JP2012150022A - Proximity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity sensor capable of preventing picking up noise light.SOLUTION: A proximity sensor A1 includes: a light emitting body 2; a light receiving body 3 which is disposed next to the light emitting body 2 in a first direction (x direction) and receives light emitted from the light emitting body 2 and reflected on an external object; a first translucent member 4 which covers the light receiving body 3; and a light shielding member 6 having a first opening 61 for exposing a part of the surface of the first translucent member 4 as a light incident surface 41. The light incident surface 41 is disposed deeper in the depth direction than an outer edge 611 of an inner circumferential wall 610 of the first opening 61. The inner circumferential wall 610 of the first opening 61 comprises an inclined surface which comes closer to the center of the opening towards the depth direction. The inner circumferential wall 610 has a larger inclination angle with respect to the depth direction at further positions in the x direction from the light emitting body 2.

Description

  The present invention relates to a proximity sensor for optically detecting a close object.

  FIG. 16 shows an example of a conventional proximity sensor (see, for example, Patent Document 1). The proximity sensor X shown in the figure includes a substrate 91, a light emitter 92, a light receiver 93, a first light transmissive member 94, a second light transmissive member 95, and a light shielding member 96. On the substrate 91, a light emitter 92 and a light receiver 93 are mounted side by side in the x direction. The light emitter 92 emits infrared light. The light receiver 93 receives the infrared light emitted from the light emitter 92 and reflected by an external object. The photoreceptor 93 outputs an electrical signal corresponding to the amount of received light. The first light transmissive member 94 covers the photoreceptor 93 on the substrate 91. The first light transmissive member 94 has a convex light incident surface 940 on a part of its surface. The second light transmissive member 95 covers the light emitter 92 on the substrate 91. The 2nd translucent member 95 has the convex-shaped light-projection surface 950 in a part of surface. The light blocking member 96 blocks the first light transmitting member 94 and the second light transmitting member 95 on the substrate 91 and covers them integrally. The light shielding member 96 has a first opening 961 and a second opening 962. The first opening 961 exposes the light incident surface 940 toward the z direction orthogonal to the x direction. The second opening 962 exposes the light emitting surface 950 in the same direction as the first opening 961. The topmost portions of the light incident surface 940 and the light emitting surface 950 are set at the same height as the outer edges in the depth direction (z direction) of the first opening 961 and the second opening 962.

  The proximity sensor X is incorporated in, for example, a touch panel mobile phone terminal. The proximity sensor X is disposed in the vicinity of the liquid crystal display unit D in the mobile phone terminal, and is covered with a transparent cover C made of acrylic or the like together with the liquid crystal display unit D. The infrared light L emitted from the light emitter 92 travels toward the translucent cover C through the light emission surface 950. Further, the infrared light L passes through the light-transmitting cover C and hits and reflects the object M located outside thereof. The infrared light L reflected by the object M passes through the light-transmitting cover C again. Finally, the infrared light L is received by the photoreceptor 93 through the light incident surface 940. The photoreceptor 93 outputs an electrical signal corresponding to the amount of received light to a control unit (not shown). The control unit recognizes that there is an object M close to the liquid crystal display unit D when the output level of the photoreceptor 93 exceeds a preset threshold value. That is, in the mobile phone terminal, for example, when the cheek is brought close to the liquid crystal display portion D in order to make a call, the proximity sensor X detects the cheek. Thus, during a call, the touch panel operation using the liquid crystal display unit D is invalidated, and malfunction during the call is prevented. At the time of a call, the liquid crystal display D is also turned off, so that battery power consumption is suppressed.

  However, as shown in FIG. 16, the proximity sensor X is disposed with a certain distance from the translucent cover C. For this reason, the infrared light exiting the light exit surface 950 includes light having a relatively large incident angle with respect to the light-transmitting cover C. Such infrared light is reflected by the inner surface of the translucent cover C and becomes noise light L ′. The noise light L ′ incident on the light incident surface 940 can be received by the light receiver 93. Therefore, the conventional proximity sensor X may be erroneously detected even though there is no adjacent object.

JP 2010-34189 A

  The present invention has been conceived under the circumstances described above, and an object of the present invention is to provide a proximity sensor that can prevent erroneous detection.

  The proximity sensor provided by the present invention includes a light emitter, a light receiver that is positioned side by side with the light emitter in the first direction, receives the light emitted from the light emitter and reflected by an external object, and the light receiver. A first light-transmitting member that covers the first light-transmitting member, and a light-shielding member that covers the first light-transmitting member and has a first opening that exposes a part of the surface of the first light-transmitting member as a light incident surface. The sensor is characterized in that the light incident surface is provided on the far side in the depth direction from the outer edge of the inner peripheral wall of the first opening.

  In a preferred embodiment of the present invention, the inner peripheral wall of the first opening is composed of a sloped surface that approaches the opening center as it becomes the back side in the depth direction.

  In a preferred embodiment of the present invention, the inner peripheral wall of the first opening has a larger inclination angle with respect to the depth direction as it is farther from the light emitter in the first direction.

  In a preferred embodiment of the present invention, the inner peripheral wall of the first opening has an inclination angle of 15 ° or more with respect to the depth direction of the portion farthest from the light emitter in the first direction.

  In a preferred embodiment of the present invention, the first light transmitting member has a first convex portion disposed in the first opening, and the light incident surface is an end surface of the first convex portion. .

  In preferable embodiment of this invention, the end surface of the said 1st convex part is formed in planar shape.

  In preferable embodiment of this invention, the said 1st convex part provides a clearance gap between the inner peripheral walls of the said 1st opening part, and is arrange | positioned.

  In a preferred embodiment of the present invention, the substrate includes a substrate on which the light emitter and the light receiver are arranged and mounted in the first direction, and a second light transmissive member that covers the light emitter, and the light shielding member includes the substrate. The first light-transmitting member and the second light-transmitting member are shielded and covered together, and a second opening that exposes a part of the surface of the second light-transmitting member as a light emitting surface is formed on the first. It is on the same side as the opening.

  In a preferred embodiment of the present invention, the light emitting surface is provided on the far side in the depth direction from the outer edge of the inner peripheral wall of the second opening.

  In a preferred embodiment of the present invention, the inner peripheral wall of the second opening is composed of a sloped surface that approaches the opening center as it becomes deeper in the depth direction.

  In a preferred embodiment of the present invention, the light shielding member has a light scattering region between the first opening and the second opening.

  In a preferred embodiment of the present invention, the depth direction of the first opening and the second opening is orthogonal to the first direction, and the light scattering region includes the first opening and the first opening. A plurality of grooves extending in the second direction orthogonal to both the depth direction of the two openings and the first direction are formed.

  In a preferred embodiment of the present invention, the plurality of grooves have a plurality of inclined surfaces inclined with respect to the first direction.

  In a preferred embodiment of the present invention, the inclined surface has an inclination angle of 50 ° to 70 ° with respect to the first direction.

  In a preferred embodiment of the present invention, the second light transmissive member has a second convex portion disposed in the second opening, and the light emitting surface is included in the second convex portion.

  In a preferred embodiment of the present invention, the light emitting surface is formed in a convex shape.

  In a preferred embodiment of the present invention, the second convex portion has a pair of flat cutout surfaces that are continuous with the light emitting surface on both ends in the first direction.

  In a preferred embodiment of the present invention, the inner peripheral wall of the second opening exposes the notch surface far from the photoreceptor toward the first direction, while the inner wall of the second opening is on the side close to the photoreceptor. A portion opposed to the notch surface is provided.

  In a preferred embodiment of the present invention, the notch surface on the side close to the photoreceptor is disposed with a gap between the inner peripheral wall of the second opening.

  In a preferred embodiment of the present invention, the light emitter is an LED that emits infrared light.

  In the proximity sensor having such a configuration, for example, a translucent cover is disposed to face the light incident surface. The light emitted from the light emitter travels toward the translucent cover. At this time, a part of the light is reflected by the inner surface of the translucent cover and becomes noise light. The noise light travels toward the first opening, but proceeds obliquely with respect to the depth direction of the first opening. Thereby, noise light is hard to enter with respect to the light-incident surface located in the depth direction back | inner side of a 1st opening part. Therefore, according to the proximity sensor according to the present invention, it is difficult to pick up noise light, and it is difficult to cause erroneous detection.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

1 is a perspective view of a proximity sensor according to a first embodiment of the present invention. It is sectional drawing which follows the II-II line of FIG. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing which follows the IV-IV line of FIG. It is a top view of the proximity sensor shown in FIG. It is sectional drawing which follows the VI-VI line of FIG. It is sectional drawing which follows the VII-VII line of FIG. It is a top view of the photoreceptor with which the proximity sensor shown in FIG. 1 was equipped. It is an equivalent circuit diagram which shows typically the photon detection part of the photoreceptor shown in FIG. It is sectional drawing for demonstrating one manufacturing process of a proximity sensor. It is sectional drawing for demonstrating the effect | action of a proximity sensor. It is sectional drawing for demonstrating the effect | action of a proximity sensor. It is a graph for demonstrating the reduction effect of the optical noise in the principal part of a proximity sensor. It is a graph for demonstrating the reduction effect of the optical noise in the principal part of a proximity sensor. It is sectional drawing of the proximity sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows an example of the conventional proximity sensor.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 to 12 show a proximity sensor according to a first embodiment of the present invention. As well shown in FIG. 2, the proximity sensor A <b> 1 includes a substrate 1, a light emitter 2, a light receiver 3, a first light transmissive member 4, a second light transmissive member 5, and a light shielding member 6.

  As shown in FIGS. 2 to 4, the substrate 1 has a mounting surface 10 and a back surface 11 on the opposite side. The mounting surface 10 and the back surface 11 are rectangular surfaces having the long side in the x direction and the short side in the y direction. A wiring pattern (not shown) is formed on the mounting surface 10 and the back surface 11. As shown in FIG. 2, the light emitter 2 and the light receiver 3 are mounted on the mounting surface 10 side by side in the x direction.

  The light emitter 2 is composed of an LED chip that emits infrared light. The light emitter 2 is connected to a wiring pattern on the mounting surface 10 via a bonding wire (not shown). The light emitter 2 has, for example, a 0.35 mm square shape. The light emitter 2 emits infrared light radially to some extent toward the side opposite to the mounting surface 10.

  The photoreceptor 3 is composed of an optical semiconductor chip capable of receiving visible light and infrared light. The photoreceptor 3 is connected to a wiring pattern on the mounting surface 10 via a bonding wire (not shown). The photoreceptor 3 has, for example, a 1.6 × 1.8 mm square shape.

  As shown in FIG. 8, the photoreceptor 3 includes a semiconductor substrate 30, a visible light detection unit 31, an infrared light detection unit 32, a functional element unit 33, and a laminated optical film 34. In the figure, the laminated optical film 34 is indicated by hatching for convenience.

  In the semiconductor substrate 30, a visible light detection unit 31, an infrared light detection unit 32, and a functional element unit 33 are built as semiconductor elements. The visible light detection unit 31 and the infrared light detection unit 32 are located in the central part of the semiconductor substrate 30. The functional element unit 33 is located around the visible light detection unit 31 and the infrared light detection unit 32. On the semiconductor substrate 30, a wiring layer conducting to the semiconductor element is formed in multiple layers (not shown). Of the wiring layer on the semiconductor substrate 30, portions corresponding to the infrared light detection unit 32 and the functional element unit 33 are covered with the laminated optical film 34. A portion of the wiring layer corresponding to the visible light detector 31 is exposed without being covered with the laminated optical film 34.

  The visible light detection unit 31 includes a plurality of photodiodes PDA1, PDA2, PDA3, PDB1, PDB2, and PDB3. The photodiodes PDA1, PDA2, and PDA3 are formed by providing a pn junction region at a predetermined depth in the semiconductor substrate 30. Thus, the photodiodes PDA1, PDA2, and PDA3 receive visible light and infrared light, and output a photocurrent corresponding to the amount of received light by photoelectric conversion. The photodiodes PDA1, PDA2, and PDA3 are formed with a relatively large area. On the other hand, the photodiodes PDB1, PDB2, and PDB3 are formed in the semiconductor substrate 30 by providing pn junction regions deeper than the previous photodiodes PDA1, PDA2, and PDA3. That is, in the photodiodes PDB1, PDB2, and PDB3, the peak of the spectral sensitivity characteristic is shifted to the long wavelength side. As a result, the photodiodes PDB1, PDB2, and PDB3 receive only infrared light, and output a photocurrent corresponding to the amount of received light by photoelectric conversion. The photodiodes PDB1, PDB2, and PDB3 are formed with a relatively small area.

  As shown in FIG. 9A, the pair of photodiodes PDA 1 and PDB 1 constitute a first light receiving unit 311. The pair of photodiodes PDA2 and PDB2 constitute a second light receiving unit 312. The pair of photodiodes PDA3 and PDB3 constitute a third light receiving unit 313. The photodiodes PDA1 and PDB1 of the first light receiving unit 311 are connected in series between the power supply potential Vcc and the ground potential. The photodiodes PDA2 and PDB2 of the second light receiving unit 312 and the photodiodes PDA3 and PDB3 of the third light receiving unit 313 are also connected in series between the power supply potential Vcc and the ground potential. The pairs of photodiodes PDA1, PDB1: PDA2, PDB2: PDA3, PDB3 paired in the first to third light receiving units 311 to 313 are set to different area ratios.

  In the first light receiving unit 311, a current I1 is output from between the photodiodes PDA1 and PDB1. This current I1 is obtained by subtracting the photocurrent including the infrared light component of the photodiode PDB1 from the photocurrent including the visible light component and the infrared light component of the photodiode PDA1. That is, the first light receiving unit 311 outputs a current I1 corresponding to the difference in the amount of received light according to the area ratio of the photodiodes PDA1 and PDB1. Similarly, the second light receiving unit 312 outputs a current I2 corresponding to the difference in received light amount according to the area ratio between the photodiodes PDA2 and PDB2. The third light receiving unit 313 outputs a current I3 corresponding to the difference in the amount of received light according to the area ratio between the photodiodes PDA3 and PDB3.

  The infrared light detection unit 32 includes a photodiode PDC. The photodiode PDC is formed by providing a pn junction region in the semiconductor substrate 30 at the same depth as the photodiodes PDB1, PDB2, and PDB3 described above. Thus, the photodiode PDC receives only infrared light and outputs a photocurrent corresponding to the amount of received light by photoelectric conversion. The photodiode PDC is formed to have a considerably larger area than the photodiode PDA1 of the visible light detector 31 and the like. As shown in FIG. 9B, the photodiode PDC is connected to the power supply potential Vcc and outputs a photocurrent Ic corresponding to the amount of received infrared light.

  In the functional element section 33, an analog circuit and a digital circuit are built. The functional element unit 33 captures currents I1 to I3 and Ic from the first light receiving unit 311, the second light receiving unit 312, the third light receiving unit 313, and the photodiode PDC. The functional element unit 33 calculates the amount of received infrared light as a digital value based on the photocurrent Ic from the photodiode PDC. When the amount of received infrared light exceeds a preset threshold value, the functional element unit 33 outputs a proximity signal indicating that there is an adjacent object to the outside. The functional element unit 33 calculates the received light amount of visible light as a digital value based on the currents I1 to I3 from the first light receiving unit 311, the second light receiving unit 312, and the third light receiving unit 313. The functional element unit 33 outputs an illuminance signal indicating the illuminance corresponding to the amount of visible light received to the outside.

  The laminated optical film 34 is made of a resin having translucency only for a long wavelength region corresponding to infrared light. Since the infrared light detection unit 32 and the functional element unit 33 are covered with the laminated optical film 34, only the infrared light is received without receiving visible light. On the other hand, since the visible light detection unit 31 is not covered with the laminated optical film 34, the visible light detection unit 31 reliably receives visible light.

  As shown in FIG. 2, the first light transmissive member 4 covers the photoreceptor 3 on the mounting surface 10. The 1st translucent member 4 consists of transparent resin which has translucency with respect to the wavelength range from visible light to infrared light. The first light transmissive member 4 has a first convex portion 40 at a portion facing the visible light detection unit 31 and the infrared light detection unit 32 of the photoreceptor 3 on the surface facing the z direction. The 1st convex part 40 is exhibiting the column shape, for example, an outer diameter is 1 mm. The 1st convex part 40 has the light-incidence surface 41 as an end surface which faces az direction. The light incident surface 41 is formed in a planar shape.

  As shown in FIG. 2, the second light transmissive member 5 covers the light emitting body 2 on the mounting surface 10. The second light transmissive member 5 is made of the same material as the first light transmissive member 4. The second light transmissive member 5 is formed together with the first light transmissive member 4 through a primary mold resin molding step. The 2nd translucent member 5 has the 2nd convex part 50 in the part which opposes the light-emitting body 2 in the surface which faces az direction. The 2nd convex part 50 has the light-projection surface 51 and a pair of notch surfaces 52A and 52B. The light emitting surface 51 forms a convex lens surface that bulges in the z direction. As shown in FIG. 5, outermost edges having a circular arc shape in plan view are formed on both sides in the y direction of the light emitting surface 51. The maximum diameter of the light emission surface 51 between the outermost edges is, for example, 0.44 mm. The pair of cutout surfaces 52A and 52B form a flat surface that is continuous with the light emitting surface 51 on both ends in the x direction. The cutout surfaces 52A and 52B are generally directed in the x direction. The cut-out surface 52A is located on the side closer to the photoreceptor 3. The notch surface 52B is located on the far side from the photoreceptor 3.

  As shown in FIG. 2, the light blocking member 6 covers the first light transmitting member 4, the second light transmitting member 5, and the entire mounting surface 10. The thickness dimension of the light shielding member 6 along the z direction on the mounting surface 10 is, for example, 1 mm. The light blocking member 6 blocks the first light transmitting member 4 and the second light transmitting member 5 in the x direction. The light shielding member 6 is made of a non-translucent resin that does not transmit visible light and infrared light. The light shielding member 6 is formed through a secondary mold resin molding step after the primary mold resin molding step. As shown in FIG. 1, the light shielding member 6 is formed in a square shape as a whole. As shown in FIGS. 1 and 5, the light shielding member 6 has a first surface 6A, a pair of second surfaces 6B and 6C, and a pair of third surfaces 6D and 6E. The first surface 6A forms a surface facing the z direction as a whole. The first surface 6A has, for example, a long side along the x direction of 5 mm and a short side along the y direction of 2.5 mm. The second surfaces 6B and 6C are substantially oriented in the x direction. The second surface 6B is located on the side closer to the light emitter 2. The second surface 6 </ b> C is located on the side closer to the photoreceptor 3. The third surfaces 6D and 6E are surfaces generally facing the y direction.

  As well shown in FIGS. 1 and 2, the first surface 6 </ b> A is provided with a first opening 61 and a second opening 62. The first opening 61 and the second opening 62 are aligned in the x direction, and the z direction is the depth direction. The depth dimension of the first opening 61 and the second opening 62 is, for example, 0.42 mm. The first opening 61 has the first protrusion 40 disposed therein, and exposes the light incident surface 41 in the z direction. The second opening 62 has the second protrusion 50 disposed therein, and exposes the light emitting surface 51 in the z direction. As shown in FIG. 5, the first opening 61 has an inner peripheral wall 610 having a circular shape in plan view. The inner diameter of the first opening 61 is, for example, 1.3 mm. In the plan view shown in the figure, the second opening 62 has an outer peripheral edge of the light emitting surface 51 and an inner peripheral wall 620 having a shape along the notch surface 52A. The maximum inner diameter along the y direction of the second opening 62 is, for example, 0.59 mm. As shown in FIG. 2 and FIG. 3, the first convex portion 40 is disposed with a gap between it and the inner peripheral wall 610. The light incident surface 41 is located on the far side in the depth direction from the outer edge 611 of the inner peripheral wall 610. As shown in FIG. 2 and FIG. 4, the second convex portion 50 is arranged with a gap between it and the inner peripheral wall 620. The topmost part of the light emitting surface 51 is located on the far side in the depth direction from the outer edge 621 of the inner peripheral wall 620.

  As shown in FIGS. 6 and 7, the inner peripheral wall 610 is formed of an inclined surface that approaches the center of the opening as it becomes deeper in the depth direction. The inclination angle of the inner peripheral wall 610 with respect to the depth direction increases as the distance from the light emitter 2 increases in the x direction. For example, the inner peripheral wall 610 includes a first portion 610A that is the closest to the light emitter 2, a second portion 610B that is located in the middle, and a third portion 610C that is the farthest. The first portion 610A has almost no inclination angle. The inclination angle of the portion between the first portion 610A and the second portion 610B gradually increases as it proceeds from the first portion 610A to the second portion 610B. The inclination angle α1 of the second portion 610B is, for example, 7.5 °. Further, the inclination angle of the portion between the second portion 610B and the third portion 610C gradually increases as it proceeds from the second portion 610B to the third portion 610C. The inclination angle α2 of the third portion 610C is set to, for example, 15 ° as the maximum inclination angle. The maximum inclination angle may be set to 15 ° or more according to the depth dimension, the inner diameter, and the like of the first opening.

  As shown in FIG. 2 and FIG. 4, the inner peripheral wall 620 is formed of an inclined surface that approaches the opening center side as it goes to the back side in the depth direction. The inclination angle of the inner peripheral wall 620 with respect to the depth direction is set to a substantially uniform angle over the entire circumference. As shown in FIGS. 1 and 5, the inner peripheral wall 620 includes a pair of first portions 620A and a second portion 620B. The first portion 620 </ b> A has an arc shape in plan view and is along the outermost edge of the light emitting surface 51. The second portion 620B has a planar shape and faces the notch surface 52A. The inner peripheral wall 620 is opened without forming a wall surface on the side far from the photoreceptor 3 in the x direction. Thereby, the inner peripheral wall 620 exposes the notch surface 52B in the x direction. As shown in FIGS. 1 and 2, the second surface 6B has an open portion 6b following the second opening 62, and a part of the second light transmissive member 5 is exposed in the open portion 6b.

  As shown in FIGS. 1 and 2, a large number of grooves 63 extending in the y direction are formed on the entire first surface 6A. In particular, a light scattering region LS is formed by the plurality of grooves 63 between the first opening 61 and the second opening 62. As shown well in FIG. 6, the plurality of grooves 63 have a plurality of inclined surfaces 630 inclined with respect to the x direction. The inclination angle β of the inclined surface 630 with respect to the x direction is set to 50 ° to 70 °. In FIG. 5, the groove 63 is omitted. In the present embodiment, the plurality of grooves 63 are formed on the entire first surface 6 </ b> A, but the grooves 63 may be formed only between the first opening 61 and the second opening 62.

  As shown in FIG. 10, when the light shielding member 6 is formed by the secondary mold resin molding process at the time of manufacture, it has a cylindrical portion 70 corresponding to the shape of the first opening 61 and the second opening 62. A mold 7 is used. In the figure, a cylindrical portion 70 corresponding to the first opening 61 is shown. The cylindrical portion 70 of the mold 7 is disposed around the first convex portion 40 and the second convex portion 50 and is removed after the resin is cured. As a result, the inner peripheral wall 610 of the first opening 61 is formed without contacting the first convex portion 40. This prevents the resin constituting the light shielding member 6 from adhering to the light incident surface 41. Similarly, the inner peripheral wall 620 of the second opening 62 is formed without being in contact with the second convex portion 50, and the resin constituting the light shielding member 6 is prevented from adhering to the light emitting surface 51.

  Next, the optical action of the proximity sensor A1 will be described.

  As shown in FIGS. 11 and 12, the proximity sensor A1 is incorporated into a mobile phone terminal including a liquid crystal touch panel type liquid crystal display unit D, for example. Proximity sensor A1 is arrange | positioned in the vicinity of the liquid crystal display part D, and is covered with the translucent cover C made from an acrylic etc. with the liquid crystal display part D. FIG. The proximity sensor A1 is disposed with a distance d between the proximity sensor A1 and the translucent cover C. The distance d is, for example, about 0.25 to 1 mm. The proximity sensor A <b> 1 of the present embodiment detects an illuminance by the visible light detection unit 31 of the light receiver 3 and also detects an object close to the liquid crystal display unit D using the infrared light L of the light emitter 2.

  Infrared light L emitted from the light emitter 2 travels toward the light-transmitting cover C through the light emitting surface 51. Further, the infrared light L passes through the light-transmitting cover C and hits and reflects the object M located outside thereof. A part of the infrared light L reflected by the object M passes through the transparent cover C again. Finally, part of the infrared light L passes through the light incident surface 41 and is received by the infrared light detector 32 of the photoreceptor 3. When there is no object outside the translucent cover C, the light transmitted through the translucent cover C toward the outside is not received by the infrared light detection unit 32 by traveling as it is.

  The infrared light detection unit 32 outputs a photocurrent Ic corresponding to the amount of received infrared light L to the functional element unit 34. When the photocurrent Ic exceeds a preset threshold value, the functional element unit 34 recognizes that there is an object M close to the liquid crystal display unit D, and outputs a proximity signal to the outside.

  On the other hand, the infrared light L that has exited the light exit surface 51 also includes light having a relatively large incident angle with respect to the translucent cover C. Such infrared light L is reflected by the inner surface of the translucent cover C and becomes noise light L ′. Part of the noise light L ′ travels toward the light scattering region LS and the first opening 61.

  At this time, in the second opening 62, the light emission surface 51 is located on the far side in the depth direction from the outer edge 621 of the inner peripheral wall 620. Therefore, light traveling from the light emitting surface 51 in a direction with a larger incident angle with respect to the translucent cover C is effectively blocked by the inner peripheral wall 620. Thereby, the noise light L ′ reflected toward the first opening 61 on the inner surface of the translucent cover C is reduced.

  In addition, in the second opening 62, the infrared light L is also emitted from the cutout surface 52B. The infrared light L travels directly to the opposite side of the first opening 61 in the x direction without hitting the inner peripheral wall 620. This also reduces the noise light L ′ traveling toward the first opening 61.

  In the light scattering region LS, part of the noise light L ′ is reflected by the inclined surface 630 of the groove 63. As a result, the noise light L ′ is likely to travel toward the second opening 62 in the x direction. Therefore, according to the light scattering region LS, the noise light L ′ traveling toward the first opening 61 is reduced.

  FIG. 13 shows, by simulation, the received light amount of the optical noise L ′ received by the photoreceptor 3 in accordance with the inclination angle of the slope 630 with respect to the distance d between the proximity sensor A1 and the transparent cover C as a relative value. It is a chart. In the figure, the output level of the photoreceptor when the first surface is a flat surface is “1” as the reference value of the optical noise. According to the figure, when the inclination angle of the inclined surface 630 is 50 °, 60 °, and 70 °, the optical noise L received by the light receiver 3 even if the distance d changes in the range of 0.25 to 1 mm. It is understood that 'is effectively reduced.

  In the first opening 61, the light incident surface 41 is located on the far side in the depth direction from the outer edge 611 of the inner peripheral wall 610. Therefore, a part of the noise light L ′ that is about to enter the light incident surface 41 can be blocked by the outer edge 611 of the inner peripheral wall 610. Thereby, the noise light L ′ that reaches the photoreceptor 3 through the light incident surface 41 is reduced.

  As shown in FIG. 12, in the first opening 61, part of the noise light L ′ enters the inside. Part of the noise light L ′ that has entered the first opening 61 hits the third portion 610 </ b> C of the inner peripheral wall 610 and is reflected. The third portion 610 </ b> C approaches the light incident surface 41 toward the back in the depth direction, and is relatively largely inclined with respect to the depth direction (z direction). Therefore, part of the noise light L ′ deviates from the light incident surface 41 and travels toward the first portion 610 </ b> A. Therefore, the noise light L ′ incident on the light incident surface 41 can be reduced.

  FIG. 14 is a chart showing the light reception amount of the optical noise L ′ received by the photoreceptor 3 as a relative value with respect to the inclination angle α2 of the third portion 610C of the inner peripheral wall 610 by simulation. In the figure, the output level of the photoreceptor when the inner peripheral wall is inclined at 0 ° over the entire circumference is set to “100%” as the reference value of the optical noise. As can be seen from the drawing, when the inclination angle α2 is 15 ° or more, the optical noise L ′ is substantially reduced to the lower limit level.

  Therefore, according to the proximity sensor A1 according to the first embodiment, it is possible to make it difficult to pick up the noise light L ′ in the state covered with the light-transmitting cover C. Thereby, in the proximity sensor A1 incorporated in the mobile phone terminal, when there is no object in the vicinity of the liquid crystal display unit D, it is possible to reduce erroneous detection that behaves as if by the noise light L ′.

  FIG. 15 shows a proximity sensor according to the second embodiment of the present invention. In the proximity sensor A2 shown in the figure, a large number of grooves 63 having a rectangular cross section are formed on the entire first surface 6A. The proximity sensor A2 is the same as the proximity sensor A1 according to the first embodiment described above in other points. In the light scattering region LS, the noise light L ′ is also effectively scattered by the plurality of grooves 63 having a rectangular cross section. Thereby, the noise light L ′ traveling toward the first opening 61 can be reduced.

  In addition, this invention is not limited to embodiment mentioned above. The specific configuration of the proximity sensor according to the present invention can be varied in design in various ways.

A1, A2 Proximity sensor LS Light scattering region 1 Substrate 2 Light emitter 3 Light receiver 4 First light transmitting member 40 First convex portion 41 Light incident surface 5 Second light transmitting member 50 Second convex portion 51 Light emitting surface 52A, 52B Notch surface 6 Light shielding member 61 First opening 610 Inner peripheral wall 611 Outer edge 62 Second opening 620 Inner wall 621 Outer edge 63 Groove 630 Slope

Claims (20)

A light emitter;
A light receiving body that is positioned side by side with the light emitting body and that receives the light emitted from the light emitting body and reflected by an external object;
A first light transmissive member covering the light receiver;
A light shielding member having a first opening that covers the first light transmissive member and exposes a part of the surface of the first light transmissive member as a light incident surface;
A proximity sensor comprising:
The proximity sensor according to claim 1, wherein the light incident surface is provided on a deeper side in a depth direction than an outer edge of an inner peripheral wall of the first opening.   2. The proximity sensor according to claim 1, wherein the inner peripheral wall of the first opening is formed of an inclined surface that approaches the center of the opening toward the back in the depth direction.   3. The proximity sensor according to claim 2, wherein the inner peripheral wall of the first opening portion has an inclination angle with respect to a depth direction that increases with distance from the light emitter in the first direction.   4. The proximity sensor according to claim 3, wherein the inner peripheral wall of the first opening has an inclination angle of 15 ° or more with respect to a depth direction of a portion farthest from the light emitter in the first direction.   The said 1st translucent member has a 1st convex part arrange | positioned in the said 1st opening part, The said light-incidence surface is an end surface of the said 1st convex part in any one of Claim 1 thru | or 4 The proximity sensor described.   The proximity sensor according to claim 5, wherein an end surface of the first convex portion is formed in a planar shape.   The proximity sensor according to claim 5 or 6, wherein the first convex portion is disposed with a gap between the first convex portion and an inner peripheral wall of the first opening. A substrate on which the light emitter and the light receiver are mounted side by side in the first direction;
A second light transmissive member covering the light emitter,
The light-shielding member shields the first light-transmissive member and the second light-transmissive member on the substrate, covers them together, and exposes a part of the surface of the second light-transmissive member as a light emitting surface. The proximity sensor according to claim 1, which has two openings on the same side as the first opening.   9. The proximity sensor according to claim 8, wherein the light emitting surface is provided on a deeper side in a depth direction than an outer edge of an inner peripheral wall of the second opening.   10. The proximity sensor according to claim 8, wherein an inner peripheral wall of the second opening portion is formed of an inclined surface that approaches the opening center side as the depth side is closer to the depth direction.   The proximity sensor according to claim 8, wherein the light shielding member has a light scattering region between the first opening and the second opening.   The depth direction of the first opening and the second opening is orthogonal to the first direction, and the light scattering region includes the depth direction of the first opening and the second opening and the first direction. The proximity sensor according to claim 11, wherein a plurality of grooves extending in a second direction orthogonal to both directions are formed.   The proximity sensor according to claim 12, wherein the plurality of grooves have a plurality of inclined surfaces inclined with respect to the first direction.   The proximity sensor according to claim 13, wherein the slope has an inclination angle with respect to the first direction set to 50 ° to 70 °.   The said 2nd translucent member has a 2nd convex part arrange | positioned in the said 2nd opening part, The said light-projection surface is contained in the said 2nd convex part in any one of Claim 8 thru | or 14. Proximity sensor.   The proximity sensor according to claim 15, wherein the light emitting surface is formed in a convex shape.   17. The proximity sensor according to claim 16, wherein the second convex portion has a pair of flat cutout surfaces that are continuous with the light emitting surface on both ends in the first direction.   The inner peripheral wall of the second opening is a portion facing the notch surface on the side close to the light receiver while exposing the notch surface on the side far from the light receiver toward the first direction. The proximity sensor according to claim 17, comprising:   The proximity sensor according to claim 18, wherein the notch surface on the side close to the photoreceptor is disposed with a gap between the cutout surface and the inner peripheral wall of the second opening.   The proximity sensor according to claim 1, wherein the light emitter is an LED that emits infrared light.

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