KR20120119985A - Input device - Google Patents

Abstract

PURPOSE: An input unit is provided to suppress the discoloration of reflected light by reducing the degradation of a reflection preventing function caused by a light transmission film including an electrode layer. CONSTITUTION: Two of light transmission films(41,42) are overlapped with each other and formed on a more inner side than a polarizing layer(22). The light transmission film is a sensing film having light transmission electrode layers. The light transmission films are crossed with each other. The electrode layers are formed on both sides of the sensing film.

Description

Input device {INPUT DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a translucent input device disposed in front of a display device, and more particularly to an input device having a function of preventing reflection of external light.

In various electronic devices such as portable devices, a light transmissive input device is formed in front of the display device. The input device is provided with a transmissive electrode layer that intersects each other, for example in a capacitance detection type, and the detection output is changed based on the capacitance formed between the electrode layer and the finger when a human finger approaches.

In an electronic device using a light-transmitting input device, external light transmitted through the input device is reflected on the display screen of the display device located inside the input device, the electrode layer of the display device, or the like, which makes it difficult to see the display contents of the display device. .

In the touch panel described in Patent Document 1 below, a polarizing plate in which a polarizing layer and a quarter wavelength phase layer are integrated is formed on the outermost surface, and an upper substrate and a lower substrate having light transmitting electrode layers formed therein respectively. The substrate is arranged below. In addition, a polarizing plate is formed between the base plate and the liquid crystal display device.

In the touch panel described in Patent Document 2 below, two transparent substrates each having a λ / 4 retardation plate and a transparent conductive film are formed in front of the display device, and a polarizing plate is further formed in front of the display panel.

The inventions described in Patent Literature 1 and Patent Literature 2 are both intended to prevent internal reflection of external light by forming a λ / 4 retardation plate and a polarizing plate in front of the display device.

Japanese Laid-Open Patent Publication No. 2008-262326 WO2006 / 028131 republished patent

In the inventions described in Patent Literature 1 and Patent Literature 2, external light becomes linearly polarized light in a polarizing plate, and linearly polarized light is converted into rotation polarized light by the birefringence action of the λ / 4 retardation plate. When this rotational polarization is reflected on the reflecting surface, the phase is changed by 180 degrees to become circular polarization of reverse rotation, which again passes through the λ / 4 retardation plate to become linearly polarized light. The polarizing plate prevents the output of this linearly polarized light.

In this case, since two transparent substrates having a transparent electrode layer are located inside the polarizing plate, when this transparent substrate exhibits birefringence, the phase difference due to birefringence of the transparent substrate is added to the phase difference of the? / 4 retardation plate, The light passing through the λ / 4 retardation plate tends to be converted into elliptical polarization instead of circularly polarized light. As a result, the problem that the antireflection effect is lowered or the display image becomes brown or the like tends to occur.

Patent Document 2 describes that a transparent substrate on which a transparent conductive layer is formed is formed of an isotropic substrate. However, when it is going to form a board | substrate with an isotropic film, since drawing force is received toward the flow direction MD of a film in the manufacturing process, it may not be optically completely isotropic and it may show birefringence. Although the anisotropy at this time is not so great, when two isotropic films having an electrode layer are used in the same direction, the anisotropy is amplified and the above-described optical problems are likely to occur.

This invention solves the said conventional subject, Comprising: Even if the translucent film which has an electrode layer shows birefringence, it aims at providing the input device of the structure which is easy to prevent the fall of antireflection function or the generation of the penetration of transmitted light. have.

This invention has a polarizing layer, the (lambda) / 4 phase (s) difference layer formed inward from the said polarizing layer, and the detection film formed inward from the said polarizing layer, and is arrange | positioned in front of a display apparatus,

Two translucent films which mutually crossed the direction of the flow direction (MD) at the time of film manufacture mutually overlap each other inside the said polarizing layer, and at least one translucent film is the said detection film which has a translucent electrode layer in the surface. It is characterized by.

The input device of this invention has a polarizing layer and (lambda) / 4 phase (s) difference layer, and exhibits an antireflection function. It is preferable that the detection film used for this input device is formed from the optically isotropic light transmissive film. For example, when a resin film in which optical anisotropy occurs randomly depending on a place, i.e., a material whose birefringence is not controlled, the blocking rate of reflected light is partially different, or stains such as rainbow colors are likely to occur in the reflected light. . However, even in the case of the resin film which is considered to be optically isotropic, since the stretching force acts in the flow direction MD at the time of film manufacture, optical isotropy collapses and the material which shows birefringence with the slow axis toward the flow direction MD Cannot be avoided. As a result, the retardation of the detection film is added to the retardation imparted by the λ / 4 retardation layer, so that the antireflection effect of external light is reduced, or a brownish color or the like tends to occur in the reflected light.

Therefore, this invention uses the two translucent films which function at least one as a detection film, and intersects the birefringence slow axis of each film by intersecting the flow direction MD, and the phase difference which arises in a translucent film Offset. As a result, the blocking function of the reflected light can be enhanced and the damping of the reflected light can be easily suppressed.

As for the said translucent film in this invention, the thing in which the slow axis of birefringence is located in the range of +/- 15 degree on the basis of the flow direction MD is used, The phase difference of birefringence of the said translucent film is 3? One in the range of 20 nm is used.

In the present invention, only one light-transmitting film of the two light-transmissive films may be the detection film having an electrode layer, or both of the light-transmissive films may be the detection film having an electrode layer.

In the present invention, the two translucent films have the same relationship in the direction in which the flow direction MD and the electrode layer extend, and the two translucent films overlap in the direction in which the electrode layers intersect, so that the flow direction MD It can be configured as crossing each other.

As described above, in the case where the flow direction MD and the direction in which the electrode layers extend are related, when the electrode layers of the two translucent films are crossed and assembled, the flow direction MD can necessarily cross.

As for the input device of this invention, a polarizing layer, (lambda) / 4 phase (s) difference layer, and two translucent films are arrange | positioned in front of a liquid crystal display, or a polarizing layer, (lambda) / 4 phase (s) difference layer, and two translucent films are electroluminescent display. It is placed in front of the device.

The input device of this invention can reduce the fall of the antireflection function resulting from the translucent film which has an electrode layer, and can suppress the damping of reflected light.

1 is an exploded perspective view of a portable device on which the input device of the embodiment of the present invention is mounted.
2 is a cross-sectional view showing an input device and a display device according to the first embodiment of the present invention.
3 is a cross-sectional view showing an input device and a display device according to a second embodiment of the present invention.
4 is an explanatory diagram showing optical characteristics of each layer constituting the input device.
5 is an explanatory diagram showing another example of the combination of optical characteristics of each layer constituting the input device.
It is an exploded perspective view which shows the structural example of a detection film.

The portable device 10 shown in FIG. 1 is used as a mobile phone, a portable information processing device, a portable storage device, a portable game device, or the like.

The portable device 10 has a case 2 made of synthetic resin. The case 2 has the recessed part 3 which opened upward, and the circuit board and display apparatus 30 which mounted the electronic circuit inside the recessed part 3 are accommodated. The opening part of the recessed part 3 is blocked by the input device 20 of embodiment of this invention. The input device 20 has a display area 20a through which display light from the display device 30 is transmitted, and a non-display area 20b that surrounds the display area 20a so that light cannot be transmitted. .

The display apparatus 30 used for the portable apparatus 10 shown in FIG. 2 is comprised by the liquid crystal display device and the backlight part which provides the light from LED or a lamp from behind the liquid crystal display device.

The liquid crystal display device has a transparent electrode facing each other with a liquid crystal material layer interposed therebetween, and has an alignment layer and a polarizing layer facing each other with a liquid crystal material layer interposed therebetween. Therefore, the display light provided from the backlight unit and transmitted through the liquid crystal display device is linearly polarized light. (Lambda) / 4 phase (s) difference film 31 is formed in the whole surface which is the display light transmission side of the display apparatus 30. FIG.

The spacer 32 is fixed to the front surface 31a of the λ / 4 retardation film 31, and the input device 20 is fixed to the front of the spacer 32. In the input device 20, the surface facing the display device 30 is the rear surface 20c, and the surface on which the display light is sent is the front surface 20d. The spacer 32 has a frame shape surrounding the display area 20a of the input device 20, and in the display area 20a, the front surface 31a and the input device 20 of the λ / 4 retardation film 31 are provided. The thin air layer 33 is formed between the back surfaces 20c of the. The said spacer 32 is a double-sided adhesive tape, an adhesive bond layer, or an adhesive layer.

As shown in FIG. 2, the input device 20 has the translucent cover layer 21, and the surface of this cover layer 21 is the said front surface 20d. Translucent in this specification means the state which can permeate | transmit light, such as transparent or semitransparent, and means that the total light transmittance is 50% or more, Preferably it is 80% or more.

The cover layer 21 is formed of light and translucent resins such as PMMA (methyl methacrylate resin), PC (polycarbonate), COP (cyclic olefin copolymer), and TAC (triacetyl cellulose). A decorative layer is formed on the back or front surface of the cover layer 21, and is colored so that light may not permeate | transmit in the non-display area 20b, as shown in FIG.

On the inner side (back side) of the cover layer 21, the polarizing film 22 which is a polarizing layer, the lambda / 4 phase difference film 23 which is a (lambda) / 4 phase difference layer, and the touch sensor part 40 turn to the rear in order. It is stacked. The cover layer 21 and each layer arrange | positioned inside are adhere | attached through the translucent adhesive agent, such as an acryl type.

In FIG. 4, the absorption axis 22a direction of the polarizing film 22 and the slow axis 23a direction of the (lambda) / 4 phase (s) difference film 23 are shown. The absorption axis 22a direction of the polarizing film 22 formed inside the cover layer 21 is the same as the absorption axis direction of the polarizing layer formed on the side which transmits the display light of the display device 30 which is a liquid crystal display device. . Further, the slow axis 23a of the lambda / 4 phase difference film 23 located inside the cover layer 21, and the slow axis direction of the lambda / 4 phase difference film 31 formed on the entire surface of the display device 30 Orthogonal to each other.

As shown in FIG. 6, the touch sensor part 40 has the 1st light transmissive film 41, the 2nd light transmissive film 42, and the insulating layer 43 interposed between both films. The films 41 and 42 and the insulating layer 43 are bonded through translucent adhesives, such as an acryl type. Alternatively, the insulating layer 43 may be a transparent adhesive layer. The 1st electrode layer 44 is formed in the front surface 41a of the 1st translucent film 41, and the 2nd electrode layer 45 is formed in the front surface 42a of the 2nd translucent film 42. As shown in FIG. The first electrode layer 44 and the second electrode layer 45 are formed of ITO (indium oxide-tin) or a translucent organic conductive layer.

The first light-transmitting film 41 and the second light-transmitting film 42 are formed of a resin material which is easy to control optical properties, and are formed of, for example, COP (cyclic olefin copolymer) or TAC (triacetylcellulose). . The light transmissive film formed by COP or TAC is easy to control birefringence, and can be formed almost optically isotropically. However, at the time of film manufacture, since the drawing force acts in the flow direction MD of a film at the time of conveying a film between rolls, the molecule | numerator of a film is oriented in a flow direction MD, and shows birefringence. In this case, the slow axis of birefringence almost faces the flow direction MD.

That is, even if it is a translucent film called isotropic, it shows birefringence like the slow axis located in the range of +/- 15 degree with respect to the flow direction MD, and the phase difference of birefringence is 3? It cannot be avoided to fall in the range of 20 nm. Usually, the slow axis of birefringence is located in a range of ± 10 degrees with respect to the flow direction MD, and the phase difference of birefringence is 3? Even if it becomes the range of 10 nm, it is said to be optically isotropic.

As shown in FIG. 4, the flow direction MD1 of the 1st translucent film 41 which comprises the touch sensor part 40, and the flow direction MD2 of the 2nd translucent film 42 are orthogonal to each other.

It is preferable that the 1st light transmissive film 41 and the 2nd light transmissive film 42 are formed from the film manufactured by the same film manufacturing process. More preferably, the 1st light transmissive film 41 and the 2nd light transmissive film 42 are cut out from the continuous film strip, and are used. As a result, the relationship between the flow direction (MD direction) and the slow axis becomes the same in the first light-transmitting film 41 and the second light-transmitting film 42, and the birefringence phase difference becomes almost the same.

Therefore, if the flow direction MD1 and the flow direction MD2 are orthogonal to each other, the slow axis of the first light-transmissive film 41 and the slow axis of the second light-transmissive film 42 can be orthogonal, and the first light-transmissive film 41 And is optically isotropic by the combination of the second translucent film 42. As a result, the phase difference of the light which passed the (lambda) / 4 phase (s) difference film 23 can be prevented from changing further by birefringence of the translucent films 41 and 42. FIG.

As shown in FIG. 6, the 1st electrode layer 44 is formed in parallel with the flow direction MD1 of the 1st translucent film 41, and the 2nd electrode layer 45 is the flow direction of the 2nd translucent film 42. As shown in FIG. It is preferable that it is formed in parallel with. In this way, when combining the 1st light transmissive film 41 and the 2nd light transmissive film 42, if the 1st electrode layer 44 and the 2nd electrode layer 45 are orthogonal to each other, the flow direction MD1 and a flow direction It becomes possible to orthogonally cross (MD2).

Therefore, when assembling the touch sensor part 40, the slow axis can be reliably orthogonal by making reference to the direction of an electrode layer, without considering which direction the flow direction is. However, in the 1st translucent film 41, the flow direction MD1 and the direction of the 1st electrode layer 44 are orthogonal, and in the 2nd translucent film 42, the flow direction MD2 and the 2nd electrode layer 45 The first light-transmitting film 41 and the second light-transmitting film 42 may be combined to orthogonal to each other so that the two electrode layers 44 and 45 are perpendicular to each other.

In the portable device 10 shown in FIG. 1, display light displayed on the display device 30 passes through the display area 20a of the input device 20 and is forwarded, and the user views the display area 20a. When the finger touches the front surface 20d of the input device 20 while viewing the displayed display image, the touch position of the finger is detected by the touch sensor unit 40.

In the touch sensor unit 40, voltages are sequentially applied to the plurality of first electrode layers 44 by a driving circuit (not shown), and voltages are sequentially applied to the plurality of second electrode layers 45 at different timings. . When a human finger, which is a conductor of approximately ground potential, contacts the front surface 20d at a position approaching an electrode layer, a capacitance is formed between the electrode layer and the finger, and a current flows through the finger when voltage is applied. By detecting this change in current, it is possible to calculate the position approached by the finger.

2, the transmission path of the external light 1 entering the display area 20a of the input device 20 from the outside is indicated by (A), and the transmission of the display light 4 emitted from the display device 30 is shown. The path is shown by (B).

As shown by (A) in FIG. 2, the external light 1 which permeate | transmitted the cover layer 21 permeate | transmits the polarizing film 22, and becomes linearly polarized light, and this linearly polarized light is (lambda) / 4 phase (s) difference film 23 Is transmitted, the circularly polarized light 2 is obtained. The circularly polarized light 2 is reflected at the boundary surface of each subsequent layer, and particularly, is easily reflected at the interface between the air layer 33 and the front surface 30a of the display device 30. These reflected lights return 180 degrees in phase difference between the circularly polarized light 2 and become the circularly polarized light 3 of reverse rotation. The circularly polarized light 3 becomes linearly polarized light by transmitting the lambda / 4 phase difference film 23 again, but the optical axis of the linearly polarized light is orthogonal to the absorption axis 22a of the polarizing film 22 positioned at the foremost part. Therefore, the reflected light is prevented from being blocked by the polarizing film 22 and returned to the outside.

As shown in FIG. 2B, the light emitted from the backlight unit in the display device 30 passes through the liquid crystal display device. However, since the polarization layer is formed at the exit portion of the light of the liquid crystal display device, It is sent out as the display light 4. The linearly polarized display light 4 becomes circular polarized light 5 by passing through the λ / 4 retardation film 31 located behind. When the circularly polarized light 5 passes through the front lambda / 4 phase difference film 23, it becomes linearly polarized light 6, but the optical axis of the linearly polarized light 6 is the same direction as the absorption axis 22a of the polarizing film 22. For this reason, the linearly polarized light 6 is radiated forward without being blocked by the polarizing film 22, so that the display light can be seen.

In this input device 20, the 1st light-transmitting film 41 and the 2nd light-transmitting film 42 which comprise the touch sensor part 40 are optical films of the near isotropic property whose slow axis and fastening axis were adjusted. Formed. Therefore, the problem that a coloring of iridescent color arises in the reflected light like the case of using the optically unadjusted film in which the optical characteristic changes randomly in each area | region of a film does not arise.

As described above, even a light transmissive film having an optically near isotropic property exhibits birefringence in the flow direction (MD) at the time of film production, and in reality, the phase difference is 3? Even if it occurs in the range of 20 nm and is close to isotropic, 3? A phase difference of 10 nm is occurring.

However, in this embodiment, since the slow axis of birefringence is orthogonal to each other by orthogonal to the flow direction MD1 of the 1st translucent film 41, and the flow direction MD2 of the 2nd translucent film 42, a touch sensor part 40 becomes optically isotropic as a whole. As a result, the phase difference of the light transmitted through the [lambda] / 4 retardation film 23 does not deviate greatly from [lambda] / 4, and the reflected light can be treated as circularly polarized light, and the reflected light can be blocked by the polarizing film 22. Become.

On the other hand, 3? 20 nm range or 3? If the flow direction MD1 of the first light-transmitting film 41 and the flow direction MD2 of the second light-transmitting film 42 are generated to coincide with each other in the range of 10 nm, the touch sensor unit 40 as a whole is large. Birefringence is shown. In this case, the phase difference of the light transmitted through the λ / 4 retardation film 23 is shifted from λ / 4 and becomes elliptically polarized, so that the ratio of blocking the reflected light is lowered, and browning or the like tends to occur in the reflected light.

3 shows a portable device 110 of a second embodiment of the present invention.

The input device 20 used for this portable device 110 is the same as that shown in FIG.

The display device 130 shown in FIG. 3 is a self-luminous display device such as an organic electroluminescent display device. The display light emitted from the display device 130 is artificial light in a state close to natural light, not linearly polarized light, circularly polarized light, or elliptical polarized light. In addition, the rear surface 20c of the input device 20 is in close contact with the front surface 130a of the display device 130.

As shown by (C) in the right side of FIG. 3, the external light 1 permeate | transmits the polarizing film 22 and (lambda) / 4 phase (s) difference film 23, and becomes circularly polarized light 2. Part of the circularly polarized light 2 enters the inside of the display device 130 and is reflected by the electrode layer formed on the display device 130, but the reflected light also becomes the circularly polarized light 3 of reverse rotation, and thus returns. It is blocked by the polarizing film 22 after being converted into linearly polarized light in the λ / 4 retardation film 23.

As shown by (D) in FIG. 2, since the display light 4 emitted from the self-emission display device 130 is artificial light close to natural light, (lambda) / 4 phase (s) difference film 23 and a polarizing film ( 22) It is penetrated and moved forward to show the display contents.

5 shows another example of the arrangement order of the layers constituting the input device.

In the input device 120 shown in FIG. 5, the polarizing film 22 is formed in the foremost part, and the 2nd light transmissive film 42 and the 1st light transmissive film 41 which comprise the touch sensor part 40 in the inside are provided. Is formed. And (lambda) / 4 phase (s) difference film 23 is formed in back of the 1st light transmissive film 41. FIG.

Also in this input device 120, the flow direction MD1 of the 1st translucent film 41 and the flow direction MD2 of the 2nd translucent film 42 are orthogonal, and is optically isotropic as a whole to the touch sensor part 40. FIG. It can be set as this, and it becomes easy to suppress that the light which passed the (lambda) / 4 phase (s) difference film 23 becomes an elliptically polarized light.

In addition, although the electrode layers 44 and 45 are formed in both the 1st light transmissive film 41 and the 2nd light transmissive film 42, the touch sensor part 40 shown in FIG. The electrode layer may be formed on both surfaces, or the electrode layer may be formed only on one side of one light-transmitting film. In this case, in addition to the light-transmitting film (one detection film) which has an electrode layer, the light-transmitting film which does not have an electrode layer is used, and the flow direction (MD) in the light-transmitting film (one detection film) which has an electrode layer and the light-transmissive film which does not have an electrode layer is used. By orthogonal), the effect equivalent to the said embodiment can be acquired.

In addition, as a display device, a liquid crystal display device having no polarizing plate on the emission side of the display light is used, and the input device 20 or the input device 120 is disposed in front of the polarizing film located at the foremost part of the input device ( 22) may be used as a polarizing plate on the emission side of the liquid crystal display device.

2: case
10: mobile device
20: input device
20a: display area
21: cover layer
22: polarizing film
22a: absorption shaft
23: lambda / 4 phase difference film
23a: slow axis
30: display device
31: lambda / 4 phase difference film
40: touch sensor unit
41: first light-transmitting film
42: second light-transmitting film
44: first electrode layer
45: second electrode layer
110: mobile device
120: input device
130: display device

Claims (19)

In the input device which has a polarizing layer, the (lambda) / 4 phase (s) difference layer formed inward from the said polarizing layer, and the detection film formed inward from the said polarizing layer, and is arrange | positioned in front of a display apparatus,
Two translucent films which mutually crossed the direction of the flow direction (MD) at the time of film manufacture mutually overlap each other inside the said polarizing layer, and at least one translucent film is the said detection film which has a translucent electrode layer in the surface. Input device, characterized in that. The method of claim 1,
The input device in which two said transparent films are the said detection film which has an electrode layer. The method of claim 2,
The two translucent films have the same relationship between the flow direction MD and the direction in which the electrode layers extend, and the two translucent films overlap the transmissive films in the direction in which the electrode layers intersect, whereby the flow directions MD cross each other. Device. The method of claim 1,
An input device in which only one light-transmissive film is the detection film having an electrode layer among the two light-transmissive films. The method of claim 4, wherein
An input device in which electrode layers are formed on both surfaces of the detection film. The method of claim 4, wherein
An input device in which an electrode layer is formed only on one side of the detection film. The method of claim 1,
The said detection film is an input device which detects the change of the electric current which flows through a finger when a capacitance is formed between a human finger and the said electrode layer, and a voltage is applied to the said electrode layer. The method of claim 1,
The input device in which the said polarizing layer and the said (lambda) / 4 phase (s) difference layer are located in front of the said two transparent films. The method of claim 1,
The polarizing layer is located in front of the two light-transmitting film, the λ / 4 retardation layer is located behind the light-transmitting film. 10. The method according to any one of claims 1 to 9,
The said translucent film is an input device in which the slow axis of birefringence is located in the range of +/- 15 degree with respect to the flow direction MD. 10. The method according to any one of claims 1 to 9,
The light transmissive film has a phase difference of birefringence of 3? Input device in the range of 20 nm. 11. The method of claim 10,
The light transmissive film has a phase difference of birefringence of 3? Input device in the range of 20 nm. 11. The method of claim 10,
The said translucent film is an input device formed with the cyclic olefin copolymer (COP) or triacetyl cellulose (TAC). The method of claim 11,
The said translucent film is an input device formed with the cyclic olefin copolymer (COP) or triacetyl cellulose (TAC). 13. The method of claim 12,
The said translucent film is an input device formed with the cyclic olefin copolymer (COP) or triacetyl cellulose (TAC). The method of claim 1,
The input device in which a polarizing layer, (lambda) / 4 phase (s) difference layer, and two translucent films are arrange | positioned in front of a liquid crystal display device. 17. The method of claim 16,
An input device of a polarizing layer formed on a side for transmitting display light of the liquid crystal display device and an absorption axis in the polarizing layer in the same direction. The method according to claim 16 or 17,
An input device in which a slow axis is orthogonal to each other in a lambda / 4 phase difference layer formed on the front surface of the liquid crystal display and the lambda / 4 phase difference layer. The method of claim 1,
The input device in which a polarizing layer, (lambda) / 4 phase (s) difference layer, and two translucent films are arrange | positioned in front of an electroluminescent display apparatus.

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