JP2008167792A - Biological information acquisition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that there are the case that the wavelength of light to be radiated can not be selected on the basis of the sensitivity characteristics of an imaging apparatus and the case that images of excellent quality can not be acquired. <P>SOLUTION: The biological information acquisition device D1 for emitting inspection light to a living body part, receiving reflected light from the living body part and picking up images comprises: a light emitting device 4a for generating the inspection light; the imaging apparatus 31 provided with an imaging region R2 including a plurality of pixels PX and having higher sensitivity to the light of the wavelength different from the wavelength of the inspection light; and a wavelength conversion element 60 for converting the inputted inspection light to the light of the wavelength different from the wavelength of the inspection light so as to increase the sensitivity of the imaging apparatus 31 and outputting it to the imaging region R2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biological information acquisition device.

  In modern information society, security technology for personal property and information is regarded as important. A system that uses a signature, a personal identification number, or fingerprint verification as a means of personal identification has been developed for personal authentication at the entrance, such as using a credit card or depositing a bank deposit. Among them, attention has been focused on personal authentication technology (so-called biometrics personal authentication technology) using information (biological information) in a biological part as a personal authentication technology excellent in convenience and confidentiality.

  Biometrics personal authentication technology that uses fingerprints, irises, voices, faces, and veins is being studied. Authentication by face or voice is not high. Therefore, it still takes time to put the authentication technology using face and voice into practical use. On the other hand, in personal authentication using veins, since internal information of a living body is used, it is difficult to disguise biometric data, and high security can be ensured.

  When solid-state authentication is performed based on a human finger vein pattern, light having a wavelength in the near-infrared region (hereinafter simply referred to as near-infrared light) is generally used. This is because near infrared rays have a high transmittance for water constituting the living body and a low transmittance for hemoglobin (Hb) contained in red blood cells flowing through veins. Therefore, it is possible to acquire vein pattern information at a predetermined part by irradiating a predetermined part of a human with near infrared rays and imaging reflected light from the predetermined part.

A device described in Patent Document 1 is known as a device for acquiring biological information. In the imaging apparatus described in Patent Document 1, a light source (100), a support base (300), and an image authentication unit (200) are stacked.
JP 2001-119008 A

  By the way, in order to improve the quality of an image, it is preferable to determine the wavelength of light to be irradiated in consideration of the wavelength sensitivity characteristic of the imaging device. However, as described above, when imaging a vein pattern, the transmittance is high for water constituting the living body, and the transmittance is low for hemoglobin (Hb) contained in red blood cells flowing through the vein. It is necessary to use near infrared rays. Depending on the imaging device, the sensitivity to near-infrared light is insufficient, so that a high-quality image may not be acquired.

  The present invention has been made to solve such problems, and even when the wavelength of light to be irradiated cannot be selected based on the wavelength sensitivity characteristic of the imaging device, a higher quality image is obtained. The purpose is to be able to get.

  A biological information acquisition device according to the present invention is a biological information acquisition device that emits inspection light to a biological part and receives reflected light or transmitted light from the biological part to capture an image. (1) Generates the inspection light And (2) an imaging device having an imaging region including a plurality of pixels and having higher sensitivity to light having a wavelength different from the wavelength of the inspection light, and (3) the input inspection A wavelength conversion element that converts light into light having a wavelength different from the wavelength of the inspection light and outputs the light to the imaging region so that the sensitivity of the imaging device is increased.

  The wavelength conversion element shifts the wavelength of the inspection light so that the sensitivity of the imaging device is increased. Then, the light whose wavelength is shifted is input to the imaging region of the imaging device. Therefore, even when it is not possible to select the wavelength of light to be irradiated based on the wavelength sensitivity characteristic of the imaging device, it is possible to obtain a higher quality image.

  The imaging apparatus has higher sensitivity to light having a wavelength shorter than the wavelength of the inspection light, and the wavelength conversion element converts the input inspection light into light having a wavelength shorter than the wavelength of the inspection light. And output to the imaging area. A biological information acquisition device can be realized using a general imaging device.

  The inspection light may be light having a wavelength within a range of 700 nm to 1000 nm. A biometric information device suitable for vein authentication can be realized.

  The imaging device includes a plurality of semiconductor layers formed on an insulating substrate so as to correspond to the plurality of pixels, and has the highest sensitivity to light having a wavelength shorter than 700 nm. Good. A biological information acquisition device can be realized using a general imaging device.

  The wavelength conversion element may be a plate-like glass including an active element that absorbs the inspection light and emits light having a wavelength different from that of the inspection light. A biological information acquisition device can be realized using a general wavelength conversion element.

  A lens array having a plurality of lenses provided corresponding to the plurality of pixels is further provided, and the plurality of lenses included in the lens array are formed on a first surface of the wavelength conversion element as a plate-like member. It is good. By providing the lens array, it is possible to acquire biological information with higher accuracy. In addition, since the wavelength conversion element also serves as a lens forming substrate, an increase in the thickness of the device is also suppressed.

  A light shielding layer having a plurality of openings formed corresponding to each condensing portion of the plurality of lenses is further provided, and the light shielding layer is formed on the second surface of the wavelength conversion element as a plate-like member. Good. By providing the light shielding layer, biological information can be acquired with higher accuracy. Moreover, since the wavelength conversion element serves as the substrate for forming the light shielding layer, an increase in the thickness of the device is also suppressed.

  A biological information acquisition device according to the present invention is a biological information acquisition device that emits inspection light to a biological part and receives reflected light or transmitted light from the biological part to capture an image. (1) Generates the inspection light A light emitting device, (2) a lens array having a plurality of lenses for condensing the inspection light reflected or transmitted from a living body part on a pixel of the imaging device, and (3) at each condensing portion of the plurality of lenses A light-shielding layer having a plurality of correspondingly disposed openings, and (4) an imaging region including a plurality of pixels that photoelectrically convert the inspection light incident through the openings, and the wavelength of the inspection light An imaging device having higher sensitivity to light of a different wavelength from (5), and (5) the input inspection light having a wavelength different from the wavelength of the inspection light so as to increase the sensitivity of the imaging device. Convert to light and output to the imaging area Comprises a long transform element.

  The wavelength conversion element shifts the wavelength of the inspection light so that the sensitivity of the imaging device is increased. Then, the light whose wavelength is shifted is input to the imaging region of the imaging device. Therefore, even when it is not possible to select the wavelength of light to be irradiated based on the wavelength sensitivity characteristic of the imaging device, it is possible to obtain a higher quality image. In addition, by providing the lens array and the light shielding layer, biological information can be acquired with higher accuracy.

  The imaging apparatus has higher sensitivity to light having a shorter wavelength than the wavelength of the inspection light, and the wavelength conversion element converts the input inspection light into light having a wavelength shorter than the wavelength of the inspection light. And output to the imaging area. A biological information acquisition device can be realized using a general imaging device.

  The inspection light may be light having a wavelength within a range of 700 nm to 1000 nm. A biometric information device suitable for vein authentication can be realized.

  The imaging device includes a plurality of semiconductor layers formed on an insulating substrate so as to correspond to the plurality of pixels, and has the highest sensitivity to light having a wavelength shorter than 700 nm. good. A biological information acquisition device can be realized using a general imaging device.

  The wavelength conversion element may be a plate-like glass including an active element that absorbs the inspection light and emits light having a wavelength different from that of the inspection light. A biological information acquisition device can be realized using a general wavelength conversion element.

  The plurality of lenses included in the lens array may be formed on a first surface of the wavelength conversion element as a plate-like member. Since the wavelength conversion element also serves as a lens forming substrate, an increase in the thickness of the device is also suppressed.

  The said light shielding layer is good to be formed on the 2nd surface of the said wavelength conversion element as a plate-shaped member. Since the wavelength conversion element also serves as the substrate for forming the light shielding layer, an increase in the thickness of the device is also suppressed.

  Even when it is not possible to select the wavelength of the light to be irradiated based on the wavelength sensitivity characteristic of the imaging device, it is possible to obtain a higher quality image.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment is simplified for convenience of explanation. Since the drawings are simple, the technical scope of the present invention should not be interpreted narrowly based on the drawings. The drawings are only for explaining the technical matters, and do not reflect the exact sizes or the like of the elements shown in the drawings. The same elements are denoted by the same reference numerals, and redundant description is omitted. Words indicating directions such as up, down, left, and right are used on the assumption that the drawing is viewed from the front.

[First Embodiment]
A first embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view of the biological information acquisition device D1. FIG. 2 is a schematic top view of the biological information acquisition device D1. FIG. 3 is a schematic end view of the biological information acquisition device D1 between XX in FIG. 2 (limited to the upper part from the bandpass filter 34). FIG. 4 is a schematic explanatory view of the biological information acquisition device D1 as viewed from the point A in FIG. FIG. 5 is a schematic explanatory diagram of the biological information acquisition device D1 as seen from the point B side in FIG. 4 and 5 also show schematic sectional views of the biological information acquisition device D1 from the point A or the point B for convenience of explanation. FIG. 6 is an explanatory diagram for explaining that the sensitivity characteristic of the TFT sensor is improved. FIG. 7 is a schematic cross-sectional view of the TFT sensor 31.

  As shown in FIG. 1, the biological information acquisition device D1 includes a wiring board 30, a TFT (Thin Film Transistor) sensor (imaging device) 31, a wavelength conversion member (wavelength conversion element) 60, an optical channel separation layer 32, a microlens array. 33, a band-pass filter 34, and light irradiation devices LEa and LEb.

  The biological information acquisition device D1 operates as follows. Inspection light is emitted from the light irradiation devices LEa and LEb toward the finger (illustrated in FIGS. 3 to 5) placed on the surface region R1 of the biological information acquisition device D1. The inspection light is light having a wavelength in the near infrared region (wavelength: 700 nm to 1000 nm). Here, the wavelength of the inspection light is 760 nm. The inspection light receives reflection in the finger and enters the surface region R1 of the main surface 34a of the bandpass filter 34. The inspection light incident on the surface region R1 passes through the bandpass filter 34, the microlens array 33, the optical channel separation layer 32, and the wavelength conversion member 60 in this order, and is received by the pixels in the imaging region R2 of the TFT sensor 31. The In each pixel of the TFT sensor 31, the detected inspection light is photoelectrically converted. An image signal is output from the TFT sensor 31. The inspection light is absorbed by a vein in the finger. Therefore, the examined human vein pattern appears in the image obtained from the TFT sensor 1. By using the image (image information) acquired in this way, it is determined by a subsequent processing circuit or the like whether the inspected person is a specific person set in advance.

  The surface region R1 is a surface region of the biological information acquisition device D1 into which the inspection light reflected from the finger (biological part) is incident. Here, the surface region R <b> 1 coincides with the main surface 34 a of the bandpass filter 34.

  Next, FIG. 2 shows a schematic configuration of the upper surface of the biological information acquisition device D1. As shown in FIG. 2, the light irradiation device LEa and the light irradiation device LEb are arranged to face each other with the surface region R1 interposed therebetween.

  As shown in FIG. 2, the light irradiation device LEa includes a light guide 3a, a light emitting diode (light emitting device) 4a, and a light emitting diode 5a on the light shielding plate 2a.

  The light guide 3a is a plate-like member having a five-side shape when viewed from above. The light guide 3a is a member that is substantially transparent to the inspection light (transmittance of 90% or more. Here, the transmittance is 99%) and is made of a resin material such as polyimide.

  The light guide 3a has a light incident surface 3a2, a light reflecting surface 3a3, a light reflecting surface 3a4, and a light incident surface 3a5 on the side surfaces. The light incident surface 3a2 and the light incident surface 3a5 are flat surfaces extending along the x axis with the x axis as the longitudinal direction. A light emitting diode 5a is attached to the light incident surface 3a2 via an adhesive 11. A light emitting diode 4a is attached to the light incident surface 3a5 via an adhesive 11. In other words, the light emitting diode 5a is optically coupled to the light incident surface 3a2 via the adhesive 11, and the light emitting diode 4a is optically coupled to the light incident surface 3a5 via the adhesive 11.

  The adhesive 11 has a high transmittance with respect to the inspection light and is substantially transparent with respect to the inspection light. Therefore, good optical coupling can be ensured between the light incident surface and the light emitting diode. The light emitting diodes 4a and 5a are elements in which monolithic semiconductor elements are packaged. The light emitting diodes 4a and 5a emit near infrared rays (wavelength: 760 nm) when a current is applied thereto.

  The light emission surface 3a1 is a side surface facing a finger (illustrated in FIGS. 3 to 5) placed on the surface region R1. The light emitting surface 3a1 is a flat surface extending along the z axis with the z axis as the longitudinal direction. The light reflecting surface 3a3 and the light reflecting surface 3a4 are side surfaces facing the light emitting surface 3a1. The light reflecting surface 3a3 and the light reflecting surface 3a4 are also flat surfaces extending along the z axis with the z axis as the longitudinal direction. The light reflecting surface 3a3 moves away from the light emitting surface 3a1 as it extends from the light incident surface 3a2 along the z-axis. The light reflecting surface 3a3 moves away from the light emitting surface 3a1 as it extends along the z-axis from the light incident surface 3a5.

  The configuration of the light guide 3b of the light irradiation device LEb is substantially the same as the configuration of the light guide 3a of the light irradiation device LEa. That is, the light emitting surface 3b1 corresponds to the light emitting surface 3a1, the light incident surface 3b2 corresponds to the light incident surface 3a2, the light reflecting surface 3b3 corresponds to the light reflecting surface 3a3, and the light reflecting surface 3b4 is the light reflecting surface 3a4. The light incident surface 3b5 corresponds to the light incident surface 3a5.

  Here, the function of the light irradiation device LEa will be described. The inspection light emitted from the light emitting diode 4a is incident on the light incident surface 3a5 of the light guide 3a via the adhesive 11, and is confined in the core layer 7a (described later with reference to FIG. 3) of the light guide 3a. In the state, it propagates in the light guide 3a along the z-axis. The inspection light incident on the light incident surface 3a2 is reflected by a light reflecting surface 3a3 described later and guided to the light emitting surface 3a1. Note that the entire size of the light guide 3a can be reduced by propagating the inspection light incident on the light incident surface 3a5 along the light emitting surface 3a1. This is because the light emission surface 3a1 is set to have a certain width along the side surface of the finger.

  The inspection light emitted from the light emitting diode 5a is incident on the light incident surface 3a2 of the light guide 3a via the adhesive 11, and is lighted along the z-axis while being confined in the core layer 7a of the light guide 3a. It propagates in the guide 3a. The inspection light incident on the light incident surface 3a2 is reflected by a light reflecting surface 3a4 described later and guided to the light emitting surface 3a1. As in the case described above, the entire size of the light guide 3a can be reduced by propagating the inspection light incident on the light incident surface 3a2 along the light emitting surface 3a1.

  From the core layer 7a of the light emitting surface 3a1 of the light guide 3a, inspection light having substantially uniform intensity is emitted along the longitudinal direction of the light emitting surface 3a1. In other words, inspection light having a substantially uniform intensity is emitted from the core layer 7a of the light emitting surface 3a1 of the light guide 3a along the z axis (axis perpendicular to the stacking direction of the layers constituting the light guide). The The range (predetermined area) of the light exit surface 3a1 from which the inspection light having substantially uniform intensity is emitted is substantially equal to the width of the light exit surface 3a1.

  The inspection light having substantially uniform intensity is emitted along the longitudinal direction of the light emitting surface 3a1 because each of the light reflecting surface 3a3 and the light emitting surface 3a5 is provided with a plurality of reflecting surfaces (not shown). Because it is. In other words, a plurality of reflecting surfaces are arranged on the light reflecting surface 3a3 and the light reflecting surface 3a5 so that inspection light having substantially uniform intensity is emitted along the longitudinal direction of the light emitting surface 3a1. Because. The light reflecting surface 3a3 and the reflecting surface provided on the light reflecting surface 3a5 are light reflected by the light guide 3a through a plurality of grooves 10 extending along the y axis (axis that coincides with the stacking direction of the layers constituting the light guide). It is good to form by providing in the surface 3a3. In addition, the arrangement positions of the plurality of reflection surfaces provided on the light reflection surface are appropriately set according to the characteristics of the light emitting diode. Therefore, the light reflecting surface 3a3 may be formed in an arc shape that bulges outward from the light incident surface 3a2 toward the light reflecting surface 3a4. Similarly, the light reflecting surface 3a4 may be formed in an arc shape that bulges outward from the light incident surface 3a5 toward the light reflecting surface 3a3.

  The function of the light irradiation device LEb is the same as the function of the light irradiation device LEa. That is, the light emitting diode 4b corresponds to the light emitting diode 4a, the light incident surface 3b5 corresponds to the light incident surface 3a5, the light emitting surface 3b1 corresponds to the light emitting surface 3a1, and the light reflecting surface 3b3 corresponds to the light reflecting surface 3a3. To do. The light emitting diode 5b corresponds to the light emitting diode 5a, the light incident surface 3b2 corresponds to the light incident surface 3a2, the light emitting surface 3b1 corresponds to the light emitting surface 3a1, and the light reflecting surface 3b4 corresponds to the light reflecting surface 3a4. To do.

  FIG. 3 shows a schematic configuration diagram of the biological information acquisition device D1 between XX in FIG. 2 (limited to the upper part from the band pass filter 34). As shown in FIG. 3, light irradiation devices LEa and LEb are disposed on the main surface 34 a of the bandpass filter 34.

  The light irradiation device LEa has a light guide 3a on the light shielding plate 2a. The light guide 3a is configured as a laminated body in which a cladding layer (first cladding layer) 6a, a core layer 7a, and a cladding layer (second cladding layer) 8a are stacked along the y-axis. The clad layer 6a and the clad layer 8a have the same refractive index. The refractive indexes of the cladding layer 6a and the cladding layer 8a are both lower than that of the core layer 7a. Therefore, the inspection light that propagates effectively can be confined.

  As shown in FIG. 3, the light exit surface 3a1 is cut into a tapered shape in order to define the exit direction of the emitted inspection light. In other words, at the end of the light guide 3a on the surface region R1 side, a surface (surface desired for the finger 100 placed on the surface region R1) that is inclined from the upper surface to the lower surface is provided toward the surface region R1. ing. That is, the light guide 3a has a tapered end portion whose thickness (width along the y-axis) decreases as the surface region R1 is approached. The upper surface of the light guide 3a is narrower than the lower surface of the light guide 3b in accordance with the end portion that is cut into a tapered shape. With this configuration, physical stress on the human finger 100 is also alleviated.

  The light shielding plate 2a is a plate-like member made of a metal material as described above. The light shielding plate 2a is substantially opaque to the inspection light emitted from the light emitting diodes 4a and 5a. The light shielding plate 2a has a portion that protrudes to the surface region R1 side from the light emitting surface 3a1 of the light guide 3a. Here, as shown in FIG. 3, the light-shielding plate 2a has a portion protruding from the light exit surface 3a1 to the surface region R1 side by the width W3. Since the light shielding plate 2a has such a protruding portion, the inspection light emitted from the light emitting surface 3a1 toward the surface region R1 is reflected by the light shielding plate 2a. Therefore, it is possible to suppress the inspection light from directly entering the surface region R1 from the light emitting surface 3a1. The light shielding plate 2a may also have a tapered configuration like the light guide 3a.

  The configuration of the light guide 3b of the light irradiation device LEb is substantially the same as the configuration of the light guide 3a of the light irradiation device LEa. That is, the cladding layer 6b corresponds to the cladding layer 6a, the core layer 7b corresponds to the core layer 7a, and the cladding layer 8b corresponds to the cladding layer 8a. Further, the light shielding plate 2b of the light irradiation device LEb has the same configuration as the light shielding plate 2a of the light irradiation device LEa. However, the light shielding plate 2b has a portion protruding from the light exit surface 3b1 to the surface region R1 side by the width W4. Here, the width W3 and the width W4 are substantially equal.

  As schematically shown in FIG. 3, the inspection light emitted from the core layer 7 a of the light emitting surface 3 a 1 of the light irradiation device LEa is absorbed by the vein 101 of the human finger 100. Further, the inspection light emitted from the core layer 7b of the light emitting surface 3b1 of the light irradiation device LEb is reflected inside the human finger 100 and enters the surface region R1. As is clear from the schematic diagram of FIG. 3, the light emitting surface 3 a 1 is disposed to face the side surface of the human finger 100.

  FIG. 4 shows a schematic explanatory view of the biological information acquisition device D1 from the point A side in FIG. In conjunction with FIG. 4, FIG. 5 shows a schematic explanatory view of the biological information acquisition device D1 from the point B side in FIG. Hereinafter, a description will be given with reference to FIGS.

  As shown in FIG. 4, on the upper surface of the wiring substrate 30, a TFT sensor 31, a wavelength conversion member 60, an optical channel separation layer 32, a microlens array 33, a bandpass filter 34, and light irradiation devices LEa and LEb are arranged in this order. It is arranged with. A semiconductor integrated circuit 35 and a connector 36 are disposed on the lower surface of the wiring board 30.

  The configurations of the light irradiation devices LEa and LEb are as described above. However, in FIG.4 and FIG.5, the edge part by the side of surface region R1 of the light-shielding plate 2a and the light-shielding plate 2b is cut by the taper shape similarly to light guide 3a, 3b. With this configuration, physical stress on the human finger 100 can be reduced.

  The bandpass filter 34 is a plate-like optical member that allows only near-infrared light (700 nm to 1000 nm, more preferably 700 nm to 800 nm) including inspection light to pass therethrough. The light irradiation devices LEa and LEb are fixed to the upper surface of the bandpass filter 34.

    The microlens array 33 is disposed below the bandpass filter 34. The microlens array 33 includes a transparent substrate 50, a lens 52, and a spacer layer 51. On the upper surface of the transparent substrate 50, a plurality of lenses 52 arranged in a two-dimensional manner and a spacer layer for supporting the bandpass filter 34 are arranged corresponding to each pixel PX of the TFT sensor 31. The transparent substrate 50 and the lens 52 are made of a material that is substantially transparent to the inspection light. The transparent substrate 50 is a so-called quartz substrate. The lens 52 is an optical member formed by partially removing the resist layer formed on the transparent substrate 50 by photolithography using a gray scale mask.

  The optical channel separation layer 32 is disposed below the microlens array 33. The optical channel separation layer 32 includes a light shielding film 40, a first transparent layer 41, a second transparent layer 42, and a resist layer (light shielding layer) 43.

  The light shielding film 40 is a layer in which a metal material is formed in a lattice shape on the lower surface of the microlens array 33 based on a normal semiconductor process technology (sputtering, vapor deposition, etc.). The light shielding film 40 has a plurality of openings OP <b> 1 formed in a matrix corresponding to each pixel PX of the TFT sensor 31. The plurality of openings OP1 means openings in an optical sense. Here, the opening OP1 is filled with the first transparent layer 41.

  The first transparent layer 41 is a resist layer made of a resin material and is substantially transparent to inspection light. After the light shielding film 40 is formed, the first transparent layer 41 is formed on the lower surface of the microlens array 33 by a normal coating method (spin coating method or the like).

  The second transparent layer 42 is a resist layer made of the same material as the first transparent layer 41. Therefore, the second transparent layer 42 is also substantially transparent to the inspection light. The second transparent layer 42 has a plurality of lands 42a. In the land 42a, the second transparent layer 42 is formed on the lower surface of the first transparent layer 41 by a normal coating method (spin coating method or the like), and then a lattice-like groove is formed in the second transparent layer 42. Is formed. That is, a plurality of lands 42a separated from each other are formed by forming the lattice-like grooves. The separated lands 42a are two-dimensionally arranged corresponding to the respective pixels PX of the TFT sensor 31. In addition, a land means the island-shaped part prescribed | regulated by a groove | channel. Each land need not be completely separated from each other.

  A resist layer 43 is filled between the separated lands 42a. A resist layer 43 is also laminated between the second transparent layer 42 and the TFT sensor 31. The resist layer 43 is a resist containing a material (such as phthalocyanine) that absorbs inspection light, and functions as a light shielding layer. The resist layer 43 is formed by applying a resist material so as to fill the grooves formed in the second transparent layer 42 based on a spin coating method or the like. Then, based on photolithography, a plurality of openings OP3 are formed in the resist layer 43 applied to the lower surface of the second transparent layer 42 so as to correspond to the condensing positions of the respective lenses 52 of the microlens array 33. . The opening OP3 also corresponds to the arrangement position of each pixel PX of the TFT sensor 31. The opening OP2 is two-dimensionally arranged corresponding to each pixel PX of the TFT sensor 31.

In the present embodiment, the wavelength conversion member 60 is disposed in the upper layer of the TFT sensor 31 (lower layer of the optical channel separation layer 32). The wavelength conversion member 60 is a plate-like glass layer that converts light in the near infrared region into light in the visible region, and is doped with an active element (Yb). Here, the wavelength conversion member 60 is transparent crystallized glass (trade name: Yagrass) containing fluoride microcrystals. The wavelength conversion member 60 is, for example, glass having a composition of 22SiO ₂ -10GeO ₂ -15Al0 _1.5 -3TiO ₂ -39PbF ₂ -10YbF ₃ -1ErF ₃ . The wavelength conversion member 60 is a plate-like member as described above, and has one surface and the other surface that face each other.

  The above active elements absorb near infrared rays. When the near infrared ray is absorbed by the active element, energy transfer occurs, and light (visible light) having a shorter wavelength than the near infrared ray is emitted. That is, the near infrared ray input to the wavelength conversion member 60 is converted into visible light and output from the wavelength conversion member 60. In other words, the inspection light reflected from the living body part is shifted to the shorter wavelength side by the wavelength conversion member 60. Then, light (visible light) shifted to a short wavelength is input to the imaging region R2 of the TFT sensor 31. As will be described later, the TFT sensor 31 has higher sensitivity to light in the visible light region than light in the near infrared region. When light having a wavelength with higher sensitivity is input to the TFT sensor 31, the amount of light photoelectrically converted in the TFT sensor 31 is increased, and the S / N of the TFT sensor 31 is improved. The wavelength conversion member 60 performs wavelength conversion using rare earth up-conversion fluorescence.

  The TFT sensor 31 is disposed below the wavelength conversion member 60. The TFT sensor 31 has an imaging region R2 in which a plurality of pixels PX are two-dimensionally arranged on the upper surface. Each pixel PX is arranged corresponding to the opening OP3 formed in the resist layer 43. Therefore, the light condensed by the lens 52 is efficiently incident on the pixel PX.

  Note that the imaging region R2 is wider in the z-axis direction than the surface region R1. That is, the imaging region R2 does not coincide with the surface region R1. Even in such a case, the inspection light reflected from the finger 100 can be imaged by using a portion corresponding to the surface region R1 in the imaging region R2.

  The wiring board 30 is a wiring board made of glass epoxy resin or the like, and elements are mounted on both upper and lower sides as described above.

  A driving circuit 37 that controls the reading operation of the TFT sensor 31 and the like is disposed on the upper surface of the TFT sensor 31. A signal acquired by the TFT sensor 31 is communicated to the semiconductor integrated circuit 35 through a wire 38, a through electrode 39 that connects the upper surface and the lower surface of the wiring substrate 30, and a wiring formed on the lower surface of the wiring substrate 30. . The connector 36 constitutes an interface part related to the connection between the biological information acquisition device D1 and an external signal processing circuit.

  The semiconductor integrated circuit 35 is a so-called ASIC (Application Specific Integrated Circuit). In the semiconductor integrated circuit 35, predetermined information processing (for example, determination of consistency between acquired image information and pre-stored image information) is executed. The information processing result in the semiconductor integrated circuit 35 is communicated to another information processing unit (not shown).

  Further, as shown in FIG. 4, the thickness from the light irradiation devices LEa and LEb to the bandpass filter 34 is preferably 1.7 mm or less. The thickness from the microlens array 33 to the TFT sensor 31 is preferably 1.0 mm or less. If it does in this way, the thickness from light irradiation device LEa, LEb to TFT sensor 31 can be 3 mm or less. Therefore, a very thin biological information acquisition device can be realized.

  In addition, as shown in FIG. 4, the width | variety along the x-axis of surface region R1 was 25 mm. Moreover, as shown in FIG. 5, the width along the z-axis of the surface region R1 was 15 mm. In such a case, it is preferable to place a finger on the surface region R1, as schematically shown in FIGS. In this case, the surface region R1 is substantially covered by the finger. Therefore, disturbance light incident on the surface region R1 is suppressed. In this case, the longitudinal direction of the light emitting surface of each light irradiation device LEa, LEb is arranged to face the side surface of the finger. Therefore, it is possible to irradiate the finger with the inspection light emitted from the light emitting surface with high efficiency.

  Next, the function of the biological information acquisition device D1 will be described with reference to FIG. As schematically shown in FIG. 4, the inspection light reflected by the internal region RP of the finger 100 is incident on the pixel PX of the TFT sensor 31 via the lens 52 of the microlens array 33. In the following, description will be given in order. The internal region RP is a region having a depth of about 1 mm from the lower surface of the finger 100.

  The inspection light emitted from the light emission surfaces of the light irradiation devices LEa and LEb is applied to the human finger 100. Inside the human finger 100, the inspection light is reflected by an internal scatterer. Further, the inspection light is absorbed by the vein inside the human finger 100. The inspection light reflected by the human finger 100 enters the surface region R1.

  The inspection light incident on the surface region R1 passes through the band pass filter 34. The disturbance light other than the inspection light is effectively blocked by the band pass filter 34. Since the noise component can be blocked by the band pass filter 34, a higher quality image can be acquired.

  The inspection light that has passed through the bandpass filter 34 enters the microlens array 33. In the microlens array 33, the light is condensed on each pixel PX of the TFT sensor 31 by each lens 52 disposed on the upper surface of the transparent substrate 50.

  The light condensed by the lens 52 of the microlens array 33 enters the optical channel separation layer 32. As described above, the optical channel separation layer 32 has the openings OP1 and OP3 that are two-dimensionally arranged corresponding to the respective pixels of the TFT sensor 31. Further, a land 42 a is arranged in a two-dimensional manner corresponding to each pixel of the TFT sensor 31. A resist layer 43 is filled between adjacent lands 42a. A resist layer 43 is also formed on the lower surface of the land 42a. The resist layer 43 contains a pigment that absorbs near infrared rays.

  With such a configuration, the optical channel separation layer 32 separates optical paths (optical channels) from the lens 52 of the microlens array 33 to the pixel PX of the TFT sensor 31. The stray light incident on the resist layer 43 is effectively absorbed by the pigment contained in the resist layer 43. Then, crosstalk (interference) that can occur between optical channels is suppressed. Since the inspection light is collected as it proceeds from the lens 52 to the pixel PX, the opening width of the opening OP3 is set to be narrower than the opening width of the opening OP1. Further, the pigment contained in the resist layer 43 may be one that does not absorb the exposure light used in the step of forming the opening OP3 in the resist layer 43 (photolithography).

  In the present embodiment, as described above, the wavelength conversion member 60 is disposed in the upper layer of the TFT sensor 31 (the lower layer of the optical channel separation layer 32). The wavelength conversion member 60 is a wavelength conversion element that converts input inspection light into visible light (light having a wavelength different from the wavelength of the inspection light) and outputs the converted light to the imaging region R <b> 2 of the TFT sensor 31. Therefore, the inspection light (wavelength: 760 nm) reflected from the living body part is converted into light having a shorter wavelength (wavelength: 650 nm) by the wavelength conversion member 60. In other words, the wavelength of the inspection light (760 nm) is shifted to the wavelength on the short wavelength side (650 nm). Then, light having a wavelength shorter than the near infrared ray is input to the imaging region R2 of the TFT sensor 31. Thereby, the light quantity photoelectrically converted by the TFT sensor 31 is increased, and the S / N of the TFT sensor 31 is improved. The TFT sensor 31 is an imaging device having sufficient sensitivity in the visible light region, and has the highest sensitivity at a wavelength of about 650 nm. It is desirable that the wavelength conversion efficiency of the wavelength conversion member 60 is higher.

  Here, the effect of disposing the wavelength conversion member 60 in FIG. 6 will be described. As schematically shown in FIG. 6, the sensitivity of the TFT sensor 31 is in the light in the visible region rather than the light in the near infrared region. That is, the sensitivity of the TFT sensor 31 is rapidly deteriorated when the wavelength of incident light becomes longer. On the other hand, it improves when the wavelength of the incident light is on the short wavelength side. The TFT sensor 31 does not have sufficient sensitivity to near-infrared light than a normal semiconductor imaging device (CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), PDA (Photodiode Array)).

  As shown in FIG. 6, the sensitivity (mA / W) of the TFT sensor 31 for the wavelength 650 nm of the light after the wavelength shift is more than the sensitivity (mA / W) of the TFT sensor 31 for the wavelength 760 nm of the light before the wavelength shift. high. That is, the sensitivity of the TFT sensor 31 can be increased by shifting the wavelength of the inspection light to the short wavelength side where the sensitivity of the TFT sensor 31 is high by the wavelength conversion member 60. FIG. 6 is a schematic diagram for convenience of explanation.

Here, in order to clarify the explanation, FIG. 7 shows a schematic cross-sectional view of the TFT sensor 31. As shown in FIG. 7, the TFT sensor 31 includes a pixel 215 having a double gate structure. The TFT sensor 31 has an imaging region R2 including a plurality of pixels 215 shown in FIG. The pixel 215 includes an insulating substrate 211, a bottom gate electrode 231, a bottom gate insulating film 232, a semiconductor layer 233, a blocking layer 240, an n ⁺ silicon layer 236, a source electrode (S) 234, a drain electrode (D) 235, and a top gate insulation. A film 237, a top gate electrode (TG) 238, and an overcoat film 239 are included.

The bottom gate electrode (BG) 231 is formed on the insulating substrate 211. The bottom gate insulating film 232 is formed so as to cover the bottom gate electrode 231. The semiconductor layer 233 is formed on the bottom gate insulating film 232. The blocking layer 240 is formed at the center of the upper surface of the semiconductor layer 233. N ⁺ silicon layers 236 are formed on both ends of the semiconductor layer 233, respectively. The source electrode (S) 234 and the drain electrode (D) 235 are provided on the n ⁺ silicon layer 236, respectively. The top gate insulating film 237 is formed so as to cover the source electrode (S) 234 and the drain electrode (D) 235. The top gate electrode (TG) 238 is formed on the top gate insulating film 237. The overcoat film 239 is formed on the top gate electrode (TG) 238.

Thus, the pixel 215 constituting the TFT sensor 31 includes a semiconductor layer (semiconductor layer 233, n ⁺ silicon layer 236) formed on the insulating substrate. Note that the semiconductor layer of one pixel and the semiconductor layer of another pixel are formed apart from each other. As described above, since the TFT sensor 31 does not use a substrate made of a semiconductor material such as a silicon substrate, unlike a normal CCD or the like, sufficiently secure sensitivity to near infrared rays absorbed in a deep portion of a semiconductor layer. Is difficult. Although it is possible to irradiate the living body with stronger near infrared rays to eliminate the lack of sensitivity of the TFT sensor 31 to the near infrared rays, the power consumption of the light emitting diode increases.

  In the present embodiment, in view of this point, the wavelength conversion member 60 is disposed in the upper layer of the TFT sensor 31 (lower layer of the optical channel separation layer 32) as described above. The wavelength conversion member 60 is a wavelength conversion member that converts light in the near infrared region into light in the visible region. Thereby, the light quantity photoelectrically converted in the TFT sensor 31 is increased, and the S / N (Signal / Noise) characteristic of the TFT sensor 31 is improved. The inspection light may be converted by the wavelength conversion member 60 from a wavelength in the range of 700 to 1000 nm to a wavelength in the range of 500 to 700 nm.

  The light shifted to the short wavelength side by the wavelength conversion member 60 is received by each pixel of the TFT sensor 31 described above. Then, the charges accumulated in each pixel of the TFT sensor 31 are sequentially read out from the TFT sensor 31. Then, it is processed by the subsequent signal processing circuit.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. FIG. 8 is an explanatory view corresponding to FIG. 4 in the first embodiment, and is a schematic explanatory view of the biological information acquisition device from the point A side of FIG. FIG. 9 is a schematic explanatory view of a method for producing an optical channel separation layer included in the lens module. FIG. 10 is a schematic explanatory diagram of a manufacturing method of a microlens array included in a lens module.

  As shown in FIG. 8, the biological information acquisition device D <b> 2 according to the present embodiment uses a wavelength conversion member 60 instead of the transparent substrate 50 as a substrate for forming the optical channel separation layer 32. Similarly, a wavelength conversion member 60 is used in place of the transparent substrate 50 as a substrate for forming the plurality of lenses 52. Therefore, even if the wavelength conversion member 60 is further added, it is possible to suppress an increase in the overall thickness of the biological information acquisition device D2.

  The microlens array 33 includes the wavelength conversion member 60, the lens 52, and the spacer layer 51. The optical channel separation layer 32 and the microlens array 33 are collectively referred to as a lens module LM1.

  Here, a manufacturing method of the lens module LM1 will be described with reference to FIGS. FIG. 9 is an explanatory diagram of a manufacturing method for forming the optical channel separation layer 32 on one surface (second surface) of the wavelength conversion member 60 included in the microlens array 33. FIG. 10 is an explanatory diagram of a manufacturing method for forming a plurality of lenses 52 on the other surface (first surface) of the wavelength conversion member 60 included in the microlens array 33.

  First, a manufacturing method for forming the optical channel separation layer 32 on the wavelength conversion member 60 will be described with reference to FIG. FIG. 9 discloses a more detailed configuration of the optical channel separation layer 32 as compared to FIG.

  First, as shown in FIG. 9A, the light shielding film 40 is formed in a lattice pattern on one surface of the wavelength conversion member 60 based on a normal thin film pattern forming technique (sputtering, vapor deposition, etc.).

  Next, as shown in FIG. 9B, the transparent layer 41 is formed on one surface of the wavelength conversion member 60 by a general coating method such as spin coating. As described above, the transparent layer 41 is made of a normal resist material (resin material). Therefore, when applied, the transparent layer 41 has a predetermined viscosity. After the transparent layer 41 is coated on one surface of the wavelength conversion member 60, the transparent layer 41 is heated by heating the transparent layer 41 in that state.

  Next, as illustrated in FIG. 9C, the transparent layer 42 is formed on one surface of the wavelength conversion member 60. Similar to the transparent layer 41, the transparent layer 42 is made of a normal resist material. Therefore, the transparent layer 42 when applied has a predetermined viscosity. Then, the transparent layer 42 is heated on one surface of the wavelength conversion member 60 to heat the transparent layer 42.

  Next, as shown in FIG. 9D, lattice-like grooves 42b are formed in the transparent layer 42 based on a normal process technique. A land 42a is formed in the transparent layer 42 by the lattice-shaped grooves 42b.

  Next, as shown in FIG. 9E, a resist layer 43 is applied to one surface of the wavelength conversion member 60 based on a normal coating method. The resist layer 43 is prepared by previously mixing 0.5 parts by weight of phthalocyanine with 100 parts by weight of resist. In order to uniformly disperse phthalocyanine in the resist, it is preferable to disperse phthalocyanine in a solvent such as methyl ethyl ketone at a concentration of about 10% wt in advance. Then, the transparent layer 42 is heated on one surface of the wavelength conversion member 60 to heat the transparent layer 42. Through this step, the groove 42 b formed in the transparent layer 42 is filled with the resist layer 43. And the part of the transparent layer 42a and the transparent layer 42b is formed.

  Next, as shown in FIG. 9F, a resist layer 43c is applied to one surface of the wavelength conversion member 60 based on a normal coating method. The resist layer 43c is a resist layer in which phthalocyanine is not mixed. Then, the transparent layer 42c is heated on one surface of the wavelength conversion member 60, and the transparent layer 42c is dried. This protects the transparent layer 42b containing phthalocyanine from the chemical solution as described above.

  Next, as shown in FIG. 9G, an opening OP3 is formed in the resist layer 43 using a photomask. Since the resist 43b and the resist 43c are negative resists, the portion where the opening OP3 is to be formed is irradiated with exposure light (g line: 436 nm). In the resist layer 43b and the resist layer 43c, a photochemical reaction by exposure light proceeds. Thereafter, a chemical solution (xylene-based organic solvent or the like) is applied to the surface of the resist layer 43 and developed. By this development processing, an opening OP3 is formed in the resist layer 43b and the resist layer 43c. As described above, the resist layer 43c serves to protect the resist layer 43b during the development process.

  In addition, the alignment between the light shielding film 40 and the opening OP3 and the light shielding film 40 and the transparent layer can be performed by using an alignment mark formed in the peripheral portion (not shown) of the wavelength conversion member 60 simultaneously with the formation of the light shielding film 40. The accuracy of alignment with the groove 42b formed in 42 can be ensured.

  Next, the process of forming the lens 52 on the wavelength conversion member 60 will be described with reference to FIG.

  First, as shown in FIG. 10A, a product after the step of FIG. 9G is prepared.

  Next, as shown in FIG. 10B, a positive resist layer 52p is applied to the other surface of the wavelength conversion member 60 based on a normal coating method. And the thing with the resist layer 52p coat | covered on the other surface of the wavelength conversion member 60 is heated, and the resist layer 52p is dried.

  Next, as shown in FIG. 10C, the resist layer 52p is exposed using a gray scale mask so that a plurality of lenses 52 are formed, and development processing is performed. Note that the alignment mark described above may be used for alignment with the opening OP1 of the lens to be formed.

  As described above, the wavelength conversion member 60 is used as a substrate for forming the optical channel separation layer 32 including the resist layer (light shielding layer) 43. Further, the wavelength conversion member 60 is used as a substrate for forming the plurality of lenses 52. Therefore, even if the wavelength conversion member 60 is newly added, the thickness (width along the y-axis) of the biological information acquisition device does not increase. That is, in this embodiment, in addition to the effects described in the first embodiment, the apparatus of the biological information acquisition device can be reduced in size.

[Other Embodiments]
Other embodiments will be described with reference to FIGS. FIG. 11 is an explanatory view corresponding to FIG. 4 of the first embodiment, and is a schematic explanatory view of the biological information acquisition device from the point A side of FIG. FIG. 12 is an explanatory diagram corresponding to FIG. 4 of the first embodiment, and is a schematic explanatory diagram of the biological information acquisition device viewed from the point A in FIG.

  As shown in FIG. 11, the biological information acquisition device D3 includes a wavelength conversion member 60 between the microlens array 33 and the bandpass filter 34. Even if it is such a structure, the effect similar to 1st Embodiment can be acquired.

  As illustrated in FIG. 12, the biological information acquisition device D4 includes a wavelength conversion member 60 instead of the bandpass filter 34. Even if it is such a structure, the effect similar to 1st Embodiment can be acquired. However, the effect of the bandpass filter 34 cannot be obtained.

  The technical scope of the present invention is not limited to the above-described embodiment. Whether or not to provide a bandpass filter is arbitrary. It is not essential to provide a microlens array or a light shielding layer. As the wavelength conversion element, glass materials of other components can be used. The imaging device is not limited to a TFT sensor, and other general solid-state imaging devices can also be used.

It is a schematic perspective view of biometric information acquisition device D1. It is a schematic top view of the biological information acquisition device D1. FIG. 3 is a schematic end view of the biological information acquisition device D1 between XX in FIG. 2 (limited to a portion above the bandpass filter 34). FIG. 2 is a schematic explanatory view (a schematic cross-sectional view is also shown) of the biological information acquisition device D1 as viewed from a point A side in FIG. FIG. 2 is a schematic explanatory view (a schematic cross-sectional view is also shown) of the biological information acquisition device D1 as viewed from a point B side in FIG. It is explanatory drawing for demonstrating that the sensitivity characteristic of a TFT sensor improves. 3 is a schematic cross-sectional view of a TFT sensor 31. FIG. It is explanatory drawing which concerns on 2nd Embodiment. It is a schematic explanatory drawing of the manufacturing method of the optical channel separation layer contained in a lens module. It is a schematic explanatory drawing of the manufacturing method of the micro lens array contained in a lens module. It is explanatory drawing concerning other embodiment. It is explanatory drawing concerning other embodiment.

Explanation of symbols

D1 Biological information acquisition device 4a, 5a Light emitting diode (light emitting device)
PX pixel R2 imaging region 31 TFT sensor (imaging device)
60 Wavelength conversion member (wavelength conversion element)

Claims (14)

A biological information acquisition device that emits inspection light to a living body part, receives reflected light or transmitted light from the living body part, and images it,
A light emitting device for generating the inspection light;
An imaging device having an imaging region including a plurality of pixels and having higher sensitivity to light having a wavelength different from the wavelength of the inspection light;
A wavelength conversion element that converts the input inspection light into light having a wavelength different from the wavelength of the inspection light so as to increase the sensitivity of the imaging device, and outputs the light to the imaging region;
A biological information acquisition device comprising: The imaging device has higher sensitivity to light having a wavelength shorter than the wavelength of the inspection light,
The biological information acquisition device according to claim 1, wherein the wavelength conversion element converts the input inspection light into light having a wavelength shorter than the wavelength of the inspection light and outputs the light to the imaging region.   The biological information acquisition device according to claim 2, wherein the inspection light is light having a wavelength within a range of 700 nm to 1000 nm.   The imaging device includes a plurality of semiconductor layers formed on an insulating substrate so as to correspond to the plurality of pixels, and has the highest sensitivity to light having a wavelength shorter than 700 nm. The biological information acquisition device according to claim 3, wherein:   The biological information acquisition device according to claim 1, wherein the wavelength conversion element is a plate-like glass containing an active element that absorbs the inspection light and emits light having a wavelength different from that of the inspection light. A lens array having a plurality of lenses provided corresponding to the plurality of pixels;
The biological information acquisition device according to claim 1, wherein the plurality of lenses included in the lens array are formed on a first surface of the wavelength conversion element as a plate-like member. A light-shielding layer having a plurality of openings formed corresponding to each condensing portion of the plurality of lenses;
The biological information acquisition device according to claim 6, wherein the light shielding layer is formed on a second surface of the wavelength conversion element as a plate-like member. A biological information acquisition device that emits inspection light to a living body part, receives reflected light or transmitted light from the living body part, and images it,
A light emitting device for generating the inspection light;
A lens array having a plurality of lenses for condensing the inspection light reflected or transmitted from the living body part on the pixels of the imaging device;
A light shielding layer having a plurality of openings arranged corresponding to each condensing portion of the plurality of lenses;
An imaging device having an imaging region including a plurality of pixels that photoelectrically convert the inspection light incident through the opening, and having higher sensitivity to light having a wavelength different from the wavelength of the inspection light;
A wavelength conversion element that converts the input inspection light into light having a wavelength different from the wavelength of the inspection light so as to increase the sensitivity of the imaging device, and outputs the light to the imaging region;
A biological information acquisition device comprising: The imaging device has higher sensitivity to light having a shorter wavelength than the wavelength of the inspection light,
The biological information acquisition device according to claim 8, wherein the wavelength conversion element converts the input inspection light into light having a wavelength shorter than the wavelength of the inspection light, and outputs the light to the imaging region.   The biological information acquisition device according to claim 9, wherein the inspection light is light having a wavelength within a range of 700 nm to 1000 nm.   The imaging device includes a plurality of semiconductor layers formed on an insulating substrate so as to correspond to the plurality of pixels, and has the highest sensitivity to light having a wavelength shorter than 700 nm. The biometric information acquisition device according to claim 10.   The biological information acquisition device according to claim 8, wherein the wavelength conversion element is a plate-like glass containing an active element that absorbs the inspection light and emits light having a wavelength different from that of the inspection light.   The biological information acquisition device according to claim 8, wherein the plurality of lenses included in the lens array are formed on a first surface of the wavelength conversion element as a plate-like member.   The biological information acquisition device according to claim 13, wherein the light shielding layer is formed on a second surface of the wavelength conversion element as a plate-like member.

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