JP2021092757A - Image projection device - Google Patents

Abstract

To make it possible to accurately determine the state of components of a projection optical system.SOLUTION: An image projection device projects an image through a projection optical system and detects, with a light detection unit, the quantity of light before incident on the projection optical system and the quantity of light after passage through the projection optical system. The image projection device detects, with a comparison unit, the difference between the quantity of light before incident on the projection optical system and the quantity of light after passage through the projection optical system, which are detected by the light detection unit. When the difference between the quantities of light is equal to or more than a predetermined value, a notification control unit controls a notification unit to perform a predetermined notification operation. The image projection device can thus optically determine with accuracy the state of components of the projection optical system based on the light before and behind the projection optical system.SELECTED DRAWING: Figure 9

Description

The present invention relates to an image projection device.

Today, DLP (Digital Light Processing) projector devices are known. This DLP projector device irradiates the color wheel with the light emitted from the light source. The color wheel is formed by arranging several types of filters that transmit a specific wavelength along the circumferential direction of the disk, and is rotationally driven at a high distance on the optical path of light from a light source. The light transmitted through each filter of such a color wheel is applied to the light modulation element through the light tunnel. The light modulation element forms an image for projection based on the light transmitted through each filter of the color wheel. The image for projection is projected on a screen or the like via a projection optical system.

As the light modulation element, for example, a DMD (Digita1 Micro mirror Device) is used. The DMD forms a projected image in synchronization with the rotation of the color wheel based on the image data input from an external device such as a personal computer device. That is, the DMD forms a projected image while synchronizing the color modulation of the signal by driving the image conversion element in synchronization with the rotation reference position signal obtained based on the rotation reference position of the color wheel.

Further, the color light other than one color light emitted from the projection lens is detected by the color light detector, and the rotation timing of the color wheel or the color modulation is performed so that the output of this color light detector becomes the minimum or zero <0>. Projection projection devices that control synchronization timing are also known.

In Patent Document 1 <Japanese Unexamined Patent Publication No. 2004-163876>, a screen image can be read by an image reading means (image sensor) arranged on the central optical axis of the incident optical path when the optical switch is turned off in the reflective optical switch panel. It is disclosed. Further, it is disclosed that the image signal processing unit performs projection adjustment processing (projection image correction processing, setting update, etc.) based on the read image information. Further, it is disclosed that monitor output and data utilization are performed, and that the projected image is devised (test pattern, etc.) to simultaneously perform image projection and image reading.

However, in the conventional DLP projector device, when determining the component state of the projection optical system, the image projected on the screen is measured or visually determined. Therefore, it has been difficult to accurately determine the state of parts of the projection optical system.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image projection apparatus capable of accurately determining a component state of a projection optical system.

In order to solve the above-mentioned problems and achieve the object, the present invention is an image projection device that projects an image through a projection optical system, and the amount of light before the incident of the projection optical system and projection. Comparison between the photodetector that detects the amount of light that has passed through the optical system, the amount of light that was detected by the photodetector before the incident, and the amount of light that has passed through the projection optical system. It has a unit and a notification control unit that controls the notification unit so as to perform a predetermined notification operation when the difference in the amount of light is equal to or greater than a predetermined value.

According to the present invention, there is an effect that the state of parts of the projection optical system can be accurately determined.

FIG. 1 is a perspective view showing the appearance of the projector of the embodiment. FIG. 2 is a perspective view of the optical engine of the projector of the embodiment. FIG. 3 is a perspective view of the illumination optical system unit of the projector of the embodiment. FIG. 4 is a hardware configuration diagram of the projector of the embodiment. FIG. 5 is a functional block diagram of the projector of the embodiment. FIG. 6 is a perspective view for explaining the optical paths of the ON light and the OFF light of the projector of the embodiment. FIG. 7 is a diagram for explaining the arrangement positions of the first receiver that receives the OFF light and the second receiver that receives the ON light of the projector of the embodiment. FIG. 8 is a diagram showing optical characteristics of an optical filter that filters light from a light source. FIG. 9 is a diagram showing the transition of the difference between the received light amounts of the OFF light and the ON light by the first receiver and the second receiver based on the deterioration of the projection lens. FIG. 10 is a diagram showing the optical characteristics of the folded mirror in which the ON light that has passed through the projection lens is incident.

Hereinafter, a projector according to an embodiment of the image projection device will be described with reference to the attached drawings.

(Projector configuration)
FIG. 1 is a perspective view showing a projection state of the projector 1 of the embodiment. FIG. 2 is a perspective view of the optical engine of the projector 1 of the embodiment. FIG. 3 is a perspective view of the illumination optical system unit of the projector 1 of the embodiment.

First, as shown in FIG. 1, the projector 1, which is an example of an image projection device, has an exit window 3 and an external interface (external I / F) 9. Further, an optical engine for generating a projected image is provided inside the projector 1. In the projector 1, the optical engine generates a projected image based on image data transmitted from, for example, a personal computer device (personal computer) or a digital camera connected to an external I / F9, and the exit window 3 is as shown in FIG. Projects an image onto the screen S from. The X1-X2 direction shown in FIG. 1 indicates the width direction of the projector 1, the Y1-Y2 direction indicates the depth direction of the projector 1, and the Z1-Z2 direction indicates the height direction of the projector 1.

(Optical engine configuration)
As shown in FIG. 2, the optical engine 15 provided in the projector 1 of the embodiment includes a light source 30, an illumination optical system unit 40, an image display unit 50, and a projection optical system unit 60.

The light source 30 is provided on the side surface of the illumination optical system unit 40 and irradiates light in the X2 direction. The illumination optical system unit 40 guides the light emitted from the light source 30 to the image display unit 50 provided at the lower part. The image display unit 50 generates a projected image using the light guided by the illumination optical system unit 40. The projection optical system unit 60 is provided above the illumination optical system unit 40, and projects the projected image generated by the image display unit 50 to the outside of the projector 1.

The optical engine 15 according to the present embodiment is configured to project an image upward using the light emitted from the light source 30, but it may also be configured to project an image in another direction such as a horizontal direction. Good.

(Configuration of illumination optical system unit)
As shown in FIG. 3, the illumination optical system unit 40 provided in the projector 1 of the embodiment has a color wheel 401, a light tunnel 402, relay lenses 403 and 404, a cylinder mirror 405, and a concave mirror 406. There is.

The color wheel 401 is, for example, a disk in which filters of each color of R (red), G (green), and B (blue) are provided in different portions in the circumferential direction. The color wheel 401 is rotationally driven at high speed, and converts the light emitted from the light source 30 into light of each RGB color in a time division manner.

The light tunnel 402 is formed in a square tubular shape by, for example, laminating flat glass or the like. The light tunnel 402 multiple-reflects the light of each RGB color transmitted through the color wheel 401 on the inner surface to make the brightness distribution uniform and guide the light to the relay lenses 403 and 404. The relay lenses 403 and 404 collect the light emitted from the light tunnel 402 while correcting the axial chromatic aberration.

The cylinder mirror 405 and the concave mirror 406 reflect the light emitted from the relay lenses 403 and 404 to the DMD (Digita1 Micro mirror Device) 551 provided in the image display unit 50. The DMD 551 is an example of an image forming unit, and forms a projected image by modulating the reflected light from the concave mirror 406.

(Hardware configuration)
FIG. 4 is a hardware configuration diagram of the projector 1. As shown in FIG. 4, the projector 1 has a control unit 10 and an optical engine 15.

(Control unit configuration)
The control unit 10 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, an SDRAM (Synchronous Dynamic Random Access Memory) 103, and an NVRAM (Non Volatile Random Access Memory) 104. Further, the control unit 10 includes a fan 105, an operation unit 5, a remote controller receiving unit (remote control receiving unit) 107, an external I / F9, a network I / F109, a media I / F110, and a power supply unit 4. Each of these units 101 to 110 and the power supply unit 4 are connected to each other via a bus line 111.

The CPU 101 controls the operation of the entire projector 1. Various programs executed by the CPU 101 are stored in the ROM 102. For example, the rotation control program of the color wheel 401 is stored in the ROM 102. By executing this rotation control program, the CPU 101 realizes each function described later with reference to FIG. The SDRAM 103 is used as a work area of the CPU 101.

The operation unit 5 is provided with various keys, buttons, a light emitting unit (LED), a liquid crystal display screen, and the like. By operating the operation unit 5, the user can perform instruction operations such as adjusting the size of the image to be projected, adjusting the color tone, adjusting the focus, adjusting the keystone, changing the power mode, changing the image projection mode, and the like. And so on. These operation contents are notified (output) to the CPU 101. Further, the light emitting unit (LED) or the liquid crystal display screen has a function of notifying the user of the state of the device or the current setting. That is, the operation unit 5 also has a function as a notification unit.

The remote control receiver 107 has a receiver for receiving commands from the remote controller. The remote control receiver 107 receives and accepts instruction operations from the remote controller such as, for example, the size adjustment operation of the projected image, the color tone adjustment operation, the focus adjustment operation, the keystone adjustment operation, the power mode change, and the image projection mode change. Notify (output) the operation details to the CPU.

The fan 105 rotates or stops based on the control signal from the CPU 101 to exhaust the inside of the projector 1 and cool the inside of the projector 1. The media I / F 110 controls reading or writing (storage) of data to a recording medium such as a flash memory. The bus line is an address bus, a data bus, or the like for electrically connecting each component.

The network I / F109 is an interface for performing data communication using a communication network such as the Internet. An external device such as a personal computer device is connected to the external I / F9. The control signal or image data from the personal computer device is acquired via this external I / F9.

(Optical engine configuration)
The optical engine 15 forms a projected image based on the image data controlled by the CPU 101 and input to the projector 1. The optical engine 15 includes a light source unit 30, a lighting unit 40, an image display unit 50, and a projection optical system unit 60.

The light source unit 30 includes a light source such as a light emitting diode (LED), and irradiates the lighting unit 40 with light under the control of the CPU 101. The light source may be, for example, a mercury high-pressure lamp or a xenon lamp other than the LED.

The lighting unit 40 includes, for example, a color wheel 401, a rotation detection sensor 400, a light tunnel 402, relay lenses 403 and 404, a cylinder mirror 405, a reflection mirror 406, and the like. The lighting unit 40 guides the light emitted from the light source to the image display unit 50.

The color wheel 401 has a disk shape in which a plurality of segments (RGB transmission regions) that transmit only light in a specific wavelength region are arranged in order in the rotation direction. The light emitted from the light source is converted into light of each color by a segment of the rotating color wheel 401. Further, by passing through the color wheel 401, the light in which each color of RGB is repeated every unit time is emitted toward the light tunnel 402.

The light tunnel 402 is formed of, for example, flat glass laminated in a polygonal tubular shape. Then, silver or a dielectric multilayer film or the like is vapor-deposited on the inner surface of the light tunnel 402 to reflect light. The light tunnel 402 guides the light emitted from the color wheel 401 to the relay lenses 403 and 404 with uniform illuminance.

The relay lenses 403 and 404 are formed by two combined lenses. The relay lenses 403 and 404 correct the axial chromatic aberration of the light emitted from the light tunnel 402 and collect the light. The light that has passed through the relay lenses 403 and 404 is incident on the light modulation element (display element) that is the image forming portion of the image display unit 50 via the cylinder mirror 405 and the reflection mirror 406.

The image display unit is controlled by the CPU 101 and modulates the light guided by the lighting unit 40 to generate a display image. As an example, a micromirror (DMD (Digital Micro mirror Device) 551) 551 can be used as the display element. The input light is modulated by driving the DMD 551 on and off according to the image data by the CPU 101. As the display element, for example, a liquid crystal panel or the like can be used other than DMD551.

The projection optical system unit 60 includes a projection mirror 601 and a projection lens 602. The projection optical system unit 60 magnifies the projected image formed by the DMD 551 of the image display unit 50 with the projection lens 602 and projects it on the screen S. The number of projection lenses 602 may be plural, or may be provided with an optical element such as a mirror.

Further, FIG. 1 is a diagram showing a state in which a projected image is projected from the upright projector 1 onto the screen S. The projector 1 can be installed by tilting it 90 degrees so that the wide area portion is on the bottom, and the projected image can be projected on the installation surface.

Here, at the timing when the light of each color of RGB emitted through the color wheel 401 is applied to the DMD 551, it is necessary for the DMD 551 to perform a modulation operation corresponding to the light of that color. Therefore, it is necessary to synchronize the output timing of the drive signal for causing the DMD 551 to perform the modulation operation with the rotation timing of the color wheel 401. In order to achieve this synchronization, the color wheel 401 of the lighting unit 40 is provided with the above-mentioned first marker 700 (and the second marker 750) for detecting the rotation position.

Further, the lighting unit 40 is provided with a rotation detection sensor 400 for detecting the first marker 700 (and the second marker 750) provided at the rotation reference position of the color wheel 401.

When the first marker 700 (or the second marker 750) is in a position facing the rotation detection sensor 400, the rotation detection sensor 400 causes the first marker 700 (or the second marker 750) to be in the rotation reference position. A position detection signal indicating that it has arrived is output. Based on this position detection signal, the above-mentioned synchronization control is performed.

When the CPU 101 is started by being supplied with electric power from the power supply unit 4, it controls lighting of the light source of the light source unit 30 based on the rotation control program stored in advance in the ROM 102, and rotates the fan 105 at a predetermined rotation speed. Control. When the power supply of the power supply to the projector 1 is started, the optical engine 15 is in a state where the image can be displayed, and the power supply unit 4 supplies power to various other components.

Further, when the power switch of the projector 1 is turned off, a power off signal is supplied to the CPU 101. When the CPU 101 detects the power OFF signal, it turns off the light source. After that, when a predetermined time elapses, the CPU 101 stops and controls the fan 105 to end the control process.

(Functional configuration)
FIG. 5 is a functional block diagram of the projector 1. The CPU 101 of the projector 1 executes an operation reception unit 250, a data reception unit 251 and a fan control unit 252, a position signal acquisition unit 253 and a display control unit 254, and an optical engine control by executing a rotation control program stored in the ROM 102. Each function of the unit 255, the storage control unit 259, and the comparison unit 260 is realized. The optical engine control unit 255 includes an image generation unit 256, a light source control unit 257, and a synchronization control unit 258.

The operation reception unit 250 processes the CPU 101 and the operation unit 5, or the CPU 101 and the remote controller reception unit 107, and receives various inputs by the user. The display control unit 254 displays various information about the projector 1, for example, to the user by performing display processing of the CPU 101 and the operation unit 5. For example, when the operation unit 5 has a lamp, the display control unit 254 controls the lighting and extinguishing of the lamp, and when the operation unit 5 has a touch panel, the display control unit 254 controls the display on the touch panel.

The data receiving unit 251 processes the CPU 101 and the external I / F9, and receives various data such as image data input from an external device such as a personal computer device. Further, the data receiving unit 251 processes the CPU 101 and the network I / F 109, and receives various data such as image data input via a predetermined network such as a LAN (Local Area Network) or the Internet.

The fan control unit 252 controls the rotation and stop of the fan 105. The position signal acquisition unit 253 is realized by the processing of the rotation detection sensor 400, detects a signal indicating the rotation position of the color wheel 401, and notifies the optical engine control unit 255.

The optical engine control unit 255 has a light source control unit 257, an image generation unit 256, and a synchronous control unit 258, and controls the entire optical engine 15. The light source control unit 257 controls the output of the light source. The light source control unit controls the output of the light source by controlling the power supplied to the light source as an example.

The image generation unit 256 controls the DMD 551 provided in the image display unit 50 of the optical engine 15 based on the input image data or the superimposed image (OSD) data such as menu information, and outputs an image to be projected on the screen S. Generate.

The synchronization control unit 258 generates a synchronization signal to the light source, the color wheel 401, and the DMD551 based on the rotation position signal from the position signal acquisition unit 253, and synchronizes these movements. For example, the cycle of displacement of the DMD 551 and the cycle of rotating the color wheel 401 are synchronously controlled, and an image of each color is generated by synchronous control time division.

In the storage control unit 259, the CPU 101 stores and controls various data in a storage unit such as the SDRAM 103 or NVRAM 104, or reads and controls various data from the storage unit. Further, the storage unit stores in advance the magnitude of the voltage of the rotation detection pulse detected by the rotation detection sensor 400 as a position signal or the pulse width of the rotation detection pulse.

The comparison unit 260 describes the amount of light measured by the first light receiver 701 before being incident on the projection lens 602 and the amount of light measured by the second light receiver 702 through the projection lens 602. Compare the amount of light. The display control unit 254 controls the display of, for example, a message related to an abnormality of the optical component based on the comparison result of the comparison unit 260.

In this example, the operation reception unit 250 to the memory control unit 259 are realized by software, but even if some or all of them are realized by hardware such as an IC (Integrated Circuit). Good.

Further, the rotation control program may be provided by recording a file in an installable format or an executable format on a recording medium readable by a computer device such as a CD-ROM or a flexible disk (FD). Further, the rotation control program may be provided by recording on a recording medium readable by a computer device such as a CD-R, a DVD (Digital Versatile Disk), a Blu-ray disc (registered trademark), or a semiconductor memory. Further, the rotation control program may be provided in the form of being installed via a network such as the Internet, or may be provided by being incorporated in advance in a ROM or the like in the device.

(ON light and OFF light)
FIG. 6 is a perspective view of such a projector 1. Of these, FIG. 6A is a perspective view of the projector 1 viewed from diagonally above right, and FIG. 6B is a perspective view of the projector 1 viewed from the substantially right side. .. The color-sequential projector 1 using the color wheel 401 divides the light emitted from the light source unit 30 into each color by the color wheel 401 in which RGB color filters are sequentially arranged around the rotation axis. The time-divisioned light of each color is projected onto the DMD551, which is an example of the light modulation element, via the light tunnel 402, the relay lenses 403 and 404, the cylinder mirror 405, and the concave mirror 406.

The DMD 551 performs optical modulation based on the signal data of each color, and projects the projected light (projected image) through the projection lens 602. The DMD 551 forms one color image (projected image) by superimposing time-division images of each color. The light directed to the projection lens 602 is called "ON light". On the other hand, the light unnecessary for projection does not enter the projection lens 602 and becomes unused light. This unused light is called "OFF light".

The ON light (light required for the image) reflected by the DMD 551 is incident from the lower side of the projection lens 602. The OFF light (light unnecessary for the image) reflected by the DMD 551 is applied to the light absorber 800 attached to the side surface of the projection optical system unit 60, and the light energy becomes heat and is cooled by the outside air flow. The light energy. A folded mirror 405 and a concave mirror 406 are provided on the upper side of the projection lens 602.

The light emitted from the upper part of the projection lens 602 along the path of the projected light is folded back by the folded-back mirror 405 and then further folded back by the concave mirror 406 to reach the screen, thereby forming an image and projecting an image.

To explain in detail again, the DMD551 is laid out with a large number (for example, millions) of extremely small reflective mirrors made of a member having a high reflectance such as an aluminum member, and the inclination of each reflective mirror and the light source. By control, it is possible to project various images.

The tiny reflection mirrors are arranged in an array. Each reflection mirror can be independently driven and controlled (switched), for example, in a tilt ON state or a tilt OFF state. By switching the tilt of the reflection mirror in this way, the portion that passes through the projection optical system unit 60 and is irradiated with light (bright pixels) and the portion that is not irradiated (dark pixels) with respect to the projection surface such as the screen S (dark pixels). Is formed. One reflection mirror corresponds to one pixel and can be switched ON / OFF at high speed.

The brightness of the projected image is, for example, the brightness according to the ON / OFF interval of each reflection mirror in one frame. When the period in which the reflection mirror is turned on is lengthened, the projection time of the light source on the irradiation surface becomes long, so that the projected image becomes bright. On the contrary, if the period in which the reflection mirror is turned off is lengthened, the projection time of the light source on the irradiation surface is shortened, resulting in a dark projection image. The DMD controller controls the ON / OFF period of such a reflection mirror by PWM (Pulse Width Modulation) control.

The color expression of the projected image is realized by irradiating the DMD 551 with a light source of each color in a time-division manner. Each reflection mirror is controlled to the ON state at the timing when the light source of the color to be projected is irradiated on the DMD 551. The reflection mirror can switch between the ON state and the OFF state several thousand times per second, for example. Therefore, it is possible to visually recognize a color image in which each color is combined by the illusion of the human eye (afterimage effect).

That is, a color image is formed by combining the lighting time of the light source of each color and the ON / OFF time of the extremely small reflection mirror. As the light source, any light source may be used as long as the extremely small mirror can be reflected, and for example, a lamp, an LED (light emitting diode), a laser light, or the like can be used. In addition to visible light, invisible light such as ultraviolet light and near infrared light can also be used.

(Arrangement position of receiver)
FIG. 7 is a diagram for explaining the arrangement positions of the first receiver and the second receiver provided in the projector 1. Of these, FIG. 7A is a perspective view of the projector 1 viewed from diagonally upper left, and FIG. 7B shows ON light and OFF for the projection optical system unit 60, which is a main part of the projector 1. It is a figure which shows the optical path of light. In FIG. 7B, the solid arrow indicates the projected optical path when DMD551 is OFF, and the dotted arrow indicates the incident optical path.

Further, as shown in FIGS. 7 (a) and 7 (b), in the case of the projector 1 of the embodiment, the position where the OFF light, which is the light that is not used because it does not enter the projection lens 602, is received, is located. The receiver 701 of 1 is provided. Further, in the case of the projector 1 of the embodiment, the second receiver 702 is provided on the back surface of the folded mirror 405. The first receiver 701 and the second receiver 702 are examples of the photodetector. The first photodetector 701 is an example of a first photodetector, and the second photodetector 702 is an example of a second photodetector. The light may be detected by three or more receivers.

As shown in FIG. 7A, in the optical path when the DMD 551 is OFF, all the light other than the ON light is in the OFF light region, and the OFF light in this range is read by the first receiver 701. Further, as shown in FIG. 7B, a part of the light transmitted through the projection lens 602 is read by the second receiver 702 provided on the back surface of the folded mirror 405.

(Optical characteristics of optical filter)
Further, in the projector 1 of the embodiment, an optical filter 801 is provided between the light source and the color wheel 401 as described above. FIG. 8 is a diagram showing the optical characteristics of the optical filter 801. The light emitted from the light source is light including an ultraviolet region (420 nm or less) to an infrared region (700 nm or more). The optical filter 801 has a transmittance characteristic that blocks light in an unnecessary region. The optical fill 801 suppresses deterioration of the components inside the optical system and heat generation more than necessary for the components inside the optical system.

The light source light transmitted through the optical filter 801 is colored and emitted as light of each color of RGB (red, green, blue) by each segment of RGB of the color wheel 401. Here, among the light transmitted through the optical filter 801 the light near the short wavelength in the ultraviolet region shown by the circle in the middle dotted line in FIG. 8 or the light near the long wavelength in the infrared region has relative luminous efficiency or optical characteristics. Has little effect on. The first receiver 701 and the second receiver 702 read light that does not affect such a projected image as light for measurement.

That is, the first receiver 701 and the second receiver 702 are light having a wavelength that can be used for measurement without affecting the projected image or the optical performance. It has sensitivity to light closer to short wavelengths or light closer to long wavelengths in the infrared region, and reads these lights.

When a receiver having sensitivity in the ultraviolet region is used as the first receiver 701 and the second receiver 702, it is preferable to use white light or blue light. When a receiver having sensitivity in the infrared region is used as the first receiver 701 and the second receiver 702, it is preferable to use white light or red light. Further, the measurement timing may be performed every time the projector 1 is started, or may be performed at a predetermined timing such as every several hours, every few days, every few weeks, every time instructed by the user, and the like. Good.

The first receiver 701 and the second receiver 702 may have sensitivity only on the short wavelength side or may have sensitivity only on the long wavelength side. Since the amount of light is small on the short wavelength side, it is desirable that the long wavelength side is in a region where the red optical characteristics are not affected.

(Measurement operation of receiver)
FIG. 9 is a diagram for explaining the measurement operation of the first receiver 701 and the second receiver 702. In FIG. 9, the horizontal axis represents the usage time of the projection lens 602, and the vertical axis represents the measured values (light receiving values) of the receivers 701 and 702. The solid line graph shows the transition of the measured value of the first receiver 701, and the dotted line graph shows the transition of the measured value of the second receiver 702.

In FIG. 9, the relationship between the measured values of the first receiver 701 and the second receiver 702 is a substantially constant difference unless the projection lens 602 is deteriorated. The comparison unit 260 shown in FIG. 5 acquires the measured values of the light receivers 701 and 702 each time a predetermined time elapses, and compares the deteriorated state of the projection lens 602.

Although the difference between the measured values is substantially constant, there is a measurement error, so a tolerance such as 5% may be provided for the measurement width.

(Notification operation)
Next, in the display control unit 254 (an example of the notification control unit) shown in FIG. 5 of the projector 1 of the embodiment, the difference between the measured values of the first receiver 701 and the second receiver 702 is equal to or greater than a predetermined value. When it is detected that the difference between the two is detected, a message prompting the maintenance of the projector 1, such as "The projection lens is deteriorated. Please contact the maintenance man", is sent to the liquid crystal display screen (notification unit) of the operation unit 5. It is displayed in (an example), etc. As a result, the user can recognize the deterioration of the projection lens 602 and can take appropriate measures such as maintenance. The maintenance of the projector 1 may be notified by controlling the lighting or blinking of the light emitting unit (LED) of the operation unit 5, or may be notified by voice, electronic sound, or the like.

(Optical characteristics of folded mirror)
Here, FIG. 10 shows the optical characteristics of the folded mirror 405. For example, when the second receiver 702 is given sensitivity on the long wavelength side, it is preferable to use a mirror that transmits a specific wavelength, such as a dichroic mirror, as the folded mirror 405. The example of FIG. 10 is an example in which the optical characteristics of the folded mirror 405 are such that the reflectance in the wavelength region of 430 nm to 650 nm is 95% or more. In this case, among the light that has reached the folding mirror 405 from the projection lens 602, the light in the wavelength region other than the wavelength region of 430 nm to 650 nm that passes through the folding mirror 405 is detected and measured by the second receiver 702. ..

(Effect of embodiment)
As is clear from the above description, in the projector 1 of the embodiment, the amount of light before being incident on the projection lens 602 is measured by the first receiver 701, and the light transmitted through the projection lens 602 is measured. The amount of light is measured by the second receiver 702. Then, when the difference between the measured values of the two becomes a difference of a predetermined value or more, the projection lens 602 is recognized to have deteriorated, and the user or the like performs a notification operation.

As a result, it is possible to accurately determine the state of parts such as deterioration of the projection lens 602 and notify the user.

Finally, the embodiments described above are presented as an example and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention.

In the description of the embodiment, two receivers 701 and 702 are used to monitor the component state of the projection lens 602, but three or more receivers are used to monitor the component status of the projection lens 602. May be monitored.

Moreover, the embodiment and the modification of each embodiment are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Projector 3 Exit window 9 External interface 10 Control unit 15 Optical engine 30 Light source unit 40 Illumination optical system unit 50 Image display unit 60 Projection optical system unit 253 Position signal acquisition unit 254 Display control unit 255 Optical engine control unit 260 Comparison unit 401 Color Wheel 405 Folded mirror 551 DMD
602 Projection lens 701 First receiver 702 Second receiver 801 Optical filter

Japanese Unexamined Patent Publication No. 2004-163876

Claims (7)

An image projection device that projects an image via a projection optical system.
A photodetector that detects the amount of light before the incident of the projection optical system and the amount of light that has passed through the projection optical system.
A comparison unit that compares the amount of light before the incident of the projection optical system detected by the photodetector unit and the amount of light that has passed through the projection optical system.
A notification control unit that controls the notification unit so as to perform a predetermined notification operation when the difference in the amount of light is equal to or greater than a predetermined value.
An image projection device characterized by having. The photodetector
A first photodetector that receives light that deviates from the optical path of light that travels to the projection optical system, and
A second photodetector that receives light that has passed through the projection optical system,
The image projection apparatus according to claim 1, wherein the image projection apparatus is characterized by the above. An image projection device that projects an image via a projection optical system.
A first photodetector that receives light that deviates from the optical path of light that travels to the projection optical system, and
A second photodetector that receives light that has passed through the projection optical system,
A comparison unit that compares the amount of light detected by the first photodetector and the second photodetector, and a comparison unit.
A notification control unit that controls the notification unit so as to perform a predetermined notification operation when the difference in the amount of light is equal to or greater than a predetermined value.
An image projection device characterized by having. The image projection device according to claim 2 or 3, wherein the first photodetector and the second photodetector detect light in the infrared region. The image projection device according to claim 2 or 3, wherein the first photodetector and the second photodetector detect light in an ultraviolet region. It has a reflection-transmitting member that reflects a part of the light that has passed through the projection optical system to guide the light to the projection surface and transmits the part.
The image projection device according to any one of claims 2 to 5, wherein the second photodetector receives light transmitted through the reflection-transmitting member. A light source that generates light incident on the projection optical system,
It has a plurality of reflection mirrors, and has an image forming unit provided on an optical path of light from the light source.
The plurality of reflection mirrors of the image forming unit can be independently driven in a direction in which light from the light source is reflected in the direction of the projection optical system and in a direction in which the light is reflected in a direction different from that of the projection optical system. And
The light deviating from the optical path of the light traveling to the projection optical system is the light reflected by the reflection mirror in a direction different from that of the projection optical system, and the light passing through the projection optical system is reflected by the reflection mirror. The image projection apparatus according to any one of claims 1 to 6, wherein the light is reflected in the direction of the projection optical system.

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