JP2016212458A - Input device and input system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an input device capable of reducing the reflection of sunlight, illumination light, or the like and capable of preventing light in a light guide plate from being made incident on a sheet-like diffusion member and to provide an input system.SOLUTION: An input device (3A) includes a light guide plate (10) which propagates the light from the position of a light-emitting pen (50) on a surface inside, an optical member (40) which emits a part of the light propagated through the light guide plate (10) from the rear surface of the light guide plate (10), imaging units (20 and 30) which receive the light emitted through the optical member (40), and a detection part which detects the position of the light-emitting pen (50) on the surface of the light guide plate (10) on the basis of light reception by the imaging units (20 and 30). A diffusion sheet 11 having light diffusion is provided on the front surface side of the light guide plate (10) through an air layer (12) whose refractive index is lower than the refractive index of the light guide plate (10).SELECTED DRAWING: Figure 9

Description

  The present invention relates to an input device and an input system including the input device.

  Conventionally, an optical input device (a “position detection device”) having a light guide plate that receives coordinate input by a detection object such as a stick-like operation member (hereinafter referred to as “pen”) or a finger, such as a touch pen or a stylus pen. Also known are input systems such as tablets and touch panels that combine an input device and a display panel.

  In the input system, the coordinates of the position where the input device approaches or contacts the pen or finger is obtained by bringing the pen or finger close to or in contact with the input area of the input device. The obtained coordinates are, for example, for displaying an object such as a point image or a straight line image on a display screen such as a liquid crystal display separate from the input device or a liquid crystal display panel laminated integrally with the input device. Used for.

  As this type of input device, for example, input devices disclosed in Patent Documents 1 to 3 are known.

  In the coordinate input device 100 as an input device disclosed in Patent Document 1, as shown in FIG. 13, the four corners 101a, 101b, 101c, and 101d of a light guide plate 101 made of a flat plate to which a fluorescent dye (not shown) is uniformly added are provided. The light receivers 102a, 102b, 102c, and 102d are arranged toward the concave surface. The light receivers 102a to 102d are connected to the detection circuit unit 110, respectively.

  Thus, when the pen 120 having a light source (not shown) is touched on the light guide plate 101, the spot light emitted from the pen 120 enters the light guide plate 101 from the upper surface thereof. As a result, incident light hits the fluorescent dye added to the inside of the light guide plate 101, and the fluorescent dye is excited to emit fluorescence radially. The fluorescence propagates through the light guide plate 101, reaches the concave surfaces of the four corners 101a to 101d, and is emitted toward the light receivers 102a to 102d. As a result, the light receivers 102a to 102d receive this fluorescence, and as a result, the position where the fluorescent dye is excited to emit light can be calculated and specified by the triangulation method. The fluorescent light directed toward the four sides of the light guide plate 101 is absorbed by the light absorbing members 103a, 103b, 103c, and 103d disposed on the four sides of the light guide plate 101, respectively.

  As the same type of technology, the present applicant has proposed an input device disclosed in Patent Document 2, for example.

  Next, as shown in FIGS. 14A and 14B, the touch panel 200 disclosed in Patent Document 3 includes a light guide plate 201, a light source 202 that makes light incident on the light guide plate 201, and a side surface of the light guide plate 201. Are provided with light receiving elements 203 and 204 and an image forming unit 205. The imaging unit 205 is provided between the light guide plate 201 and the light receiving elements 203 and 204, and forms an image on the light receiving elements 203 and 204 from the light source 202 scattered by the detection target 210. Light absorbing means 206 is disposed on the side surface of the light guide plate 201 on which the light receiving elements 203 and 204 are disposed. The light receiving elements 203 and 204 are disposed outside the irradiation range 207 of the light source 202.

  A notch 208 having a surface perpendicular to the surface of the light guide plate 201 is formed at a corner of the light guide plate 201, and the light receiving elements 203 and 204 receive light emitted from the notch 208. ing.

  The principle of coordinate detection of the touch panel 200 is as follows.

  Light emitted from the light source 202 disposed on the side surface of the light guide plate 201 propagates while repeating total reflection inside the light guide plate 201. In a state where the detected object 210 such as a finger is not touched on the light guide plate 201, the light receiving elements 203 and 204 are disposed outside the irradiation range 207 of the light source 202, and thus do not receive the propagation light propagating inside the light guide plate 201. . On the other hand, when the detection object 210 such as a finger is touched on the transparent light guide plate 201, the propagation light in the light guide plate 201 is disturbed at the touch position of the detection object 210, and scattered light is generated. A part of the scattered light propagates in the direction of the light receiving elements 203 and 204 and is received by the light receiving elements 203 and 204. Thereby, the azimuth angle is measured, and the point where the scattered light is generated by the triangulation method, that is, the point where the detected object 210 such as a finger is touched is specified.

Japanese Patent Laid-Open No. 11-327769 (published on November 30, 1999) JP 2013-182345 A (published on September 12, 2013) JP 2009-258967 A (published on November 5, 2009)

  However, in the conventional coordinate input device 100 disclosed in Patent Document 1 and the touch panel 200 disclosed in Patent Document 3, light such as sunlight and indoor lighting is reflected on the surfaces of the light guide plates 101 and 201, and the operation is performed. The reflection that the person visually recognizes the reflected light occurs. This reflection makes it difficult for the operator to see the display screen.

  Therefore, in general, as a solution for reflection in a liquid crystal television, a tablet terminal, or the like, a measure of sticking a diffusive diffusion sheet to a display screen or a light guide plate is taken. Reflection is reduced by diffusing light such as sunlight and room lighting with a diffusion sheet.

  However, in the case of an input system using a light guide method such as the coordinate input device 100 disclosed in the above-described conventional Patent Document 1 and the touch panel 200 disclosed in Patent Document 3, light is transmitted by total reflection in the light guide plates 101 and 201. Is propagating. Therefore, when a diffusion sheet is attached to the surfaces of the light guide members 101 and 201, the total reflection condition is lost because the difference between the refractive index of the light guide plate and the refractive index of the diffusion sheet is small. As a result, most of the light in the light guide plates 101 and 201 is incident on the diffusion sheet without being totally reflected at the interface between the light guide plate and the diffusion sheet, and the light cannot be propagated in the light guide plate. Occurs.

  The present invention has been made in view of the above problems, and its purpose is to reduce reflection of sunlight, illumination light, and the like, and to allow light in the light guide plate to enter the sheet-like diffusion member. An object of the present invention is to provide an input device and an input system that can be prevented.

  In order to solve the above-described problem, an input device according to one embodiment of the present invention includes a light guide plate that propagates light from a position of a detection object on a surface inside, and a part of the light that propagates through the light guide plate. An optical member that is emitted from the back surface of the light guide plate, a light receiving portion that receives light emitted through the optical member, and a position of the detected object on the surface of the light guide plate based on light reception by the light receiving portion. In the input device including a detection unit for detection, a sheet-like diffusion member having light diffusibility is provided on the surface side of the light guide plate via a low refractive index layer having a refractive index lower than that of the light guide plate. It is characterized by being provided.

  In order to solve the above-described problems, an input system according to an aspect of the present invention includes the input device described above and an image display module provided on the back surface of the input device.

  According to one aspect of the present invention, an input device and an input system capable of reducing reflection of sunlight, illumination light, and the like and preventing light in the light guide plate from entering the sheet-like diffusion member are provided. There is an effect.

It is a perspective view which shows the structure of the input system provided with the input device in Embodiment 1 of this invention. It is an expanded sectional view which shows the interface of the light-guide plate and diffusion sheet of the said input device. The structure of the optical member of the said input device is shown, Comprising: It is AA 'arrow sectional drawing of FIG. It is sectional drawing which shows the structure of the light emission pen of the said input device. It is sectional drawing which shows the mode of the propagation of the light in the said input device. (A) is a perspective view explaining the coordinate detection principle of the said input device, (b) is a top view which shows the detection light in the image pick-up element in the imaging unit of the said input device. 1 is an enlarged sectional view showing an input system including an input device according to a comparative example of the present invention and showing the principle of reflection of sunlight, illumination light, and the like. The input system provided with the input device in the other comparative example of this invention is an expanded sectional view which shows the problem at the time of providing a diffusion sheet directly on the surface of a light-guide plate. 1 illustrates an input system including an input device according to Embodiment 1 of the present invention, and reduces reflection of sunlight, illumination light, and the like, and allows light in a light guide plate to enter a sheet-like diffusion member. It is an expanded sectional view showing the input device and input system which can be prevented. It is an expanded sectional view of the interface of the light-guide plate and diffusion sheet of an input system provided with the input device in Embodiment 2 of the present invention. It is a mode that the light-emitting pen is pressed against the input device, and is an enlarged sectional view of the interface between the light guide plate and the diffusion sheet. It is a top view which shows the structure of the input system provided with the input device in Embodiment 3 of this invention. It is a top view which shows the structure of the conventional input device. (A) is a perspective view which shows the structure of the touchscreen as an input system provided with the other conventional input device, (b) is an expansion perspective view which shows the structure of the light receiving element of the said input device.

Embodiment 1
One embodiment of the present invention is described below with reference to FIGS.

(Configuration of input system)
A configuration of an input system including the input device according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing a configuration of an input system 1A of the present embodiment.

  As shown in FIG. 1, the input system 1A of the present embodiment includes a liquid crystal display module 2 as an image display module, and an input device 3A provided with a gap on the front side of the liquid crystal display module 2. ing.

  The liquid crystal display module 2 includes a liquid crystal display panel (not shown). The liquid crystal display panel sandwiches a liquid crystal layer between a pair of substrates, and each substrate is provided with at least various electrodes for changing the orientation of liquid crystal molecules of the liquid crystal layer by applying a voltage. Then, by changing the orientation of the liquid crystal molecules by applying a voltage, the amount of light transmitted through the liquid crystal layer of each pixel is adjusted to perform a desired display. Note that a conventionally known liquid crystal display module can be used as the configuration of the liquid crystal display module 2.

  In the input system 1A, while looking at the screen displayed on the liquid crystal display panel of the liquid crystal display module 2, for example, a light emitting pen 50 as a detection object is placed on the diffusion sheet 11 of the input device 3A provided on the front side of the liquid crystal display panel. By making contact, the coordinates of the contact position on the light emitting pen 50 are specified, and desired data can be input.

(Configuration of input device)
Next, the configuration of the input device 3A provided in the input system 1A will be described with reference to FIG. 1 and FIG. FIG. 2 is an enlarged cross-sectional view showing an interface between the light guide plate 10 and the diffusion sheet 11 of the input device 3A.

  As shown in FIG. 1, the input device 3 </ b> A of the present embodiment includes a light guide plate 10, a diffusion sheet 11 as a diffusion member, imaging units 20 and 30 as light receiving units, and a light guide plate 10 and imaging units 20 and 30. Are provided with an optical member 40 that is tightly fixed to the back surface of the light guide plate 10, a detection unit 4 as a detection unit, and a light-emitting pen 50 as a detection object. With this configuration, when the light emitting pen 50 touches (contacts) the touch surface that is the surface of the diffusion sheet 11, the touch position coordinates on the touch surface can be obtained.

  The light guide plate 10 is, for example, a rectangular flat plate made of a translucent material, and is disposed with a gap on the display surface side of the liquid crystal display module 2 as shown in FIG. The light guide plate 10 is configured such that one side where the imaging units 20 and 30 are disposed is larger than the liquid crystal display module 2, and at least a part of each of the imaging units 20 and 30 is disposed on the back surface, that is, the lower surface side. Thereby, the enlargement of the size of the direction which spreads along the touch surface of input device 3A is controlled, and it contributes to realization of a compact size.

  The light guide plate 10 is made of, for example, glass. Thereby, compared with the case where it is comprised with a plastic, it is excellent in environmental resistance, and a bending does not arise. In this embodiment, it is a mechanism which detects the propagation direction of the light which propagates the inside of the light-guide plate 10, and based on it detects the incident position of the light to the diffusion sheet 11, ie, the position coordinate of a touch position. Therefore, the bending of the light guide plate 10 deteriorates the detection accuracy. Therefore, as in the present embodiment, the light guide plate 10 is made of glass, which contributes to the realization of highly accurate position coordinate detection without bending. However, the present invention does not limit the material of the light guide plate 10 to glass, and may be configured using plastic or a conventionally known material as a light guide material other than these.

  The diffusion sheet 11 has a light diffusive sheet shape and is provided on the upper surface of the light guide plate 10. The surface roughness of the diffusion sheet is a general roughness, and the arithmetic average roughness (Ra) is several μm. The diffusion sheet 11 diffuses light such as sunlight and indoor lighting incident on the diffusion sheet 11. By providing the diffusion sheet 11, it is possible to prevent reflection of light such as sunlight or room illumination reflected on the surface of the light guide plate 10 and the operator viewing the light. Moreover, the diffusion sheet 11 has flexibility and is configured to be able to bend when pressed.

  By the way, generally, when adhering a diffusion sheet to a display screen or the like, the entire surface of the diffusion sheet is adhered to the display screen using an adhesive or the like. When it is made to adhere using an adhesive agent, a diffusion sheet and a light guide plate will be in the state where it adhered completely.

  However, in this embodiment, the diffusion sheet 11 is in close contact with the light guide plate 10 only at the outer peripheral portion, and is not in close contact with the light guide plate 10 in other regions. Thereby, the air layer 12 can be secured in the center of the light guide plate 10.

  Moreover, in the input device 3A of this embodiment, as shown in FIG. 2, the diffusion sheet 11 has a surface roughness of several μm in terms of arithmetic average roughness (Ra). As a result, the diffusion sheet 11 is not in close contact with the light guide plate 10 in all regions, but is in contact with the light guide plate 10 at a plurality of points. Therefore, an air layer 12 as a low refractive index layer of several μm exists between the light guide plate 10 and the diffusion sheet 11.

  When viewed from above, the outer peripheral portion that closely attaches the diffusion sheet 11 to the light guide plate 10 is outside the optical member 40 described later in this embodiment. Therefore, in the region between the light incident position on the diffusion sheet 11 and the optical member 40, the light guide plate 10 and the diffusion sheet 11 are not in close contact, and an air layer is formed between the light guide plate 10 and the diffusion sheet 11. There are 12. Moreover, it is possible to prevent the diffusion sheet 11 from being bent and causing wrinkles by being closely fixed at the outer peripheral portion.

  The optical member 40 is a translucent member disposed between the back surface of the light guide plate 10 and the imaging units 20 and 30. The structure of the optical member 40 of this embodiment is demonstrated based on FIG. FIG. 3 shows the outer shape of the optical member 40, and is a cross-sectional view taken along line AA 'in FIG.

  As shown in FIG. 3, the optical member 40 has a flat surface and is bonded and fixed to the back surface of the light guide plate 10 with an adhesive. The optical member 40 has a configuration in which light propagating inside the light guide plate 10 is extracted from the back surface of the light guide plate 10, and the extracted light is incident on itself and coupled inside to propagate inside. ing.

  The bonding method between the optical member 40 and the light guide plate 10 is not particularly limited. However, as described above, since the optical member 40 takes out light from the light guide plate 10 and makes it incident, a method or material that does not hinder this is used. It is preferable to use and fix the adhesive. For example, after an adhesive made of an ultraviolet curable resin is applied to the adhesive surface of the optical member 40 and the optical member 40 is affixed to the light guide plate 10, it is cured by irradiating ultraviolet rays from the light guide plate 10 side and the optical member 40 side. -Adhere and fix.

  In this embodiment, the light guide plate 10 is made of glass and the optical member 40 is made of acrylic. However, the material of the optical member 40 may be, for example, translucent glass or polycarbonate.

  Also, the material of the light guide plate 10 can be replaced with a light-transmitting material such as acrylic.

  As shown in FIGS. 1 and 3, the optical member 40 is provided with a conical cutout 44 as a concave portion in a region near the corner of the light guide plate 10 on the end surface adjacent to the upper surface. The angle (γ shown in FIG. 3) formed by the conical surface of the notch 44 and the back surface of the optical member 40 is 45 degrees or less, and 30 degrees or 45 degrees is selected. The conical cutout 44 may be mirror-coated.

  In the present embodiment, the notch 44 is formed in a conical surface, but the present invention is not limited to this. For example, the notch 44 may be configured in a parabolic shape or a polygonal pyramid shape. That is, the notch 44 needs to have an inclined surface.

  Moreover, in this embodiment, as shown in FIG. 1, the shape of the optical member 40 is circular when viewed from the upper surface side, but is not limited thereto. For example, the optical member 40 may be a polygonal column or an elliptical column having an elliptical cross section.

  Moreover, the manufacturing method of the optical member 40 is not particularly limited, but can be manufactured at low cost by plastic molding or glass molding.

  As shown in FIG. 1, the optical member 40 is disposed on the back surface in the vicinity of two adjacent corners of the four corners of the rectangular light guide plate 10. However, the arrangement position of the optical member 40 is not limited to this. In the present embodiment, the two imaging units 20 and 30 are arranged apart from each other in order to realize a detection method described later. Therefore, the optical member 40 is in the middle of the path of the light that has propagated through the light guide plate 10 and finally incident on each of the imaging units 20 and 30 in correspondence with the arrangement positions of the imaging units 20 and 30.・ You can arrange 40.

  The imaging units 20 and 30 are disposed immediately below the conical cutout 44 of the optical member 40, and are disposed at two positions apart from each other at the end of the light guide plate 10. Further, the imaging units 20 and 30 do not protrude above the touch surface of the light guide plate 10.

  The imaging unit 20 includes a lens 21, an optical filter 22, and an imaging element 23. Similarly, the imaging unit 30 includes a lens 31, an optical filter 32, and an imaging element 33. The imaging units 20 and 30 are connected to at least one of the light guide plate 10 and the optical member 40, and have a structure in which light that does not propagate through the light guide plate 10 is not coupled to the imaging elements 23 and 33.

  Next, details of the light emitting pen 50 of the input device 3A will be described with reference to FIG. FIG. 4 is a cross-sectional view showing the configuration of the light emitting pen 50.

  The light emitting pen 50 of the present embodiment is an operation member called a so-called touch pen or stylus pen. As shown in FIG. 4, the light-emitting pen 50 has a light-emitting element 52 a that emits light and a light guide member 52 b that guides light to the tip of the light-emitting pen 50 inside a casing 51 that is an outer shape. The unit 52, the power supply device 53, and the control device 54 are stored.

  As a characteristic configuration of the light-emitting pen 50 of the present embodiment, a light-emitting unit 52 is disposed at the tip of the light-emitting pen 50, and a light diffusion member 55 that diffuses light is attached to the light-emitting side.

  The light diffusing member 55 is made of a resin having light diffusibility and elasticity. Examples of such a resin include a fluororesin such as polytetrafluoroethylene, or silicon rubber. By having elasticity, the surface of the diffusion sheet 11 is not damaged when the tip of the light-emitting pen 50, that is, the light diffusion member 55 is used in contact with the diffusion sheet 11 of the input device 3A. Moreover, since the contact portion is slightly deformed by the contact and the contact area with the surface of the diffusion sheet 11 can be increased, the amount of light coupled to the surface of the diffusion sheet 11 can be increased.

  The light exit surface of the light diffusing member 55 has a curved surface as shown in FIG. That is, the light diffusing member 55 is generally hemispherical. The curved surface does not need to be configured with a uniform curvature, and the curvature may be different between the region that is the most distal end portion of the light-emitting pen 50 and the region that surrounds it. The curved surface may have a fine uneven shape on the surface.

  Further, the light exit surface of the light diffusing member 55 is preferably subjected to wear resistance processing.

  Further, the light diffusing member 55 is configured to be detachable from the light emitting pen 50. Even if the light diffusing member 55 is damaged for some reason including deterioration with time, it is possible to continue using the light emitting pen 50 only by replacing the light diffusing member 55. Compared with the configuration in which the entire light emitting pen 50 is replaced, the use can be continued at a low cost. In addition, since it is detachable, a groove structure, an occlusal structure, or a structure that fits into the light guide member 52b that is a member to which the light diffusing member 55 is attached, in a portion that contacts the light diffusing member 55. Is provided. Therefore, the light diffusion member 55 is provided with a structure (not shown) that matches the structure.

  In the present embodiment, the light diffusion member 55 is attached to the light guide member 52b. However, the present invention is not limited to this, and the light diffusion member 55 may be attached to the housing 51. It may be other embodiments.

  As the light emitting element 52a, an LED (light emitting diode) or an LD (laser diode) emitting light can be used. The number of LEDs or LDs is not limited to one provided for one light-emitting pen 50, and a plurality of LEDs or LDs may be mounted.

  Light emitted from the light emitting element 52a that receives light from the power supply device 53 enters the light diffusing member 55 through the light guide member 52b, and is irregularly reflected by the light diffusing material and fine unevenness of the light diffusing member 55. Then, it is emitted as diffused light from the light emitting surface of the light diffusing member 55.

  The power supply device 53 may be configured to be rechargeable, for example, in addition to a configuration in which a battery is incorporated.

  The control device 54 controls the light emission of the light emitting element 52a. For example, a mechanism for emitting light only when the light emitting element 52a comes into contact with the light guide plate 10 is included. This mechanism is configured by using a pressure-sensitive switch or the like, and can control the light emission time, thereby reducing power consumption and extending battery life.

  As described above, the light-emitting pen 50 is provided with a light source that emits light, and is configured to diffuse and radiate light from the pen tip.

  As shown in FIG. 1, the light propagating through the light guide plate 10 (hereinafter referred to as “propagating light 5a and 5b”) is captured by the imaging units 20 and 30 via the optical member 40, respectively. Then, the detection unit 4 obtains the two-dimensional position coordinates of the contact from each image obtained from the imaging elements 23 and 33. The light receiving surfaces of the image sensors 23 and 33 are disposed so as to be parallel to the surface of the light guide plate 10.

(Input device coordinate detection principle)
The principle of coordinate detection when pen input is performed in the input device 3A having the above configuration will be described in detail with reference to FIGS. 5 and 6A and 6B. FIG. 5 is a diagram illustrating a state where the light-emitting pen 50 contacts the diffusion sheet 11 and light propagates. 6A is a perspective view for explaining the detection principle of the input device 3A, and FIG. 6B is a plan view showing detection light from the image sensor 23 in the imaging unit 20 of the input device 3A. is there.

  As shown in FIG. 5, when the pen tip of the light emitting pen 50 comes into contact with the surface of the diffusion sheet 11 that is the touch surface of the input device 3 </ b> A, the light emitting pen 50 presses the diffusion sheet 11. Due to this pressing, the flexible diffusion sheet 11 is bent, and the air layer 12 existing on the lower surface of the diffusion sheet 11 is crushed to bring the diffusion sheet 11 and the light guide plate 10 into contact. Since the thickness of the air layer 12 is as thin as 1 to 2 μm, the air layer 12 is crushed by the pressing of the light emitting pen 50, and the diffusion sheet 11 and the light guide plate 10 can be brought into contact with each other.

  Next, light is emitted from the light-emitting pen 50 in a state where the diffusion sheet 11 and the light guide plate 10 are in contact with each other. Since the light emitting pen 50 is provided with the light diffusing member 55, the light emitted from the light emitting pen 50 is emitted in various directions, not in one direction. Moreover, since the light emitted from the light emitting pen 50 is diffused even when passing through the diffusion sheet 11, the light emitted from the light emitting pen 50 can be used with high efficiency.

Here, the refractive index _{N 11} of the diffusion sheet 11 is 1.5 to 1.6, the refractive index _{N 10} of the light guide plate 10 is 1.5 to 1.6. Accordingly, since there is almost no difference in refractive index between the diffusion sheet 11 and the light guide plate 10, the light emitted from the light emitting pen 50 is hardly reflected at the interface between the diffusion sheet 11 and the light guide plate 10, and is not inside the light guide plate 10. Incident.

On the lower surface of the light guide plate 10, since a gap is provided between the light guide plate 10 and the liquid crystal display module 2, an air layer exists. On the upper surface of the light guide plate 10, an air layer 12 exists between the light guide plate 10 and the diffusion sheet, as shown in FIG. 2. Therefore, the propagation angle θ _P in the light guide plate 10 out of the light incident on the light guide plate 10 is
sin (90 ° −θ _P )> 1 / N ₁₀
The light beam that satisfies the conditions shown in FIG. 5 is reflected at the interface between the upper and lower surfaces of the light guide plate 10, is confined in the light guide plate 10, is repeatedly reflected on the front and back surfaces of the light guide plate 10, and travels in the light guide plate 10. it can.

  The region where the diffusion sheet 11 bends when the light-emitting pen 50 is pressed is only the region where the light-emitting pen 50 presses the diffusion sheet 11, and in other regions, as shown in FIG. 2, the diffusion sheet 11 and the light guide plate 10 is in point contact at a plurality of locations. Therefore, the amount of light incident on the diffusion sheet 11 from the light guide plate 10 is very small and does not significantly affect the coordinate detection.

  The light propagating through the light guide plate 10 enters the optical member 40 when it reaches the interface between the light guide plate 10 and the optical member 40.

  As a result, the light emitted from the light emitting pen 50 is diffused radially around the pen tip, passes through the diffusion sheet 11, enters the light guide plate 10, propagates in the light guide plate 10, A part of the propagating light 5a and 5b (see FIG. 1) is guided to the conical cutout 44 of the optical member 40. The light reaching the notch 44 changes its optical path toward the lower side of the optical member 40, that is, toward the back surface of the optical member 40 by the notch 44. That is, the light propagating through the light guide plate 10 travels downward from the lower surface of the light guide plate 10. Thereby, the propagating lights 5a and 5b are reflected by the conical surface of the notch 44 of the optical member 40, guided below the optical member 40, and received by the imaging units 20 and 30.

  In the imaging units 20 and 30, the light emitted from the optical member 40 is first condensed by the lenses 21 and 31. Subsequently, the light passes through the optical filters 22 and 32 and is finally received by the image sensors 23 and 33. The optical filters 22 and 32 transmit light emitted from the light emitting pen 50 and play a role of blocking light in other wavelength bands. By the optical filters 22 and 32, stray light such as sunlight or liquid crystal display panel backlight light is blocked, and the SN ratio can be increased.

  As the optical filters 22 and 32, a band-pass filter that passes only light near the center wavelength of the light source used in the light-emitting pen 50, and a short-pass filter that cuts light having a wavelength larger than light near the center wavelength of the light source. Alternatively, a long pass filter or the like that cuts light having a wavelength smaller than the light near the center wavelength of the light source is used.

  Next, as shown in FIG. 6A, the light emitted from the light emitting pen 50, passing through the diffusion sheet 11 and propagating through the light guide plate 10 and the optical member 40, the emitted light is A linear image 25 is formed on the imaging elements 23 and 33 in the imaging units 20 and 30 through the lens 21. The position of the linear image 25 varies depending on the position of the light emitting pen 50. Therefore, by analyzing the acquired images of the image sensors 23 and 33, angles α and β formed by the propagation lights 5a and 5b and one side of the light guide plate 10 are obtained. Thereby, the position coordinate of the point which the pen tip used as a light emission source touched can be calculated | required using the principle of triangulation. For example, in FIG. 6A, when the light-emitting pen 50 is at the position P1, the linear image 25 is formed on the imaging element 23 in the imaging unit 20. When the light emitting pen 50 moves to the position P2, a linear image 27 is formed as shown in FIG.

  Here, when the pen tip of the light emitting pen 50 in the state of irradiating light is not in contact with the diffusion sheet 11, nothing appears in the acquired image of the image sensor 23. On the other hand, when the pen tip of the light emitting pen 50 in the state of irradiating light comes into contact with the diffusion sheet 11 and the light is coupled to the light guide plate 10, as shown in FIG. Lights 5 a and 5 b are guided to the image sensor 23 via the optical member 40. Thereby, as shown in FIGS. 6A and 6B, a linear image is formed on the imaging surface of the imaging element 23, and the linear image 25 appears on the acquired image.

  The position of the linear image 25 shown in FIGS. 6A and 6B changes depending on the position of the contact point of the pen tip of the light-emitting pen 50. The image 25 changes like a linear image 27 indicated by a broken line. The locus of the linear image has a fan shape 26 indicated by a one-dot chain line. The rotation angle α1 ′ of the line segment connecting the center 28 of the fan shape 26 and the line image (with the center 28 of the arc as the rotation center) is the line segment connecting the light-emitting pen 50 and the image sensor 23 and the light guide plate 10 described above. The angle is the same as the angle α1 formed by the side A. The angle α1 ′ is obtained from the acquired image of the image sensor, and the angle α1 is obtained from the angle α1 ′. Similarly, when the pen moves to the position P2, a linear image 27 is formed, and the angle α2 ′ is obtained by obtaining the inclination angle α2 ′ of the linear image 27.

  Similarly, for the image sensor 33 of the image pickup unit 30, the position of the light emitting point is specified from the analysis of the acquired image, and the angle β formed by the line segment connecting the light emitting pen 50 and the image sensor 33 and the side A is obtained.

The distance between the image sensors 23 and 33 is L, the bright spot displacement angle obtained by reading the image from the image sensor 23 is α, and the bright spot displacement angle obtained by reading the acquired image from the image sensor 33. Where β is β, the coordinates (X, Y) of the bright spot are the following relational expressions (1) and (2)
Y = tan α · X (1)
Y = tan β · (L−X) (2)
Satisfied.

Solving this, the coordinates (X, Y) of the bright spot are
X = tan β · L / (tan α + tan β) (3)
Y = (tan α · tan β) · L / (tan α + tan β) (4)
It is expressed.

  Based on the angles α and β obtained as described above and the interval L that can be obtained in advance, the coordinates X and Y of the point where the pen tip contacts are obtained. Among these, the space | interval L is a space | interval between the image pick-up element 23 and the image pick-up element 33, and is a fixed value. By obtaining the angles α and β, the pen input coordinates X and Y (position coordinates) can be obtained.

  Note that the distance L between the imaging elements 23 and 33 is a distance between the optical axis center of the lens 21 and the optical axis center of the lens 31.

  In order to obtain the position coordinates of the light-emitting pen 50 by the above method, the input system 1A is provided with a detection unit 4 as shown in FIG. The detection unit 4 can be provided in the input device 3A.

  Further, based on the position coordinates of the light-emitting pen 50 obtained by the above method, the user drives the pixels at the position corresponding to the position coordinates of the liquid crystal display module 2 so as to shine, for example, and the user It is possible to make the touch position visible. For this purpose, a control unit (not shown) that controls driving of the liquid crystal display module 2 may acquire information on the position coordinates obtained by the detection unit 4 and drive the liquid crystal display module 2 based on the information.

(Measures to prevent light in the light guide plate from entering the diffusion sheet)
By the way, the input device for propagating light in the light guide plate has the following problems.

  That is, for example, in the input system 1X as the comparative example 1, as shown in FIG. 7, the light such as sunlight or room illumination is reflected on the surface of the light guide plate 10, and the operator sees the reflected light. Will occur. This reflection makes it difficult for the operator to see the display screen.

  Therefore, as a solution for reflection in a liquid crystal television, a tablet terminal, etc., in the input system 1Y as the comparative example 2, as shown in FIG. Measures are taken. As a result, it is possible to reduce the reflection by diffusing light such as sunlight and room lighting by the diffusion sheet 11.

  However, when the diffusion sheet 11 is adhered and adhered to the light guide plate 10, the difference between the refractive index of the light guide plate 10 and the refractive index of the diffusion sheet 11 is small. As a result, as shown in FIG. 8, most of the light propagating in the light guide plate 10 enters the diffusion sheet 11 without reflection at the interface between the light guide plate 10 and the diffusion sheet 11. And since the light which injected into the diffusion sheet 11 will be spread | diffused, the total reflection conditions will collapse | crumble and the problem that light cannot be propagated in the light-guide plate 10 arises.

  Therefore, in the input system 1A in the present embodiment, an air layer 12 is provided between the diffusion sheet 11 and the light guide plate 10 as shown in FIG. As a result, reflection of light is reduced by the diffusion sheet, and part of the light propagating in the light guide plate 10 is reflected on both the upper and lower surfaces of the light guide plate 10 due to the air layer 12 being provided. 10 can be propagated.

  As described above, the input system 1 </ b> A of the present embodiment can obtain the position coordinates of the light-emitting pen 50 by capturing the propagated light at at least two locations on the diffusion sheet 11 that are separated from each other.

  Further, according to the configuration of the input device 3 </ b> A of the present embodiment, the imaging units 20 and 30 are provided at positions that do not protrude upward from the touch surface of the diffusion sheet 11. For this reason, the touch surface of the diffusion sheet 11 becomes the uppermost surface of the input device 3A, and the imaging unit does not protrude above the touch surface. Therefore, even when the input device 3A of the input system 1A of the present embodiment is applied to a table type terminal, the table surface can be made completely flat without the surroundings rising like a bank.

  In addition, the input system 1A according to the present embodiment is not a light shielding method, but has a configuration in which light propagating through the light guide plate 10 is received by the image sensors 23 and 33, so that erroneous recognition is caused by stray light including sunlight. Therefore, accurate position detection can be realized. For this reason, it is also possible to place the device directly under the lighting device, outdoors, or near a window.

  In the present embodiment, the configuration using a total of two image sensors, that is, the image sensors 23 and 33 has been described. However, the present invention is not limited to this, and mirrors are provided from various locations at the end of the light guide plate 10. In addition, the images may be collected in one image sensor using a shutter.

  As described above, the input device 3A of the present embodiment guides the light guide plate 10 that propagates light from the position of the light-emitting pen 50 as the detection target on the surface, and part of the light propagated through the light guide plate 10. An optical member 40 that emits light from the back surface of the optical plate 10, imaging units 20 and 30 that receive light emitted through the optical member 40, and light guide plate 10 based on light reception by the imaging units 20 and 30. And a detection unit 4 for detecting the position of the light-emitting pen 50 on the surface. A diffusion sheet 11 as a sheet-like diffusion member having light diffusivity is provided on the surface side of the light guide plate 10 through a low refractive index layer having a refractive index lower than that of the light guide plate 10. ing.

  According to the above configuration, the diffusion sheet 11 is provided on the front surface side of the light guide plate 10, so that light such as sunlight and room lighting is reflected on the surface of the light guide plate 10, and the operator can reflect the reflected light. Can be reduced.

  In the present embodiment, an air layer 12 is further provided between the light guide plate 10 and the diffusion sheet 11. Thereby, the light propagating through the light guide plate 10 can be prevented from entering the diffusion sheet 11 without being reflected at the interface between the light guide plate 10 and the diffusion sheet 11. As a result, a part of the light incident on the light guide plate 10 can propagate while totally reflecting the light guide plate 10.

  Therefore, it is possible to provide an input device 3A that can reduce reflection of sunlight, illumination light, and the like and prevent light in the light guide plate from entering the diffusion sheet 11.

  In the input device 3 </ b> A according to the present embodiment, the diffusion sheet 11 is made of a flexible material that can contact the light guide plate 10. Thereby, since the diffusion sheet 11 is flexible, the diffusion sheet 11 can be bent by the pressing of the light emitting pen 50. Thereby, the air layer 12 can be crushed and the light-guide plate 10 and the diffusion sheet 11 can be made to contact. Therefore, the light emitted from the light emitting pen 50 can be reliably incident on the light guide plate 10.

  Further, in the input device 3A according to the present embodiment, the diffusion sheet 11 has a more peripheral portion than the portion where the optical member 40 is provided when the diffusion sheet 11, the light guide plate 10, and the optical member 40 are viewed in plan view. The light guide plate 10 is bonded. Thereby, since the diffusion sheet 11 is not in contact with the light guide plate 10 at the center of the light guide plate 10, the air layer 12 can be reliably formed between the diffusion sheet 11 and the light guide plate 10. .

  Moreover, the adhesion part to the light-guide plate 10 of the diffusion sheet 11 is an outer peripheral part rather than the location in which the optical member 40 in the light-guide plate 10 is provided. For this reason, since the diffusion sheet 11 side in the section from the contact position to the imaging units 20 and 30 is the air layer 12, the light is reliably transmitted because it is totally reflected on the surface of the light guide plate 10. Therefore, when the light emitting pen 50 is brought into contact with the light guide plate 10, the light based on the light emitting pen 50 can be guided to the imaging units 20 and 30 through the optical member 40.

  Furthermore, by making the adhesion part of the diffusion sheet 11 to the light guide plate 10 an outer peripheral portion of the light guide plate 10, it is possible to prevent the diffusion sheet 11 from being wrinkled.

  Further, in the input system 1A of the present embodiment, an input device 3A and a liquid crystal display module 2 as an image display module provided on the back surface of the input device 3A are provided.

  Therefore, a plurality of pixels of the liquid crystal display panel in the liquid crystal display module 2 can be driven based on the position coordinates detected by the detection unit 4.

  In addition, this invention is not limited to said embodiment, A various change is possible within the scope of the present invention.

  For example, in the present embodiment, the example in which the air layer 12 is a low refractive index layer has been described. However, the low refractive index layer may be a layer having a refractive index lower than that of the light guide plate 10 and is limited to the air layer 12. Absent. For example, a gas other than air or a liquid having a refractive index lower than that of the light guide plate 10 may be sealed between the light guide plate 10 and the diffusion sheet 11 to form a low refractive index layer. However, the configuration in which the air layer 12 is a low refractive index layer as in the present embodiment is simple and preferable.

  The light source used in the light-emitting pen 50 may be any wavelength as long as the light guide plate 10 and the optical member 40 are transmissive and can be detected by the image sensors 23 and 33. For example, infrared light or visible light Either may be sufficient, and also the light which a fluorescent paint emits like patent document 1 described in [background art] may be sufficient.

  Moreover, in this embodiment, the to-be-detected body demonstrated and demonstrated the light-emitting pen 50 which emits light.

  However, in the present invention, the detection target is not limited to the light emitting pen 50 that emits light, but can be applied to a non-light emission detection target including a finger and a hand. That is, when using a non-light-emitting detection target, for example, an illumination light source for illuminating the inside of the light guide plate 10 is provided at the edge of the light guide plate 10. Thereby, it becomes possible to apply the input device 3A and the input system 1A to the detection of the coordinate position where the non-light emitting detection object including the finger and the hand is in contact.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. 10 and FIG. For convenience of explanation, members having the same functions as those described in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the input system 1B including the input device 3B according to the present embodiment, the configuration method of the air layer 12 existing between the light guide plate 10 and the diffusion sheet 11 is the same as the input system 1A including the input device 3A according to the first embodiment. Is different.

  A configuration of an input system 1B including the input device 3B of the present embodiment will be described based on FIG. FIG. 10 is an enlarged view of the interface between the light guide plate 10 and the diffusion sheet 11 of the input device 3B in the input system 1B of the present embodiment. FIG. 11 is an enlarged view of the interface between the diffusion sheet 11 and the light guide plate 10 when the light-emitting pen 50 contacts the diffusion sheet 11 in the present embodiment.

  As shown in FIG. 10, the input device 3 </ b> B in the input system 1 </ b> B of the present embodiment is provided with a plurality of microbeads 60 as spacers between the light guide plate 10 and the diffusion sheet 11. The microbead 60 is a spherical bead having a diameter of several μm.

  By providing the microbeads 60 between the light guide plate 10 and the diffusion sheet 11, even when the surface roughness of the diffusion sheet 11 is small, an air layer having a thickness of several μm between the light guide plate 10 and the diffusion sheet 11. 12 can be formed.

  In the input device 3B in the input system 1B configured as described above, when the light-emitting pen 50 contacts the diffusion sheet 11 and presses the diffusion sheet 11, the flexible diffusion sheet 11 is bent as shown in FIG. And the diffusion sheet 11 and the light-guide plate 10 contact because the air layer 12 which exists in the lower surface of the diffusion sheet 11 is crushed. Since the thickness of the air layer 12 is as thin as several μm, the air layer 12 is crushed by pressing the light emitting pen 50, and the diffusion sheet 11 and the light guide plate 10 can be brought into contact with each other.

  At this time, even if the microbead 60 is present in the pressing area of the light-emitting pen 50, the microbead 60 is as small as several μm, so that the light emitted from the light-emitting pen 50 is reflected by the microbead 60. The proportion of light is small. Further, since the light diffusing member 55 of the light emitting pen 50 has elasticity, the light diffusing member 55 can be bent and the contact area can be increased. For this reason, even if the microbeads 60 exist in the pressing region, a sufficient amount of light can be incident on the light guide plate 10.

  Further, since the light diffusion member 55 of the light-emitting pen 50 has elasticity, when the light-emitting pen 50 is pressed against the diffusion sheet 11, the light diffusion member 55 bends and the light diffusion member 55 and the diffusion sheet 11 are not bent. The contact area increases. Thereby, a sufficient amount of light can be emitted to the light guide plate 10.

Also in the input device 3B in the input system 1B of the present embodiment, the lower surface of the light guide plate 10 is located between the light guide plate 10 and the liquid crystal display module 2 in the same manner as the input device 3A in the input system 1A of the first embodiment. Since there is a gap, there is an air layer. Further, on the upper surface of the light guide plate 10, the air layer 12 exists between the light guide plate 10 and the diffusion sheet 11 due to the presence of the microbeads 60 as shown in FIG. 11. Therefore, of the light incident on the light guide plate 10, the propagation angle θ _P in the light guide plate 10 is
sin (90 ° −θ _P )> 1 / N ₁₀
The light beam satisfying the condition shown in FIG. 5 is reflected at the interface between the upper and lower surfaces of the light guide plate 10, is confined in the light guide plate 10, is repeatedly reflected on the front and back surfaces of the light guide plate 10, and travels in the light guide plate 10. it can.

  As described above, in the input device 3B in the input system 1B of the present embodiment, a plurality of microbeads 60 as spacers are disposed between the light guide plate 10 and the diffusion sheet 11. Thereby, an air layer 12 of several μm can be formed between the light guide plate 10 and the diffusion sheet 11. As a result, part of the light incident on the light guide plate 10 is reflected at the upper and lower interfaces of the light guide plate 10 and confined in the light guide plate 10, and repeatedly reflected on the front and back surfaces of the light guide plate 10. You can proceed through 10.

[Embodiment 3]
Another embodiment of the present invention is described below with reference to FIG. For convenience of explanation, members having the same functions as those described in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  The input system 1C provided with the input device 3C in the present embodiment is capable of detecting the input coordinate positions of the two light emitting pens 50a and 50b that emit light having different wavelengths, respectively. This is different from the input systems 1A and 1B provided with 3B.

  A configuration of an input system 1C including the input device 3C according to the present embodiment will be described with reference to FIG. FIG. 12 is a plan view showing the configuration of the input system 1C of the present embodiment.

  As shown in FIG. 12, the input system 1C of the present embodiment includes a liquid crystal display module 2 as an image display module, and an input device 3C disposed with a gap on the front side of the liquid crystal display module 2. ing.

  The input device 3C of the present embodiment includes a light guide plate 10 (not shown), a diffusion sheet 11 as a diffusion member provided on the surface side of the light guide plate 10, imaging units 20a, 30a, 20b, and 30b as light receiving units, Between each of the light guide plate 10 and the imaging units 20a, 30a, 20b, and 30b, an optical member 40 that is closely fixed to the back surface of the light guide plate 10, a detection unit 4 (not shown), and a light emitting pen 50a as a detection target. -50b is provided. With this configuration, when the two light-emitting pens 50a and 50b touch (contact) the touch surface, which is the surface of the diffusion sheet 11, the touch position coordinates on the touch surface can be obtained.

  The light guide plate 10 is a single rectangular flat plate made of a translucent material, and is arranged with a gap on the display surface side of the liquid crystal display module 2. The light guide plate 10 is configured such that a pair of opposing sides is larger than the liquid crystal display module 2. At least a part of each of the imaging units 20a and 30a and at least a part of each of the imaging units 20b and 30b are respectively sandwiched between the liquid crystal display modules 2 in a region that does not overlap with the liquid crystal display module 2 when viewed from above. It is arrange | positioned in the back surface, ie, the lower surface side.

  The diffusion sheet 11 is provided on the upper surface of the light guide plate 10. The diffusion sheet 11 is in close contact with the light guide plate 10 only at the outer peripheral portion, and is not in close contact with the light guide plate 10 in other regions. The diffusion sheet 11 is not in close contact with the light guide plate 10 and is in contact with the light guide plate 10 at a plurality of points. Therefore, an air layer 12 as a low refractive index layer of several μm exists between the light guide plate 10 and the diffusion sheet 11.

  The outer peripheral part which makes the diffusion sheet 11 adhere to the light guide plate 10 is outside the optical member 40 described later when viewed from above. Therefore, in the region between the light incident position on the diffusion sheet 11 and the optical member 40, the light guide plate 10 and the diffusion sheet 11 are not in close contact, and an air layer is formed between the light guide plate 10 and the diffusion sheet 11. There are 12.

  The optical member 40 is disposed between the back surface of the light guide plate 10 and the imaging units 20a, 30a, 20b, and 30b. The optical member 40 is provided with a conical cutout 44 (not shown) as a recess in a region near the corner of the light guide plate 10 on the end surface adjacent to the upper surface.

  The imaging units 20 a, 30 a, 20 b, and 30 b are disposed immediately below the conical surface notch 44 of the optical member 40. The imaging units 20a and 30a are disposed at two positions apart from each other at the end of the light guide plate 10, and the imaging units 20b and 30b are opposite to the ends where the imaging units 20a and 30a are disposed. It is arrange | positioned in two places away from each other in the edge part.

  The imaging unit 20a includes a lens 21a, an optical filter 24a, and an imaging element 23a. The imaging unit 30a includes a lens 31a, an optical filter 34a, and an imaging element 33a. The imaging unit 20b includes a lens 21b, an optical filter 24b, and an imaging element 23b. The imaging unit 30b includes a lens 31b, an optical filter 34b, and an imaging element 33b. The wavelengths of light shielded by the optical filters 24a and 34a are different from the wavelengths of light shielded by the optical filters 24b and 34b.

  The imaging units 20a, 30a, 20b, and 30b are connected to at least one of the light guide plate 10 and the optical member 40, and have a structure in which light that does not propagate through the light guide plate 10 is not coupled to the imaging elements 23 and 33.

  In the present embodiment, two light emitting pens 50a and 50b that emit light having different wavelengths are used.

  The light emitted from the light emitting pen 50a can pass through the optical filters 24a and 34a, but cannot pass through the optical filters 24b and 34b. On the other hand, the light emitted from the light emitting pen 50b can pass through the optical filters 24b and 34b, but cannot pass through the optical filters 24a and 34a.

  Thereby, the imaging unit 20a / 30a detects the coordinate input position of the light emitting pen 50a using the principle of triangulation, and the imaging unit 20b / 30b detects the coordinate of the light emitting pen 50b using the principle of triangulation. Detect input position.

  As described above, the input system 1C including the input device 3C according to the present embodiment is configured to be able to detect the coordinate positions of the two light emitting pens 50a and 50b.

  Further, the diffusion sheet 11 is in close contact with the light guide plate 10 at the outer peripheral portion rather than the position where the imaging units 20a, 30a, 20b, 30b and the optical member 40 are provided. Thereby, the air layer 12 exists between the light guide plate 10 and the diffusion sheet 11 in other regions. Since the air layer 12 is present, part of the light emitted from the light-emitting pens 50 a and 50 b, passing through the diffusion sheet 11 and entering the light guide plate 10 is reflected on both the upper and lower surfaces of the light guide plate 10. 10 can be propagated.

[Summary]
The input devices 3A to 3C according to the first aspect of the present invention include a light guide plate 10 that propagates light from the position of the detection object (light emitting pen 50) on the surface, and a part of the light that propagates through the light guide plate 10. An optical member 40 that is emitted from the back surface of the light guide plate 10, a light receiving unit (imaging units 20 and 30) that receives light emitted through the optical member 40, and a light receiving unit (imaging units 20 and 30). In the input device including the detection unit 4 that detects the position of the detection target (light emitting pen 50) on the surface of the light guide plate 10 based on the received light, the light guide plate 10 has a light guide plate on the surface side of the light guide plate 10. A sheet-like diffusion member (diffusion sheet 11) having light diffusibility is provided through a low refractive index layer having a refractive index lower than the refractive index of 10. The detected object is not necessarily limited to the light-emitting pen, and may be a non-light-emitting finger or the like. In this case, the position of a finger or the like can be detected by providing a light source around the light guide plate.

  According to the above invention, the diffusion member is provided on the surface side of the light guide plate, so that light such as sunlight and indoor lighting is reflected on the surface of the light guide plate, and the operator detects the reflected light. Reflection can be reduced.

  In the present invention, a low refractive index layer is further provided between the light guide plate and the diffusing member. Thereby, it is possible to prevent light propagating in the light guide plate from entering the diffusion member without being reflected at the interface between the light guide plate and the diffusion member. As a result, part of the light incident on the light guide plate can propagate while totally reflecting inside the light guide plate.

  Therefore, it is possible to provide an input device that can reduce reflection of sunlight, illumination light, and the like, and can prevent light in the light guide plate from entering the sheet-like diffusion member.

  In the input device 3A to 3C according to the second aspect of the present invention, in the input device according to the first aspect, the diffusion member (diffusion sheet 11) is made of a flexible material that can contact the light guide plate 10. preferable.

  According to said structure, since a diffusion member is the flexibility which can contact a light-guide plate, a diffusion member can be bent by the press of a to-be-detected body. Thereby, a low refractive index layer can be crushed and a light-guide plate and a diffusion member can be made to contact. Therefore, the light emitted from the detection object can be reliably incident on the light guide plate.

  In the input device 3B according to the third aspect of the present invention, in the input device according to the first and second aspects, a spacer (microbead 60) is provided between the light guide plate 10 and the diffusion member (diffusion sheet 11). Preferably it is.

  According to said structure, a low refractive index layer can be reliably formed between a light-guide plate and a diffusion member by supporting a diffusion member with a spacer.

  The input device 3B according to the fourth aspect of the present invention is the input device according to the first, second, or third aspect, wherein the diffusion member (the diffusion sheet 11) is the diffusion member (the diffusion sheet 11), the light guide plate 10, and the optical member 40. When viewed from above, it is preferable that the light guide plate 10 is bonded to the outer peripheral portion rather than the portion where the optical member 40 is provided.

  According to the above configuration, since the diffusion member is not in contact with the light guide plate at the center of the light guide plate, the low refractive index layer can be reliably formed between the diffusion member and the light guide plate. .

  Moreover, the adhesion part to the light-guide plate of a diffusion member is an outer peripheral part rather than the location in which the optical member in a light-guide plate is provided. For this reason, when the detected body is brought into contact with the light guide plate, light based on the detected body can be guided to the light receiving section via the optical member.

  Furthermore, it is possible to prevent wrinkles from occurring in the diffusing member by setting the bonding portion of the diffusing member to the light guide plate as the outer peripheral portion of the light guide plate.

  The input systems 1A to 1C according to the fifth aspect of the present invention include the input devices 3A to 3C according to any one of the first to fourth aspects and an image display module (liquid crystal display module 2) provided on the back surface of the input devices 3A to 3C. It is characterized by having. The image display module refers to a module used for displaying an object such as a point image or a straight line image on a display screen such as a liquid crystal display or a liquid crystal display panel integrally laminated on an input device.

  According to the above invention, since the image display module is provided on the back surface of the input device, a plurality of pixels of the image display panel in the image display module are driven based on the position coordinates detected by the detection unit. be able to.

  Moreover, in this invention, while reducing reflection of sunlight, illumination light, etc., while providing the input system provided with the input device which can prevent that the light in a light-guide plate injects into a sheet-like diffusion member. it can.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  The present invention can be used for an input device and an input system that obtain a coordinate position of a detected object using a detected object such as a light-emitting pen.

1A-1C input system 2 Liquid crystal display module (image display module)
3A to 3C Input device 4 Detector 5a / 5b Propagated light 10 Light guide plate 11 Diffusion sheet (diffusion member)
20 Imaging unit (light receiving unit)
21 Lens 22 Optical filter 23 Imaging device 30 Imaging unit (light receiving unit)
31 Lens 32 Optical Filter 33 Image Sensor 40 Optical Member 44 Notch 50 Light-Emitting Pen (Detected Object)
60 micro beads (spacer)

Claims (5)

A light guide plate that propagates light from the position of the detected object on the surface inside, an optical member that emits part of the light propagated through the light guide plate from the back surface of the light guide plate, and the light emitted through the optical member. In an input device comprising: a light receiving unit that receives the received light; and a detection unit that detects the position of the detected object on the surface of the light guide plate based on light reception by the light receiving unit.
An input characterized in that a sheet-like diffusion member having light diffusibility is provided on the surface side of the light guide plate through a low refractive index layer having a refractive index lower than that of the light guide plate. apparatus.   The input device according to claim 1, wherein the diffusion member is made of a flexible material that can contact the light guide plate.   The input device according to claim 1, wherein a spacer is provided between the light guide plate and the diffusion member.   When the diffusion member, the light guide plate, and the optical member are viewed in plan, the diffusion member is bonded to the light guide plate at an outer peripheral portion rather than a portion where the optical member is provided. The input device according to claim 1, 2, or 3. The input device according to any one of claims 1 to 4,
An input system comprising: an image display module provided on a back surface of the input device.

Images