JP2006189949A - Image detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a bad influence due to an infrared ray transmitted through a substrate for improvement of detection accuracy in a fingerprint sensor detecting a fingerprint by using scattered light inside a finger. <P>SOLUTION: A solid pattern 90 is arranged in an area for mounting a linear optical sensor chip 52 on the upper face of the substrate 51. The pattern 90 is provided with a mounting area corresponding part 91 corresponding to a linear optical sensor chip mounting area 83 and expansion area parts 92X1, 92X2, 99Y1, and 99Y2 expanding from the mounting area corresponding part 91 in the whole circumference directions. The expansion area parts 92X1, 92X2, 99Y1, and 99Y2 restrict leakage of the infrared ray 10B, which is transmitted through the substrate, to the upper face of the substrate 51 in the circumference part of the linear optical sensor chip 52. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image detection apparatus, and more particularly, to a line-type optical sensor that uses scattered light in a finger that is scattered inside the fingertip and exits from the surface of the fingertip, and in which light receiving elements are arranged in a straight line. The present invention relates to an image detection apparatus that is configured to collect a fingerprint by sliding a fingertip.

  In recent years, from the viewpoint of security, electronic devices such as computers and portable communication devices such as mobile phones have been required to include a fingerprint sensor as an image detection device for identifying fingerprints of fingers of a hand for personal authentication. . Here, in addition to being small in size so that it can be incorporated into a small device such as a portable communication device, the fingerprint sensor is required to be highly resistant to noise and high in detection accuracy.

  10 to 12 show a conventional fingerprint sensor 20. Each figure is shown through the inside so that the internal structure can be easily understood. FIG. 12 is a cross section taken along the vertical plane SXII in FIG. X1-X2 is the longitudinal direction, Y1-Y2 is the width direction, and Z1-Z2 is the thickness direction.

  The fingerprint sensor 20 is a system that uses scattered light in the finger and collects fingerprints by sliding the finger, and the light receiving elements 22a are formed in a straight line on a substrate 21 made of glass epoxy resin. The linear light sensor chip 22, the infrared light emitting diode chips 23-1 to 23-5 and the chip capacitors 27-1 and 27-2 are mounted, and the light guide image guide is mounted on the linear light sensor chip 22. The member 24 is mounted, the light guide member 25 is mounted by an adhesive portion so as to straddle the infrared light emitting diode chips 23-1 to 23-5, and the whole is a light-shielding synthetic resin mold portion It is covered and surrounded by 28 and has an integrated structure.

  The substrate 21 has a plurality of pads 30 for mounting the infrared light emitting diode chips 23-1 to 23-5 and a plurality of pads 31 for mounting the chip capacitors 27-1 and 27-2 on the upper surface. It is formed.

The fingerprint sensor 20 is attached to the casing of the mobile phone as shown in FIG. When collecting a fingerprint, as shown in FIG. 12, the fingertip 1 is pressed against the upper surface 20a of the fingerprint sensor 20, and in this state, an operation of sliding in the Y2 direction is performed. The infrared light emitting diode chips 23-1 to 23-5 emit light, and the infrared illumination light 10 passes through the light guide member 25, exits from the upper surface of the fingerprint sensor 10, enters the fingertip 1, and enters the fingertip 1. Scattered by the tissue as shown at 12. In-finger scattered light emitted from the surface of the part of the fingertip 1 that is in contact with the upper surface of the light guide image guide member 24 passes through the light guide image guide member 24 and reaches the light receiving element 22a of the linear optical sensor chip 22, Information from the linear optical sensor chip 22 is processed to obtain linear fingerprint information of a portion of the fingertip 1 that is in contact with the light guide image guide member 24. By sliding the fingertip 1, the linear fingerprint information obtained from time to time is combined to obtain the surface fingerprint information of the fingertip 1. A portion 28 a between the light guide member 25 and the linear optical sensor chip 22 in the light-shielding synthetic resin mold portion 28 shields the infrared illumination light 10 leaking from the light guide member 25 in the Y1 direction.
U.S. Pat. No. 4,932,776 JP 2003-21732 A

  The light guide image guide member 24 is bonded and mounted on the linear optical sensor chip 22. Therefore, when there are a lot of adhesives, the adhesive protrudes to the surroundings and the adhesive part 29 is formed. The protruding adhesive portion 29 transmits light.

  The infrared light emitting diode chips 23-1 to 23-5 emit the infrared illumination light 10 not only from the upper surface but also from the lower back surface. Further, the substrate 21 made of glass epoxy resin has a property of passing the infrared illumination light 10. For this reason, as indicated by reference numeral 10A in FIG. 12, the infrared light emitted from the back surface of the infrared light emitting diode chip 23-3 enters the substrate 21, and becomes the in-substrate transmitted infrared light 10B. A part of the light 10B1 propagates through the protruding adhesive part 29 and enters the light receiving element 22a from the side surface of the linear optical sensor chip 22. Further, a part of the light 10B2 may pass through the linear optical sensor chip 22 from the back surface of the linear optical sensor chip 22 and enter the light receiving element 22a. This transmitted infrared light 10B in the substrate is an input of light unnecessary for the linear optical sensor chip 22, and becomes noise for the above-described linear fingerprint information, resulting in a decrease in accuracy of the linear fingerprint information.

  Accordingly, an object of the present invention is to provide an image detection apparatus that solves the above-described problems.

The present invention provides an image detection device having a configuration in which an optical sensor chip and a light emitting element member are mounted on an upper surface of a substrate, and a light guide image guide member is mounted on the optical sensor chip.
A light emitting element that is solid on the upper surface of the substrate and that expands in the direction of the light emitting element member across the mounting area corresponding portion in addition to the mounting area corresponding portion corresponding to the area where the optical sensor chip is mounted It has the structure which has the pattern of the magnitude | size which has a member side expansion area part.

  According to the present invention, on the upper surface of the substrate, in addition to the mounting area corresponding portion, the light emitting element member side enlarged area portion that extends beyond the mounting area corresponding portion in the direction of the light emitting element member is formed. A certain pattern restricts leakage of light transmitted through the substrate that is emitted from the back surface of the light emitting element member, enters the substrate, and propagates through the substrate, from the upper surface of the substrate. Therefore, it is possible to prevent the adverse effect of the transmitted light in the substrate on the optical sensor chip, and it is possible to detect an image with less noise.

  Next, an embodiment of the present invention will be described.

  1, FIG. 2, FIG. 3 (A), (B) and FIG. 4 show a fingerprint sensor 50 according to Embodiment 1 of the present invention. FIG. 1 is an exploded view of the fingerprint sensor 50 shown in FIG. 2, 3 </ b> A, and 3 </ b> B are shown through the inside so that the internal structure can be easily understood. FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. X1-X2 is the longitudinal direction, Y1-Y2 is the width direction, and Z1-Z2 is the thickness direction.

  The fingerprint sensor 50 as an image detection device is a system that uses scattered light within a finger and is configured to collect a fingerprint by sliding the finger. A linear light sensor chip 52 and infrared light emission are formed on the upper surface of a substrate 51. The diode chips 53-1 to 53-5 and the chip capacitors 57-1 and 57-2 are mounted, wire-bonded and a wire 59 is stretched between the linear optical sensor chip 52 and the substrate 51. Further, The light guide image guide member 60 is bonded and mounted on the linear optical sensor chip 52, and the light guide member 70 is mounted by an adhesive portion so as to cover the infrared light emitting diode chips 53-1 to 53-5. Furthermore, the entire structure is covered and surrounded by the light-shielding synthetic resin mold portion 58 and integrated. 59a is a wire bonding portion of the wire 59 on the substrate 51.

  The substrate 51 is made of glass epoxy resin, and a pad 80 for mounting the infrared light emitting diode chips 53-1 to 53-5 and chip capacitors 57-1 and 57-2 are mounted on the upper surface 51a. A pad 81, a solid copper pattern 90, and the like are formed.

  The linear optical sensor chip 52 has an elongated rectangular shape, and has a structure in which a large number of light receiving elements 52a are formed in a straight line on the upper surface.

  The infrared light emitting diode chips 53-1 to 53-5 are divided into two, one, and two, and are arranged along the linear optical sensor chip 52.

  The distance between the photosensor chip 52 and the infrared light emitting diode chips 53-1 to 53-5 in the X1-X2 direction is A1. The distance A1 is longer than the corresponding distance A in FIG.

  The light guide image guide member 60 is a configuration in which an infinite number of optical fiber pieces 61 are densely arranged in an oblique posture inclined by 40 degrees in the X2 direction from a vertical posture, and has a rectangular parallelepiped shape that is long in the X1-X2 direction. Have. As will be described later, the light guide image guide member 60 has a function of selectively guiding scattered light from the fingertip to the linear optical sensor chip 52.

  The light guide member 70 has a shape in which the upper surface of the rectangular parallelepiped is inclined in the Y1 direction with respect to the bottom surface and inclined at an angle α (about 13 degrees), and the shape viewed from the X2 side is a parallelogram. On the bottom side, recesses 75, 76 and 77 in which the light emitting diode chip 53-1 and the like are received are formed. The concave portions 75, 76, 77 do not penetrate to the Y1 side, and wall portions 78, 79, 80 are formed on the Y1 side of the concave portions 75, 76, 77.

  The light guide member 70 has the recesses 75, 76, and 77 formed on the upper surfaces of the infrared light emitting diode chips 53-1 to 53-5. 5 and is positioned as will be described later, and adhesion within the gap between the inner surface of each recess 75, 76, 77 and the surface of the infrared light emitting diode chips 53-1 to 53-5. It is bonded and mounted by the agent part.

  The light guide member 70 is inclined to the light guide image guide member 60 side, and the distance B1 between the light guide image guide member 60 and the light guide member 70 on the upper surface 50a of the fingerprint sensor 50, that is, the light guide image. A distance B1 between the upper surface 62 of the guide member 60 and the upper surface 72 of the light guide member 70 is shorter than the corresponding distance B in FIG.

  The synthetic resin mold part 58 has a light shielding property. A portion of the synthetic resin mold portion 58 that fills between the light guide member 70 and the light guide image guide member 60 forms a light shielding wall portion 58a.

  In FIG. 1, reference numeral 83 denotes an area where the linear optical sensor chip 52 is mounted. Reference numeral 85 denotes an area where the light guide member 70 is mounted.

  The solid pattern 90 includes a mounting area corresponding portion 91 corresponding to the linear optical sensor chip mounting area 83 and an enlarged area portion that expands all around the mounting area corresponding portion 91, that is, an expansion that expands in the X1 direction. The area portions 92X1 and 92X2 are enlarged in the direction X2, the enlarged area portion 92Y1 is enlarged in the Y1 direction, and the enlarged area portion 92Y2 is enlarged in the Y2 direction. The pattern 90 is solid and not a mesh.

  The enlarged area portion 92Y2 enlarged in the Y2 direction is formed up to the light guide member mounting area 85, and the edge portion 92Y2a of the enlarged area portion 92Y2 forms a slight step with respect to the upper surface 51a of the substrate 51. , Which coincides with the Y1 side edge of the light guide member mounting area 85 and is used for positioning the light guide member 70.

  As shown in FIG. 4, the light guide member 70 is mounted with its position determined by abutting the edge portion on the Y1 side of the surface on the Z2 side against the edge portion 92Y2a. Therefore, the light guide member 70 is simply positioned and mounted.

  Similarly, as shown in FIG. 4, the solid pattern 90 occupies the peripheral portion of the linear photosensor chip 52 in addition to the lower portion of the mounted linear photosensor chip 52. The portion 92Y2 occupies a region between the linear optical sensor chip 52 and the light guide member 70, and transmits infrared light propagating through the glass epoxy resin substrate 51 to the light receiving element 52a as described later. And has a role of shielding light. This light shielding will be described later.

  The fingerprint sensor 20 is attached to the housing of the device as shown in FIG. When collecting a fingerprint, the fingertip 1 is pressed against the upper surface 50a of the fingerprint sensor 50 and slid in the Y2 direction as shown in FIG.

  The infrared light emitting diode chips 53-1 to 53-5 emit light, and the infrared illumination light 10 passes through the adhesive portion, enters the light guide member 70, passes through it, and shines uniformly from the upper surface 72, It exits from the upper surface 50 a of the fingerprint sensor 50, enters the fingertip 1, and is scattered by the tissue in the fingertip 1 as indicated by reference numeral 12.

  As shown in an enlarged view in FIG. 6, scattered light within the finger that has come out from the surface of the part of the fingertip 1 that is in contact with the fingerprint sensor 50 enters the light guide image guide member 60 from the upper surface 62. Of the incident light, the light 13 b that has exited from the concave portion 1 b and once entered the light guide image guide member 60 through the space 15 is absorbed in the light guide image guide member 60 and reaches the linear optical sensor chip 52. Instead, the light 13a that has exited from the convex portion 1a and is directly incident on the light guide image guide member 60 is totally reflected in the light guide image guide member 60 and reaches the light receiving element 52a of the linear light sensor chip 52. Information from the chip 52 is processed to obtain linear fingerprint information of a portion of the fingertip 1 that is in contact with the light guide image guide member 60. By sliding the fingertip 1, the portion of the fingertip 1 that is in contact with the light guide image guide member 60 moves to the fingertip side, and the linear fingerprint information obtained from time to time is combined with the fingertip 1. Planar fingerprint information can be obtained.

  Here, with reference to FIG. 5, the behavior of the transmitted infrared light 10B in the substrate that is emitted from the back surface of the infrared light emitting diode chip 53-3, enters the substrate 51, and propagates through the substrate 51 will be described.

  Part of the in-substrate transmitted infrared light 10B travels toward the linear optical sensor chip 52 and tends to exit from the upper surface of the substrate 51 in the Z1 direction as indicated by reference numeral 10B1.

  However, in the present invention, first, the enlarged area portion 92Y2 of the solid copper pattern 90 is present, so that the enlarged area portion 92Y2 is a portion between the linear optical sensor chip 52 and the light guide member 70. In FIG. 5, the in-substrate transmitted infrared light 10B1 that is about to exit in the Z1 direction from the upper surface of the substrate 51 is shielded to prevent it from exiting in the Z1 direction from the upper surface of the substrate 51. Therefore, a part of the adhesive used when the light guide image guide member 60 is mounted on the upper surface of the linear optical sensor chip 52 overflows to the light guide member 70 side and the adhesive part 29 is formed. Even if it exists, it will be restrict | limited that the transmitted infrared light 10B1 in a board | substrate protrudes and enters into the adhesive agent part 29. FIG. Further, even when the protruding adhesive portion 29 is not formed, the in-substrate transmitted infrared light 10B1 is also restricted from entering the boundary 100 between the Y2 side edge of the linear optical sensor chip 52 and the light shielding wall portion 58a.

  First, since the mounting area portion 91 of the solid copper pattern 90 exists, the mounting area portion 91 protrudes from the upper surface of the substrate 51 in the Z1 direction at a position directly below the linear photosensor chip 52. The in-substrate transmitted infrared light 10 </ b> B <b> 2 is shielded so that the in-substrate transmitted infrared light 10 </ b> B <b> 2 reaches the lower surface of the linear optical sensor chip 52.

  Therefore, the in-substrate transmitted infrared light 10 </ b> B travels from the side surface side of the linear photosensor chip 52 and enters the light receiving element 52 a, and the backside of the linear photosensor chip 52 transmits through the linear photosensor chip 52. From being incident on the light receiving element 52a. As a result, generation of noise is suppressed, and fingerprint information can be obtained with higher accuracy than in the past.

  In addition to the enlarged area portion 92Y2, the pattern 90 includes an enlarged area portion 92X1 that is enlarged in the X1 direction, an enlarged area portion 92X2 that is enlarged in the X2 direction, and an enlarged area portion 92Y1 that is enlarged in the Y1 direction. Therefore, the in-substrate transmitted infrared light 10B is also restricted from going around from the Y1, X1, and X2 sides toward the light receiving element 52a. This also suppresses the generation of noise, and fingerprint information can be obtained with higher accuracy.

  Further, as shown in FIG. 4, the distance A1 is longer than the distance A. Therefore, the influence of the infrared light emitting diode chips 23-1 to 23-5 on the optical sensor chip 52 is difficult compared to the conventional case. The distance B1 is shorter than the distance B. Therefore, the position where the light is emitted from the light guide member 70 and the position where the light is incident on the light guide image guide member 60 are close to each other. Fingerprint information can be obtained with higher accuracy than in the past by increasing the intensity of light that exits from the portion in contact with the optical image guide member 60 and enters the light guide image guide member 60. It is done.

  7, 8 and 9 show a fingerprint sensor 50A according to the second embodiment of the present invention. FIG. 7 shows an exploded view of the fingerprint sensor 50A. FIG. 8 is an enlarged cross-sectional view taken along a vertical plane including the line VIII-VIII in FIG. FIG. 9 is an enlarged cross-sectional view taken along a vertical plane including the line IX-IX in FIG.

  The fingerprint sensor 50A limits the transmission of the in-substrate transmitted infrared light 10B traveling toward the linear optical sensor chip 52 in the Z1 direction from the upper surface of the substrate 51 in the same manner as the fingerprint sensor 50 according to the first embodiment. In addition, the amount of in-substrate transmitted infrared light 10B traveling toward the linear optical sensor chip 52 is reduced.

  The fingerprint sensor 50A is different from the fingerprint sensor 50 shown in FIG. 1 in the following configuration.

  The substrate 51 </ b> A has a plurality of through holes 110 arranged side by side in the enlarged area portion 92 </ b> Y <b> 2 of the copper solid pattern 90, particularly in the portion corresponding to the pad 80. As shown in FIG. 8, the through hole 110 has a structure having a copper plating film 111 on the inner peripheral surface. The through hole 110 is filled and filled with a light-shielding synthetic resin when the synthetic resin mold portion 58 is formed. In FIG. 8, reference numeral 112 denotes a light-shielding synthetic resin cylindrical portion filling the through hole 110.

  Further, as shown in FIG. 7, the substrate 51 </ b> A has a through-hole 120 in a portion corresponding to the pad 80 on the outer side of the pattern 90. The through-hole 120 is filled and filled with a light-shielding synthetic resin when the synthetic resin mold portion 58 is formed. In FIG. 9, reference numeral 121 denotes a light-shielding synthetic resin cylindrical portion filling the through hole 120.

  As shown in FIG. 8, a part of the in-substrate transmitted infrared light 10 </ b> B that is emitted from the back surface of the infrared light-emitting diode chip 53-3, enters the substrate 51, and propagates through the substrate 51 is part of the through hole 110. It hits the copper plating film 111 on the inner peripheral surface of the film and is blocked here, and further propagation in the Y1 direction is limited. Further, as shown in FIG. 9, a part of the in-substrate transmitted infrared light 10 </ b> B that is emitted from the back surface of the infrared light emitting diode chip 53-2, enters the substrate 51, and propagates through the substrate 51 passes through. It hits the light-shielding synthetic resin cylindrical portion 121 in the hole 120 and is blocked here, and further propagation in the Y1 direction is restricted.

  Therefore, the amount of in-substrate transmitted infrared light 10B1 traveling toward the linear optical sensor chip 52 is reduced, noise generation is further suppressed as compared with the first embodiment, and fingerprint information is further reduced as compared with the first embodiment. Obtained with high accuracy.

  Instead of the structure in which a plurality of through holes 110 and through holes 120 are formed in the substrate 51A and the through holes 120 are filled with a light-shielding synthetic resin, the through holes 110 and the through holes 120 are formed in the substrate 51A. A groove may be formed in the portion, and the groove may be filled with a light-shielding synthetic resin.

  In addition, as the size of the solid pattern 90 of the present invention having an enlarged area portion that is expanded all around from the mounting area corresponding portion 91 corresponding to the linear optical sensor chip mounting area 83, the transmitted infrared light 10B in the substrate is The technical idea of trying to limit leakage from the upper side of the substrate is an area-type photosensor chip in which the photosensor chip is arranged in a matrix, and the light guide image guide member has a cross section. The present invention is also applicable when the size corresponds to the fingertip.

It is a disassembled perspective view of the fingerprint sensor which becomes Example 1 of this invention. It is a perspective view of the fingerprint sensor which becomes Example 1 of the present invention. (A) is a top view of the fingerprint sensor of FIG. 2, (B) is a front view. FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. It is a figure which shows a state when fingerprint information is obtained. It is a figure which shows the state which the light emitted from the fingertip propagates in the inside of a light guide image guide member. It is a disassembled perspective view of the fingerprint sensor which becomes Example 2 of this invention. FIG. 8 is a cross-sectional view showing an enlarged view of a vertical plane including a line VIII-VIII in FIG. 7. FIG. 8 is an enlarged cross-sectional view taken along a vertical plane including the line IX-IX in FIG. 7. It is a perspective view of a conventional fingerprint sensor. It is a disassembled perspective view of the fingerprint sensor of FIG. FIG. 11 is a cross-sectional view taken along the vertical plane SXII in FIG. 10 and shows a state when fingerprint information is obtained.

Explanation of symbols

10B In-substrate transmitted infrared light 50, 50A Fingerprint sensor 51 Substrate 52 Optical sensor chip 52a Light receiving element 53-1 to 53-5 Infrared light emitting diode chip 58 Synthetic resin mold part 60 Light guide image guide member 70 Light guide member 90 Solid Pattern 91 Mounting area corresponding part 92X1, 92X2, 92Y1, 92Y2 Enlarged area part 110 Through hole 111 Copper plating film 112 Light shielding synthetic resin cylindrical part 120 Through hole 121 Light shielding synthetic resin cylindrical part

Claims (5)

In the image detection device having a configuration in which the light sensor chip and the light emitting element member are mounted on the upper surface of the substrate, and the light guide image guide member is mounted on the light sensor chip.
A light emitting element that is solid on the upper surface of the substrate and that expands in the direction of the light emitting element member across the mounting area corresponding portion in addition to the mounting area corresponding portion corresponding to the area where the optical sensor chip is mounted An image detection apparatus having a pattern having a size having a member-side enlarged area portion. The image detection apparatus according to claim 1,
The pattern on the upper surface of the substrate has an enlarged area portion that is enlarged in a direction different from the direction of the light emitting element member in addition to the enlarged area portion on the light emitting element member side. . In the image detection device according to claim 1 or 2,
The image detection apparatus according to claim 1, wherein the substrate has a plurality of through holes in the enlarged area portion on the light emitting element member side of the pattern. In the image detection device according to claim 1 or 2,
The image detection apparatus according to claim 1, wherein the substrate has a portion filled with a light-shielding resin at a position between the light emitting element member and the optical sensor chip. In the image detection device according to claim 1 or 2,
A light guide member for guiding light from the light emitting element member to the upper surface of the image detection device;
The light emitting element member side enlarged area portion of the pattern on the upper surface of the substrate is formed so that the edge thereof coincides with the edge of the mounting area of the light guide member,
An image detection apparatus characterized in that the light guide member is configured to abut on the edge of the light emitting element member side enlarged area portion to determine the position.

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