JP2011117952A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device in which its body can be thinned down while detection area of thermal infrared detection element can be wide-angled, and also its design characteristics can be prevented from being spoiled. <P>SOLUTION: The electronic device 100 includes a display with the thermal infrared detection element 1 for detecting infrared radiated from a human body H placed inside the body 101. It has the thermal infrared detection element 1 comprising a pyroelectric element which detects infrared radiated from a human body H, and an infrared lens 3 comprising an aspheric lens arranged forward the thermal infrared detection element 1 to collect infrared rays into the light-receiving surface on the thermal infrared detection element 1. The aspheric lens composing the infrared lens 3 is a semiconductor lens, which includes an infrared entrance window 103 formed by decentrally-preparing a plurality of point-like pores 103 on forward area of the infrared lens 3 in the body 101 to allow incidence of infrared rays into the infrared lens 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic device.

  Conventionally, in order to reduce power consumption in various electronic devices such as keyboards used as input devices such as personal computers (hereinafter referred to as personal computers) and terminal devices, displays used as output devices, notebook computers, word processors, and the like. In addition, a human body detection sensor is installed, and based on the output of the human body detection sensor, a low power consumption mode (such as a sleep mode that stops functions other than those required for startup) and an active mode in which normal operation is possible (normal operation mode) Electronic devices having a switching power management function have been proposed (for example, Patent Documents 1 and 2).

  Here, in the above-mentioned Patent Document 1, as an electronic device of this type, as shown in FIGS. 6A and 6B, a flat vessel body (case) 101 and an opening on the front wall of the vessel body 101 are disclosed. A plurality of push button handles (operation keys) 112 exposed from 101a, a circuit board (not shown) housed in the vessel 101 and provided with a control circuit, and a control signal from the control circuit (not shown) And a human body detection sensor 123 comprising a micro air pressure change detection sensor disposed in the body 101 so as to face a detection hole 113 formed in the front wall of the body 101. An electronic device 100 including a wireless keyboard on which (see FIG. 6C) is mounted is disclosed. Here, the control circuit is configured to generate and output a control signal corresponding to the operation of each push button handle 112, and when the push button handle 112 is not operated for a predetermined time, The power consumption is reduced by switching to the sleep mode, and the control circuit and the transmission unit are shifted from the sleep mode to the active mode based on a detection signal from the human body detection sensor 123. .

  Further, in Patent Document 2, as an electronic device, as shown in FIG. 7, a flat body (main body) 101 provided with a keyboard 104 on the upper surface side, a position covering the keyboard 104, and a position where the keyboard 104 is opened The display 105 includes a display 105 that is hinged to the body 101 so as to be rotatable between the two and serves also as a lid, and a human body detection sensor 123 ′ that detects the presence or absence of the human body H in a predetermined detection area E ′. An electronic device 100 including a notebook personal computer provided in the periphery of the display unit 105a is disclosed. In the electronic device 100 having the configuration shown in FIG. 7, when the absence of the human body H is detected by the human body detection sensor 123 ′, the normal operation mode is immediately shifted to the low power consumption mode, and the human body H is again detected by the human body detection sensor 123 ′. When detected, the mode automatically returns from the low power consumption mode to the normal operation mode, so that the power consumption can be reduced and the usability can be improved. Here, in the above-mentioned Patent Document 2, as the human body detection sensor 123 ', infrared rays or ultrasonic waves are transmitted and received to detect the presence or absence of the human body H in the detection area E'.

Japanese Patent Laid-Open No. 11-288351 JP 10-207584 A

  By the way, the electronic device 100 having the configuration shown in FIG. 6 is relatively large so that the user of the electronic device 100 can easily visually recognize the body 101 in order to detect a change in air pressure by the human body detection sensor 123. Since it is necessary to provide the detection hole 113, the design may be impaired, and there is a possibility that foreign objects such as dust or dust may enter the detection hole 113 and the human body detection sensor 203 cannot detect the human body. . Further, in the electronic device 100 having the configuration illustrated in FIG. 6, it is necessary for the user to bring his / her hand close to the detection hole 113 in order to return from the sleep mode to the active mode. Further, in the electronic device 100 having the configuration shown in FIG. 6, there is a possibility that erroneous detection of the human body detection sensor 123 may occur due to the influence of air flow from an air conditioner or the like in an office or the like.

  Further, in the electronic device 100 having the configuration shown in FIG. 7, it is necessary to intermittently transmit infrared rays or ultrasonic waves in the human body detection sensor 123 ', and power consumption in the human body detection sensor 123' increases. Further, in the electronic device 100 having the configuration shown in FIG. 7, since it is necessary to secure a space for arranging the human body detection sensor 123 ′ around the display unit 105 a in the display 105, the design is impaired. End up. Further, in the case where the presence or absence of the human body H is detected by transmitting and receiving infrared rays in the human body detection sensor 123 ′, there is a possibility that erroneous detection may occur due to the influence of external noise such as illumination light or sunlight, and the human body detection sensor 123 ′. In the case of detecting the presence or absence of the human body H by transmitting and receiving ultrasonic waves, there is a possibility that erroneous detection may occur due to the influence of external noise.

  Therefore, an electronic device in which a human body detection sensor using a thermal infrared detection element such as a pyroelectric element that detects infrared rays radiated from the human body is arranged in the body can be considered. In this case, it is conceivable to form a pinhole lens for causing the infrared rays to enter the light receiving surface of the thermal infrared detection element, but the user can easily see the pinhole lens. Pinhole lens will damage the design. On the other hand, if the hole diameter (inner diameter) of the pinhole lens is reduced, the sensitivity is lowered.

  On the other hand, it is conceivable to arrange an infrared lens made of a polyethylene lens as an optical system for condensing infrared rays on the light receiving surface of the thermal infrared detection element in front of the thermal infrared detection element. However, since polyethylene has a lower refractive index and a higher infrared absorption rate than infrared transmitting materials such as silicon and germanium, it cannot form a bright infrared lens with a short back focus. Moreover, in the human body detection sensor in which an infrared lens made of a polyethylene lens is arranged in front of the light receiving surface of the thermal infrared detection element, since the refractive index of the infrared lens is low, the aperture diameter of the infrared lens is increased in order to widen the detection area. It is necessary to make it larger than the aperture diameter of a semiconductor lens such as a silicon lens or a germanium lens, and the sensitivity decreases due to the increase in the lens thickness accompanying the increase in the aperture diameter. It will be difficult to reduce the thickness. In addition, when a polyethylene lens is used as an infrared lens, it may be possible to arrange the polyethylene lens so as to be exposed from the body, but when a semiconductor lens is used, the semiconductor lens is damaged and damaged. In order to prevent this, it is conceivable to arrange a protective cover made of polyethylene separately from the container in front of the semiconductor lens, but due to differences in the material and color of the container and the protective cover, Design may be impaired.

  The present invention has been made in view of the above-mentioned reasons, and its purpose is to reduce the thickness of the body while widening the angle of the detection area of the thermal infrared detection element, and to impair the design. An object of the present invention is to provide an electronic device that can prevent the above-described problem.

  The electronic apparatus of the present invention is an electronic apparatus in which a thermal infrared detecting element for detecting infrared rays radiated from a human body is arranged in the body, and the heat comprising the pyroelectric element for detecting infrared rays radiated from the human body. A non-spherical lens comprising an aspherical lens that is arranged in front of the thermal infrared detection element and that is arranged on the light receiving surface of the thermal infrared detection element to collect infrared rays. The spherical lens is a semiconductor lens, and has an infrared incident window portion that is formed by dispersing a plurality of dot-like fine holes at a front portion of the infrared lens in the body and that allows infrared rays to enter the infrared lens. It is characterized by.

  In this electronic apparatus, it is preferable that the infrared light incident window part constitutes a part of a character or a figure.

  In the electronic apparatus of the present invention, the body can be made thinner while widening the detection area of the thermal infrared detection element, and the design can be prevented from being impaired.

Regarding the electronic apparatus of the embodiment, (a) is a schematic explanatory view, (b) is a main part front view, (c) is a main part schematic sectional view, and (d) is an operation explanatory view. It is a circuit block diagram of the human body detection sensor in the same as the above. It is explanatory drawing of the human body detection sensor in the same as the above, and its comparative example. It is a principal part front view of the other structural example same as the above. It is a principal part schematic sectional drawing of another structural example same as the above. (A) is a schematic top view, (b) is a schematic side view, (c) is a schematic perspective view of a human body detection sensor regarding the electronic device of a prior art example. It is a schematic explanatory drawing of the electronic device of another conventional example.

  In the present embodiment, as an example of an electronic device in which a thermal infrared detecting element for detecting infrared rays radiated from a human body is arranged in the body, a peripheral device (output device) of a personal computer as shown in FIG. The electronic device 100 which consists of a display used as will be exemplified. Electronic device 100 is not limited to the above-described display, and may be, for example, a notebook computer, a terminal device, an input device such as a keyboard, a television, a telephone, a copy machine, an interphone, or the like.

  As shown in FIG. 1, the electronic device 100 according to the present embodiment includes a thermal infrared detection element 1 (see FIG. 2) including a pyroelectric element that detects infrared rays emitted from a human body H, and a thermal infrared detection element 1. And a human body detection sensor A having an infrared lens 3 composed of an aspherical lens for condensing infrared rays on the light receiving surface of the thermal infrared detection element 1, and in front of the infrared lens 3 in the body 100. It has an infrared incident window portion 103 that is formed by dispersing a plurality of dot-like fine holes 102 at a site and allows infrared rays to enter the infrared lens 3. Here, in the electronic device 100, the human body detection sensor A is disposed on the rear side of the front wall of the container body 101 in the upper part on the left side when viewed from the front. In the electronic device 100, the front wall of the container body 101 is formed in a rectangular frame shape, and the display unit 105a is exposed. The human body detection sensor A is mounted on a wiring board (not shown) made of a printed wiring board, and the wiring board is held by the container body 101.

  The electronic device 100 according to the present embodiment includes a low power consumption mode (such as a sleep mode in which functions other than those required for activation are stopped) and an active mode (normal operation mode) in which normal operation is possible based on the output of the human body detection sensor A. And a control unit (not shown) including a microcomputer having a power management function for switching between. Here, the control unit shifts from the normal operation mode to the low power consumption mode as soon as the absence of the person is detected by the human body detection sensor A, and automatically decreases when the human body detection sensor A detects the person again. Since the mode returns from the power consumption mode to the normal operation mode, the power consumption can be reduced and the usability can be improved.

  The human body detection sensor A includes a circuit block 6 provided with a thermal infrared detection element 1 and a signal processing circuit 20 (see FIG. 2) that performs signal processing on the output of the thermal infrared detection element 1, and a canister that houses the circuit block 6. And a package 140 made of a package.

  The package 140 includes a metal stem 141 on which the circuit block 6 is mounted via a spacer 7 made of an insulating material, and a metal cap 142 fixed (welded) to the stem 141 so as to cover the circuit block 6. And a plurality of (here, three) terminal pins 145 that are electrically connected to appropriate portions of the circuit block 6 are provided so as to penetrate the stem 141. Here, the stem 141 is formed in a disc shape, and the cap 142 is formed in a bottomed cylindrical shape whose rear surface is opened, and the rear surface is closed by the stem 141. The spacer 7 is fixed to the circuit block 6 and the stem 141 with an adhesive.

  In addition, a rectangular (in this embodiment, square) window 142 a is formed on the front wall of the cap 142 positioned in front of the thermal infrared detection element 1, so that the thermal infrared detection element 1 receives light. The above-described infrared lens 3 which is an optical system for condensing infrared rays on the surface is disposed from the inside of the cap 142 so as to cover the window 142a.

  The circuit block 6 is provided with the above-described signal processing circuit, the thermal infrared detecting element 1 is mounted, and an appropriate shield plate (not shown) and a shield layer (not shown) are provided.

  The circuit block 6 has a through hole (not shown) through which the terminal pin 145 is inserted in the thickness direction, and the thermal infrared detection element 1 and the signal processing circuit 20 are connected via the terminal pin 145. Electrically connected.

  Of the three terminal pins 145 described above, the power supply terminal pin 145 and the signal output terminal pin 145 are electrically insulated from the stem 141 by a sealing portion made of an insulating material (glass), and are used for grounding. The terminal pin 145 is electrically connected to the stem 141 by a sealing portion made of a conductive material, and is set to the same potential as the above-described shield plate (for example, ground potential).

  The circuit block 6 is provided with a thermal insulation hole 67a for thermally insulating a later-described element element 12 of the thermal infrared detection element 1 and the circuit block 6, so that the element element of the infrared detection element 1 is formed. An air layer is formed between the circuit block 6 and the circuit block 6 to increase sensitivity.

  The thermal infrared detecting element 1 composed of the above pyroelectric elements is a quad type element that can be expressed by the equivalent circuit shown in FIG. 2, and two element elements (light receiving portions) 12 are arranged on the same pyroelectric substrate. It is formed in a × 2 array and is appropriately connected by a wiring pattern, and is provided with two output terminals 13.

  In the thermal infrared detecting element 1 described above, the element elements 12 at the diagonal positions of the four element elements 12 are connected in parallel so that the directions of the spontaneous polarization are the same, and the element elements are positioned at different diagonal positions. The 12 are connected in parallel so that the direction of spontaneous polarization is opposite. In short, the thermal infrared detecting element 1 having the configuration shown in FIG. 2 has a rectangular outer peripheral shape in plan view, the direction along one side of the rectangular shape is the X direction, and the direction orthogonal to the X direction is When the Y direction is assumed, the directions of spontaneous polarization of the element elements 12 formed side by side along the X direction are opposite to each other, and the directions of the element elements 12 formed side by side along the Y direction are spontaneous. The directions of polarization are opposite to each other. Therefore, noise (dark noise, etc.) in the two element elements 12 due to changes in the environmental temperature, etc. is offset between the element elements 12 connected in parallel so that the direction of spontaneous polarization is reversed. It is possible to prevent erroneous detection by the human body detection sensor A. It is also possible to know which element element 12 has been detected first by the change order of the polarity of the output.

  As shown in FIG. 2, the signal processing circuit 20 includes a current-voltage conversion circuit 22 that converts an output current (pyroelectric current) output from the thermal infrared detection element 1 into a voltage signal, and a current-voltage conversion circuit 22. A voltage amplifier circuit (bandpass amplifier) 23 that amplifies a voltage in a predetermined frequency band among the voltage signals converted by the above-described method, and compares the voltage signal amplified by the voltage amplifier circuit 23 with a threshold value set as appropriate. Is provided with a detection circuit 24 that outputs a detection signal when the threshold value exceeds a threshold value, and an output circuit 25 that outputs the detection signal of the detection circuit 24 as a predetermined human body detection signal.

  The infrared lens 3 includes a lens portion 3 a that collects infrared rays on the light receiving surface of the thermal infrared detection element 1, and extends outward from the peripheral portion of the lens portion 3 a. And a flange portion 3b to be fixed.

  The infrared lens 3 described above is a semiconductor lens made of a silicon lens, the lens portion 3a is formed in the shape of a plano-convex aspheric lens, and the outer peripheral shape of the flange portion 3b, which is a part other than the lens portion 3a. Is formed in a rectangular shape (in this embodiment, a square shape).

  Further, in the human body detection sensor A described above, the window 142a of the cap 142 is opened in a rectangular shape, and is positioned on the flange portion 3b of the infrared lens 3 on the inner peripheral surface and the peripheral portion of the window 142a in the cap 142. The step portion 3c is formed, and the step portion 3c in the flange portion 3b of the infrared lens 3 is fixed to the cap 142 via the joint portion 68 made of the above-mentioned joining material. Therefore, the parallelism between the infrared lens 3 and the thermal infrared detection element 1 can be increased, and the distance accuracy between the infrared lens 3 and the thermal infrared detection element 1 in the optical axis direction of the infrared lens 3 can be increased. The alignment accuracy between the optical axis of the infrared lens 3 and the optical axis of the light receiving surface of the thermal infrared detector 1 can be increased. Further, in the human body detection sensor A described above, a thin aspherical lens having a shorter focal point than the spherical lens is formed as the lens portion 3a of the infrared lens 3, so that the human body detection sensor A as a whole is made thinner (smaller). I can plan.

  By the way, since the silicon lens has a higher refractive index than that of the polyethylene lens and has a short focal point (note that the refractive index of silicon is 3.42 and the refractive index of polyethylene is 1.53), the silicon lens shown in FIG. When the opening diameter of the infrared lens 3 made of a lens and the opening diameter of the infrared lens 3 ′ made of a polyethylene lens shown in FIG. 5B are the same, the distance from the thermal infrared detecting element 1 is the same distance. The detection area can be widened (note that the alternate long and short dash line in FIGS. 3A and 3B indicates the light passing through the center of the light receiving surface of the thermal infrared detector 1 and the centers of the infrared lenses 3 and 3 ′. The axis shows the axis, and the thin solid line shows the path of infrared radiation).

  Here, if the focal length (back focus) of the infrared lenses 3 and 3 ′ is f [mm] and the aperture diameter is D [mm], the F number (F value) of the infrared lenses 3 and 3 ′ is F = Although calculated | required by f / D, the infrared lens 3 which consists of a silicon lens can be used as a bright lens with a small F number compared with infrared lens 3 'which consists of a polyethylene lens. In this embodiment, since the infrared lens 3 made of a silicon lens is used, for example, while the lens thickness is 0.3 mm, the focal length f is 1 mm, the aperture diameter is 3 mm, and the F value is 0.33. Can be a bright lens. However, these numerical values are examples and are not particularly limited.

  By the way, as described above, the electronic device 100 according to the present embodiment is formed by dispersing a plurality of dot-like microscopic holes 102 in the front portion of the infrared lens 3 in the body 101, and forming infrared rays into the infrared lens 3. It has an infrared incident window 103 for incidence. Here, the dot-like fine hole 102 is a hole whose inner diameter is sufficiently smaller than an effective diameter (hereinafter referred to as an opening diameter) of the infrared lens 3, and is visually (when visually observed) when the electronic device 100 is used. The inner diameter is set so that it cannot be visually recognized as a hole. In the present embodiment, the diameter of the lens portion 3a of the infrared lens 3 is the opening diameter, the opening diameter of the lens portion 3a is set to 3 mm, and the inner diameter is set to 0.1 mm to 0.3 mm, for example. The length may be set within a range of about 0.1 mm to 0.5 mm. It is desirable that the minimum value (minimum diameter) of the inner diameter of the fine hole 102 is equal to or greater than the wavelength of the infrared ray to be detected by the thermal infrared detection element 1. In the case of the human body detection sensor A, since the center wavelength of the infrared ray to be detected by the thermal infrared detecting element 1 is about 10 μm, it is desirable that the minimum diameter of the fine hole 102 is 10 μm. On the other hand, the maximum value (maximum diameter) of the inner diameter of the fine hole 102 is a diameter in which the fine hole 102 is not noticeable in a state where the electronic device 100 is normally used. Here, since the inner diameter of the hole, which is not noticeable when viewed from a distance of about 30 cm unconsciously, is about 0.3 mm, the electronic device 100 that is normally viewed from a distance of about 30 cm is used. The maximum diameter of the fine hole 102 is about 0.3 mm.

  The fine holes 102 are formed along a straight line (in the optical axis direction) connecting the center of the infrared lens 3 and the center of the light receiving surface of the thermal infrared detector 1.

  In the infrared incident window 103 in the present embodiment, with respect to the container body 101, dot-like fine holes (circular holes) 102 are formed at portions corresponding to lattice points of a virtual two-dimensional square lattice having a square unit lattice. However, the unit cell is not limited to a square, and may be, for example, an equilateral triangle. In this case, the unit cell is a micropore 102 at a portion corresponding to each lattice point of a virtual two-dimensional triangular lattice having an equilateral triangle. May be formed.

  By the way, when the infrared lens 3 ′ made of a polyethylene lens is used, if the aperture diameter of the infrared lens 3 ′ is increased in order to increase the detection area, the thickness of the infrared lens 3 ′ increases and the body 101 becomes thinner. In addition, there is a concern that the number of the micropores 102 may increase and the appearance may deteriorate, and polyethylene has a higher infrared absorption rate than silicon and germanium, and thus the sensitivity of the human body detection sensor A is reduced. Resulting in.

  On the other hand, in the present embodiment, since the infrared lens 3 made of a silicon lens is used as the optical system for condensing infrared rays on the thermal infrared detection element 1, the number of the fine holes 102 can be reduced, and the design property is improved. Can be prevented from being damaged. Here, the entire image is darkened by providing the fine holes 102, but the image formation state does not change.

  In the electronic apparatus 100 according to the present embodiment described above, the aspherical lens constituting the infrared lens 3 is a semiconductor lens, and a plurality of dot-like microscopic holes 102 are dispersed in the front portion of the infrared lens 3 in the body 101. Since it has the infrared incident window part 103 which inject | emits and forms infrared rays inject into the infrared lens 3, providing the wide angle (that is, increase of image magnification) of the detection area of the thermal-type infrared detection element 1, it is a thing of the body 101 The thickness can be reduced, and the design can be prevented from being damaged.

  In this embodiment, the front cover including the front wall, which is a constituent element of the container body 101, is formed using a metal member (for example, an Al member), and the fine holes 102 can be easily formed by a known metal processing technique. Can be formed with high dimensional accuracy. Here, if the metal member having an anodized film formed on at least the surface side (front side) opposite to the infrared lens 3 side is used, the fine holes 102 are formed as compared with the case where the surface is glossy. Less noticeable.

  However, when an anodized film is formed, it is preferable to improve the anti-contamination and corrosion resistance by performing a sealing treatment. For example, after anodizing, the coating is further applied to improve the corrosion resistance. A composite membrane is preferred. Further, the material of the container body 101 is not limited to metal, and may be resin.

  By the way, as shown in FIG. 4, if a character (“P” in the illustrated example) is represented by an aggregate of fine holes 102, the infrared incident window 103 forms a part of the character. When the character is provided on the container 101, the design can be improved as compared with the case where the infrared incident window 103 is provided separately from the character. Here, the infrared incident window portion 103 is not limited to constituting a part of a character, and may constitute a part of a figure represented by an aggregate of the fine holes 102.

  By the way, in the above-described electronic device 100, if the thermal infrared detection element 1 is accommodated in a surface-mount type package, the thermal infrared detection element 1 is accommodated in a package 140 made of a can package. In comparison, the vessel body 101 can be further reduced in thickness.

  By the way, when the electronic device 100 is a display used in an office or the like, as shown in FIG. 5, the infrared lens 3 is disposed obliquely below the light receiving surface of the thermal infrared detection element 1, and the fine holes 102 are formed in the infrared lens. If it forms along the straight line (optical axis direction) which connects the center of 3 and the center of the light-receiving surface of the thermal type infrared detection element 1, possibility of detecting persons other than a user can be reduced.

  The pyroelectric element constituting the thermal infrared detecting element 1 of FIG. 2 described in the above embodiment is formed using a pyroelectric substrate, but is not limited to this, for example, micromachining technology and A chip formed using a pyroelectric thin film forming technique may be used.

E Detection Area H Human Body 1 Thermal Infrared Detector 3 Infrared Lens 100 Electronic Equipment 101 Body 102 Micro Hole 103 Infrared Incidence Window

Claims (2)

  A thermal infrared detection element for detecting infrared rays emitted from the human body is an electronic device disposed in the body, the thermal infrared detection element comprising a pyroelectric element for detecting infrared rays emitted from the human body, and An infrared lens composed of an aspheric lens arranged in front of the thermal infrared detection element and condensing infrared rays on a light receiving surface of the thermal infrared detection element, and the aspheric lens constituting the infrared lens is a semiconductor lens An electronic apparatus comprising: an infrared incident window portion that is formed by dispersing a plurality of dot-like fine holes in a front portion of the infrared lens in the vessel body and that allows infrared rays to enter the infrared lens.   The electronic device according to claim 1, wherein the infrared incident window part constitutes a part of a character or a figure.

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