JP2022038682A - Detection method and projector - Google Patents

Abstract

To provide a detection method that has a wide detection range and can detect an object near an opening and a person at a position separated from the opening.SOLUTION: A detection method is performed by a projector, and the projector has an opening from which light is emitted and a passive type infrared sensor that is arranged at a position where its detection range overlaps the opening. The method includes: repeatedly detecting temperature by using the infrared sensor; determining whether the temperature is equal to or more than a first reference value; determining whether the amount of increase in temperature in a predetermined period is equal to or more than a second reference value; and when determining that the temperature is equal to or more than the first reference value or when determining that the amount of increase in temperature is equal to or more than the second reference value, the projector performing a predetermined operation.SELECTED DRAWING: Figure 5

Description

The present invention relates to a projector and a detection method performed by the projector.

A large amount of projected light is emitted from the projection unit of the projector in order to project a bright and large image. When a person approaches the projector, the projected light may get into the eyes. Therefore, a technique for detecting that a person has entered the projection range has been proposed.

For example, the projection device of Patent Document 1 has an object detection sensor, and when a person (object) is detected in the irradiation range, the light flux of the projection device is blocked by a light shielding means. Further, it is described that a pyroelectric sensor and an ultrasonic sensor are used as the object detection sensor. Both sensors used so-called active detection sensors that irradiate detection ultrasonic waves and infrared rays toward the detection range.

Jitsukaihei No. 5-8556

However, both of the detection sensors used in the projection device of Patent Document 1 are so-called active detection sensors that irradiate ultrasonic waves and infrared rays for detection toward the detection range. Since the detection range of the active detection sensor is narrow, there is a risk that a person will be too close to the irradiation range before detection. There is also a need to detect the presence of an object near the opening from which the projected light is emitted. There has been a demand for technology that can detect objects and people in a wider detection range.

The detection method according to one aspect of the present application is a detection method performed by a projector, wherein the projector is a passive infrared sensor arranged at a position where an opening through which light is emitted and a detection range overlap with the opening. And, the temperature is repeatedly detected using the infrared sensor, it is determined whether or not the temperature is equal to or higher than the first reference value, and the amount of increase in the temperature in a predetermined period is determined. It is determined whether or not the temperature is equal to or higher than the second reference value, and when it is determined that the temperature is equal to or higher than the first reference value, or the amount of increase in the temperature is equal to or higher than the second reference value. The present invention includes that the projector performs a predetermined operation when it is determined that the temperature is high.

The projector according to one aspect of the present application includes a light source that emits light, an optical modulation device that generates modulated light by modulating the light, a lens that emits the modulated light, and an opening through which the modulated light passes. The control unit includes a passive infrared sensor arranged at a position where the detection range overlaps with the opening, and a control unit, and the control unit repeatedly detects the temperature using the infrared sensor. To determine whether or not the temperature is equal to or higher than the first reference value, and to determine whether or not the amount of increase in the temperature in a predetermined period is equal to or higher than the second reference value in a predetermined period. When it is determined that the temperature is equal to or higher than the first reference value, or when it is determined that the amount of increase in the temperature is equal to or higher than the second reference value, a predetermined control signal is output. To do and to do.

FIG. 3 is an installation mode diagram of the projector according to the first embodiment. External perspective view of the projector. Functional block diagram of the projector. Side sectional view of the projector. Flow chart diagram of the detection program. FIG. 6 is an installation mode diagram of the projector according to the second embodiment.

Embodiment 1
*** Overview of the projector ***
FIG. 1 is an installation mode diagram of a projector according to the present embodiment. FIG. 2 is an external perspective view of the projector.
The projector 100 of the present embodiment is a short-focus type projector that is installed directly below or directly above the projection surface and projects a projection image on a projection surface at a short distance.

As shown in FIG. 1, the projector 100 is placed on the floor in front of the wall surface on which the screen SC is installed, and irradiates the modulated light 88 diagonally upward toward the screen SC. The modulated light 88 is a full-color image light corresponding to an image signal, and is also referred to as a projected light.
In FIG. 1, the side surface of the projector 100 is shown, and the side view shows a substantially rectangular shape. Hereinafter, the direction along the long side of the rectangle is defined as the Y direction. Further, as shown in FIG. 2, the projector 100 has a three-dimensionally flat rectangular parallelepiped shape. The direction along the depth when viewed from the side surface of the projector 100 is the X direction, and the direction orthogonal to the X direction and the Y direction is the Z direction. Further, the Z plus direction is also referred to as an upper direction, and the Z minus direction is also referred to as a lower direction.

As shown in FIG. 2, a V-shaped groove 40 is provided on the upper surface of the case 2 of the projector 100. The groove portion 40 is formed of two inclined surfaces 31 and an inclined surface 32 on the end side of the case 2 in the plus direction of the Y axis, and the portion where the inclined surface 31 and the inclined surface 32 intersect is the bottom 35. ..
The inclined surface 32 is provided with an opening 5 from which the modulated light 88 is emitted, a peripheral edge portion 33 surrounding the opening 5, and the like. The opening 5 is an opening provided in the case 2 and has a substantially rectangular shape. The peripheral edge portion 33 is a rectangle slightly larger than the opening portion 5. The opening 5 is formed at a position deeper than the peripheral edge 33, and the slope 34 is formed between the peripheral edge 33 and the opening 5. In other words, the opening 5 is provided on the bottom surface of the mortar shape by the slope 34.

With such a configuration, as shown in FIG. 1, the modulated light 88 emitted from the opening 5 is projected onto the screen SC on the wall surface of the projector 100 in the Y-minus direction.
Further, on the side surface of the projector 100, an intake port 30 which is an intake port for outside air for cooling an internal light source, a light modulation device, and the like is formed.

*** Projector configuration ***
FIG. 3 is a functional block configuration diagram of the projector.
Here, a schematic configuration of the projector 100 will be described.

As shown in FIG. 3, the projector 100 includes a control unit 10, a storage unit 11, an operation unit 12, an operation signal receiving unit 13, a communication unit 14, an image information input unit 15, an image information processing unit 16, and an OSD (On-Screen). Display) It is composed of a processing unit 17, an image forming unit 28, a projection unit 7, a sensor unit 4, a detection unit 36, a light source control unit 37, a voice synthesis unit 38, a voice output unit 39, and the like.

The control unit 10 is configured to include one or a plurality of processors, and controls the operation of the projector 100 by operating according to the control program stored in the storage unit 11.

The storage unit 11 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The RAM is used for temporary storage of various data and the like, and the ROM stores a control program for controlling the operation of the projector 100 and accompanying data. The control program stores an activation program that instructs the order and contents of processing when the projector 100 is activated, a program that detects the temperature of an object from the detection data of the sensor unit 4, a detection program described later, and the like. The accompanying data includes various notification data for warning in addition to the first reference value and the second reference value used in the object detection program.

The operation unit 12 includes a plurality of operation keys for the user to give various instructions to the projector 100. The operation keys include a "power key" for switching the power on and off, and a "menu key" for displaying a menu for making various settings. When the user operates various operation keys of the operation unit 12, the operation unit 12 outputs an operation signal according to the operation content to the control unit 10.
The operation signal receiving unit 13 is an infrared communication module including an infrared receiving unit, receives an operation signal from the remote controller 3, decodes it, and transmits it to the control unit 10. The operation signal receiving unit 13 may be provided with a communication device conforming to Bluetooth (registered trademark), for example, as long as short-range communication is possible.

As a preferred example, the communication unit 14 uses a module for wireless communication conforming to a wireless LAN (Local Area Network) standard. An image source such as an image signal is also supplied from the network NW. It should be noted that the present invention is not limited to wireless communication, and each device may be connected by wire using a LAN cable.

The image information input unit 15 is connected to an external image supply device (not shown) such as a computer or an image reproduction device, and receives image information from the image supply device.
Based on the control of the control unit 10, the image information processing unit 16 performs necessary image processing on the image information input from the image information input unit 15, and outputs the processed image information to the OSD processing unit 17. do.

Based on the control of the control unit 10, the OSD processing unit 17 performs processing for superimposing and displaying an OSD image such as a message image or a menu image on the image. The OSD processing unit 17 includes an OSD memory (not shown), and stores OSD image information representing figures, fonts, and the like for forming an OSD image. When the control unit 10 instructs to superimpose the OSD image, the OSD processing unit 17 reads the necessary OSD image information from the OSD memory, and the image information processing unit 17 superimposes the OSD image on a predetermined position on the image. This OSD image information is combined with the image information input from 16.

The image forming unit 28 includes a light source 21, a light modulation device 22, a light bulb driving unit 24, and the like. The optical modulation device 22 includes three liquid crystal light valves 22R, 22G, and 22B, and modulates the light emitted from the light source 21 to generate the modulated light 88.
The light source 21 is configured to include a solid-state light source such as a light emitting diode or a semiconductor laser. A discharge type light source lamp such as an ultra-high pressure mercury lamp or a metal halide lamp may be used. The light emitted from the light source 21 is converted into light having a substantially uniform brightness distribution by an integrator optical system (not shown), and the three primary colors of light, red (R), green (G), and blue, are converted by a color separation optical system (not shown). After being separated into the respective color light components of (B), they are incident on the liquid crystal light valves 22R, 22G, and 22B, respectively.

The liquid crystal light bulbs 22R, 22G, and 22B are each composed of a transmissive liquid crystal panel or the like in which a liquid crystal is enclosed between a pair of transparent substrates. A rectangular image forming region 22i composed of a plurality of pixels arranged in a matrix is formed on each liquid crystal panel, and a driving voltage can be applied to the liquid crystal for each pixel.
In the above description, it has been described that the transmissive liquid crystal light bulbs 22R, 22G, and 22B are used as the optical modulator 22, but it is possible to use a reflective optical modulator such as a reflective liquid crystal light bulb. Is also good. Further, a digital mirror device or the like that modulates the light emitted from the light source 21 by controlling the emission direction of the incident light for each micromirror as a pixel may be used. Further, the configuration is not limited to the configuration in which a plurality of optical modulation devices are provided for each color light, and a configuration in which a plurality of color lights are modulated by time division by one optical modulation device may be used.

The light bulb drive unit 24 forms an image in the image forming region 22i of the liquid crystal light bulbs 22R, 22G, 22B. Specifically, the light valve drive unit 24 applies a drive voltage corresponding to the image information input from the OSD processing unit 17 to each pixel of the image forming region 22i, and makes each pixel transmit light according to the image information. Set to rate. The light emitted from the light source 21 is modulated for each pixel by passing through the image forming region 22i of the liquid crystal light bulbs 22R, 22G, 22B, and the image light corresponding to the image information is formed for each colored light. The formed image light of each color is combined for each pixel by a color synthesis optical system (not shown) to become modulated light 88 representing a color image, and is emitted to the projection unit 7.
The image information input unit 15, the image information processing unit 16, and the OSD processing unit 17 may be configured by one or a plurality of processors, or may be composed of an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). ) And other dedicated processing devices. Further, it may be a part of the control unit 10 and the storage unit 11.

FIG. 4 is a side sectional view taken along the line BB of FIG. 2.
As shown in FIG. 4, the projection unit 7 is an optical unit composed of an accommodating unit 18, a plurality of lenses 8, an aspherical mirror 9, and the like, and emits modulated light 88 from the opening 5.
The accommodating portion 18 is a lens accommodating frame, and a plurality of lenses 8 and an aspherical mirror 9 are arranged at predetermined positions. The plurality of lenses 8 are convex lenses in a preferred example. A concave lens may be included.

The aspherical mirror 9 is a reflection mirror provided with a reflection surface 9A having a free curved surface shape that is not rotationally symmetric, and reflects the modulated light 88 guided by the plurality of lenses 8 so as to be folded diagonally upward and widened. That is, the modulated light 88 emitted from the lens 8 is reflected by the aspherical mirror 9, passes through the opening 5, and then projects an image on the screen SC (FIG. 1).
Here, the opening 5 is formed in the vicinity of the focusing point P where the modulated light 88 reflected by the aspherical mirror 9 is focused. By providing the opening 5 in the vicinity of the light collecting point P, the area of the opening 5 can be reduced. The modulated light 88 emitted from the opening 5 is projected onto a wide-angle irradiation range 88e.

The sensor unit 4 is a passive infrared sensor, and in a preferred example, a photovoltaic type sensor is used. It should be noted that any passive sensor that measures the temperature of an object may be used, and for example, a far infrared detection type infrared sensor may be used.
The detection unit 36 is a detection circuit including an operational amplifier, and converts the detection data by the sensor unit 4 into, for example, voltage data and transmits it to the control unit 10.
The light source control unit 37 controls lighting and extinguishing of the light source 21 and adjusts the illuminance according to the control signal from the control unit 10.

The voice synthesis unit 38 is a voice synthesis circuit, and in a preferred example, a voice synthesis LSI (Large Scale Integration) is used. A plurality of voice notification patterns are stored in the voice synthesis unit 38, and the notification patterns corresponding to the control signals from the control unit 10 are converted into voice data and transmitted to the voice output unit 39. Further, the voice synthesis unit 38 also has a pass-through function of transmitting voice data accompanying the image signal being projected to the voice output unit 39.
The audio output unit 39 is a speaker.

*** Detection range of infrared sensor ***
As shown in FIGS. 2 and 4, the sensor unit 4 is provided directly above the opening 5. It should be noted that the present invention is not limited to directly above, and may be provided in the vicinity of the opening 5 as long as the detection range of the sensor unit 4 can be secured. good.
As shown in FIG. 4, the infrared detection range 4e by the sensor unit 4 overlaps with the projection center region 5e in which the shape of the opening 5 is extended, and substantially coincides with the irradiation range 88e of the modulated light 88. In other words, the temperature detection range 4e by the sensor unit 4 overlaps with the opening 5.

Here, the difference between the passive infrared sensor of the present embodiment and the conventional active detection sensor will be described.
The active infrared sensor consists of a light emitting part that emits infrared rays and a light receiving part that receives the infrared rays reflected by the object, and detects the object by the presence or absence of the reflected infrared rays, but because the detection range is narrow, it is several cm from the sensor. Objects at a distance could be detected, but human bodies at a distance of several tens of centimeters to 1 m could not be detected. Therefore, a person may approach the center of the projected light by the time it is detected.

In addition, an active ultrasonic sensor equipped with an ultrasonic oscillating unit and a receiving unit cannot receive reflected waves for a certain period of time due to the influence of reverberation vibration after generating sound waves, so measurements up to about 30 cm can be performed. Was difficult. In addition, the field of view is also linear and narrow, and it is difficult to detect an object in the vicinity of the opening 5.
Therefore, it is difficult for one active detection sensor to detect an object near the opening and a person at a position away from the opening, and in order to detect both, a plurality of detection sensors are used. Needed to be used.

On the other hand, according to the sensor unit 4 of the present embodiment, since a passive infrared sensor that measures the radiant heat of the object is used, the detection is performed according to the detection program described later, so that the vicinity of the opening is detected. An object and a person at a position away from the opening can be detected by one detection sensor.

*** How to detect people and objects ***
FIG. 5 is a flowchart showing the flow of the object detection program.
The object detection program is a program for the projector 100 to execute a detection method for detecting an object near the opening 5 and a person at a position away from the opening 5, and the control unit 10 of the projector 100. It is executed by controlling each part.
The execution subject in the following description is the control unit 10.

In step S1, it is determined whether or not the projection has started. If it is determined that the projection has started (step S1: Yes), the process proceeds to step S2. If it is determined that the projection has not started (step S1: No), it waits until it starts.

In step S2, the temperature detection by the sensor unit 4 is started. In a preferred example, the sampling time is 100 ms or more and 1 s or less. That is, the temperature of the object is repeatedly detected using the sensor unit 4.

In step S3, it is determined whether or not the detected temperature is equal to or higher than the first reference value. Since the first reference value is a reference value for detecting the human body, it is a value based on the standard body temperature. In a preferred example, the first reference value is 36 ° C. The first reference value may be in the range of 35 ° C. or higher and 38 ° C. or lower. If it is determined that the detected temperature is equal to or higher than the first reference value (step S3: Yes), the process proceeds to step S5. If it is determined that the value is less than the first reference value (step S3: No), the process proceeds to step S4.

In step S4, it is determined whether or not the amount of temperature increase in a predetermined period is equal to or greater than the second reference value. Since the second reference value is a reference value for detecting an object near the opening 5, the temperature change when the object is irradiated with the modulated light 88 is set as a detectable value. For example, assuming that the object is paper such as a document and the paper covers the opening 5, the temperature gradually rises because the paper is irradiated with the modulated light 88. In this case, the second reference value is 3 ° C./sec. The second reference value may be appropriately set in the range of 2 ° C. or higher and 5 ° C. or lower / sec according to the assumed object. If it is determined that the amount of temperature increase in the predetermined period is equal to or greater than the second reference value (step S4: Yes), the process proceeds to step S5. If it is determined that the value is less than the second reference value (step S4: No), the process returns to S2.

In step S5, a predetermined operation is performed according to the determination result.
First, when it is determined in step S3 that the detected temperature is equal to or higher than the first reference value, the control unit 10 outputs a control signal for reducing the illuminance to the light source control unit 37 as a predetermined control signal. , A control signal for outputting a first notification prompting the user to move away from the opening 5 is transmitted to the voice synthesis unit 38. As a result, the light source control unit 37 reduces the light source 21 to the lowest illuminance that can be maintained. A control signal for turning off the light source 21 may be output. The voice synthesis unit 38 sends a voice message such as "Please move away from the projector" from the voice output unit 39.
Further, the control unit 10 may output, as a predetermined control signal, a control signal for displaying the warning message "Please move away from the projector" on the projected image to the OSD processing unit 17.

When it is determined in step S4 that the amount of temperature rise in a predetermined period is equal to or greater than the second reference value, the control unit 10 uses the light source control unit 37 as a predetermined control signal to reduce the illuminance. Is output, and a control signal for outputting a second notification indicating that an object exists in the vicinity of the opening 5 is transmitted to the voice synthesis unit 38. The second notification has a different notification pattern from the first notification. A control signal for turning off the light source 21 may be output.
As a result, the light source control unit 37 reduces the light source 21 to the lowest illuminance that can be maintained. The voice synthesis unit 38 sends a voice message from the voice output unit 39 saying, "There is an obstacle in the projection unit, please remove it." It should be noted that the present invention is not limited to the voice message, and an alert sound for notifying the abnormality may be emitted.

In step S6, it is determined whether or not the projection is completed. When it is determined that the projection is completed (step S6: Yes), the detection program is terminated. If it is determined that the projection has not been completed (step S6: No), the process returns to step S2 and the detection program is continued.

As described above, according to the projector 100 of the present embodiment and the object detection method, the following effects can be obtained.
According to the object detection method of the present embodiment, the temperature of the object is repeatedly detected by using the sensor unit 4 which is a passive infrared sensor, and whether or not the detected temperature is equal to or higher than the first reference value. , And whether or not the amount of temperature rise in a predetermined period is equal to or higher than the second reference value, and when it is determined that the temperature is equal to or higher than the first reference value, or. When it is determined that the amount of temperature rise is equal to or greater than the second reference value, the projector 100 is made to perform a predetermined operation.

According to this method, since the sensor unit 4, which is a passive infrared sensor for measuring the radiant heat of an object, is used, the detection range of the sensor unit 4 is both near the opening 5 and at a position away from the opening 5. Be inside. In other words, the detection range can be wider than when an active sensor is used. Further, when the detected temperature is equal to or higher than the first reference value, it can be determined that a person who is a heating element has invaded, and when the amount of temperature increase in a predetermined period is equal to or higher than the second reference value, the temperature rise is equal to or higher than the second reference value. It can be determined that an object such as paper in the vicinity of the opening 5 receives the projected light and the temperature gradually rises. Then, depending on the determination result, the projector 100 can be made to perform a predetermined operation such as reducing the illuminance of the light source 21.
Therefore, it is possible to provide a detection method and a detection program which have a wide detection range and can accurately detect an object near the opening and a person at a position away from the opening with one detection sensor.

Further, the predetermined operation includes outputting the first notification when it is determined that the detected temperature is equal to or higher than the first reference value, and the amount of temperature increase is equal to or higher than the second reference value. If it is determined to be, it includes outputting a second notification different from the first notification.
According to this, different notifications can be output depending on whether a person is detected or an object is detected. Therefore, an appropriate warning can be given according to the determination result.

Further, the first notification includes a notification urging the user to move away from the opening 5, and the second notification includes a notification indicating that an object is present in the vicinity of the opening 5.
According to this, it is possible to give a highly effective warning according to the determination result.

Further, after determining whether or not the detected temperature is equal to or higher than the first reference value, it is determined whether or not the amount of temperature increase is equal to or higher than the second reference value.
According to this, it is possible to give priority to the detection of human intrusion.

Further, the predetermined operation includes reducing the illuminance of the light source 21.
According to this, by reducing the illuminance of the light source 21, glare can be suppressed, and the temperature rise inside the object or the projector 100 can be reduced.

The projector 100 passes through a light source 21 that emits light, an optical modulation device 22 that modulates the light to generate modulated light 88, a projection unit 7 that emits modulated light, and a modulated light 88 emitted from the projection unit 7. The control unit 10 includes a case 2 having an opening 5, a sensor unit 4 which is a passive infrared sensor arranged at a position where the detection range 4e overlaps the opening 5, and a control unit 10. The temperature of the object is repeatedly detected using the part 4, it is determined whether or not the detected temperature is equal to or higher than the first reference value, and the amount of temperature increase in the predetermined period is the first in the predetermined period. It is determined whether or not it is equal to or higher than the reference value of 2, and when it is determined that the temperature is equal to or higher than the first reference value, or when it is determined that the amount of increase in temperature is equal to or higher than the second reference value. If so, a predetermined control signal is output.

Since the projector 100 uses the sensor unit 4, which is a passive infrared sensor that measures the radiant heat of an object, the sensor unit 4 detects both the vicinity of the opening 5 and the position away from the opening 5. It will be within the range. Further, when the detected temperature is equal to or higher than the first reference value, it can be determined that a person who is a heating element has invaded, and when the amount of temperature increase in a predetermined period is equal to or higher than the second reference value, the temperature rise is equal to or higher than the second reference value. It can be determined that an object such as paper near the opening 5 receives the projected light and the temperature gradually rises. Then, depending on the determination result, an appropriate predetermined operation such as reducing the illuminance of the light source 21 can be performed.
Therefore, it is possible to provide the projector 100 which has a wide detection range and can accurately detect an object near the opening and a person at a position away from the opening with one detection sensor.

Embodiment 2
*** Different installation modes of the projector ***
FIG. 6 is an installation mode diagram of the projector according to the present embodiment, and corresponds to FIG. 1. Hereinafter, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
In the above embodiment, the projector 100 has been described as being installed on the floor, but the installation mode is not limited to this, and any installation mode capable of projecting onto the projection surface may be used.
For example, as shown in FIG. 6, the projector 100 may be installed directly above the projection surface.

As shown in FIG. 6, the projector 100 is installed above the wall surface on which the screen SC is installed so as to project from the wall surface by the support equipment 50 and to be substantially parallel to the ceiling. The installation mode of FIG. 6 is such that the top and bottom are inverted from that of FIG. 1, and the projector 100 irradiates the modulated light 88 diagonally downward from the ceiling side toward the screen SC on the wall surface. The installation mode is the same as that of the above embodiment except that the top and bottom are inverted, and the configuration of the projector 100 is the same as that of the first embodiment.

Even in this installation mode, since the detection range 4e of the sensor unit 4 is substantially the same as the irradiation range 88e of the modulated light 88, it is possible to detect an object that has invaded the irradiation range 88e as in the first embodiment. It is possible, and the same action and effect as in the first embodiment can be obtained.

Although the projector 100 has been described as a short-focus type so far, the projector is not limited to the short-focus type, and any projector having a projection opening may be used. Even with these projectors, the above-mentioned object detection method can be applied, and the same effects as those of the above embodiment can be obtained. For example, it may be applied to a small household projector that is easy to carry. Household projectors are often used by placing them on the floor or table depending on the usage environment. In such a case, the probability that a person or an object will invade the irradiation range increases. Therefore, the above-mentioned object detection method. It is useful to apply.

2 ... Case, 4 ... Sensor unit, 4e ... Detection range, 5 ... Aperture, 5e ... Projection center region, 7 ... Projection unit, 8 ... Lens, 9 ... Aspherical mirror, 9A ... Reflection surface, 10 ... Control unit, 11 ... Storage unit, 12 ... Operation unit, 15 ... Image information input unit, 16 ... Image information processing unit, 17 ... OSD processing unit, 21 ... Light source, 22 ... Optical modulator, 28 ... Image forming unit, 31 ... Inclined surface , 32 ... Inclined surface, 34 ... Slope, 35 ... Bottom, 36 ... Detection unit, 37 ... Light source control unit, 38 ... Audio synthesis unit, 39 ... Audio output unit, 40 ... Groove unit, 88 ... Modulated light, 88e ... Irradiation range , 100 ... Projector.

Claims (6)

This is the detection method used by the projector.
The projector
The opening from which light is emitted and
It has a passive infrared sensor arranged at a position where the detection range overlaps with the opening.
Repeatedly detecting the temperature using the infrared sensor,
Determining whether or not the temperature is equal to or higher than the first reference value,
Determining whether or not the amount of increase in temperature in a predetermined period is equal to or higher than the second reference value.
When it is determined that the temperature is equal to or higher than the first reference value, or when it is determined that the amount of increase in the temperature is equal to or higher than the second reference value, the projector performs a predetermined operation. That and, including,
Detection method. The predetermined operation is
When it is determined that the temperature is equal to or higher than the first reference value, the first notification is output.
When it is determined that the amount of increase is equal to or greater than the second reference value, it includes outputting a second notification different from the first notification.
The detection method according to claim 1. The first notification includes a notification urging the user to move away from the opening.
The second notification includes a notification indicating the presence of an object in the vicinity of the opening.
The detection method according to claim 2. After determining whether the temperature is above or below the first reference value,
Determining whether or not the amount of increase in temperature is equal to or greater than the second reference value.
The detection method according to any one of claims 1 to 3. The predetermined operation includes reducing the illuminance of the light source.
The detection method according to any one of claims 1 to 4. A light source that emits light and
An optical modulator that generates modulated light by modulating the light, and
The lens that emits the modulated light and
A case having an opening through which the modulated light passes, and a case
A passive infrared sensor located at a position where the detection range overlaps the opening, and
Including the control unit
The control unit
Repeatedly detecting the temperature using the infrared sensor,
Determining whether or not the temperature is equal to or higher than the first reference value,
Determining whether or not the amount of increase in temperature in a predetermined period is equal to or higher than the second reference value in a predetermined period.
When it is determined that the temperature is equal to or higher than the first reference value, or when it is determined that the amount of increase in the temperature is equal to or higher than the second reference value, a predetermined control signal is output. And do,
projector.

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