JP2011209333A - Touch panel-integrated illuminator and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel-integrated front light which is capable of achieving good touch operability and accurate position detection even while using one substrate of a resistive film touch panel as a light guide plate, and a display device employing the front light.SOLUTION: In a touch panel-integrated front light 2 installed on the front surface side from which display on a liquid crystal display panel 1 is observed, front and rear resistance films 23 and 24 are formed on counter surfaces (inner surfaces) 211 and 221 of a pair of front and rear transparent substrates 21 and 22 disposed to face each other with a predetermined gap therebetween, by deposition respectively, and an LED 27 is arranged on one end face 222 of the rear transparent substrate 22 serving also as the light guide plate, and protrusions 224 for emitting light propagating in the rear transparent substrate 22 are uniformly provided on an outer surface 223 facing the liquid crystal display panel 1.

Description

  The present invention relates to a touch panel integrated lighting device in which a substrate of a touch panel also serves as a light guide plate, and a display device using the same.

  In recent years, many mobile devices equipped with a liquid crystal display panel or the like as a display monitor are equipped with a touch panel as an input device on the front side of the display monitor in order to meet the demand for a reduction in size and thickness.

  In the case where the display monitor on which the touch panel is mounted is a display monitor that requires a lighting device such as a liquid crystal display panel, the touch panel and the lighting device are a great obstacle to promoting thinning.

  Therefore, in order to realize a small and thin display monitor with a lighting device equipped with a touch panel, a front light integrated with a touch panel as disclosed in Patent Document 1 has been proposed.

JP 2002-216585 A

  The above-described touch panel integrated front light is a resistive film type touch panel, and a first resistance film and a second resistance film are formed on each facing surface of a pair of transparent substrates arranged opposite to each other, and the first resistance on the observation side is formed. The outer surface of the substrate on which the film is formed is pressed (touched) to bring the first resistive film at the pressed position into conductive contact with the second resistive film, and the potential in the direction perpendicular to the contact position (XY direction) is measured. Thus, the touch position is detected. In this front light, since the transparent substrate on which the second resistance film is attached is used as the light guide plate, the surface on which the second resistance film is attached is provided with irregularities. The unevenness is provided to diffusely reflect the light propagating through the transparent substrate and to emit the light toward the irradiation target such as a liquid crystal display panel from the opposite outer surface.

  However, by forming the diffuse reflection unevenness, the second resistance film surface of the first and second resistance films facing each other on the touch panel becomes an uneven surface, and as a result, for each position of the second resistance film surface. Since the pressing force (touch pressure) at the time of conducting contact with the electrode varies, and the linearity of the resistance value from the voltage application electrode to the contact position is lost, the touch operability is deteriorated and the accurate touch position is difficult to detect. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a touch panel integrated illuminating device capable of good touch operability and accurate position detection while using one substrate of a resistive touch panel as a light guide plate, and a display device using the same Is to provide.

  The touch panel integrated lighting device according to claim 1 of the present invention includes a first transparent substrate in which a first resistance film is attached to a rear surface which is one main surface of a pair of flat main surfaces; A second transparent substrate having a second resistance film deposited on the front surface, which is one main surface of the pair of flat main surfaces, and an irregular surface formed on the rear surface, which is the other main surface; The second transparent substrate on the rear side of the transparent substrate, a bonding member bonded to the first resistance film in an arrangement in which the second resistance film is opposed to each other while maintaining a predetermined gap, and an end surface of the second transparent substrate And a light source that emits light toward the second transparent substrate. The first resistance film and the second resistance film when the front surface of the first transparent substrate is pressed. The pressed position is detected from the resistance value of the conductive contact position, and the light emitted from the light source and incident on the second transparent substrate is Is characterized in that is injected into the planar from said rear face of the serial second transparent substrate.

  The invention of the display device according to claim 2 of the present invention is installed on the front side of the display panel that performs at least reflective display by reflecting light irradiated from the front side toward the display surface. The touch panel-integrated lighting device according to claim 1 is provided.

  According to a third aspect of the present invention, in the display device according to the second aspect, the reflective display panel has a liquid crystal sandwiched between a pair of transparent substrates, and a light reflecting plate is provided facing the outer surface of one of the transparent substrates. The touch panel integrated lighting device is installed with the rear surface of the second transparent substrate facing the outer surface of the other transparent substrate of the liquid crystal display panel. To do.

  ADVANTAGE OF THE INVENTION According to this invention, while using one board | substrate of a resistive film type touch panel as a light guide plate, favorable touch operativity and an accurate position detection which can perform an exact position detection, and a display apparatus using the same Can be provided.

It is typical sectional drawing which shows the liquid crystal display device as one Embodiment of this invention. It is the top view which showed the light-guide plate in the said liquid crystal display device. It is explanatory drawing which shows the effect | action operation | movement of the irradiation light by the front light of the said liquid crystal display device. It is explanatory drawing which shows the effect | action operation | movement of the irradiation light by the frontlight as a modification of the said embodiment.

  As shown in FIG. 1, the liquid crystal display device according to the present embodiment is generally configured such that a touch panel integrated front light 2 is installed on the front side of a liquid crystal display panel 1. In the liquid crystal display device of this embodiment, the display is observed from the front side of the liquid crystal display panel 1.

  The liquid crystal display panel 1 has a pair of rectangular glass substrates 11 and 12 on which electrodes (not shown) are formed, and a predetermined gap is maintained by a frame-shaped sealing material (not shown) with the electrode forming surfaces facing each other. The liquid crystal (not shown) is sealed between the glass substrates 11 and 12 surrounded by a frame-shaped sealing material. A pair of polarizing plates 13 and 14 are attached to the outer surfaces of the glass substrates 11 and 12 opposite to the liquid crystal sealing side, respectively.

  The liquid crystal display panel 1 of this example is a reflective liquid crystal display panel that performs reflective display by reflecting light irradiated from the front toward the display surface, and therefore, a front glass substrate (hereinafter referred to as a front glass substrate). 11 is superimposed on a polarizing plate (rear polarizing plate 14) attached to a rear glass substrate (hereinafter referred to as a rear glass substrate) 12, and is arranged on the rear outer surface of the rear glass substrate 12 (the rear glass substrate 12 has). A light reflecting plate 15 is attached so as to face a main surface on the opposite side of the pair of main surfaces to the side where the liquid crystal is arranged. Instead of the external light reflection plate 15, a light reflection layer may be laminated on the inner surface of the rear glass substrate 12 on the liquid crystal encapsulation side.

  Of the front glass substrate 11 and the other rear glass substrate 12 in the liquid crystal display panel 1 of this example, one edge of the rear glass substrate 12 protrudes more appropriately than the corresponding edge of the front glass substrate 11, and the protruding edge 121. Is formed. The projecting edge 121 is provided with a signal wiring for applying various signal voltages drawn from electrodes (not shown) and connection terminals (not shown) at each end thereof to form a drive circuit portion. The driver circuit 16 as a drive circuit element is directly mounted on the drive circuit unit by a COG (Chip On Glass) method.

  The liquid crystal display panel 1 configured as described above is housed in a metal shield case 3. The front plate 31 of the shield case 3 is provided with a skylight 32 having a size capable of sufficiently facing the entire area Dd where the display of the liquid crystal display panel 1 is performed.

  On the other hand, the touch panel integrated front light 2 disposed on the front side of the liquid crystal display panel 1 includes rear transparent substrates 21 and 22 before forming a pair of rectangles. The touch panel integrated front light 2 is disposed so as to face each other such that the front transparent substrate 21 is on the front side and the rear transparent substrate 22 is on the rear side, and the inner surfaces of the pair of front and rear transparent substrates 21 and 22 facing each other. A frame for joining the transparent front and rear resistance films 23 and 24, which are deposited and installed over substantially the entire surface excluding the peripheral edges of 211 and 221 to a pair of front and rear transparent substrates 21 and 22 with a predetermined gap therebetween. A sealing material 25, an insulating spacer 26 that regulates the gap between the front and rear transparent substrates 21 and 22 to be constant, and one end face 222 of the rear transparent substrate 22 that also serves as a light guide plate are disposed as light sources. It comprises a plurality of LEDs (Light-Emitting Diodes) 27 and the like.

  The front transparent substrate 21 of the pair of front and rear transparent substrates 21 and 22 is a substrate whose outer surface 212 is a touch operation surface, and has a rigidity that allows the touched portion to bend smoothly with an appropriate pressure. Good. In this embodiment, a PET (Poly-Eethylene Trephthalate) resin molded plate having a plate thickness of about 0.3 mm is used.

  On the other hand, the rear transparent substrate 22 is a substrate that also serves as a light guide plate, so that light incident from the end face 222 on which the LEDs 27 are disposed propagates while totally reflected on the front and rear (both main surfaces) interfaces of the rear transparent substrate. , And a refractive index with respect to air (hereinafter simply referred to as a refractive index) is 1.4 or more. In the present embodiment, a PC (poly carbonate) resin molded plate having a refractive index of 1.6 and a thickness of about 0.7 mm is used.

  The transparent front and rear resistance films 23 and 24, which are respectively attached to the opposing surfaces 211 and 221 of the front and rear transparent substrates 21 and 22, are formed of ITO (indium tin oxide), respectively. The resistance is set to about 200Ω / □.

  A plurality of spacers 26 made of insulating transparent resin particles such as melamine resin are sandwiched between the front and rear transparent substrates 21 and 22 (strictly between the resistance films 23 and 24) in an evenly dispersed arrangement. The gap is kept constant.

  As described above, in the touch panel of the present embodiment, the front and rear resistance films 23 and 24 face each other in parallel over the entire touch input area corresponding to the display area Dd, and the resistance film 23 and 24 are separated by the spacer 26. Since the distance between the two resistance films 23 and 24 can be surely brought into conductive contact with a constant pressing force at any pressing location at any time, the linearity of the resistance value is not impaired. The touch position is accurately detected.

  As shown in FIG. 2, three LEDs 27 are equally disposed on one end surface 222 of the transparent substrate 22 that is formed thick so as to serve also as a light guide plate. Each LED 27 is installed such that its light exit surface 271 is in close contact with the end surface 222 on which light of the rear transparent substrate 22 is incident.

  Thus, the outer surface 223 to which the rear resistance film 24 of the rear transparent substrate 22 that is also used as the light guide plate is not attached is entirely present at the interfaces between the inner surfaces 221 and 223 in the rear transparent substrate 22 that becomes the light guide plate. Concavities and convexities are formed for emitting light that repeatedly propagates reflection from the outer surface 223 toward the liquid crystal display panel 1.

  In the present embodiment, the plurality of protrusions 224 are provided with a uniform distribution density over substantially the entire area corresponding to the display area Dd of the outer surface 223. These protrusions 224 may be protrusions having side surfaces substantially perpendicular to the outer surface 223 (the bottom surface of the protrusion 224).

  The protrusions 224 in the present embodiment are formed in a cylindrical shape and are equally arranged in a staggered arrangement. In this case, the height of the protrusion 224 is preferably 10 μm or more and 150 μm or less from the viewpoint of avoiding a diffraction phenomenon and a decrease in display visibility of the liquid crystal display panel 1. Further, the diameter of the protrusion 224 is preferably about twice the height in order to guide the light propagating while totally reflecting in the rear transparent substrate 22 as much as possible into the protrusion 224. The protrusions 224 are not limited to a cylindrical shape, and may be formed in a polygonal prism shape such as a quadrangular prism. The protrusions 224 are not limited to a staggered lattice arrangement, and are arranged in a random arrangement with a substantially uniform distribution density. Also good.

  The touch panel integrated front light 2 configured as described above is housed in a metal shield case 4. The front plate 41 of the shield case 4 is provided with a skylight 42 having a size capable of sufficiently facing the entire touch area including the display area Dd of the liquid crystal display panel 1, and the rear plate 43 has a liquid crystal display. A communication window 44 corresponding to the skylight of the shield case 3 that accommodates the panel 1 is formed.

  Next, the light irradiation operation in the touch panel integrated front light 2 in the present embodiment will be described.

  In FIG. 1, the light R emitted from the LED 27 enters the rear transparent substrate 22 from the light incident end surface 222 and repeats total reflection alternately at the interfaces between the main surfaces of the inner surface 221 and the outer surface 223 of the rear transparent substrate 22. However, it propagates through the rear transparent substrate 22. Eventually, as shown in FIG. 3, when the propagating light R enters the projection 224 and enters the side surface 2241, it is emitted outside the projection 224 based on the known law of refraction.

Here, since the side surface 2241 of the protrusion 224 is provided so as to protrude perpendicular to the outer surface 223, the injection direction can be along the substantially normal direction of the outer surface 223. Incidentally, when the incident elevation angle φ when the propagation light R in the rear transparent substrate 22 is totally reflected by the inner surface 221 is 15 °, the angle A with respect to the normal when exiting from the projection side surface 2241 is about 19 °. Since the refractive index (relative to air) of the rear transparent substrate 22 of the PC resin plate is 1.6, its total reflection angle is 38.7 °, and the angle θ 2 in FIG. The incident angle θ2 with respect to
(Φ + θ2) = 90−38.7 = 51.3
It is an angle satisfying.

  As described above, in the liquid crystal display device of the present embodiment, the touch panel integrated front light 2 is installed on the display viewing side of the liquid crystal display panel 1, and the rear transparent substrate 22 in the touch panel integrated front light 2 is surface-illuminated. Since it is also used as a light guide plate for a panel, the thinning of the liquid crystal display device with a touch panel integrated front light is greatly promoted as compared with the case where a dedicated light guide plate is used.

  In this case, in order to use the rear transparent substrate 22 of the touch panel as a light guide plate, since the projection for projecting light is projected on the outer surface (the surface facing the liquid crystal display panel 1), the front and rear transparent substrates 21, The opposing resistance surfaces 22 are parallel to each other, and the rear resistance films 23 and 24 can be opposed in parallel before being attached to these opposing surfaces. Thereby, it is suppressed that the linearity of the resistance value for each arbitrary position of both resistance films 23 and 24 is impaired, and both resistance films 23 are always at a substantially constant pressing force at any pressing location in the touch input area. , 24 can be reliably brought into conductive contact, and as a result, an accurate touch input operation can be stably performed.

  Further, since the uneven surface for emitting the light provided on the transparent substrate 22 that also serves as the light guide plate is formed by arranging the protrusions uniformly over the entire touch area, even if the rear transparent substrate 22 is also used as the light guide plate, There is no possibility of reducing the visibility when observing the display of the liquid crystal display panel 1 via the touch panel 2.

  In addition, this invention is not limited to said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, the uneven surface for emitting the light of the rear transparent substrate 22 in a planar shape is formed by protruding the plurality of protrusions 224 uniformly. As shown in the figure, it is also possible to make the outer surface 511 of the rear transparent substrate 51 an uneven surface in which a plurality of protrusions 512 having a triangular cross section extend in parallel. In this case, of the pair of side surfaces 5121 and 522 of the protrusion 512, the closer the side surface 5122 farther from the light source is to the vertical surface with respect to the outer surface 511, the more light is emitted closer to the normal direction of the substrate outer surface 511. Can be made.

  Incidentally, when the transparent substrate 51 after this modification is also formed of the same PC resin plate as that of the above-described embodiment and the inclination angle α of the inclined side surface 5122 is 5 °, the total reflection incident elevation angle φ is 15 °. The angle A with respect to the normal direction when the light R is emitted is about 29 °. On the other hand, when the inclination angle α of the inclined side surface 5122 becomes 10 °, the emission angle A becomes about 35 °.

  Unlike the above-described embodiment, the number of protrusions 224 formed per unit area may be gradually increased as the distance from the one end surface 222 of the rear transparent substrate 22 increases. The intensity of the light incident from the one end face 222 decreases as the distance from the one end face 222 decreases. Therefore, if the number of the protrusions 224 formed is appropriately adjusted according to the degree of the decrease in the intensity, The brightness can be made more uniform.

  In addition, the display device of the present invention is not limited to the liquid crystal display device, and can of course be widely applied to a reflective display device using a front light. Further, the present invention may be applied to a transflective display device using a front light and a backlight.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 11, 12 Front, back glass board | substrates 13, 14 Front, rear polarizing plate 15 Light reflecting plate 16 Driver LSI
2 Touch panel integrated front lights 21, 22 Front and rear transparent substrates 211, 221 Opposing surfaces (inner surfaces)
222 Light incident end surface 223 Outer surface (on rear transparent substrate)
224 Protrusion 2241 Side surface 23, 24 Front and rear resistance film 25 Sealing material 26 Spacer 27 LED
51 rear transparent substrate 512 ridge 5122 inclined side surface

Claims (3)

A first transparent substrate having a first resistance film deposited on a rear surface which is one of the pair of flat main surfaces;
A second transparent substrate in which a second resistance film is deposited on the front surface that is one main surface of the pair of flat main surfaces, and irregularities are formed on the rear surface that is the other main surface;
A bonding member in which the second transparent substrate is bonded to the rear side of the first transparent substrate, and the second resistance film is bonded to the first resistance film in a position facing the first resistance film with a predetermined gap;
A light source disposed opposite to the end surface of the second transparent substrate and emitting light toward the second transparent substrate;
The pressing position is detected from the resistance value of the conductive contact position between the first resistance film and the second resistance film when the front surface of the first transparent substrate is pressed, and the second light source is emitted from the light source and A touch panel integrated lighting device, wherein light incident on the transparent substrate is emitted in a planar shape from the rear surface of the second transparent substrate. A display panel that at least performs reflective display by reflecting light emitted from its front side toward the display surface;
A display device comprising the touch panel integrated lighting device according to claim 1, which is installed on a front side of the display surface. The reflective display panel is a liquid crystal display panel in which a liquid crystal is sandwiched between a pair of transparent substrates, and a light reflecting plate is installed facing the outer surface of one transparent substrate,
3. The display device according to claim 2, wherein the touch panel integrated lighting device is installed with the rear surface of the second transparent substrate facing the outer surface of the other transparent substrate of the liquid crystal display panel. .

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