pitch of the liquid crystal display 12 is 0.08 mm, the electrode interval P1 may be set according to the equation (1) so that the moire pitch R is 0.08 mm or less. When the R pixel, G pixel, and B pixel of the liquid crystal display 12 are set as one set, the pitch of this set is 0.08 mm × 3 = 0.24 mm, so the threshold of the moire pitch R is set to 0.24 mm, and the moire pitch is set to 0.2 mm. The electrode interval P1 can also be set according to Equation (1) so as to be 24 mm or less. Of course, when the threshold set based on the pitch of the liquid crystal display 12 is smaller than the threshold determined based on the distance between the user and the touch panel and the visual acuity of the user, the threshold is set based on the pitch of the liquid crystal display 12. The electrode gap P1 set to be equal to or less than the threshold value satisfies the threshold condition determined based on the distance between the user and the touch panel and the user's visual acuity, which is desirable.

  As an example, the pixel pitch of the liquid crystal display 12 is 0.08 mm, the angle deviation α is in the range of 40 degrees to 50 degrees, and the electrode gap P1 is 0.05 mm to 0.25 mm, preferably 0.08 mm ± 0. For example, 02 mm.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation is possible.

  For example, in the present embodiment, the liquid crystal display 12 is used as a display, but an organic EL display may be used.

  Moreover, any of masking, etching, and laser processing can be used for the patterning method of the transparent electrode 14 in this embodiment. Further, as the transparent electrode 14, in addition to forming ITO, ZnO or the like by sputtering, a conductive polymer may be applied and formed.

  10 substrate, 12 liquid crystal display, 13 gap (air layer), 14 transparent electrode, 16 transparent protective layer.

Claims (2)

An in-vehicle touch panel,
Display,
A transparent panel laminated on the display and having a predetermined curvature with integrated transparent electrodes;
With
A gap is formed between the display and the transparent electrode,
When the electrode gap of the transparent electrode is P1, the pixel pitch of the display is P2, and the angle deviation between the electrode pattern of the transparent electrode and the pixel pattern of the display is α,

The in-vehicle touch panel, wherein the angular deviation α and the electrode gap P1 are set so that the moiré pitch R defined in (1) is equal to or less than a threshold set based on the pixel pitch P2 of the display. The in-vehicle touch panel according to claim 1,
The on-vehicle touch panel, wherein the threshold value is equal to a pixel pitch P2 of the display.

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