JP2006162392A - Imaging device, imaging element package, and condensing lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device capable of improving the condensing rate of far-infrared light, an imaging element package and condensing lenses constituting the imaging device. <P>SOLUTION: An imaging part 12 is equipped with a circular plate-shaped substrate 127; a plate-shaped heat sink 126 whose planar shape is rectangular provided on the center part surface of the substrate 127; a rectangular imaging element 125 provided on the upper side surface of the heat sink 126, and having approximately the same size as the heat sink 126; the condensing lenses 124 made of zinc sulfide mounted on the surface of the imaging element 125; a toroidal case 123 for storing hermetically the condensing lenses 124, the imaging element 125 and the heat sink 126 by being interfitted with the substrate 127; and a circular plate-shaped transmission plate 121 mounted on a center opening part of the case 123. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device that improves the condensing rate of infrared light, an imaging element package that constitutes the imaging device, and a condenser lens.

  Video cameras that image far-infrared light are devices that directly image thermal energy generated by a heating element such as a human being or an object, and those using an electronic scanning method using an image sensor are the mainstream.

In such an image pickup apparatus, an image pickup element in which a plurality of infrared light absorption films are two-dimensionally arranged on a silicon substrate in order to improve the light collection rate of the image pickup element, increase the temperature resolution, and obtain a high-quality heat distribution. An image pickup device package is used in which a condenser lens (microarray lens) made of polysilicon or thermoplastic resin that collects infrared light on the surface is mounted (see Patent Document 1).
Japanese Patent No. 3413953

  However, in the example of Patent Document 1, polysilicon or thermoplastic resin is used as a material for the condensing lens, and in the far-infrared light region (wavelength is 8 to 12 μm), the transmittance is 30 to 40. %, There was a limit to improving the far-infrared light collection rate.

  The present invention has been made in view of such circumstances, and a zinc sulfide is used as a condensing lens for condensing infrared light onto a plurality of infrared light absorption films arranged two-dimensionally on a substrate. Accordingly, an object of the present invention is to provide an imaging device capable of improving the light collection rate as compared with the conventional one, an imaging element package and a condenser lens constituting the imaging device.

  Another object of the present invention is to provide an imaging apparatus that can be reduced in size and weight by disposing the condensing part of the condensing lens so as to face the infrared light absorbing film. It is in.

  Another object of the present invention is to improve the light collection rate at low cost by making the transmission plate made of zinc sulfide and condensing infrared light on the image sensor with the transmission plate instead of the condenser lens. An object of the present invention is to provide an image pickup device package that can be used.

  An imaging device according to a first aspect of the present invention includes an optical element that transmits infrared light, a condensing lens that collects infrared light transmitted through the optical element, and infrared light that is collected by the condensing lens. And an imaging device that picks up infrared light by absorbing with a plurality of infrared light absorption films arranged two-dimensionally on the substrate, wherein the condenser lens is made of zinc sulfide And

  The imaging device according to a second invention is the imaging device according to the first invention, wherein the condenser lens has a condenser part for condensing infrared light on the infrared light absorption film, It is characterized by being arranged two-dimensionally facing the infrared light absorption film.

  An image pickup device package according to a third aspect of the invention absorbs infrared light transmitted through the transmission plate with a transmission plate that transmits infrared light and a plurality of infrared light absorption films that are two-dimensionally arranged on the substrate. In an imaging device package comprising an imaging device that captures infrared light and a condensing lens that condenses the infrared light transmitted through the transmission plate on the imaging device, the condensing lens is made of zinc sulfide. It is characterized by.

  An image pickup device package according to a fourth aspect of the invention absorbs infrared light transmitted through the transmission plate by a transmission plate that transmits infrared light and a plurality of infrared light absorption films that are two-dimensionally arranged on the substrate. An image pickup device package including an image pickup device that picks up infrared light, wherein the transmission plate is made of zinc sulfide and focuses infrared light on the image pickup device.

  A condensing lens according to a fifth aspect of the present invention condenses infrared light on an image sensor that picks up infrared light by absorbing the infrared light with a plurality of infrared light absorption films arranged two-dimensionally on the substrate. In the condensing lens, the condensing lens is made of zinc sulfide and has a condensing part for condensing infrared light on the infrared light absorption film, and the condensing part is two-dimensional. It is arranged in that.

  In the first invention, the infrared light transmitted through the optical element that transmits the infrared light is a plurality of two-dimensionally arranged on the substrate by the condensing lens for condensing the infrared light. The condensed infrared light is condensed on the infrared light absorbing film, and the condensed infrared light is absorbed by the infrared light absorbing film and imaged by the imaging device. Since the condensing lens is made of zinc sulfide, the infrared light transmittance is about 70% as compared with the conventional lens, and the infrared light condensing rate is improved.

  In the second invention, the condensing lens has a two-dimensional arrangement of a condensing part for condensing infrared light on the infrared light absorbing film, facing the infrared light absorbing film. is there.

  In the third invention, the infrared light transmitted through the transmission plate that transmits infrared light is a plurality of two-dimensionally arranged on the substrate by the condensing lens for condensing the infrared light. The condensed infrared light is condensed on the infrared light absorbing film, and the condensed infrared light is absorbed by the infrared light absorbing film and imaged by the imaging device. Since the condensing lens is made of zinc sulfide, the infrared light transmittance is about 70% as compared with the conventional lens, and the infrared light condensing rate is improved.

  In the fourth invention, the infrared light transmitted through the transmission plate that transmits infrared light is condensed on a plurality of infrared light absorption films arranged two-dimensionally on the substrate, and the condensed red light is collected. External light is absorbed by the infrared light absorbing film and imaged by the image sensor. Since the transmission plate is made of zinc sulfide, the transmittance of infrared light is about 70% as compared with the prior art, the infrared light condensing rate is improved, and a condensing lens is not required.

  In the fifth aspect of the invention, the infrared light is condensed by the light collecting portion of the condensing lens on the plurality of infrared light absorbing films arranged two-dimensionally on the substrate, and is collected. Is absorbed by the infrared light absorbing film and imaged by an image sensor. Since the condensing lens is made of zinc sulfide, the infrared light transmittance is about 70% as compared with the conventional lens, and the infrared light condensing rate is improved.

  In the first invention, the third invention, and the fifth invention, since the condensing lens is made of zinc sulfide, the infrared light has a higher transmittance than before, and the infrared light is picked up by the imaging device. The light condensing rate is improved.

  In the second invention, by mounting the condensing part for condensing the infrared light on the infrared light absorbing film in two dimensions facing the infrared light absorbing film, It can be reduced in size and weight.

  In the fourth invention, instead of the condensing lens, the condensing lens is not required by condensing the infrared light with the zinc sulfide transmission plate, and the infrared light condensing rate is reduced. Can be improved.

  Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is a block diagram showing a configuration of an imaging apparatus according to the present invention. Reference numeral 11 denotes a lens unit. The lens unit 11 includes a plurality of germanium lenses that transmit far-infrared light and are arranged with their optical axes aligned, and the far-infrared light that has transmitted through the lens unit 11 is guided to the imaging unit 12.

  The imaging unit 12 is opposed to the lens unit 11, has an appropriate distance from the lens unit 11, and is a position where far-infrared light transmitted through the lens unit 11 forms an image. The axes are arranged so as to be located at the center of the imaging surface. Far-infrared light transmitted through the lens unit 11 is input to the imaging unit 12. The imaging unit 12 converts the input far infrared light into a luminance signal corresponding to the intensity of the far infrared light, and outputs the luminance signal to the signal processing unit 13.

  The signal processing unit 13 performs processing for removing various distortions generated in the optical system, low-frequency noise removal processing, correction processing for correcting gamma characteristics, and the like on the luminance signal input from the imaging unit 12. The luminance signal after processing is temporarily stored in the image memory 15 as image data.

  The interface unit 14 performs control for outputting the image data stored in the image memory 15 to the image processing apparatus in accordance with a command transmitted from an image processing apparatus (for example, an image processing ECU) (not shown) or the like. The transfer rate is converted according to the resolution of the image, and packet data is created from the image data. Further, the interface unit 14 outputs the image data stored in the image memory 15 to the image processing device under the control of the control unit 16.

  The control unit 16 controls processing of the imaging unit 12, the signal processing unit 13, and the interface unit 14 via the bus 17. For example, a command from the image processing apparatus is interpreted, and the image data captured by the imaging unit 12 is stored in the image memory 15. The stored image data is read out and output to the image processing apparatus via the interface unit 14.

  FIG. 2 is an exploded perspective view showing the configuration of the imaging unit 12, and FIG. 3 is a longitudinal sectional view of the imaging element and the condenser lens. The imaging unit 12 (imaging device package) is provided on a circular plate-like base 127, a planar heat sink 126 having a rectangular planar shape provided on the center surface of the base 127, and an upper surface of the heat sink 126. The rectangular imaging element 125 having substantially the same dimensions as the heat sink 126, the condenser lens 124 mounted on the surface of the imaging element 125, and the base 127 are fitted to the condenser lens 124, the imaging element 125, and the heat sink. An annular case 123 for hermetically storing 126 and a circular plate-shaped transmission plate 121 attached to the central opening of the case 123 are provided.

  The base 127 includes electrodes 122, 122,... For outputting a signal output from the imaging element 125 to the outside of the imaging unit 12. A signal output terminal (not shown) of the image sensor 125 and the electrodes 122, 122,... Are connected by lead wires such as wire bonding. Note that the signal output terminal of the image sensor 125 may be directly soldered to the electrodes 122, 122,.

  The heat sink 126 is made of aluminum and is attached in close contact with the image sensor 125 and the base 127, and conducts heat generated by the image sensor 125 to the base 127, thereby releasing heat to the outside of the image pickup unit 12. To do.

  The imaging element 125 has, on a silicon substrate (for example, 10 mm square), concave portions 125d, 125d,. Arranged at equal intervals, rectangular infrared light absorbing films 125a, 125a,... Having smaller dimensions than the recesses 125d, 125d,.

  The condenser lens 124 is made of zinc sulfide, has a thickness of about several to several tens of μm, and has the same number as the number of pixels of the image sensor 125 on one surface of a rectangular plate having the same dimensions as the image sensor 125. .. Are substantially hemispherical convex portions 124a, 124a,... Having a diameter of about 25 to 100 .mu.m, which are light collecting portions for collecting far-infrared light. The convex portions 124a, 124a,... Are arranged at the same positions as the positions where the concave portions 125d, 125d,... Are arranged, and the condenser lens 124 has the convex portions 124a, 124a,. It is mounted on the upper side of the image sensor 125. The condensing lens 124 can form a convex portion having a required shape by molding, for example.

  The case 123 is made of synthetic resin, and a fitting groove into which the base 127 is fitted is provided on the inner surface of the lower edge portion, and the case 123 is fitted with the base 127. Thereby, the inside of the case 123 is sealed. A transmission plate 121 that transmits far-infrared light is attached to the opening in the upper center of the case 123. Thereby, the far-infrared light transmitted through the transmission plate 121 is refracted by the convex portions 124a, 124a,... Of the condenser lens 124, and the refracted far-infrared light is each convex portion 124a, 124a,. The light is condensed on each of the infrared light absorption films 125a, 125a,.

  3, infrared light absorption films 125a, 125a,... Having a rectangular planar shape are provided on the bottom surfaces of the recesses 125d, 125d,... Arranged at equal intervals on the silicon substrate 125c. A thermopile 125b, 125b,... In which a number of thin film thermocouples made of polysilicon and aluminum are connected in series adjacent to the infrared light absorption films 125a, 125a,. Part) and the silicon substrate 125c (cold junction part).

  The condensing lens 124 has a substantially hemispherical convex portion 124a, 124a,... Provided on one surface disposed at a position facing the concave portions 125d, 125d,..., And the convex portion 124a, 124a,. It is mounted on the upper surface of 125c. The far-infrared light projected from the condenser lens 124 side is refracted by the convex portions 124a, 124a,... Of the condenser lens 124, and the refracted far-infrared light is applied to the bottoms of the concave portions 125d, 125d,. It is absorbed by the provided infrared light absorption films 125a, 125a,.

  The far infrared light is absorbed by each of the infrared light absorbing films 125a, 125a,..., And the temperature change generated at the temperature junction of the thermopiles 125b, 125b,. The signal is output from the imaging unit 12 via a signal output terminal (not shown) and an electrode 122 provided on the base 127. As a result, the imaging unit 12 can electrically generate a temperature change generated by far-infrared light absorbed by the same number of infrared light absorption films 125a, 125a,... As the number of pixels of the image sensor 125 for each pixel of the image sensor 125. Output as a signal.

  As described above, in the present invention, the condenser lens 124 that collects far-infrared light on the infrared light absorption films 125a, 125a,... Arranged two-dimensionally on the silicon substrate is made of zinc sulfide. In contrast, the transmittance of far-infrared light is smaller than 30 to 40% in the past, and the transmittance of far-infrared light is limited compared to the limit in improving the collection rate of far-infrared light. It becomes about 70%, and the condensing rate of the far-infrared light in the far-infrared region can be improved.

  Further, the condensing lens 124 in which the convex portions 124a, 124a,... That are condensing portions are two-dimensionally arranged is mounted on the image sensor 125 so as to face the infrared light absorption films 125a, 125a,. The package (imaging unit 12) can be reduced in size and weight.

  In the above-described embodiment, the condensing lens 124 is used. However, instead of the condensing lens 124, the transmission plate 121 is made of zinc sulfide, and infrared light is absorbed into the infrared light absorbing film by molding. By condensing on 125a, 125a,..., The condensing lens 124 becomes unnecessary, and the condensing rate can be improved at a lower cost.

  In the above-described embodiment, a thermopile type image pickup device is used. However, the image pickup device is not limited to this, and a material whose resistance value is changed by heat generated by infrared light is used. The bolometer type imaging device used may be used.

  In the above-described embodiment, the infrared light absorption film is provided on the bottom surface of the recess provided in the silicon substrate. However, the arrangement of the infrared light absorption film provided on the silicon substrate is limited to this. Instead of this, a configuration may be employed in which a hollow portion is formed immediately below the infrared light absorption film to reduce the heat capacity of the hot junction.

  In the embodiment described above, the substantially hemispherical convex portion is two-dimensionally arranged on one surface of the condensing lens, but the shape of the convex portion of the condensing lens is limited to this. is not. For example, depending on the number of pixels of the image sensor, the distance between the infrared light absorbing film and the condensing lens, etc., the convex shape of the condensing lens can be obtained by collecting infrared light on the infrared light absorbing film by molding. It can be formed in other shapes so as to be lighted.

  In the above-described embodiment, the far-infrared light (for example, the wavelength is 8 to 12 μm) is collected. However, the present invention is not limited to this, and the mid-infrared light (for example, the wavelength is 3). (Approx. 5 μm).

It is a block diagram which shows the structure of the imaging device which concerns on this invention. It is a disassembled perspective view which shows the structure of an imaging part. It is a longitudinal cross-sectional view of an image pick-up element and a condensing lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 12 Imaging part 121 Transmission plate 123 Case 124 Condensing lens 124a Convex part 125 Imaging element 125a Infrared light absorption film 125b Thermopile 125c Silicon substrate 125d Concave part 126 Heat sink 127 Base

Claims (5)

An optical element that transmits infrared light, a condensing lens that condenses the infrared light transmitted through the optical element, and the infrared light condensed by the condensing lens are two-dimensionally arranged on the substrate. In an imaging device comprising an imaging device that captures infrared light by absorbing with a plurality of infrared light absorbing films,
The condenser lens is
An image pickup apparatus made of zinc sulfide. The condenser lens is
A condensing part for condensing infrared light on the infrared light absorbing film;
The condensing part is
The imaging apparatus according to claim 1, wherein the imaging apparatus is two-dimensionally arranged to face the infrared light absorption film. A transmission plate that transmits infrared light; and an imaging device that captures infrared light by absorbing infrared light transmitted through the transmission plate with a plurality of infrared light absorption films arranged two-dimensionally on the substrate; In an image sensor package comprising a condensing lens for condensing infrared light transmitted through the transmission plate on the image sensor,
The condenser lens is
An image pickup device package made of zinc sulfide. A transmission plate that transmits infrared light, and an image sensor that picks up infrared light by absorbing infrared light transmitted through the transmission plate with a plurality of infrared light absorption films arranged two-dimensionally on the substrate. In the image pickup device package provided,
The transmission plate is
An image pickup device package made of zinc sulfide, wherein infrared light is condensed on the image pickup device. In a condensing lens that collects infrared light on an imaging device that picks up infrared light by absorbing infrared light by a plurality of infrared light absorption films arranged two-dimensionally on the substrate,
The condenser lens is
It is made of zinc sulfide and has a condensing part for condensing infrared light on the infrared light absorbing film,
The condensing part is
A condensing lens characterized by being arranged two-dimensionally.

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