JP6599631B2 - Touch panel device - Google Patents

Description

  The present invention relates to a touch panel device, and more particularly to a FTIR (Frustrated Total Internal Reflection) type touch panel device.

  Conventionally, an FTIR touch panel is known as an optical touch panel. The FTIR touch panel includes a light guide plate disposed on a display device such as a liquid crystal display, and a light source and a detection sensor provided on a side surface of the light guide plate. In this touch panel, the contact position on the touch panel is detected as follows. That is, light from the light source is supplied from the side surface of the light guide plate. This light propagates in the light guide plate. When a finger or a pen contacts the surface of the light guide plate, the light propagating in the light guide plate is scattered. When the scattered light is detected by the detection sensor, a contact position on the touch panel is detected.

  Patent Document 1 described later discloses a technique for reducing the influence of external light (environmental light) and improving touch position recognition accuracy in such an FTIR touch panel. The touch panel disclosed in Patent Document 1 includes a rectangular light guide plate, a light source that makes light incident on the light guide plate, a light receiving element disposed on a part of the side surface of the light guide plate, and a space between the side surface of the light guide plate and the light receiving element. And an imaging means (lens) that images light from a light source scattered by a detection target (such as a finger or an input pen) on a light receiving element. The imaging means and the light receiving element are disposed obliquely with respect to the side of the light guide plate. The light guide plate is formed in a planar shape that is cut obliquely so that the corner portion on which the imaging means is disposed faces the imaging means. Furthermore, light absorbing means (carbon black-containing resin) is disposed on a part of the side surface of the light guide plate on which the light receiving element is disposed, and the light receiving element is disposed outside the irradiation range of the light source.

JP 2009-258967 A

  In the touch panel of Patent Document 1, since the light receiving element is arranged outside the irradiation range of the light source, direct light from the light source can be prevented from entering the light receiving element. Furthermore, since the light absorbing means is arranged on a part of the side surface of the light guide plate, reflection of light at the end of the light guide plate is suppressed. Thereby, generation | occurrence | production of the ghost signal resulting from the light scattered by the to-be-detected body being reflected by the edge part of a light-guide plate and reaching | attaining a light receiving element can be prevented. Therefore, the influence of extraneous light (environmental light) is reduced.

  However, the touch panel disclosed in Patent Document 1 has the following problems. That is, even if the light receiving element is disposed outside the irradiation range of the light source, the light from the light source may enter the light receiving element due to diffusion. In this case, the position detection performance of the touch panel is degraded. Furthermore, the touch panel is used in a state where it is attached to the display device. At that time, when the light guide plate of the touch panel comes into contact with the display device, the light scattered by the detection target at the contact position is attenuated. As a result, the amount of light transmitted decreases, so the amount of light detected by the light receiving element decreases. Therefore, this also deteriorates the position detection performance of the touch panel.

  SUMMARY An advantage of some aspects of the invention is that it provides a touch panel device capable of suppressing a decrease in position detection performance.

  A touch panel device according to one aspect of the present invention includes a light source unit that emits light and a light emitting surface, and is arranged in a flat plate shape so that light from the light source unit propagates inside and exits from the light emitting surface. A first light guide member, a flat plate-like second light guide member disposed on the first light guide member so that light from the light exit surface is incident, and a second light guide member A detecting means for detecting scattered light generated on the surface, and a calculating means for calculating a position where the scattered light is generated on the second light guide member based on information on the light detected by the detecting means; A gap holding member that is disposed between the first light guide member and the second light guide member, and that holds a gap between the first light guide member and the second light guide member constant; including. The gap holding member has a plurality of protrusions that support the second light guide member.

  The light emitted from the light source unit propagates through the first light guide member and exits from the light exit surface toward the second light guide member. Light emitted from the light exit surface of the first light guide member is incident on the second light guide member. When an input member such as a finger contacts the surface of the second light guide member, scattered light is generated at the contact position. When the detection means detects the scattered light, the calculation means calculates the contacted position on the second light guide member based on the information related to the light detected by the detection means.

  The detection means detects scattered light generated by the second light guide member. On the other hand, the light from the light source unit enters the second light guide member via the first light guide member. Since the second light guide member is a separate member from the first light guide member, the first light guide member and the second light guide member are spatially separated. Therefore, the direct light from the light source unit is prevented from propagating to the second light guide member. Thereby, since it can suppress that the light from a light source part injects into a detection means directly, the sensitivity of a detection means improves.

  Further, the first light guide member and the second light guide member are in physical contact with each other by the gap holding member disposed between the first light guide member and the second light guide member. Can be prevented. Therefore, it is possible to suppress the disadvantage that the scattered light generated by the second light guide member is attenuated due to the contact between the first light guide member and the second light guide member. Since the gap holding member supports the second light guide member with a plurality of protrusions, the contact between the gap holding member and the second light guide member is substantially a point contact. For this reason, even when the gap holding member is provided, the contact area between the gap holding member and the second light guide member can be reduced, resulting in contact between the second light guide member and the gap holding member. The attenuation of scattered light can be reduced. In this way, by disposing the gap holding member between the first light guide member and the second light guide member, the propagation loss of scattered light can be reduced, and this also reduces the position detection performance. Can be suppressed.

  Preferably, the gap holding member has a moth-eye structure in which a plurality of protrusions are arranged at intervals shorter than the wavelength of light emitted from the light source unit.

  More preferably, the touch panel device further includes light diffusing means for diffusing the light propagating through the first light guide member and emitting the light from the light exit surface.

  More preferably, the light diffusing means includes a plurality of diffusing portions formed in a dot shape on a surface of the first light guide member opposite to the light emitting surface, and each of the diffusing portions contains diffusing particles. Including.

  More preferably, the light source unit is provided at an end of the first light guide member, and the plurality of diffusion units are formed such that the density of the diffusion unit increases as the distance from the light source unit increases.

  As mentioned above, according to this invention, the touch panel apparatus which can suppress the fall of a position detection performance can be obtained.

It is a figure which shows schematic structure of the touchscreen display apparatus containing the touchscreen apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the touchscreen display apparatus shown in FIG. It is sectional drawing which shows typically the structure of the touchscreen display apparatus shown in FIG. It is a figure which shows the structure of the light source part of the touchscreen apparatus shown in FIG. FIG. 2 is a control block diagram illustrating a hardware configuration of the touch panel display device illustrated in FIG. 1. It is a figure which shows the path | route of the light which propagates the inside of a light-guide plate. It is the top view which looked at the touch panel device shown in Drawing 1 from the upper surface side. It is a figure which shows the path | route of the scattered light which propagates the inside of a light-guide plate. It is a top view which shows the calculation method of a touch position. It is a perspective view which shows typically the structure of the touchscreen apparatus which concerns on the 2nd Embodiment of this invention. It is the top view which looked at the 1st light-guide plate of the touch-panel apparatus shown in FIG. 10 from the back side. It is the top view which looked at the touch panel device shown in Drawing 10 from the upper surface side. It is a figure which shows the path | route of the light which propagates the inside of a light-guide plate. It is a figure which shows the 1st light guide plate (the figure which shows the path | route of the light which propagates the inside of a 1st light guide plate) of the touchscreen apparatus which concerns on the 2nd Embodiment of this invention.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their functions and names are also the same. Therefore, detailed description thereof will not be repeated.

(First embodiment)
[Constitution]
Referring to FIG. 1, touch panel display device 50 according to the present embodiment includes a display device 200 that displays an image, and an FTIR touch panel device 100 arranged on display device 200. The display device 200 includes a display panel 210 such as a liquid crystal display panel, and a display control unit 220 that controls display on the display panel 210.

  The touch panel device 100 according to the present embodiment includes a first light guide plate 110, a second light guide plate 112, a light source unit 120, a light source control unit 130, a sensor unit 140, a sensor control unit 150, and a main control unit 160. The sensor unit 140 includes a first sensor unit 140a and a second sensor unit 140b. The touch panel device 100 is disposed on the display panel 210 so as to cover the display screen of the display panel 210.

  Referring to FIG. 2, each of the first light guide plate 110 and the second light guide plate 112 is a flat light guide member having a thickness of about 2 mm, and is formed of an acrylic resin. The first light guide plate 110 may be made of a material different from that of the second light guide plate 112. The first light guide plate 110 and the second light guide plate 112 are each formed in a rectangular shape. Referring to FIG. 7, the second light guide plate 112 is formed to be slightly larger in size than the first light guide plate 110, and on the first light guide plate 110 so as to cover the surface (upper surface) of the first light guide plate 110. Are arranged opposite to each other. The sensor unit 140 is disposed in a region of the second light guide plate 112 that protrudes from the first light guide plate 110.

  Referring to FIG. 3, the second light guide plate 112 is disposed on the first light guide plate 110 at a predetermined distance from the first light guide plate 110 in order to avoid contact with the first light guide plate 110. Yes. That is, a gap is provided between the first light guide plate 110 and the second light guide plate 112. Touch panel device 100 according to the present embodiment further includes a gap holding member 250 for holding a gap provided between first light guide plate 110 and second light guide plate 112 constant. The gap holding member 250 is disposed between the first light guide plate 110 and the second light guide plate 112. Details of the gap holding member 250 will be described later.

  Referring to FIG. 2 again, the light source unit 120 is a bar-shaped illumination light source extending in one direction, and is arranged on one side (parallel to the longitudinal direction) of the first light guide plate 110 on the back surface of the end portion of the first light guide plate 110. It is installed along one side. Referring to FIG. 4, light source unit 120 includes an LED (Light Emitting Diode) array unit 122 and a triangular prism 124. The LED array unit 122 includes a substrate 128 and a plurality of LED elements 126 arranged in an array on the substrate 128. The triangular prism 124 is bonded to the first light guide plate 110, and the LED element 126 is disposed in contact with the inclined surface of the triangular prism 124. The inclined surface of the triangular prism 124 forms a predetermined angle φ with respect to the surface of the first light guide plate 110. The predetermined angle φ is preferably larger than an angle at which light emitted from the LED element 126 in the front direction of the LED element 126 is totally reflected in the first light guide plate 110, that is, a critical angle. The critical angle is determined by the refractive index of the first light guide plate 110 and the refractive index of air. When the first light guide plate 110 is formed of acrylic resin (refractive index 1.49), the critical angle is 42.15 °. Therefore, the predetermined angle of the inclined surface of the triangular prism 124 is preferably about 50 °. As described above, the LED array unit 122 is optically bonded to the first light guide plate 110 via the triangular prism 124.

  Referring again to FIG. 1, the light source control unit 130 controls the driving of the light source unit 120 under the control of the main control unit 160. The light source unit 120 emits light from the LED array unit 122 in response to power supply and control by the light source control unit 130. The emitted light is, for example, infrared light having a wavelength of 850 nm. The light emitted from the LED array unit 122 enters the first light guide plate 110 via the triangular prism 124. In a state where the gap holding member 250 is not in contact with the first light guide plate 110, the incident light propagates through the first light guide plate 110 while repeating total reflection by both surfaces of the first light guide plate 110.

  The gap holding member 250 is made of a film member (moth eye film) having a moth-eye (registered trademark) structure. The moth-eye film (optical film) is made of a thermoplastic resin material such as an acrylic resin or a PC (Poly Carbonate) resin. The moth-eye film is preferably made of a material having the same or lower refractive index than that of the second light guide plate 112.

  Referring to FIG. 3 again, a large number of conical or bell-shaped fine protrusions 252 (fine structure) are formed on the surface (upper surface) of the moth-eye film (gap holding member 250). A moth-eye structure is constituted by the fine protrusions 252. The fine protrusions 252 are regularly arranged on the surface of the moth-eye film at a predetermined interval (pitch). The average height of the protrusions 252 is, for example, 250 nm to 300 nm, and the pitch between the protrusions 252 is, for example, 200 nm to 300 nm. The aspect ratio of the protrusion 252 is preferably 1 or more and 2 or less. Thus, the fine protrusions 252 are arranged at a pitch smaller than the wavelength (850 nm) of the light emitted from the light source unit 120 (see FIG. 1). As the moth-eye structure, it is only necessary that the protrusions (fine structures) are arranged at a pitch narrower than the short wavelength (purple) in the visible light region (wavelength: 380 nm to 750 nm).

  The gap holding member 250 is disposed between the first light guide plate 110 and the second light guide plate 112 so that the protrusions 252 formed on the surface protrude toward the first light guide plate 110 side. . The gap holding member 250 substantially supports the second light guide plate 112 in a point contact with the plurality of protrusions 252.

  The gap holding member 250 is fixed on the upper surface of the first light guide plate 110 by an adhesive layer 254. For the adhesive layer 254, for example, an acrylic solvent type resin adhesive is used. Various adhesives can be used for the adhesive layer 254 as long as the adhesive has high optical transparency and high resistance to foaming that does not generate bubbles at the adhesive interface. For example, an ultraviolet curable adhesive can be used for the adhesive layer 254 in place of the acrylic solvent resin adhesive.

  Referring to FIG. 6, by adhering gap holding member 250 to the upper surface of first light guide plate 110, the interface condition of first light guide plate 110 changes. Part of the light propagating in the first light guide plate 110 is transmitted to the gap holding member 250 side at the interface between the upper surface of the first light guide plate 110 and the gap holding member 250. That is, the first light guide plate 110 propagates the light emitted from the light source unit 120 and emits the light from the upper surface toward the second light guide plate 112. Therefore, the first light guide plate 110 has a light emission surface 110a formed from the upper surface. The light emitted from the light exit surface 110a is transmitted through the gap holding member 250 in a direction closer to the light exit surface 110a due to the diffraction effect of the moth-eye structure. The light transmitted through the gap holding member 250 enters the second light guide plate 112 from the back surface of the second light guide plate 112. The incident light is transmitted through the second light guide plate 112, and when the input member such as the finger 310 comes into contact with the surface (upper surface) of the second light guide plate 112, the input member is irradiated.

  When an input member such as a finger 310 contacts (touches) the surface (upper surface) of the second light guide plate 112, the light emitted from the light source unit 120 and incident on the second light guide plate 112 via the first light guide plate 110 is Scatter at touch position. A part of the scattered light propagates to the first sensor unit 140a and the second sensor unit 140b (indicated by a downward broken arrow in FIG. 1).

  The first sensor unit 140a and the second sensor unit 140b include a light detection element such as a CCD sensor or a CMOS sensor. The 1st sensor part 140a and the 2nd sensor part 140b detect scattered light with a photon detection element, and output the detection signal according to the detected scattered light. Referring to FIG. 2, the first sensor unit 140 a and the second sensor unit 140 b are disposed on the back surface of the second light guide plate 112. Thus, the sensor unit 140 (the first sensor unit 140a and the second sensor unit 140b) detects the scattered light generated on the surface of the second light guide plate 112.

  With reference to FIG. 1, the sensor control unit 150 controls the first sensor unit 140 a and the second sensor unit 140 b under the control of the main control unit 160. The first sensor unit 140a and the second sensor unit 140b transmit a detection signal to the main control unit 160 under the control of the sensor control unit 150. The main control unit 160 includes an arithmetic element such as a CPU. As will be described later, the light detection element is, for example, a two-dimensional image sensor (image pickup element), and the main control unit 160 calculates the touch position from the image pickup data detected by the image sensor.

  The main controller 160 detects the light from the first sensor unit 140a and the second sensor unit 140b in a state where the light source unit 120 is driven by the light source controller 130 at a predetermined timing and light is emitted into the light guide plate 110. Wait for the signal. When the surface of the second light guide plate 112 is touched, scattered light is generated at the touch position as described above. A part of the scattered light is detected by the first sensor unit 140a and the second sensor unit 140b. The first sensor unit 140 a and the second sensor unit 140 b output a detection signal corresponding to the detected scattered light to the main control unit 160 via the sensor control unit 150. The main control unit 160 calculates a touch position based on detection signals from the first sensor unit 140a and the second sensor unit 140b. That is, the main control unit 160 calculates the position (contact position) where the scattered light is generated on the second light guide plate 112 based on the information regarding the light detected by the sensor unit 140.

  Referring to FIG. 5, the main control unit 160 includes a contact coordinate calculation unit 162 that calculates the coordinates of the touch position (contact position) based on the received detection signal, and information (instruction information) indicating the calculated coordinates. A position information output unit 164 which is an output interface is further included. The contact coordinate calculation unit 162 calculates the coordinates of the touch position of the input member (for example, the finger 310) with respect to the second light guide plate 112 based on detection signals from the first sensor unit 140a and the second sensor unit 140b, and It has a function of converting (correcting) the coordinates of the touch position on the light guide plate 110 into the coordinate system of the display screen of the display device 200 (display panel 210). The position information output unit 164 is connected to a host device 300 such as a computer. The main control unit 160 outputs the calculated touch position information to the host device 300 via the position information output unit 164, so that the host device 300 can execute processing according to the touch position. Become.

  The touch panel device 100 further includes a storage unit 170 that stores various information necessary for calculating the touch position. The information stored in the storage unit 170 includes information indicating the correspondence between the coordinate system of the light guide plate 110 and the coordinate system of the display screen, that is, parameters necessary for coordinate conversion. This information is referred to when the coordinates of the touch position on the light guide plate 110 are converted (corrected) into the coordinate system of the display screen of the display device 200 (display panel 210).

  Referring to FIGS. 1 and 5, display panel 210 displays an image corresponding to an instruction from display control unit 220 on the display screen. The display control unit 220 controls the display state of the display panel 210 according to image data input from the host device 300.

  As shown in FIG. 1, the touch panel device 100 is disposed on the display panel 210. Therefore, a touch operation on the touch panel device 100 can be handled as a user operation on an image displayed on the display panel 210, and a user interface for the host device 300 can be realized.

[Detection of scattered light by sensor unit 140]
Referring to FIG. 7, in the second light guide plate 112, regions where the first sensor unit 140 a and the second sensor unit 140 b are disposed are conical recesses 114 a and 114 b (hereinafter, collectively referred to as “ A recess 114 ”is formed. With reference to FIG. 8, the recessed part 114 is formed by hollowing out the 2nd light-guide plate 112 from the upper surface (surface) in the thickness direction at cone shape. The recess 114 has an inclined surface that reflects light propagating through the second light guide plate 112 toward the sensor unit 140.

  As shown in FIG. 6, the light emitted from the light source unit 120 propagates through the first light guide plate 110 and is emitted upward from the light exit surface 110a. The emission angle of the light emitted from the light exit surface 110a changes to an angle closer to the perpendicular to the light exit surface 110a due to the diffraction effect of the gap holding member 250. Therefore, the light from the light emitting surface 110 a is incident on the second light guide plate 112 at an angle closer to the vertical with respect to the back surface of the second light guide plate 112. Referring to FIG. 8, as described above, when the user's finger 310 or the like comes into contact with the surface of the second light guide plate 112, scattered light 320 is generated at the contact position (touch position). A part of the scattered light 320 propagates toward the recess 114, is reflected by the inclined surface of the recess 114, and is detected by the sensor unit 140.

  The first sensor unit 140 a includes a lens unit 142, a band pass filter 144, and a sensor 146. The sensor 146 is the above-described light detection element, for example, a two-dimensional image sensor (imaging element). The bandpass filter 144 has a wavelength band that selectively allows light emitted from the light source unit 120 to pass therethrough. The band pass filter 144 has a function of preventing light other than the light emitted from the light source unit 120 (light entering the light guide plate from the outside) from entering the sensor 146 and being erroneously detected. The lens unit 142 converges the light reflected by the inclined surface of the recess 114 and makes it incident on the sensor 146. In this way, by condensing light on the image sensor surface of the sensor 146, scattered light from the finger is detected as bright spot information. The incident angle of light can be easily calculated from the detected bright spot information (imaging data).

  The second sensor unit 140b is configured similarly to the first sensor unit 140a and has the same function.

[Calculation of touch position]
Referring to FIG. 9, the incident angles θ1 (rad) and θ2 (rad) of the corresponding light are obtained from the image data obtained by the first sensor unit 140a and the second sensor unit 140b. From the incident angles θ1 and θ2, angles α (rad) and β (rad) that the light forms with a straight line connecting the first sensor unit 140a and the second sensor unit 140b are obtained. That is, the angles α and β are calculated by α = π / 2−θ1 and β = π / 2−θ2. When the touch position is P, the distance between the line segment connecting the first sensor unit 140a and the second sensor unit 140b and the touch position P is d, and the distance between the first sensor unit 140a and the second sensor unit 140b is L, L = D / tan α + d / tan β is established. By substituting the values of the angles α and β and the distance L between the first sensor unit 140a and the second sensor unit 140b into this equation, d is calculated. When d is calculated, y in the position coordinates (x, y) of the touch position P is calculated by y = d, and x is calculated by x = d / tan α. Thereby, the position coordinates (x, y) of the touch position P can be determined. Note that the value of the distance L is stored in the storage unit 170 in advance.

  The obtained position coordinates (x, y) are position coordinates in a coordinate system of the light guide plate 110, for example, a coordinate system having a point 330 on the light guide plate 110 as an origin. In order to represent the touch position P as, for example, the position coordinate of the display panel 210 (display screen), a coordinate transformation that translates the origin from the point 330 to the point 332 is performed on the obtained position coordinate (x, y). Just do it. Parameters necessary for coordinate conversion are stored in advance in the storage unit 170. The main control unit 160 calculates the position coordinates of the touch position with respect to the display panel 210 by performing coordinate conversion using the parameters stored in the storage unit 170.

[Effects of the present embodiment]
As is clear from the above description, the following effects can be obtained by using the touch panel device 100 according to the present embodiment.

  The sensor unit 140 detects scattered light generated by the second light guide plate 112. Meanwhile, light from the light source unit 120 enters the second light guide plate 112 through the first light guide plate 110. The second light guide plate 112 is a separate member from the first light guide plate 110, and the first light guide plate 110 and the second light guide plate 112 are spatially separated. Therefore, direct light from the light source unit 120 does not propagate to the second light guide plate 112. Thereby, since it can suppress that the light from the light source part 120 injects into the sensor part 140 directly, the detection sensitivity of the sensor part 140 improves. That is, by arranging the sensor unit 140 on the second light guide plate 112 that is a separate member from the first light guide plate 110 on which the light source unit 120 is arranged, stray light from the light source unit 120 is directly incident on the sensor unit 140. Can be suppressed. Thereby, since the background noise of a signal can be reduced, the dynamic range of the sensor part 140 can be raised. As a result, the touch position detection accuracy can be improved.

  Further, the gap holding member 250 disposed between the first light guide plate 110 and the second light guide plate 112 can prevent physical contact between the first light guide plate 110 and the second light guide plate 112. Therefore, it is possible to suppress a disadvantage that the scattered light generated in the second light guide plate 112 is attenuated due to the contact between the first light guide plate 110 and the second light guide plate 112. Since the gap holding member 250 supports the second light guide plate 112 with a plurality of protrusions 252, the contact between the gap holding member 250 and the second light guide plate 112 is substantially a point contact. For this reason, even when the gap holding member 250 is provided, the contact area between the gap holding member 250 and the second light guide plate 112 can be reduced, so that the contact between the second light guide plate 112 and the gap holding member 250 is caused. The attenuation of scattered light can be reduced. More specifically, since the contact between the gap holding member 250 and the second light guide plate 112 is a point contact, the interface of the second light guide plate 112 on the gap holding member 250 side has an air layer in terms of refractive index distribution. It becomes an interface close to the interface. Therefore, the scattered light generated by the second light guide plate 112 can be efficiently propagated. As described above, since the propagation loss of scattered light can be reduced by disposing the gap holding member 250 between the first light guide plate 110 and the second light guide plate 112, this also suppresses a decrease in position detection performance. it can.

  Furthermore, by using a moth-eye film having a moth-eye structure for the gap holding member 250, the refractive index of the moth-eye structure changes gently, so that reflection of light can be suppressed. Therefore, the gap holding member 250 can enter (transmit) the light to the second light guide plate 112 without affecting the light (infrared light) emitted from the light exit surface 110 a of the first light guide plate 110. Thereby, it is possible to suppress the occurrence of propagation loss in the light propagating through the first light guide plate 110 and the second light guide plate 112.

  A part of the scattered light generated by the input member such as the finger 310 coming into contact with the surface of the second light guide plate 112 propagates through the second light guide plate 112 and is detected by the sensor unit 140. Other scattered light passes through the second light guide plate 112 and enters the gap holding member 250. This light is transmitted to the first light guide plate 110 side by the moth-eye structure of the gap holding member 250. Therefore, since multiple scattering due to scattered light generated in the second light guide plate 112 can be suppressed, detection accuracy by the sensor unit 140 can be further improved.

(Second Embodiment)
Referring to FIG. 10, touch panel device 400 according to the present embodiment includes a sensor unit 410 instead of sensor unit 140 (see FIG. 2), in that a dot pattern is formed on first light guide plate 110. The point and the light source part 120 (refer FIG. 2) are replaced with the touch panel apparatus 100 which concerns on 1st Embodiment in the point which contains the light source part 420. In other respects, each touch panel device has the same configuration.

  The light source unit 420 is a bar-shaped illumination light source extending in one direction, and is attached to the back surface of the end portion of the first light guide plate 110 so as to be along one side (one side parallel to the short direction) of the first light guide plate 110. It has been. The light source unit 420 includes an LED array unit and a triangular prism. That is, the light source unit 420 has the same configuration as the light source unit 120.

  Referring to FIG. 11, the dot pattern 430 diffuses the light propagating through the first light guide plate 110 and emits the light from the light exit surface 110a. The dot pattern 430 is formed on the back surface of the first light guide plate 110 (the surface opposite to the light emitting surface 110a). The dot pattern 430 also includes a plurality of diffusion portions 432 formed in a dot shape. Each diffusion unit 432 includes diffusion particles that diffuse light. The diffusion particles include titanium oxide particles having an average particle diameter of 20 nm to 50 nm. Instead of the titanium oxide particles or together with the titanium oxide particles, alumina fine particles, silica fine particles and the like may be used. In the present specification, the “average particle diameter” means a particle diameter (average particle diameter d50) at an integrated value of 50% in a particle size distribution obtained by a laser diffraction / scattering method.

  The dot diameter of the diffusing portion 432 is preferably 0.2 mm to 0.5 mm. In the present embodiment, the dot diameter of the diffusion portion 432 is 0.2 mm. The dot pattern 430 (diffusion part 432) is formed by pattern-printing a paint mainly composed of diffusion particles made of titanium oxide particles on the first light guide plate 110. Specifically, after the titanium oxide particles are uniformly dispersed in the resin solution, the resin solution is discharged (printed) onto the first light guide plate 110 with an ink jet printer, thereby forming the dot-shaped diffusion portion 432. Yes.

  The dot pattern 430 including the plurality of diffusion portions 432 is in a “sparse” pattern density as it is closer to the light source unit 420, and the pattern density is in a “dense” state as it is farther from the light source unit 420. In the present embodiment, for example, in the region close to the light source unit 420, the pattern density (printing rate) is 5% in terms of the area ratio, and the pattern density (printing rate) increases by 5% every time 100 mm away from the light source unit 420. It is formed to do. The pattern density (printing rate) in the region farthest from the light source unit 420 is 60% in terms of area ratio.

  Referring to FIG. 12, sensor unit 410 is a bar-shaped line sensor and includes a first sensor unit 410a and a second sensor unit 410b. The first sensor unit 410 a is attached to the end surface in the short direction (Y direction) of the second light guide plate 112, and the second sensor unit 410 b is a long side perpendicular to the short direction of the second light guide plate 112. It is attached to the end face in the direction (X direction). The first sensor unit 410 a and the second sensor unit 410 b detect scattered light generated when a user's finger or the like contacts the surface (touch surface) of the second light guide plate 112.

  The touch panel device 400 calculates the x coordinate of the touch position P based on the detection signal from the first sensor unit 410a, and calculates the y coordinate of the touch position P based on the detection signal from the second sensor unit 410b. .

  Referring to FIG. 13, the light emitted from the light source unit 420 propagates through the first light guide plate 110, and further to the second light guide plate 112 side by the diffusion unit 432 formed on the back surface of the first light guide plate 110. Scattered (diffused). The diffusion unit 432 is formed so that the density of the diffusion unit 432 increases as the distance from the light source unit 420 increases. Therefore, the light from the light source unit 420 that has entered the first light guide plate 110 is emitted uniformly from the light exit surface 110 a toward the second light guide plate 112 by the plurality of diffusion units 432. When an input member such as a finger 310 contacts (touches) the surface (upper surface) of the second light guide plate 112, the light emitted from the light source unit 420 and incident on the second light guide plate 112 via the first light guide plate 110 is Scattered at the touch location. The scattered light propagates in the second light guide plate 112 toward the first sensor unit 140a and the second sensor unit 140b. The coordinates of the touch position are calculated by detecting the scattered light with the first sensor unit 140a and the second sensor unit 140b.

  As described above, touch panel device 400 according to the present embodiment forms a plurality of diffusion parts 432 including diffusion particles on the back surface of first light guide plate 110 such that the density increases as the distance from light source part 420 increases. Accordingly, uniform light can be emitted from the light exit surface 110 a of the first light guide plate 110 to the second light guide plate 112. Even in a region away from the light source unit 420, a sufficient amount of light can be incident on the second light guide plate 112. Thereby, the fall of the position detection performance by the light quantity fall can be suppressed. In other words, the touch position detection performance can be effectively improved.

  Other effects are the same as those of the first embodiment.

(Third embodiment)
Referring to FIG. 14, the touch panel device according to the present embodiment is the first implementation in that it includes a wedge-shaped first light guide plate 510 instead of first light guide plate 110 (see FIGS. 2 and 6). This is different from the touch panel device 100 according to the embodiment. In other respects, each touch panel device has the same configuration.

  The first light guide plate 510 is formed so that the thickness decreases as the distance from the light source unit 120 increases. Therefore, the light emitted from the light source unit 120 is uniformly emitted upward (on the second light guide plate side) from the light emission surface 510 a while propagating through the first light guide plate 510. Similar to the second embodiment, since a sufficient amount of light can be incident on the second light guide plate even in a region away from the light source unit 120, the touch position detection performance can be effectively improved.

  Other effects are the same as those of the first embodiment.

(Modification)
In the above embodiment, an example in which a light guide plate made of acrylic resin having a thickness of about 2 mm is used for each light guide plate (first light guide plate and second light guide plate) of the touch panel device is shown. It is not limited to such an embodiment. The material and thickness of the first light guide plate and the second light guide plate are not particularly limited, and various light guide plates can be used. For example, a light guide plate made of glass such as borosilicate glass (heat resistant glass) can be used.

  In the above embodiment, an example using a gap holding member made of a moth-eye film has been shown, but the present invention is not limited to such an embodiment. As long as it is a member capable of supporting the second light guide plate substantially by point contact, the gap holding member may be composed of a member other than the moth-eye film. Examples of such a member include a film in which glass beads are periodically arranged, and a microfabricated film in which a fine structure (for example, a microlens array, a cube corner array) is formed on the surface. The protrusion provided on the gap holding member may have a convex shape other than the protrusion shape as long as the second light guide plate can be substantially supported by point contact. The member constituting the gap holding member is preferably a member whose refractive index gradually changes from the refractive index of the member to the refractive index of air, like the moth-eye film. By using such a member as a gap holding member, it is possible to effectively suppress the occurrence of propagation loss in the light propagating through each light guide plate.

  In the said embodiment, a light source part is arrange | positioned in the vicinity (end part) of the 1st light guide plate, and a sensor part is arrange | positioned in the vicinity (end part) of the 2nd light guide plate corresponding to the arrangement position of a light source part. However, the present invention is not limited to such an embodiment. For example, the sensor unit may be arranged near another side that does not correspond to the arrangement position of the light source unit.

  In the said embodiment, although the example which formed the 2nd light guide plate in the size larger than a 1st light guide plate was shown, this invention is not limited to such an embodiment. The first light guide plate and the second light guide plate may be the same size. In this case, if the sensor unit is disposed on the back side of the second light guide plate, the sensor unit and the first light guide plate may interfere with each other. In such a case, it is preferable to process the first light guide plate so that the sensor portion and the first light guide plate do not interfere with each other by providing a cutout or an opening in the first light guide plate.

  In the above embodiment, an example in which a user's finger is used as an input member that performs touch input to the touch panel device has been described. However, the present invention is not limited to such an embodiment. The input member may be a member other than a finger (for example, an input pen). Furthermore, an LED pen (light pen) that emits light can be used as an input member other than a finger. In this case, when the tip of the LED pen touches the surface of the second light guide plate, the light emitted from the LED elements arranged at the tip enters the second light guide plate. The light incident on the second light guide plate is detected by the first sensor unit and the second sensor unit in the same manner as the scattered light described above, and the coordinates of the touch position of the LED pen are calculated. When using an LED pen, it is preferable that the light source unit is configured not to emit light.

  In the said embodiment, although the touch panel device showed about the example provided with two sensor parts, this invention is not limited to such embodiment. There may be three or more sensor units. The sensor unit that detects scattered light may have a configuration other than the sensor unit described in the above embodiment.

  In the above-described embodiment, an example in which a display panel including a liquid crystal display panel is used has been described, but the present invention is not limited to such an embodiment. The display panel may be, for example, a plasma display panel or an organic EL display panel other than the liquid crystal display panel.

  In the above embodiment, an example in which the host device connected to the touch panel display device is a personal computer has been described, but the present invention is not limited to such an embodiment. The host device may be, for example, a television receiver, various video reproducing devices, etc. other than a personal computer. The host device may be integrated with the touch panel display device or may be a separate body.

  In the above embodiment, an example in which the display device is configured to include the display control unit has been described, but the present invention is not limited to such an embodiment. For example, the main control unit of the touch panel device may function as the display control unit so that the display device does not include the display control unit.

  In the second embodiment, the example in which the dot pattern for diffusing the light propagating in the first light guide plate and emitting it from the light exit surface is formed on the first light guide plate is described. It is not limited to such an embodiment. A known light diffusion pattern other than the dot pattern may be formed on the first light guide plate in order to diffuse the light propagating through the first light guide plate 110 and emit the light from the light exit surface 110a.

  In the said 2nd Embodiment, although the example which has arrange | positioned the sensor part to the end surface of the 2nd light-guide plate was shown, this invention is not limited to such an embodiment. The sensor unit may be disposed on the upper surface side or the back surface side other than the end surface, for example. In this case, in order to prevent light emission from the end surface of the second light guide plate, it is preferable to apply a black paint (for example, carbon black-containing resin) that absorbs light to the end surface of the second light guide plate.

  In the second embodiment, an example in which a dot pattern is formed on the first light guide plate using an inkjet printer has been described. However, the present invention is not limited to such an embodiment. For example, a dot pattern may be formed by silk printing. Furthermore, dot-shaped irregularities may be formed by laser irradiation instead of printing, or dot-shaped irregularities may be formed using a mold. The plurality of diffusing portions constituting the dot pattern may be configured to include diffusing particles or may be configured not to include diffusing particles. In order to efficiently diffuse the light from the light source unit, the diffusion unit is preferably configured to include diffusing particles. Thus, the dot pattern for diffusing the light incident on the first light guide plate can be formed by various methods.

  In the second embodiment, an example in which a plurality of diffusion parts having a constant dot diameter are formed on the first light guide plate so that the density changes according to the distance from the light source part is shown. It is not limited to such an embodiment. For example, each diffusing portion constituting the dot pattern may be formed with a gradation change so that the dot diameter increases as the distance from the light source portion increases. The size of the dot diameter, the density (pattern) of the diffusing portion, and the like can be appropriately set so that uniform light is emitted from the light emitting surface of the first light guide plate. Furthermore, it is more preferable that the dot pattern formed on the first light guide plate is not uniform light but is formed such that the emitted light from the light emitting surface becomes stronger as the distance from the light source unit (sensor unit) increases. In this case, even if the touch position with respect to the second light guide plate is away from the sensor unit, the scattered light generated by the touch can be accurately detected by the sensor unit.

  In the second embodiment, the example in which the light source unit is disposed only in the vicinity (end portion) of one side of the first light guide plate is shown, but the present invention is not limited to such an embodiment. The touch panel device may be configured to include two or more light source units. In this case, these light source units may be arranged in the vicinity of a plurality of sides of the first light guide plate. For example, the light source units may be arranged on two opposing sides of the first light guide plate so that the two light source units are opposed to each other.

  Embodiments obtained by appropriately combining the techniques disclosed above are also included in the technical scope of the present invention.

  The embodiment disclosed herein is merely an example, and the present invention is not limited to the embodiment described above. The scope of the present invention is indicated by each claim of the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are included. Including.

100, 400 Touch panel device 110, 510 First light guide plate 110a, 510a Light exit surface 112 Second light guide plate 114 Recess 120, 420 Light source unit 130 Light source control unit 140, 410 Sensor unit 150 Sensor control unit 160 Main control unit 170 Storage unit 200 Display Device 210 Display Panel 220 Display Control Unit 250 Gap Holding Member 252 Projection 430 Dot Pattern 432 Diffusion Unit

Claims (5)

A light source unit that emits light;
A first light guide member in the form of a plate provided with a light exit surface, and disposed so that light from the light source unit propagates inside and exits from the light exit surface;
A flat plate-like second light guide member disposed on the first light guide member so that light from the light exit surface enters;
Detecting means for detecting scattered light generated on the surface of the second light guide member;
Calculation means for calculating a position where the scattered light is generated on the second light guide member based on information on the light detected by the detection means;
A gap is provided between the first light guide member and the second light guide member, and a gap provided between the first light guide member and the second light guide member is kept constant. A gap holding member,
The gap holding member is a member in which a plurality of glass beads are periodically arranged on a film, and includes a plurality of protrusions that are formed by the plurality of glass beads and support the second light guide member. A touch panel device having and being fixedly bonded to the first light guide member.   The touch panel device according to claim 1, wherein the gap holding member has a moth-eye structure in which the plurality of protrusions are arranged at an interval shorter than the wavelength of light emitted from the light source unit.   The touch panel device according to claim 1, further comprising a light diffusing unit configured to diffuse light propagating through the first light guide member and emit the light from the light emitting surface. The light diffusing means includes a plurality of diffusing portions formed in a dot shape on a surface of the first light guide member opposite to the light emitting surface,
The touch panel device according to claim 3, wherein each of the plurality of diffusion units includes diffusion particles. The light source unit is provided at an end of the first light guide member,
The touch panel device according to claim 4, wherein the plurality of diffusion units are formed such that the density of the diffusion units increases as the distance from the light source unit increases.

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