JP2005228153A - Physical quantity detector, electronic apparatus using it and image projecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a physical quantity detector the setting position of which can be freely selected to prevent deterioration of cooling efficiency even in case of application to a control system of forced ventilation or contribute to miniaturization of a casing, and electronic apparatus using it. <P>SOLUTION: This detector comprises sensor means 56, 57, 58, 59 and 59a provided within a common casing and a sensor signal receiving means 61. Each of the sensor means comprises at least a detection means detecting a physical quantity and a transmitting means wirelessly transmitting information showing the physical quantity detected by the detection means with electromagnetic wave as a medium. The sensor signal receiving means comprises at least a receiving means receiving the electromagnetic wave transmitted from the sensor means and a reproduction means reproducing the information showing the physical quantity from the electromagnetic wave. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a physical quantity detection device that detects a physical quantity such as temperature, an electronic apparatus using the same, and an image projection apparatus.

  A physical quantity is a quantity that expresses the properties of a physical system, and that means a measurement method and a unit whose size is specified, that is, a quantity that can be measured like temperature. .

  An example of the physical quantity detection device will be described. An electronic device, for example, an image projection apparatus (so-called projector) includes a projection lamp that generates high heat and an electronic component that is easily affected by heat (particularly, an optoelectronic component such as a liquid crystal panel or a digital micromirror device). Because it is mounted, the inside of the housing is forcibly ventilated with a fan to suppress temperature rise. The drive source of the fan is a motor, but it is not preferable in terms of power consumption and noise if the motor is constantly running. Generally, the temperature inside the housing is detected by a temperature sensor, and the motor is driven according to the detected temperature. The number of rotations is controlled to increase or decrease (see, for example, Patent Document 1).

  FIG. 9 is a conceptual configuration diagram of a control system in a conventional example. The temperature sensor 1 detects the temperature of a point of interest inside the housing (for example, the temperature in the vicinity of an electronic component that is easily affected by heat). The temperature S detected by the temperature sensor 1 is transmitted to the motor control unit 3 via the signal cable 2. For example, when the motor control unit 3 determines a high temperature environment based on the detected temperature S and the operation allowable temperature of the electronic component, the motor control unit 3 calculates a control amount for controlling the rotational speed of the motor 5 to the increase side, and the control amount A drive current C having a magnitude corresponding to is generated, the motor 5 is driven via the drive cable 4, and rotation control of the motor 5 is performed.

Japanese Patent Laid-Open No. 2003-43585 ([0022]-[0025], FIG. 1)

  By the way, in the above-described image projection apparatus, the temperature sensor 1 housed in the housing detects the temperature of the point of interest inside the housing, and the number of revolutions of the motor 5 is controlled based on this detected temperature. However, there are technical issues to be improved in the following points.

  That is, (1) Since the temperature sensor 1 and the motor control unit 3 are connected by the signal cable 2, the installation place of the temperature sensor 1 can be freely set because of restrictions on the handling of the signal cable 2 inside the housing. There is an inconvenience that you cannot choose. For example, it is impossible to attach the temperature sensor 1 directly on a rotating body that freely rotates 360 degrees. An example of such a rotating body is a “color wheel” described later. (2) Further, for example, when the signal cable 2 is located on the ventilation path, the signal cable 2 may disturb the air flow, which may be an obstacle to cooling efficiency. (3) Further, the size of the housing is hindered from the viewpoint of securing the volume of the signal cable 2 itself and a space for laying the cable.

  Accordingly, the object of the present invention is to devise a configuration that makes the signal cable 2 unnecessary, paying attention to the existence of the signal cable 2 as the root cause of the above (1) to (3). This allows the sensor installation location to be freely selected and, for example, physical quantity detection that does not degrade cooling efficiency even when applied to a forced ventilation control system, and contributes to downsizing of the housing. An apparatus and an electronic apparatus using the same are provided.

The physical quantity detection device according to claim 1 includes sensor means and sensor signal receiving means provided in a common housing, and the sensor means includes at least detection means for detecting a physical quantity, and the detection means. Transmitting means for wirelessly transmitting information representing the physical quantity detected in the above using electromagnetic waves as a medium, the sensor signal receiving means at least receiving means for receiving the electromagnetic waves transmitted from the sensor means, And a reproducing means for reproducing the information representing the physical quantity from the electromagnetic wave.
The physical quantity detection device according to claim 2 is the physical quantity detection device according to claim 1, wherein the sensor signal receiving means further includes a transmission means for transmitting an interrogation signal to the sensor means, and the sensor means includes the interrogation signal. It further comprises power supply power generation means for receiving power and generating power supply power necessary for operation.
The physical quantity detection device according to claim 3 is the physical quantity detection device according to claim 1 or 2, wherein a plurality of the sensor means are provided.
An electronic device according to a fourth aspect is an electronic device equipped with the physical quantity detection device according to any one of the first, second, and third aspects, wherein the sensor signal receiving means is a transmission means of the sensor means. A loop coil antenna that receives an electromagnetic wave transmitted from the electronic device, and the installation location of the loop coil antenna is the inner surface of the upper lid of the casing of the electronic device.
The image projection apparatus according to claim 5, wherein a light source, a reflector that condenses light from the light source, a modulation unit that modulates light collected by the reflector with image information, and the modulation are provided inside the housing. In an image projection apparatus comprising projection means for projecting light modulated by the means, sensor means and sensor signal receiving means for individually measuring temperatures of the light source, the reflector and the modulation means, the sensor means, At least a detection means for detecting a physical quantity; and a transmission means for wirelessly transmitting information representing the physical quantity detected by the detection means using an electromagnetic wave as a medium, wherein the sensor signal receiving means is at least the sensor means. Receiving means for receiving the electromagnetic wave transmitted from the reproduction means, and reproducing means for reproducing the information representing the physical quantity from the electromagnetic wave.
The image projection apparatus according to claim 6 is the image projection apparatus according to claim 5, wherein a color wheel that separates the light condensed by the reflector into three primary colors of light, and sensor means that measures the temperature of the color wheel. And further comprising.

According to the physical quantity detection device of claim 1, the sensor means provided in the housing and the sensor signal receiving means provided in the same housing are connected wirelessly using an electromagnetic wave as a medium. . Therefore, since the signal cable between the sensor means and the sensor signal receiving means can be made unnecessary, various disadvantages caused by the presence of the signal cable, such as the degree of freedom of the installation location of the sensor and the obstruction factor of the cooling efficiency. It is possible to remove factors that hinder downsizing the housing.
According to the physical quantity detection device of the second aspect, the sensor means receives the interrogation signal from the sensor signal receiving means and generates the power supply power necessary for the operation, so that the power supply line to the sensor means can be eliminated. . Therefore, various inconveniences caused by the presence of the power supply line, for example, the degree of freedom of the installation location of the sensor, the obstruction factor of the cooling efficiency, the obstruction factor of the downsizing of the casing, and the like can be eliminated.
According to the physical quantity detection device of the third aspect, since a plurality of sensor means are provided, various physical quantities inside the housing can be detected.
According to the electronic device of the fourth aspect, since the installation location of the loop coil antenna is optimized, the incommunicable area inside the housing can be limited or eliminated.
According to the image projecting apparatus of the fifth aspect, the sensor means provided in the housing and the sensor signal receiving means provided in the same housing are connected wirelessly using an electromagnetic wave as a medium. . Accordingly, since the signal cable between the sensor means and the sensor signal receiving means can be made unnecessary, various disadvantages caused by the presence of the signal cable, for example, the degree of freedom of the installation location of the sensor, an obstacle to cooling efficiency It is possible to remove factors that hinder downsizing the housing.
According to the image projection apparatus of the sixth aspect, the temperature of the color wheel can also be measured wirelessly.

  Embodiments of the present invention will be described below with reference to the drawings, taking application to an image projection apparatus as an example. It should be noted that the specific details or examples in the following description and the illustrations of numerical values, character strings, and other symbols are only for reference in order to clarify the idea of the present invention, and the present invention may be used in whole or in part. Obviously, the idea of the invention is not limited. In addition, a well-known technique, a well-known procedure, a well-known architecture, a well-known circuit configuration, and the like (hereinafter, “well-known matter”) are not described in detail, but this is also to simplify the description. Not all or part of the matter is intentionally excluded. Such well-known matters are known to those skilled in the art at the time of filing of the present invention, and are naturally included in the following description.

  An image projection apparatus is an apparatus for enlarging and projecting an image of a personal computer or the like on a screen. Usually called a projector. Today's projectors are compact and lightweight that are easy to carry around, and high-brightness outputs that are easy to see not only in dark rooms, but also under illumination light such as fluorescent lights, have been put into practical use. It has come to be widely used regardless of location.

  Projectors can be broadly divided into three types: “CRT type”, “liquid crystal type”, and “DLP type”, depending on the type of image display device. “DLP” is a registered trademark of Texas Instruments Incorporated.

  The CRT type uses cold cathode fluorescent lamps (CRTs) for each of the three primary colors of light (RGB / red, green, and blue) for the image display device, has an excellent contrast ratio, is responsive, and is suitable for video playback. There are advantages such as. In the old days, this type was the mainstream. However, it is difficult to adjust the optical axis of the three tubes, it is not easy to move after installation, and the housing is large and heavy. It is.

  On the other hand, the liquid crystal type and the DLP type are the mainstream of today, the former (liquid crystal type) uses a liquid crystal panel for the image display device, and the latter (DLP type) is called DMD (Digital Micromirror Device) for the device. A reflective light valve element is used.

  The liquid crystal panel utilizes the principle that the transmittance of the liquid crystal changes when a voltage is applied to the liquid crystal sealed between two transparent glasses. Project the transmitted light on the screen. On the other hand, DMD projects the reflected light on a screen by changing the angles of a number of micro movable mirrors spread on a plane. There is an advantage that there is little loss of light.

  Hereinafter, in this embodiment, the DLP type will be described as an example for convenience, but the present invention is not limited to this type. That is, the CRT type and the liquid crystal type are not intentionally excluded.

  FIG. 1 is an external view of a DLP type image projection apparatus 10 (electronic device). The illustrated image projection apparatus 10 includes a casing 11 having a shape designed in an arbitrary design (in the illustrated example, a rectangular parallelepiped shape), and a projection hidden behind the cover 12 on the front surface of the casing 11. A lens 13 is provided. The cover 12 is normally in the position shown in the figure and hides (protects) the projection lens 13, but this projection lens 13 can be removed by manually sliding the cover 12 (see FIG. 2C). It is exposed to face the screen shown. Further, when the cover 12 is slid, the front Ir (infrared) transmission / reception unit 15 is visible from the outside through the infrared light transmitting window 14, and the front Ir (infrared) transmission / reception unit 15 is described later. Infrared type remote controller 30 is used.

  The projection lens 13 is for projecting a light image formed by a DMD 52, which will be described later, and here, the focus and the projection magnification (zoom) can be arbitrarily changed. The front Ir transmitting / receiving unit 15 receives infrared light on which a key operation signal from a remote controller 30 described later is superimposed, and transmits infrared light on which a display signal is superimposed to the remote controller 30.

  On the top surface of the housing 11, a main body operation display unit 16, a top cover 17, and a speaker 18 are disposed. The main body operation display unit 16 is composed of a flat display device with a touch panel (liquid crystal display panel, organic display panel, EL panel or the like). The main body operation display unit 16 has various operation buttons necessary for each operation state. When a corresponding button is touch-operated in a graphical display, an operation event signal is generated, and when an operation abnormality occurs, the contents thereof are displayed as a character string or a graphic.

  When projecting an image or executing arbitrary presentation software, the speaker 18 amplifies and outputs the sound information of the image and the presentation software.

  A main body subkey 19 that is normally hidden and invisible is provided under the top cover 17, and the main body subkey 19 is a button that is displayed on the main body operation display unit 16 without using the remote controller 30 described later. When performing detailed operation settings other than the operation, the upper cover 17 is appropriately opened and operated.

FIG. 2 is a top view (a), a rear view (b), and a front view (c) of the image projection apparatus 10 (when the cover 12 is slid).
On the rear surface of the housing 11, an input / output connector unit 20, a rear Ir transmission / reception unit 21, an AC power input unit 22, and the like are disposed.

  The input / output connector unit 20 is connected to one or several kinds of general-purpose standard terminals for connecting a cable from an external device such as a personal computer, for example, a USB terminal, a mini D-SUB terminal, an S terminal, an RCA terminal, a stereo mini terminal. It consists of terminals. Using these terminals, images and sounds are captured from the external device. The AC power input unit 22 is for taking in commercial power via a power cable (not shown), and the rear Ir transmission / reception unit 21 is a remote controller to be described later, like the front Ir transmission / reception unit 15. While receiving the infrared light on which the key operation signal from 30 is superimposed, the infrared light on which the display signal is superimposed is transmitted to the remote controller 30.

  Three legs 23 to 25 are provided on the lower surface of the housing 11, and one of the legs 23 to 25 (the leg 24 provided on the front side in the illustrated example) is It is a screw-type height adjustment leg. Using the height adjusting leg 24, the tilt angle (elevation angle) of the projection lens 13 is adjusted.

  FIG. 3 is an external view of the remote controller 30. The remote controller 30 has a thin main body 31 that can be held by hand, and an infrared light receiving / emitting window 31 a is disposed on the upper end surface of the main body 31, and further, near the upper front side of the main body 31. A display unit 32 composed of a flat display device (liquid crystal display panel, organic display panel, EL panel or the like) is arranged, and a key input unit 33 and an indicator unit 34 are arranged at arbitrary positions on the front side.

  Here, although not particularly limited, the key input unit 33 includes a power key 33a, a zoom key 33b, a focus key 33c, an “AFK (automatic focus and keystone correction)” key 33d, “Input” key 33e, “Auto” key 33f, “menu” key 33g, “Keystone” key 33h, “HELP” key 33i, “Esc” key 33j, “Up (↑)” key 33k, “ A down (↓) key 33m, a “left (←)” key 33n, a “right (→)” key 33o and an “Enter” key 33p are included, and the indicator section 34 includes a power / standby indicator. 34a and a temperature (TEMP) indicator 34b.

  FIG. 4 is an internal block diagram of the image projection apparatus 10. The image projection apparatus 10 includes a speaker 18, an audio processing unit 40, a front Ir transmission / reception unit 15, a rear Ir transmission / reception unit 21, a display drive unit 41, a main body operation display unit 16 (a flat display device 16a, a touch panel 16b), a main body subkey 19, Central control unit 42, input / output connector 20, input / output I / F 43, image conversion unit 44, video RAM 45, projection encoder 46, projection drive unit 47, reflector 48, projection lamp 49, color wheel 50, color wheel drive motor 51 , DMD 52, projection lens 13, focus / zoom drive motor 53, cooling fan 54, cooling fan drive motor 55, rotation sensor 56 (sensor means), first temperature sensor 57 (sensor means), and second temperature sensor 58 ( Sensor means), third temperature sensor 59 (sensor means), loop coil antenna 60 Fine sensor signal receiving unit 61 (the sensor signal receiving means) including blocks such.

  The rotation sensor 56, the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, the loop coil antenna 60, and the sensor signal receiving unit 61 constitute a physical quantity detection device 62 as a unit.

  The central control unit 42 performs overall control of the overall operation of the image projection apparatus 10, and includes a basic program (OS), required application programs (application programs), and software including various data necessary for executing these programs. A storage element (ROM) 42a for storing resources in a nonvolatile manner, and necessary software resources are loaded into a high-speed work memory (RAM) 42b for execution, and these software resources and various hardware resources (the above blocks) This is a so-called microprogram control element that includes an arithmetic processing unit (CPU) 42c that realizes a desired function, a typical example of which is shown below.

[Operation mode setting function]
The central control unit 42 graphically displays necessary operation buttons on the flat display device 16 a of the main body operation display unit 16 via the display drive unit 41. When an arbitrary operation button is touched by the user, the touch coordinates are detected by the touch panel 16b, and the central control unit 42 specifies the type of the touch-operated button based on the detected coordinates, and the specification result (For example, a setting mode such as focus and zoom, or an image projection mode) is executed.

[Setting mode such as focus and zoom]
The central control unit 42 graphically displays operation buttons necessary for settings such as focus and zoom on the flat display device 16 a of the main body operation display unit 16 via the display drive unit 41. When an arbitrary operation button is touched by the user, the touch coordinates are detected by the touch panel 16b, and the central control unit 42 specifies the type of the touch-operated button based on the detected coordinates, and the specification result The setting operation corresponding to is executed. For example, when the focus setting button is operated, the forward / reverse control of the focus / zoom drive motor 53 and the amount of rotation thereof are controlled to adjust the focus of the projection lens 13.

(Image projection mode)
The central control unit 42 operates the operation buttons necessary for setting the resolution of the input image, the selection of the used terminal of the input connector unit 20, the presence / absence of sound, etc. on the flat display device 16 a of the main body operation display unit 16 via the display driving unit 41. Graphical display of classes. When an arbitrary operation button is touched by the user, the touch coordinates are detected by the touch panel 16b, and the central control unit 42 specifies the type of the touch-operated button based on the detected coordinates, and the specification result The setting operation corresponding to is executed.

  For example, when the resolution of the input image is XGA (1024 × 768 pixels), the use terminal of the input connector unit 20 is an RCA terminal, and there is sound, the input / output I / F 43 is controlled to control the terminal of the input / output connector 20. (RCA terminal) is selected, the input image and sound from the external device added to the terminal are taken in, and they are transferred to the image conversion unit 44 and the sound processing unit 40.

  The sound processing unit 40 amplifies the sound and outputs the sound through the speaker 18, and the image conversion unit 44 converts the input image into a predetermined format and transfers the converted image to the projection encoder 46. The projection encoder 46 develops and stores the transmitted image signal in the video RAM 45 and then reads out the stored contents of the video RAM 45 to generate a video signal. The projection drive unit 47 generates a frame rate of the video signal, for example, The DMD 52 is driven at 30 [frames / second].

  Here, the DMD 52 is a semiconductor integrated optical switch in which a large number of minute movable mirrors are spread on a plane. The size of the movable mirror is, for example, a dozen μm square, and the movable mirror is attached to the column so that the inclination changes by about ± 10 degrees when the mirror is on and off. A memory element is formed immediately below the mirror, and the on / off state of the mirror is switched by the positive electric field effect of the memory element. The amount of light reflected by the DMD 52 is maximum (white gradation) when the mirror is turned on, and is minimum (black gradation) when the mirror is turned off, but the switching speed (switching speed between on and off) of each mirror is set every second. Since the number of times can be 500,000 times or more, the amount of reflected light of the DMD 52 can be set to an intermediate gradation (gray scale) by changing the switching ratio of each mirror.

  When such a DMD 52 is irradiated with high-intensity light Pa from a projection lamp 49 such as an ultra-high pressure mercury lamp disposed in the reflector 48, the reflected light Pb corresponds to on / off of each mirror of the DMD 52 and its switching ratio. Then, each pixel is light-modulated (light-modulated with the content of the video signal), and this reflected light Pb is projected onto a screen (not shown) via the projection lens 13 so that an enlarged image of the video signal is displayed on the screen. Can be projected.

  However, in the illustrated example, the number of DMDs 52 is one, and the high-intensity light Pa emitted from the projection lamp 49 is “white light”. In this case, only a monochrome video image is displayed on the screen. Cannot project. Therefore, in actuality, when the color wheel 50 is disposed in front of the projection lamp 49, the color wheel 50 is rotationally driven by the color wheel driving motor 51, and the image signal is developed and stored in the video RAM 45. The video signal components for each of the three primary colors (RGB) of light are divided and stored.

  FIG. 5A is a front view of the color wheel 50. The color wheel 50 is obtained by dividing a disk-shaped plate into three equal parts, and providing a red filter 51a, a green filter 51b, and a blue filter 51c in each equal area. When the high-intensity light Pa from the projection lamp 49 passes through the red filter 51a, only the red component of the high-intensity light Pa is extracted and the red light is irradiated on the DMD 52. When the high-intensity light Pa from the projection lamp 49 passes through the green filter 51b, only the green component of the high-intensity light Pa is extracted and the green light is irradiated on the DMD 52. Further, when the high-intensity light Pa from the projection lamp 49 passes through the blue-red filter 51c, only the blue component of the high-intensity light Pa is extracted, and the blue light is irradiated to the DMD 52.

  Therefore, by synchronizing the readout timing of the video signal component for each of the three primary colors of light from the video RAM 45 and the rotation control of the color wheel 50, an enlarged image of the color video signal can be projected on the screen.

[Cooling fan control mode]
The image projection apparatus 10 includes a projection lamp 49 that emits high heat, and also includes an electronic component such as DMD 52 that is susceptible to heat near the projection lamp 49. Measures for heat dissipation are indispensable. The cooling fan 54 and the cooling fan drive motor 55 that drives the cooling fan 54 are components for heat dissipation measures. The rotational speed of the cooling fan drive motor 55 is variable in order to suppress noise, and the central control unit 42 uses the cooling fan drive motor in order to suppress noise in a situation where there is little influence of heat. 55 is controlled at low speed or stopped, and the motor 55 for cooling fan drive is controlled at high speed to protect electronic components under the influence of heat.

  In order to perform such control, the rotational speed information of the cooling fan driving motor 55 and the temperature information of the point of interest are indispensable. In the illustrated example, although not particularly limited, a rotation sensor 56 for measuring the rotation speed of the cooling fan 54, a first temperature sensor 57 for measuring the heat of the projection lamp 49, and a surface temperature of the reflector 48 are measured. A second temperature sensor 58 for measuring, a third temperature sensor 59 for measuring the temperature in the vicinity of the color wheel 50, and a fourth temperature sensor 59a for measuring the temperature of the DMD 52 are arranged at desired locations, respectively. doing.

  The “desired place” refers to a place where a physical quantity such as the number of rotations and heat can be measured without hindering the operation and function of the object. Incidentally, in the first temperature sensor 57, the radiant heat of the projection lamp 49 can be indirectly measured, for example, it may be at a position about 1 cm away, or the conduction heat of the projection lamp 49 may be directly measured. For example, it may be a position on the holding member of the projection lamp 49 that can be measured. In the second temperature sensor 58, the surface temperature of the reflector 48 can be indirectly measured, for example, about 1 cm from the back surface of the reflector 48 (note that the surface of the reflector 48 disturbs reflected light). It may be a remote location, or it may be a location on the holding member of the reflector 48 where the conduction heat of the reflector 48 can be measured directly, for example. In the third temperature sensor 59, the temperature of the color wheel 50 can be indirectly measured. For example, the third temperature sensor 59 may be at a position about 1 cm away from the rotation surface or the rotation axis of the color wheel 50, or The position on the rotating surface of the wheel 50 may be sufficient. However, when the third temperature sensor 59 is directly mounted on the rotation surface of the color wheel 50, it is desirable to take measures against rotational blur due to the weight of the third temperature sensor 59 (for example, an appropriate balancer). . Further, in the fourth temperature sensor 59a, the temperature of the DMD 52 can be indirectly measured, for example, it may be a position about 1 cm away from the DMD 50, or the conduction heat of the DMD 52 can be directly measured. For example, the position on the holding member of the DMD 52 may be used.

  Information detected by these sensors (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor 59, fourth temperature sensor 59a) is transmitted wirelessly using electromagnetic waves as a medium, and looped. After being received by the sensor signal receiving unit 61 via the coil antenna 60, it is transmitted from the sensor signal receiving unit 61 to the central control unit 42 via the system bus SB.

  FIG. 5B is a common block diagram of the sensors (the rotation sensor 56, the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, and the fourth temperature sensor 59a). The configuration of the rotation sensor 56 will be described as a representative. The rotation sensor 56 includes a transmission / reception antenna 63, a bandpass filter 64 that extracts a signal in a predetermined frequency range from a signal received by the transmission / reception antenna 63, A receiving unit 65 that receives a signal in a predetermined frequency range that has passed through the band-pass filter 64; a rectifying unit 66 that detects and rectifies the signal received by the receiving unit 65 to generate a power supply voltage; The sensor unit 67 (detection unit), the analog / digital conversion unit 68, the control unit 69, and the transmission unit 70 (transmission unit) that operate when the power supply voltage is supplied from the unit 66.

  Here, the bandpass filters 64 of the rotation sensor 56, the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, and the fourth temperature sensor 59a pass signals of different frequency bands, respectively. Hereinafter, it is assumed that the bandpass filter 64 of the rotation sensor 56 passes the signal of the frequency band f1, the bandpass filter 64 of the first temperature sensor 57 passes the signal of the frequency band f2, and the second temperature sensor 58 The band pass filter 64 passes a signal of the frequency band f3, the band pass filter 64 of the third temperature sensor 59 passes the signal of the frequency band f4, and the band pass filter 64 of the fourth temperature sensor 59a has a frequency. It is assumed that a signal in the band f5 is passed. However, f1 ≠ f2 ≠ f3 ≠ f4 ≠ f5.

  The sensor unit 67 is a rotational speed detection element in the case of the rotation sensor 56, and is a temperature detection element in the case of the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, and the fourth temperature sensor 59a. The rotation number detection element is a device that detects the rotation number of the object in a non-contact manner using a Hall element or the like, or the temperature detection element is an element whose resistance value changes according to temperature. The analog / digital conversion unit 68 converts the information detected by the sensor unit 67 into a digital signal, and the control unit 69 transfers the digitally converted information to the transmission unit 70 at the timing of the reception signal from the reception unit 65. The transmitter 70 receives the signal frequency extracted by the bandpass filter 64 (f1 for the rotation sensor 56, f2 for the first temperature sensor 57, f3 for the second temperature sensor 58, and the third temperature sensor 59). F4, and in the case of the fourth temperature sensor 59a, f5) is modulated with the digitally converted information and transmitted through the antenna 63 for both transmission and reception. The modulation in the transmission unit 70 is digital modulation such as PSK modulation. For example, in the case of PSK modulation, “logic 0” and “logic 1” of the digital signal are represented by different frequencies and phases, respectively. Hereinafter, logic 0 is represented by one frequency (f1, f2, f3, f4, f5), and logic 1 is represented by another frequency (f1a, f2a, f3a, f4a, f5a). That is, in the transmission unit 70 of the rotation sensor 56, the binary logic of the digital signal is expressed by the frequency f1 and the frequency f1a, and in the transmission unit 70 of the first temperature sensor 57, the binary signal of the digital signal is expressed by the frequency f2 and the frequency f2a. In the transmission unit 70 of the second temperature sensor 58, the binary logic of the digital signal is represented by the frequency f3 and the frequency f3a. In the transmission unit 70 of the third temperature sensor 59, the digital signal is represented by the frequency f4 and the frequency f4a. It represents the binary logic of the signal, and the transmitter 70 of the fourth temperature sensor 59a represents the binary logic of the digital signal at the frequency f5 and the frequency f5a.

FIG. 5C is a block diagram of the loop coil antenna 60 and the sensor signal receiving unit 61. The sensor signal receiving unit 61 is configured to generate a carrier wave of different frequency bands (f1, F2, f3, f4, f5) in a time division manner according to a control signal from the control unit 71, and the carrier wave generating unit 72 is a transmitter 73 (transmitting means) that modulates the carrier wave generated by 72 with the interrogation signal from the controller 71 and transmits it via the loop coil antenna 60, and each sensor (rotation) received by the loop coil antenna 60. Receiving the signal 56, demodulating the response signals from the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, the fourth temperature sensor 59a) and reproducing the information contained in those response signals. Unit 74 (reception unit, reproduction unit), and the central control unit receives each sensor information (S _N , S _Ta , S _Tb , S _Tc , S _Td ) reproduced by the reception unit 74 via the system bus SB. 42 to Forward.

  FIG. 6 is a diagram illustrating an operation timing chart of the sensor signal receiving unit 61. In this figure, an example of an iterative loop using the variable i is shown in accordance with how to write the flowchart of the program, but this is for convenience of explanation. What is necessary is just to design the sensor signal receiving part 61 so that it may become the operation | movement similar to this. In this flowchart, first, the loop variable i is set to 1 to be initialized (step S11), an inquiry signal having the frequency fi as a carrier wave is transmitted (step S12), and then a wait is made until a response signal is received (step S13). ).

  Now, since the value of the variable i is the initial value “1”, in this case, the interrogation signal is transmitted using the carrier wave of the frequency f1. Since the rotation sensor 56 has the bandpass filter 64 having the pass characteristic of the frequency f1, the question signal at this time is received by the receiving unit 65 of the rotation sensor 56, and only the rotation sensor 56 operates. A response signal including the rotation speed information of the cooling fan 54 detected by the sensor unit 67 is returned from the rotation sensor 56.

When the response signal from the rotation sensor 56 is received (“YES” in step S13), the response signal is then demodulated (step S14), and since i = 1 (step S15), the rotation speed of the cooling fan 54 is determined. After generating the signal _SN representing the information and outputting it to the central control unit 42 (step S16), the variable i is incremented by 1 (step S23), and the interrogation signal having the frequency fi as the carrier wave is transmitted again (step S12). ).

  Now, since the value of the variable i is “2”, in this case, the interrogation signal is transmitted using the carrier wave of the frequency f2. Since the first temperature sensor 57 has the bandpass filter 64 having the pass characteristic of the frequency f2, the interrogation signal at this time is received by the receiving unit 65 of the first temperature sensor 57, and the first temperature sensor 57 is operated, and a response signal including temperature information of the projection lamp 49 detected by the sensor unit 67 is returned from the first temperature sensor 57.

When the response signal from the first temperature sensor 57 is received (“YES” in step S13), the response signal is then demodulated (step S14), and i = 2 (step S17). After generating a signal S _Ta representing temperature information and outputting it to the central control unit 42 (step S18), the variable i is further incremented by 1 (step S23), and an inquiry signal having the frequency fi as a carrier wave is transmitted again (step S18). Step S12).

  Now, since the value of the variable i is “3”, in this case, the interrogation signal is transmitted using the carrier wave of the frequency f3. Since the second temperature sensor 58 has the band pass filter 64 having the pass characteristic of the frequency f3, the interrogation signal at this time is received by the receiving unit 65 of the second temperature sensor 58, and the second temperature sensor 58 is operated, and a response signal including temperature information of the reflector 48 detected by the sensor unit 67 is returned from the second temperature sensor 58.

When the response signal from the second temperature sensor 58 is received (“YES” in step S13), the response signal is demodulated (step S14), and i = 3 (step S19), so that the temperature of the reflector 48 is increased. After generating a signal _STb representing information and outputting it to the central control unit 42 (step S20), the variable i is further incremented by 1 (step S23), and an interrogation signal having the frequency fi as a carrier wave is transmitted again (step S20). S12).

  Now, since the value of the variable i is “4”, in this case, the interrogation signal is transmitted using the carrier wave of the frequency f4. Since the third temperature sensor 59 has the band pass filter 64 having the pass characteristic of the frequency f2, the interrogation signal at this time is received by the receiving unit 65 of the third temperature sensor 59, and the third temperature sensor 59 59 is operated, and a response signal including temperature information of the color wheel 50 detected by the sensor unit 67 is returned from the third temperature sensor 59.

When the response signal from the third temperature sensor 59 is received (“YES” in step S13), the response signal is demodulated (step S14), and i = 4 (step S21). After generating a signal _STc representing temperature information and outputting it to the central control unit 42 (step S22), the variable i is further incremented by 1 (step S23), and an inquiry signal having the frequency fi as a carrier wave is transmitted again (step S22). Step S12).

  Now, since the value of the variable i is “5”, in this case, the interrogation signal is transmitted using the carrier wave of the frequency f5. Since the band temperature filter 59 having the pass characteristic of the frequency f5 is included in the fourth temperature sensor 59a, the interrogation signal at this time is received by the receiver 65 of the fourth temperature sensor 59a, and the fourth temperature sensor Only the 59a operates, and a response signal including temperature information of the DMD 52 detected by the sensor unit 67 is returned from the fourth temperature sensor 59a.

When the response signal is received from the fourth temperature sensor 59a (“YES” in step S13), the response signal is demodulated (step S14), and i ≠ 4 (“NO” in step S21). after outputting (step S24) to the central control unit 42 generates a signal S _Td representing the temperature information of DMD52, return the variable i to the initial value "1" (step S11), and a question to the carrier frequency fi again A signal is transmitted (step S12).

  FIG. 7 shows an interrogation signal from the sensor signal receiver 61 and response signals from the sensors (the rotation sensor 56, the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, and the fourth temperature sensor 59a). FIG. In this figure, when the signal frequency of the interrogation signal is f1 (A), response signals (f1 and f1a) are returned only from the rotation sensor 56.

  Similarly, when the signal frequency of the interrogation signal is f2 (b), response signals (f2 and f2a) are returned only from the first temperature sensor 57, and when the signal frequency of the interrogation signal is f3 (c) The response signals (f3 and f3a) are returned only from the second temperature sensor 58. When the signal frequency of the interrogation signal is f4 (d), the response signals (f4 and f4a) are returned only from the third temperature sensor 59. When the signal frequency of the interrogation signal is f5 (e), response signals (f5 and f5a) are returned only from the fourth temperature sensor 59a.

  This is because the frequency pass characteristics of the bandpass filter 64 of each sensor (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor 59, fourth temperature sensor 59a) are different. Specifically, the bandpass filter 64 of the rotation sensor 56 passes only the interrogation signal of the frequency f1, the bandpass filter 64 of the first temperature sensor 57 passes only the interrogation signal of the frequency f2, and the second temperature The bandpass filter 64 of the sensor 58 passes only the interrogation signal of frequency f3, the bandpass filter 64 of the third temperature sensor 59 passes only the interrogation signal of frequency f4, and the bandpass filter of the fourth temperature sensor 59a This is because 64 passes only the interrogation signal of frequency f5.

  As described above, according to this embodiment, the question signal is time-divisionally provided for each sensor (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor 59, fourth temperature sensor 59a). And a response signal returned in response to the interrogation signal is received, and each sensor (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor 59, fourth temperature sensor) is received. 59a) can be reproduced individually. In addition, since the question signal and the response signal are exchanged wirelessly using an electromagnetic wave as a medium, in other words, the signal cable of the conventional example is not necessary, each sensor (the rotation sensor 56). , The installation location of the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, the fourth temperature sensor 59a) can be freely selected, and the inconveniences (1) to (3) at the beginning are solved. be able to.

  That is, since there is no signal cable, each sensor (the rotation sensor 56, the first temperature sensor 57, the second temperature sensor 58, the third temperature sensor 59, the fourth temperature sensor 59a) can be freely installed at any place. Can do. For example, if the mass balance in the circumferential direction is ignored, the color wheel 50 can be directly installed at an arbitrary position on the disk plate. Further, since the flow of the cooling air of the cooling fan 54 is not disturbed, the cooling efficiency can be improved. Furthermore, since it is not necessary to secure a cable laying space, the housing 11 can be downsized.

  In addition, each sensor (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor 59, fourth temperature sensor 59a) of the present embodiment detects a question signal from the sensor signal receiving unit 61. Since the rectifying unit 66 that rectifies and generates the power supply voltage is provided, a power supply line is not required, which also contributes to the freedom of the sensor installation location, the cooling efficiency, and the miniaturization of the housing 11.

  FIG. 8 is a diagram showing a preferred installation location of the loop coil antenna 60. In this figure, the housing 11 has a two-part structure of an upper lid (upper portion 11a) of the housing 11 and a lower portion 11b that is integrated by covering the upper lid. It is attached to the inner peripheral surface (upper cover inner surface) of the upper part 11a. If it does in this way, the radiation pattern of loop coil antenna 60 can be spread over the whole inside of case 11 without leakage. As a result, the dead angle of the radio wave can be made almost zero, and the incommunicable area can be localized or eliminated, and the sensor (rotation sensor 56, first temperature sensor 57, second temperature sensor 58, third temperature sensor) can be located anywhere inside the housing 11. Even if the temperature sensor 59 and the fourth temperature sensor 59a) are arranged, the sensor information can be acquired without any trouble.

  In the above-described embodiment, the response signal for each sensor is identified by changing the signal frequency of the interrogation signal, but this includes a plurality of sensors (the rotation sensor 56 and the first temperature sensor 57 in the illustrated example). The second temperature sensor 58, the third temperature sensor 59, and the fourth temperature sensor 59a) are indispensable measures. If a single sensor is provided, such a countermeasure (differentiating the frequency of the question signal) is not necessary. Moreover, such a countermeasure is an example and is not limited thereto. For example, when a plurality of sensors are provided, unique identification information (ID code) is assigned to each sensor, a question signal including the identification information is transmitted, and a response signal is returned only from the sensor with the matching identification information. You may do it. In this case, it is not necessary to change the frequency of the inquiry signal.

  In the above description, “rotation speed” and “temperature” are exemplified as physical quantities to be detected, but this is only an example. Other physical quantities may be used, and application examples thereof are not limited to the image projection apparatus (projector). Any physical quantity detection device that detects various physical quantities may be used, or any electronic device that includes these physical quantity detection devices.

1 is an external view of a DLP type image projection apparatus 10. FIG. 2 is a top view, a rear view, and a front view of the image projection apparatus 10. FIG. 2 is an external view of a remote controller 30. FIG. 3 is an internal block diagram of the image projection apparatus 10. FIG. 2 is a front view of the color wheel 50, a common block diagram of sensors, and a block diagram of a sensor signal receiving unit 61. FIG. It is a figure which shows the operation | movement timing chart of the sensor signal receiving part 61. FIG. It is a time corresponding | compatible relationship figure of a question signal and a response signal. It is a figure which shows the preferable installation location of the loop coil antenna. Conceptual configuration diagram of control system in conventional example

Explanation of symbols

10 Image projection device (electronic equipment)
11 Housing 11a Upper part (upper cover)
56 Rotation sensor (sensor means)
57 First temperature sensor (sensor means)
58 Second temperature sensor (sensor means)
59 Third temperature sensor (sensor means)
59a Fourth temperature sensor (sensor means)
60 loop coil antenna 61 sensor signal receiver (sensor signal receiver)
62 Physical Quantity Detection Device 66 Rectifier (Power Supply Generation Unit)
67 Sensor part (detection means)
70 Transmitter (Transmission means)
73 Transmitter (Transmitter)
74 Receiver (Receiving means, reproducing means)

Claims (6)

Both include sensor means and sensor signal receiving means provided in a common housing,
The sensor means includes at least detection means for detecting a physical quantity, and transmission means for wirelessly transmitting information representing the physical quantity detected by the detection means using an electromagnetic wave as a medium,
The sensor signal receiving means comprises at least a receiving means for receiving an electromagnetic wave transmitted from the sensor means, and a reproducing means for reproducing information representing the physical quantity from the electromagnetic wave. The sensor signal receiving means further comprises transmission means for transmitting an interrogation signal to the sensor means, and the sensor means further comprises power supply power generation means for receiving the interrogation signal and generating power supply power necessary for operation. The physical quantity detection device according to claim 1. The physical quantity detection device according to claim 1, wherein a plurality of the sensor means are provided. An electronic apparatus equipped with the physical quantity detection device according to claim 1, claim 2, or claim 3,
The sensor signal receiving means includes a loop coil antenna that receives an electromagnetic wave transmitted from the transmitting means of the sensor means, and the installation location of the loop coil antenna is the inner surface of the upper lid of the casing of the electronic device. Electronic equipment. Inside the housing, a light source, a reflector that condenses the light from the light source, a modulation unit that modulates the light collected by the reflector with image information, and a projection that projects the light modulated by the modulation unit And an image projection apparatus comprising:
Sensor means and sensor signal receiving means for individually measuring the temperature of the light source, reflector and modulation means,
The sensor means includes at least detection means for detecting a physical quantity, and transmission means for wirelessly transmitting information representing the physical quantity detected by the detection means using an electromagnetic wave as a medium,
The image projection apparatus, wherein the sensor signal receiving means includes at least receiving means for receiving an electromagnetic wave transmitted from the sensor means, and reproducing means for reproducing information representing the physical quantity from the electromagnetic wave. 6. The image projection apparatus according to claim 5, further comprising: a color wheel that separates the light collected by the reflector into the three primary colors of light; and sensor means that measures the temperature of the color wheel.

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