JP5953627B2 - Photodetection device and method for manufacturing photodetection device - Google Patents

Description

  The present invention relates to a light detection device that detects visible light and a method for manufacturing the same.

  Photodetection devices using photodiodes have been put into practical use. For example, it is used as a light detection means in fields such as automatic lighting control of lighting devices, backlight brightness control of liquid crystal displays, backlight control of mobile phone keypads, and dark field switching control of surveillance cameras. . In addition, a proximity sensor is configured in combination with a light emitting element, and it is also used for measuring the presence or absence of an object and a distance.

  Various methods of photodetection devices have been put into practical use. Among them, there is a demand for a light detection device that detects light with a visibility characteristic close to light detected by humans. The wavelength of light that can be sensed by humans is 380 nm to 780 nm, of which 440 nm to 700 nm is the main sensing wavelength region. Even with light having the same intensity depending on the wavelength of light, humans feel light or dark. The brightness that humans feel strongly varies from wavelength to wavelength, and the relative brightness of this is the standard visual sensitivity characteristic, which has a peak in the vicinity of green having a wavelength of 500 nm to 600 nm. Therefore, if the light detected by the light detection device is close to the standard visual sensitivity characteristic, the light can be detected with the same sensitivity as that felt by humans.

  In Patent Literature 1 and Patent Literature 2, two photodiodes having different characteristics of the photodiode having the highest detection sensitivity in the visible light region and the photodiode having the infrared light region are detected with visible light. There is described a photodetector that subtracts a detection value detected with infrared light from the detected value and converts it into a standard visibility characteristic.

  Patent Documents 3 and 4 describe an illuminance sensor that detects incident light having a standard visibility characteristic by making incident light, which has been corrected for wavelength characteristics using an optical filter, incident on a photosensor. This uses an optical interference filter composed of multilayer films having different refractive indexes, and therefore the wavelength characteristics of the filter change with respect to light incident from an oblique direction. Therefore, an incident window is provided so that the incident angle of light incident on the photosensor is substantially constant.

  FIG. 4 is a partial cross-sectional perspective view showing the structure of the semiconductor illuminance sensor described in Patent Document 4 (FIG. 1 of Patent Document 4). In the illuminance sensor 100, a semiconductor chip 107 is installed on a substrate 108, and the semiconductor chip 107 is covered with a light shielding layer 104 that does not allow light to pass through. The semiconductor chip 107 is provided with a light detection element 102 constituted by a photodiode or the like. The light detection surface of the light detection element 102 is covered with a light interference type optical filter 101. The light detection element 102 has sensitivity to wavelengths from visible light to infrared light. The output current detected by the light detection element 102 is amplified by the amplifier 103 and transmitted to the electrode 109 formed on the back side via the wire bond 110.

  The optical interference type filter changes its filter characteristics according to the incident angle of light and deviates from the standard visual sensitivity characteristics. Therefore, the incident light guide path 105 is formed in the light shielding layer 104 in order to limit the change of the filter characteristics by limiting the angle of the incident light. Light enters from the light incident aperture 106, enters the light interference type filter 101 through the incident light guide path 105, and the light corrected to the standard visibility characteristic reaches the light detection element 102. Thereby, the illuminance sensor 100 close to the light perceived by human beings can be configured.

JP 2009-238944 A JP 2006-148014 A Special table 2007-536728 gazette JP 2007-48795 A

  However, in the photodetectors described in Patent Document 1 and Patent Document 2, two photodiodes having different detection characteristics with respect to the wavelength of light are used, and a calculation for performing subtraction processing or the like of detection currents of the two photodiodes. It is necessary to form a circuit. For this reason, it is inevitable that the number of parts and the number of assembling steps increase and the cost increases. Further, in the illuminance sensors of Patent Document 3 and Patent Document 4, an optical interference type filter composed of multilayer films having different refractive indexes is used. Since the optical interference filter is expensive, it is inevitable that the cost is increased. In addition, since the incident angle of incident light is limited, it is not suitable for a photodetector that requires a wide viewing angle.

  The present invention has been made in view of the above problems, and an object thereof is to provide a photodetection device having spectral characteristics close to human standard visibility characteristics, high detection accuracy, and capable of being manufactured at low cost. .

  The light detection device of the present invention includes an optical chip in which a light receiving region for light detection is formed on a light receiving surface on a light incident side, and phosphate glass, and is installed on the light receiving surface so as to cover the light receiving region And an optical filter to be provided.

  The optical chip comprises a substrate on which a concave portion is formed and the optical chip is mounted on a bottom portion of the concave portion, and a light-transmitting sealing material filled in the concave portion, and the optical chip has the light receiving surface on the light receiving surface. It is mounted on the bottom portion toward the opening side of the recess, and the sealing material is filled so as to cover the optical filter and the optical chip.

  In the optical filter, the phosphate glass has a weight of 80 to 120 with respect to the weight of the translucent resin 100.

  The phosphate glass contains phosphorus pentoxide, alumina, boric acid, alkaline earth oxide, and iron oxide.

  The translucent resin is any one of translucent epoxy resin, acrylic resin, and silicone resin.

  Further, the phosphate glass is dispersed in the translucent resin in the form of particles.

  The phosphate glass has an average particle size of 1 μm to 3 μm.

  The method for manufacturing a photodetecting device of the present invention includes a step of forming a recess in a substrate, a mounting step of mounting an optical chip on the bottom surface of the recess, and an optical filter in which phosphate glass particles are dispersed. An optical filter installation step installed on the chip and a sealing step of filling the concave portion with a translucent sealing material so as to cover the optical chip are provided.

  The phosphate glass has an average particle size of 1 μm to 3 μm.

  In the optical filter, the phosphate glass has a weight of 80 to 120 with respect to the weight of the translucent resin 100.

  The light detection device of the present invention includes an optical chip in which a light receiving region for light detection is formed on the light receiving surface on the light incident side, and phosphate glass, and covers the light receiving region within the surface of the light receiving surface. And an optical filter to be installed. As a result, it is possible to construct a high-precision photodetection device having spectral characteristics close to human standard visibility characteristics and close to human eyes at low cost.

It is a cross-sectional schematic diagram showing the basic composition of the optical device which concerns on this invention. It is explanatory drawing of the photon detection device which concerns on 1st embodiment of this invention. It is a graph showing the spectral characteristic of the optical filter used for the photon detection device which concerns on this invention. It is a partial cross section perspective view showing the structure of a conventionally well-known semiconductor illumination intensity sensor.

(Basic configuration)
FIG. 1 is a schematic cross-sectional view showing the basic configuration of a light detection device 1 according to the present invention. As shown in FIG. 1, the optical device 1 includes an optical chip 4 in which a light receiving region R for light detection is formed on a light receiving surface 5 on a light incident side, and phosphate glass, and covers the light receiving region R. Thus, an optical filter 7 installed on the light receiving surface 5 is provided. As the optical chip 4, a photodiode or other semiconductor chip having a light detection function can be used. An electrode pad 10 is formed on the light receiving surface 5 of the optical chip 4. The optical filter 7 covers the light receiving region R and is installed on the light receiving surface 5 so that the electrode pad 10 is exposed.

  As the optical filter 7, a material obtained by dispersing phosphate glass particles in a translucent resin material can be used. Phosphate glass has a maximum amount of transmitted light in a wavelength range of 500 nm to 600 nm, and has spectral characteristics close to standard visual sensitivity characteristics. The optical filter 7 in which the phosphate glass particles are dispersed in a translucent resin material also has a spectral characteristic close to the standard visibility characteristic. For this reason, light detection close to the human eye is possible without the need for multiple light detection elements, arithmetic circuits for adjusting to standard visibility characteristics, etc., and without using expensive optical interference filters consisting of multilayer films. A simple optical device 1 can be configured at low cost. This will be specifically described below.

(First embodiment)
FIG. 2 is an explanatory diagram of the light detection device 1 according to the first embodiment of the present invention, FIG. 2A is a schematic cross-sectional view of the light detection device 1, and FIG. It is a plane schematic diagram of the photodetection device 1 except for. FIG. 2A shows a cross section of the portion XX in FIG.

  As shown in FIG. 2, the light detection device 1 is mounted on the first substrate 2a, a second substrate 2b having a mortar-like circular opening in the center, and an upper surface of the first substrate 2a, The optical chip 4 which has the light-receiving surface 5 on the opposite side to the 1st board | substrate 2a, and the sealing material 11 with which the opening of the 2nd board | substrate 2b is filled are provided. That is, the mortar-shaped circular opening in the center of the second substrate 2b constitutes the concave portion 8, the optical chip 4 is mounted on the bottom of the concave portion 8, that is, the upper surface of the first substrate 2a, and the sealing material 11 is the concave portion 8. The opening of the second substrate 2b is filled. The light receiving surface 5 of the optical chip 4 faces the opening side of the recess 8 and a light receiving region R for light detection is formed. The optical filter 7 includes phosphate glass and is installed in the surface of the light receiving surface 5 so as to cover the light receiving region R. Here, the optical chip 4 uses a photodiode.

Phosphate glass easily absorbs moisture, and becomes cloudy when absorbing moisture. The phosphate glass is pulverized into a powder form and dispersed in a translucent resin material to protect the phosphate glass from moisture. An epoxy resin, an acrylic resin, a silicone resin, or the like can be used as the light-transmitting resin material. As for phosphate glass, phosphorous pentoxide (P ₂ O ₅ ) is 65 wt% to 75 wt%, alumina (Al ₂ O ₃ ) is 5 wt% to 15 wt%, and boric acid (B ₂ O ₃ ) is 5 wt% to 10 wt%. The alkaline earth oxide has a composition of 5 wt% to 15 wt% and the iron oxide (Fe ₂ O ₅ ) has a composition of 1 wt% to 10 wt%. The optical filter 7 has a phosphate glass weight of 80 to 120 with respect to the weight of the translucent sealing material 100. When the phosphate glass is less than 80 weight, the function as an optical filter having standard visibility characteristics is deteriorated, and when it exceeds 120 weight, it is difficult to uniformly disperse the phosphate glass particles in the resin material. . The average particle size of the phosphate glass is 0.1 μm to 10 μm, preferably 1 μm to 3 μm.

  FIG. 3 is a graph showing the spectral characteristics of the optical filter 7 used in the light detection device 1 of the present invention. The horizontal axis is the wavelength of light, and the vertical axis is the relative intensity of transmitted light. A solid line is a graph showing the spectral characteristic of the optical filter 7, and a broken line is a graph showing the standard visibility characteristic. The optical filter 7 has a characteristic in which the peak wavelength of the relative intensity is shifted to the long wavelength side by about 50 nm from the peak wavelength of the standard visibility characteristic, and is extended to the long wavelength side as a whole. Further, the spectral characteristics of the optical filter 7 hardly depend on the incident angle of light incident on the optical filter 7.

  Four upper surface electrodes 3 a extending from the end surface of each side to the periphery where the optical chip 4 is mounted are formed on the upper surface of the first substrate 2 a on which the optical chip 4 is mounted. It is electrically connected to a formed electrode pad (not shown) by a wire 9. Four lower surface electrodes 3b are formed on the lower surface BP opposite to the upper surface on which the optical chip 4 of the first substrate 2a is mounted, and are electrically connected to the four upper surface electrodes 3a via the wirings on the four end surfaces, respectively. Is done. A circular opening having a mortar shape at the center of the second substrate 2b constitutes the recess 8. The sealing material 7 is filled so that the upper surface thereof does not exceed the upper end surface TP around the recess 8.

  The sealing material 11 covers the bottom surface of the concave portion 8, that is, the surface exposed to the concave portion 8 side of the first substrate 2a, the upper surface electrode 3a, the optical chip 4 and the optical filter 7 installed on this surface. For example, a transparent epoxy resin, an acrylic resin, a silicone resin or the like can be used as the sealing material 11 and protects the optical filter 7 from moisture.

  The first and second substrates 2a and 2b can use synthetic resin, glass, ceramics, or the like. A black pigment is mixed in the first and second substrates 2a and 2b to absorb light and have a light shielding property. For example, if 20 wt% or more of black pigment is added to the first and second substrates 2a and 2b, the light transmittance can be 5% or less when the thickness of the substrate is 0.2 mm. The sealing material 11 is filled so that the upper surface thereof is lower than the upper end surface TP. The light incident on the light receiving surface 5 of the optical chip 4 from the back direction or the horizontal direction is shielded, and the light incident from above is detected. The incident angle of light incident from above is determined by the opening diameter of the second substrate 2 b, the depth to the light receiving region R of the optical chip 4 installed in the recess 8, and the refractive index of the sealing material 11.

  The same synthetic resin can be used as the first and second substrates 2a and 2b, metal leads can be used as the upper surface electrode 3a and the lower surface electrode 3b, and the metal leads can be formed to be embedded in the synthetic resin. Further, the same glass can be used as the first and second substrates 2a and 2b, and similarly, metal leads can be formed to be embedded in the glass. If a synthetic resin is used as the first and second substrates 2a and 2b, the light detection device 1 can be formed at a low cost. If glass is used as the first and second substrates 2a and 2b, a highly reliable photodetection device can be formed.

  In the present embodiment, the electrode (not shown) of the optical chip 4 and the upper surface electrode 3a of the first substrate 2a are electrically connected by the wire 9, but the present invention is not limited to this configuration. Instead of mounting the optical chip 4 on the upper surface of the first substrate 2a, a through hole is provided in the first substrate 2a, and the light receiving region R of the light receiving surface of the optical chip 4 is formed on the lower surface BP of the first substrate 2a. The face down can be mounted at the position. In this case, the second substrate 2b may be removed. The sealing material 11 can be filled so as to cover the light receiving surface 5 and the optical filter 7 of the optical chip 4 from the upper surface side of the first substrate 2a. Thereby, it is not necessary to electrically connect the optical chip 4 and the pad electrode on the substrate using a wire, and the optical device 1 can be reduced in height and size.

  As described above, the light receiving region R of the optical chip 4 is covered with the optical filter 7 containing phosphate glass particles, so that a plurality of light detection elements, arithmetic circuits for adjusting to the standard visibility characteristics, and the like are provided. Therefore, a photodetection device having spectral characteristics close to standard visual sensitivity characteristics can be formed at a low cost without using an expensive optical interference filter made of a multilayer film.

(Second embodiment)
A method for manufacturing the photodetection device 1 according to the second embodiment of the present invention will be described. In the following description, the reference numerals given to the components correspond to the reference numerals shown in FIG. 1 or FIG. First, in the recess forming step, the recess 8 is formed in the substrate 2. The concave portion 8 can be formed by using the same synthetic resin or glass as the first substrate 2a using synthetic resin or glass and bonding the second substrate 2b having an opening at the center. Moreover, the synthetic resin and glass can be used and the recessed part 8 can be formed by mold shaping. In these cases, a metal lead to be an electrode can be formed in advance and embedded at the time of joining the first substrate 2a and the second substrate 2b, or embedded at the time of molding. A black pigment is mixed in the first and second substrates 2a and 2b to form a light-shielding substrate.

  Next, in the mounting step, the optical chip 4 is mounted on the bottom surface of the recess 8, and then the electrode on the optical chip 4 and the upper surface electrode 3 a exposed on the bottom surface of the recess 8 are connected by the wire 9 by wire bonding. Next, in the optical filter installation step, a translucent resin material in which the phosphate glass particles are dispersed is applied to the light receiving region R of the light receiving surface 5 of the optical chip 4 using a dispenser or the like. Next, this resin material is cured to form an optical filter containing phosphate glass.

Next, in the sealing step, the recess 11 is filled with the sealing material 11 and solidified. As the sealing material, an epoxy resin, an acrylic resin, a silicone resin, or the like with high translucency can be used. Note that phosphate glass particles are dispersed in the optical filter 7. Phosphate glass uses liquid phosphoric acid (H ₃ PO ₄ ) as a main raw material, and is stirred together with other raw material powders, then dried, fired, and then pulverized to produce phosphate glass particles. Phosphate glass is composed of 65 wt% to 75 wt% of P ₂ O ₅ , 5 wt% to 15 wt% of Al ₂ O ₃ , 5 wt% to 10 wt% of B ₂ O ₃ , and 5 wt% to 15 wt% of alkaline earth oxide. And Fe ₂ O ₅ has a composition of 1 wt% to 10 wt%. This is applied as an optical filter 7 to the light receiving region R of the optical chip 4 using a dispenser. Thereafter, vacuum defoaming is performed and heating is performed to cure. In addition, when the sealing material 11 is filled in the concave portion 8, the upper end surface of the sealing material 11 is set lower than the upper end surface TP of the concave portion 8. Thereby, the angle of incident light can be limited.

  As described above, a highly reliable photodetection device having spectral characteristics close to that of the human eye can be manufactured easily and inexpensively.

DESCRIPTION OF SYMBOLS 1 Photodetection device 2 board | substrate, 2a 1st board | substrate, 2b 2nd board | substrate 3 electrode, 3a upper surface electrode, 3b lower surface electrode 4 optical chip 5 light-receiving surface 7 optical filter 8 recessed part 9 wire 10 electrode pad 11 sealing material R light-receiving area, TP top surface, BP bottom surface

Claims (7)

An optical chip in which a light receiving region for light detection is formed on the light receiving surface on the light incident side;
An optical filter in which phosphate glass is dispersed in a translucent resin in the form of particles and is installed on the light receiving surface so as to cover the light receiving region, and
The phosphate glass contains phosphorus pentoxide, alumina, boric acid, alkaline earth oxide, iron oxide, and has an average particle size of 1 μm to 3 μm.
The optical filter has a spectral characteristic in which the peak wavelength of the relative intensity of the transmitted light is shifted to a longer wavelength side by about 50 nm than the peak wavelength of the standard luminous characteristic, and the standard luminous characteristic is extended to the long wavelength side. . A substrate in which a recess is formed and the optical chip is mounted on the bottom of the recess;
A light-transmitting sealing material that is filled in the recess and does not contain the phosphate glass ;
The optical chip is mounted on the bottom with the light receiving surface facing the opening side of the recess,
The optical device according to claim 1, wherein the sealing material is filled so as to cover the optical filter and the optical chip.   The optical device according to claim 1, wherein the phosphate glass has a weight of 80 to 120 with respect to a weight of the translucent resin 100. The optical device according to claim 1 , wherein the translucent resin is a translucent epoxy resin, an acrylic resin, or a silicone resin.   The optical device according to claim 2, wherein the substrate is glass. A recess forming step for forming a recess in the substrate;
A mounting step of mounting an optical chip on the bottom surface of the recess;
Phosphate glass containing phosphorous pentoxide, alumina, boric acid, alkaline earth oxide, iron oxide and having an average particle diameter of 1 μm to 3 μm is dispersed in a translucent resin in the form of particles, and transmitted light peak wavelength of the relative intensity is shifted substantially to 50nm long wavelength side than the peak wavelength of the standard luminosity characteristics, placing an optical filter having a spectral characteristic stretching the standard visibility characteristics to the long wavelength side in the optical chip Optical filter installation process;
And a sealing step of filling the recess with a light-transmitting sealing material so as to cover the optical chip. The said optical filter is a manufacturing method of the optical device of Claim 6 with which the said phosphate glass has the weight of 80-120 with respect to the weight of the translucent resin 100.

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