JP6988494B2 - Image forming unit, image projection device, and image forming method - Google Patents

Description

The present invention relates to an image forming unit, an image projection device, and an image forming method.

In recent years, large-screen display devices have rapidly become widespread, and conferences, presentations, training, etc. using them are becoming common. For example, as such a display device, an image projection device (so-called projector) that projects an image on a screen or the like and magnifies and displays the image is used. In the image projection device, an image forming unit that forms an image by controlling the gradation of the light from the light source unit for each pixel by an image forming element such as a DMD (Digital Micromirror Device) or a liquid crystal is used.

The image forming unit includes, for example, an excitation light source, a fluorescent wheel in which a phosphor that emits light emitted from the excitation light source as excitation light is laid in the circumferential direction, a wheel motor that drives the fluorescent wheel, and a phosphor. It is equipped with a motor control means that controls the stop or drive of the wheel motor within the range where combustion destruction does not occur, and the wheel motor is stopped or stopped while checking the projection mode at the time of image projection or the drive current flowing through the excitation light source. , A light source unit that controls drive is disclosed (see, for example, Patent Document 1).

However, in the apparatus of Patent Document 1, in order to prevent the destruction of the phosphor and the decrease in the fluorescence efficiency due to the light emitted from the light source, the rotation speed of the fluorescent wheel having the phosphor region and the region without the phosphor is changed. As a result, the timing of the light emitted from the fluorescent wheel (fluorescent light fluorescent in the phosphor region, excitation light transmitted or reflected in the region without the phosphor) changes, and is formed by the image forming element (DMD). The image was sometimes distorted.

The present invention has been made in view of the above points, and the number of rotations of a fluorescent wheel having a phosphor region and a region without a phosphor is changed, and light emitted from the fluorescent wheel (fluorescence in the phosphor region). Even if the timing of the fluorescent light transmitted or the excitation light transmitted or reflected in the region without the phosphor is changed, the formed image is not disturbed, and the fluorescence is prevented from being destroyed or the fluorescence efficiency is lowered by the excitation light. That is the issue.

The image forming unit according to one aspect of the disclosed technique is a first rotating body having a light source for emitting first light, a phosphor region and a region without a phosphor, and in the phosphor region. A first light conversion means for converting the first light into a second light containing at least a fluorescent light that fluoresces the first light and the first light that has passed through a region not provided with the phosphor, and the second light. Depending on the temperature change of the image forming element that modulates the light and forms an image, the output of the first light emitted from the light source, or the temperature change of the air around the phosphor region due to the irradiation of the first light. Based on the rotation speed control means for changing the rotation speed of the first rotating body and the rotation timing of the first rotating body detected based on the detection of a predetermined position in the first rotating body , the said It is characterized by having a first synchronization means for synchronizing the rotation of the first rotating body and the image formation by the image forming element.

Even if the rotation speed of the fluorescent wheel having the phosphor region and the region without the phosphor is changed and the timing of the light emitted from the fluorescent wheel is changed, the formed image is not disturbed and the phosphor is generated by the excitation light. It is possible to prevent destruction and decrease in fluorescence efficiency.

It is a schematic diagram which illustrates the image projection apparatus of 1st Embodiment. It is a figure which illustrates the spectral transmittance characteristic of the wavelength selective polarization separation element used in 1st Embodiment. It is an enlarged plan view which illustrates the fluorescent substance wheel used in 1st Embodiment. It is an enlarged plan view which illustrates the color wheel used in 1st Embodiment. This is an example of a timing chart in which each illumination light is taken out in a time-division manner in the image projection device of the first embodiment. It is a block diagram which illustrates the functional structure of the image projection apparatus in 1st Embodiment. It is a flowchart illustrating the process in 1st Embodiment. It is a table which exemplifies a part of the apparatus specifications for each light source output mode in the image projection apparatus of 1st Embodiment. It is a schematic diagram which illustrates the image projection apparatus of 2nd Embodiment. It is a block diagram which illustrates the functional structure of the image projection apparatus in 2nd Embodiment. It is a flowchart illustrating the process in 2nd Embodiment. It is a schematic diagram which illustrates the image projection apparatus of 3rd Embodiment. It is a block diagram which illustrates the functional structure of the image projection apparatus in 3rd Embodiment. It is a flowchart illustrating the process in 3rd Embodiment. It is a figure which shows the 1st example of the relationship between the output of a light source in the image projection apparatus of 3rd Embodiment, and the rotation speed of a phosphor wheel, and a fan. It is a figure which shows the 2nd example of the relationship between the output of a light source in the image projection apparatus of 3rd Embodiment, and the rotation speed of a phosphor wheel, and a fan. It is a figure explaining the arrangement of the temperature sensor in 4th Embodiment. It is a schematic diagram which illustrates the image projection apparatus of 4th Embodiment. It is a block diagram which illustrates the functional structure of the image projection apparatus in 4th Embodiment. It is a flowchart illustrating the process in 4th Embodiment.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

<First Embodiment>
FIG. 1 is a schematic diagram illustrating the image projection device of the first embodiment. As shown in FIG. 1, the image projection device 1 includes an image forming unit 100 and a projection optical unit 200.

The image forming unit 100 includes a light source 101, a lens 102, a lens 103, a wavelength selective polarization separation element 104, a quarter wave plate 105, and a lens group 106.

Further, the image forming unit 100 includes a phosphor wheel 107, a lens 108, a color wheel 109, a light tunnel 110, a lens group 111, a mirror group 112, and an image forming element 113.

The image forming unit 100 forms an image by controlling the gradation of light sequentially emitted from the light tunnel 110 in a time-division manner for each pixel by the image forming element 113, and irradiates the projected optical unit 200 with the formed image. It is a unit.

In the image forming unit 100, the light source 101 emits light having a linearly polarized light component. In the present embodiment, as an example, the following description will be made assuming that the light source 101 is a laser diode that emits a blue laser light having a wavelength λB (which is a P wave) having a P polarization component. The wavelength λB can be, for example, 400 nm <λB <470 nm.

However, the present invention is not limited to this, and a light emitting diode (Light Emitting Diode) or an organic EL (Electro Luminescence) element that emits blue light may be used as the light source 101, or a light source in which these are combined may be used. Alternatively, a laser diode, a light emitting diode, an organic EL element, or the like that emits light in a wavelength region in the ultraviolet region may be used, or a light source that combines these may be used.

Further, the number of light sources 101 may be one or a plurality. Further, a coupling lens may be provided between the light source 101 and the lens 102 to guide the laser beam emitted from the light source 101 to the lens 102 as a substantially parallel luminous flux.

The blue laser light emitted by the light source 101 is an example of the first light. Further, the blue laser light emitted by the light source 101 is used as excitation light for causing fluorescence in the phosphor wheel 107.

The blue laser light emitted by the light source 101 enters the wavelength selection polarization separation element 104 as a substantially parallel luminous flux via the lens 102 and the lens 103. The wavelength selection polarization separation element 104 is, for example, an optical path switching means having the spectral transmittance characteristic shown in FIG. 2.

The wavelength selective polarization separation element 104 has a characteristic that the P wave is transmitted and the S wave is not transmitted (reflects the S wave) at the wavelength λB of the light source 101. As can be seen from the spectral transmittance characteristics of FIG. 2, light having a wavelength of about 500 nm or more is a wavelength selective polarization separation element regardless of whether it is a P wave or an S wave (regardless of the polarization characteristics). It is reflected at 104. As the wavelength selection polarization separation element 104, for example, a polarization beam splitter can be used.

Returning to FIG. 1, the blue laser light of the P wave incident on the wavelength selective polarization separation element 104 passes through the wavelength selective polarization separation element 104 and is a polarization conversion means for mutually converting linearly polarized light and circularly polarized light. It is guided to the wavelength plate 105. The light transmitted through the 1/4 wave plate 105 changes from P wave (P polarized light) to circularly polarized light, and is incident on the phosphor wheel 107 via the lens group 106.

The polarization conversion means is not limited to the 1/4 wave plate, and for example, a lens having an oblique vapor deposition film such as _{Ta 2} O _{5 formed on the incident surface of any of the lenses constituting the lens group 106 is used.} You may. Here, the diagonal thin-film deposition film means that the object to be vapor-deposited is placed diagonally with respect to the direction in which the vapor-film-deposited substance comes (the direction of the vapor-film deposition source), and the thin-film-deposited substance is relative to the normal line of the predetermined surface of the object to be vapor-deposited. Is formed by depositing diagonally.

The lens group 106 can be configured by appropriately combining, for example, a biconvex lens, a plano-convex lens, etc., and has a function of condensing a substantially parallel light flux on the phosphor wheel 107 in a spot shape and a function of parallelizing the divergent light from the phosphor wheel 107. It has a function of converting to a parallel luminous flux.

FIG. 3 is an enlarged plan view illustrating the phosphor wheel used in the first embodiment, and is a view of the phosphor wheel viewed from the incident light side. As shown in FIG. 3, the phosphor wheel 107 used in the present embodiment has a configuration in which a disk-shaped member, that is, a rotating body is divided into a plurality of fan-shaped regions (segments) that emit different fluorescence. It is rotationally driven so that the region irradiated with the light from the wavelength selection polarization separation element 104 is sequentially changed.

Specifically, the phosphor wheel 107 has a yellow (Y) phosphor region 1071 in which a yellow (Y) phosphor that emits yellow fluorescence is formed in the circumferential direction, and a green (G) phosphor that emits green fluorescence. It is divided into three fan-shaped regions (segments) of the green (G) phosphor region 1072 in which the is formed and the reflective surface region 1073 in which the reflecting surface for reflecting the incident light is formed.

The yellow (Y) phosphor region 1071 uses a blue laser light as an excitation light to generate yellow fluorescence having a wavelength longer than that of the blue laser light. The green (G) phosphor region 1072 uses a blue laser light as an excitation light to generate green fluorescence having a wavelength longer than that of the blue laser light. The reflecting surface region 1073 reflects the incident blue laser light as it is as blue light.

The phosphor wheel 107 extracts the reflected light of the yellow fluorescence, the green fluorescence, and the blue laser light by switching the segment arranged at the incident position of the light from the lens group 106 by rotation.

However, in the above, the example in which the reflective surface region 1073 is used for the region where the blue light is the second light is shown, but the present invention is not limited to this. For example, a transparent area, a perforated area, or a diffused area may be used to extract blue light.

The transparent region is, for example, transparent glass and transmits a blue laser beam. In the area where the hole is opened, the blue laser beam passes as it is. In the diffusion region, the blue laser beam is diffused. The diffusion region can be, for example, a structure in which a large number of uneven structures having different sizes are formed on the surface.

Further, although the example in which the yellow and green fluorescent material regions are used as the fluorescent material regions is shown, any one of them may be used, and the fluorescent material regions of other colors may be substituted or additionally provided. ..

Further, in addition to the blue laser as the light source, a light source such as a red laser diode may be separately provided.

The phosphor wheel 107 is an example of the “first light conversion means”. The yellow (Y) phosphor region 1071 and the green (G) phosphor region 1072 are examples of "fluorescent region", respectively. The fluorescence generated in the yellow (Y) phosphor region 1071 and the green (G) phosphor region 1072 is an example of "fluorescent light". The reflective surface region 1073 is an example of a “region without a phosphor”. A rotating body provided with a yellow (Y) phosphor region 1071, a green (G) phosphor region 1072, and a reflecting surface region 1073 is an example of a "first rotating body".

Returning to FIG. 1, a drive unit 107m such as a stepping motor for rotating the phosphor wheel 107 is provided at the axis of the phosphor wheel 107. By rotating the phosphor wheel 107 at a predetermined timing by driving the drive unit 107 m, the incident position of the light from the lens group 106 is changed to the yellow (Y) phosphor region 1071, the green (G) phosphor region 1072, and It switches to any of the three segments of the reflective surface region 1073. Further, the rotation speed of the phosphor wheel 107 driven by the drive unit 107 m can be changed by controlling the drive unit 107 m.

The yellow or green fluorescence generated from the yellow (Y) phosphor region 1071 or the green (G) phosphor region 1072 passes through the lens group 106 and the 1/4 wave plate 105 in the opposite direction to the previous one. It is incident on the wavelength selection polarization separation element 104. The yellow or green fluorescence at this time is in a state of random polarized light.

As described above, the wavelength selection polarization separation element 104 reflects light having a wavelength of about 500 nm or more regardless of the polarization characteristics. Therefore, the yellow and green fluorescence generated by the phosphor wheel 107 is reflected by the wavelength selective polarization separating element 104 and is incident on the color wheel 109 through the lens 108.

On the other hand, the light reflected by the reflecting surface region 1073 of the phosphor wheel 107 passes through the lens group 106 and the 1/4 wave plate 105 in the opposite direction to the forward direction. Here, the circularly polarized light incident on the reflecting surface region 1073 is maintained as circularly polarized light even after reflection, but becomes circularly polarized light that rotates in the direction opposite to the incident light due to reflection. For example, light that was clockwise circularly polarized light at the time of incident becomes counterclockwise circularly polarized light after reflection. Then, by passing through the 1/4 wave plate 105, it becomes linearly polarized light whose polarization direction is orthogonal to that of the going. Therefore, it is reflected by the wavelength selection polarization separation element 104 and is incident on the color wheel 109 through the lens 108.

FIG. 4 is an enlarged plan view illustrating the color wheel used in the first embodiment, and is a view of the color wheel viewed from the incident light side. As shown in FIG. 4, the color wheel 109 used in the present embodiment has a configuration in which a disk-shaped member, that is, a rotating body is divided into a plurality of fan-shaped regions (segments). Specifically, the color wheel 109 is divided into four fan-shaped regions (segments) of a red (R) region 1091, a green (G) region 1092, a transparent region 1093, and a diffusion region 1094 in the circumferential direction. ..

The red (R) region 1091 in the color wheel 109 is a region in which a dichroic filter that transmits red light is formed, and light in a wavelength range of about 600 nm or more is transmitted and light in a wavelength range other than that is reflected. .. The green (G) region 1092 is a region in which a dichroic filter that transmits green light is formed, and light in a wavelength range of about 500 nm to 580 nm is transmitted, and light in a wavelength range other than that is reflected.

In the transparent region 1093, light in the entire wavelength range is transmitted as it is. The transparent region 1093 may be made of transparent glass or the like, or may have a structure with holes. In the diffusion region 1094, light in the entire wavelength range is diffused and transmitted. For example, it can be a structure in which a large number of uneven structures having different sizes are formed on the surface.

The color wheel 109 extracts red, green, yellow, and blue light by switching the segment arranged at the incident position of the light from the lens 108 by rotation.

The transparent region 1093 and the diffused region 1094 are examples of regions for light-converting the second light, respectively.
As described above, the reflective surface region may be used as a region for extracting light without changing the wavelength.

Further, as a configuration for converting the second light into light, an example of a region in which a dichroic filter that transmits red and green light is formed is shown, but the present invention is not limited to this. Any one dichroic filter may be formed, or dichroic filters of other colors may be replaced or additionally formed.

Further, in addition to the blue laser as the light source, a light source such as a red laser diode may be separately provided.

The color wheel 109 is an example of a second light conversion means. The red (R) region 1091 and the green (G) region 1092 are examples of the “wavelength selection region”, respectively. The light that has passed through the red (R) region 1091 and the green (G) region 1092 is an example of “wavelength selective light”. The transparent region 1093 is an example of a “region having no wavelength selection function”. The rotating body provided with the red (R) region 1091, the green (G) region 1092, and the transparent region 1093 is an example of the “second rotating body”.

Returning to FIG. 1, a drive unit 109 m such as a stepping motor for rotating the color wheel 109 is provided at the axis of the color wheel 109. By rotating the color wheel 109 at a predetermined timing by driving the drive unit 109 m, the incident position of the light from the lens 108 is changed to the red (R) region 1091, the green (G) region 1092, the transparent region 1093, and the diffused region. Switch to any of the four segments of 1094. That is, any of the segments are arranged alternately in time on the optical path of the blue laser light and the fluorescence. Further, the rotation speed of the phosphor wheel 107 driven by the drive unit 109 m can be changed by controlling the drive unit 109 m.

The blue light is incident on the color wheel 109 at the timing when the diffusion region 1094 is arranged at the incident position of the light from the lens 108. By passing through the diffusion region 1094, the blue light is diffused. As a result, the coherence of blue light, that is, laser light is lost, and unevenness and speckle appearing on the screen or the like are reduced. The light that has passed through the diffusion region 1094 becomes blue illumination light.

The yellow fluorescence is incident on the color wheel 109 at the timing when the transparent region 1093 or the red (R) region 1091 is arranged at the incident position of the light from the lens 108. At the timing when the transparent region 1093 is arranged, yellow light is obtained with the maximum brightness. The light that has passed is yellow illumination light. Further, at the timing when the red (R) region 1091 is arranged, red light is obtained. The light that has passed is red illumination light.

The green fluorescence is incident on the color wheel 109 at the timing when the green (G) region 1092 is arranged at the incident position of the light from the lens 108. As a result, the purity of green is adjusted, and the illumination light becomes green.

The light that has passed through each region of the color wheel 109 is incident on the light tunnel 110.

The light tunnel 110 is a cylindrical member having a hollow inside. Each illumination light incident on the light tunnel 110 is repeatedly reflected inside the light tunnel 110, so that the illuminance distribution becomes uniform at the exit of the light tunnel 110. That is, the light tunnel 110 has a function as an illuminance equalizing means for reducing the unevenness of the amount of each illumination light. Instead of the light tunnel 110, another illuminance equalizing means such as a fly-eye lens may be adopted.

Each illumination light whose illuminance distribution is made uniform through the light tunnel 110 is relayed by the lens group 111, reflected by the mirror group 112, and irradiated to the image forming element 113.

The image forming element 113 is an element that forms a color projection image by controlling the gradation of each illumination light for each pixel. The image forming element 113 can be configured by, for example, a DMD (Digital Micromirror Device). The DMD has pixel-by-pixel micromirrors, each of which can maintain any of the two different angles.

That is, each of the DMD micromirrors has an angle (ON state) in which each illumination light is reflected toward the projection optical unit 200 and an angle (OFF state) in which each illumination light is reflected toward an internal absorber and not emitted to the outside. It becomes one of the states (states). This makes it possible to control the light emitted to the projection optical unit 200 for each pixel to be displayed. Further, in the DMD, the gradation can be expressed for each pixel to be displayed by adjusting the time ratio of the ON state of each micromirror by the pulse width modulation method (PWM method).

The image forming element 113 is not limited to the DMD, and for example, a liquid crystal display or the like may be used as long as it is an element capable of forming a color projection image by controlling the gradation of the illumination light for each pixel.

In the image projection device 1 of the present embodiment, the yellow, red, green, and blue illumination lights are incident on the image forming element 113 in a time division in synchronization with the timing of image formation by the image forming element 113. Then, after the gradation is controlled for each display pixel by the image forming element 113, it is projected onto a screen or the like by the projection optical unit 200. Due to the afterimage phenomenon of the eyes, a color image can be visually recognized on a screen or the like.

The image forming element 113 is arranged on the optical path defined by the light tunnel 110, the lens group 111, and the mirror group 112.

Here, an example of an image forming method by the image forming unit 100 will be described with reference to the timing chart of FIG.

In FIG. 5, items are shown in the leftmost column. As items, "ratio of light source output", "segment of phosphor wheel", "segment of color wheel", "color in image forming element", and "color of image" are shown.

The arrows on the horizontal axis represent the time axis. FIG. 5 shows a transition in which an image of each color is formed within one cycle of the frame rate (fps: frame per second) of the image. For example, if the frame rate is 120 fps, the transition in the period of 8.3 ms corresponding to one cycle is shown.

The "ratio of light source outputs" indicates the magnitude of the output of the light source 101 for each color of the projected image. However, the unit of "ratio of light source output" is%, which is a ratio to the representative value of the light source output. Therefore, the value obtained by multiplying the representative value of the light source output by the "ratio of the light source output" is the output of the light emitted from the light source. The unit of the representative value of the light source output is, for example, watts.

The "ratio of light source outputs" is switched according to the color of the image formed by the image forming unit 100.

The "ratio of light source output" also differs depending on the setting such as the hue of the formed image. For example, when the user adjusts the hue or the like via the operation unit of the image projection device 1, the "ratio of the light source output" for each color of the image becomes a different value according to the adjustment result.

The “fluorescent wheel segment” indicates the type of segment of the phosphor wheel 107 arranged at the incident position of the light from the lens group 106.

“Color wheel segment” indicates the type of segment of the color wheel 109 arranged at the incident position of the light from the lens 108.

“Color in the image forming element” indicates a color corresponding to the image whose gradation is controlled by the image forming element 113.

"Image color" indicates the color of the image formed by the image forming unit 100. The light source 101 is in the lit state (ON) during the period in which the yellow, red, blue, and green images are taken out in a time-division manner.

In FIG. 5, at the timing of forming the yellow image, the light source 101 emits light at 100% output. When the light from the light source 101 is incident on the phosphor wheel 107, the yellow (Y) phosphor region 1071 is arranged at the incident position of the light from the lens group 106. As a result, yellow fluorescence excited by the blue laser light is emitted.

The yellow fluorescence is incident on the color wheel 109 via a predetermined optical system described with reference to FIG. When the yellow fluorescence is incident on the color wheel 109, the transparent region 1093 is arranged at the incident position of the light from the lens 108. The yellow fluorescence passes through the transparent region 1093, is taken out as yellow illumination light, and enters the light tunnel 110.

The yellow illumination light passes through a predetermined optical system described with reference to FIG. 1 and is incident on the image forming element 113 during the period when the yellow image is formed. As a result, a yellow image is formed and the projection optical unit 200 is irradiated with the projection optical unit 200.

At the timing of forming the red image, the light source 101 emits light at 90% output. When the light from the light source 101 is incident on the phosphor wheel 107, the yellow (Y) phosphor region 1071 is arranged at the incident position of the light from the lens group 106. As a result, yellow fluorescence excited by the blue laser light is emitted.

The yellow fluorescence is incident on the color wheel 109 via a predetermined optical system described with reference to FIG. When the yellow fluorescence is incident on the color wheel 109, the red (R) region 1091 is arranged at the incident position of the light from the lens 108. The yellow fluorescence passes through the red (R) region 1091 and is taken out as red illumination light and is incident on the light tunnel 110.

The red illumination light passes through a predetermined optical system described with reference to FIG. 1 and is incident on the image forming element 113 during the period when the red image is generated. As a result, a red image is formed and the projection optical unit 200 is irradiated with the projection optical unit 200.

At the timing of forming the blue image, the light source 101 emits light at 70% output. When the light from the light source 101 is incident on the phosphor wheel 107, the reflection surface region 1073 is arranged at the incident position of the light from the lens group 106.

The reflected blue light enters the color wheel 109 via a predetermined optical system described with reference to FIG. When the blue light is incident on the color wheel 109, the diffusion region 1094 is arranged at the incident position of the light from the lens 108. The blue light is diffused in the diffusion region 1094, taken out as blue illumination light, and incident on the light tunnel 110.

The blue illumination light passes through a predetermined optical system described with reference to FIG. 1 and is incident on the image forming element 113 during the period when the blue image is formed. As a result, a blue image is formed and the projection optical unit 200 is irradiated with the projection optical unit 200.

At the timing of forming the green image, the light source 101 emits light at 80% output. When the light from the light source 101 is incident on the phosphor wheel 107, the green (G) phosphor region 1072 is arranged at the incident position of the light from the lens group 106. As a result, green fluorescence excited by the blue laser light is emitted.

The green fluorescence is incident on the color wheel 109 via a predetermined optical system described with reference to FIG. When the green fluorescence is incident on the color wheel 109, the green (G) region 1092 is arranged at the incident position of the light from the lens 108. The green fluorescence passes through the green (G) region 1092, the purity of the green is adjusted, and it is taken out as green illumination light. Then, it enters the light tunnel 110.

The green illumination light passes through a predetermined optical system described with reference to FIG. 1 and is incident on the image forming element 113 during the period when the green image is formed. As a result, a green image is formed and the projection optical unit 200 is irradiated with the projection optical unit 200.

The above operations are sequentially repeated in chronological order, and images of each color are projected onto a screen or the like by the projection optical unit 200.

In addition, in FIG. 5, as an example, an example in which four colors of yellow, red, blue, and green are sequentially switched at high speed in chronological order to form an image has been described, but the same applies to the case of three colors or five colors. be. Further, the same method can be applied when an image of each color is obtained only by the phosphor wheel 107 without using the color wheel 109.

The light source 101, the phosphor wheel 107, the color wheel 109, the image forming element 113, and the like can be controlled by, for example, a control device 300 provided outside the image projection device 1.

The hardware of the control device 300 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. .. The control device 300 can control the light source 101, the phosphor wheel 107, the color wheel 109, and the image forming element 113 by using the RAM as a work memory according to a program stored in advance in the ROM. The control device 300 may be provided inside the image projection device 1. Further, a part or all of the control processing performed by the CPU may be realized by hardware such as an electronic circuit.

The control device 300 can realize the functional configuration described below by the instruction of the CPU.

An example of the functional configuration of the control device 300 included in the image projection device 1 of the present embodiment will be described with reference to FIG. In FIG. 6, the control device 300 includes an output mode setting unit 301, an output mode detection unit 302, a phosphor wheel control unit 303, a phosphor wheel synchronization detection unit 304, a color wheel synchronization control unit 305, and image formation. It has an element synchronization control unit 306 and an image control unit 307.

The output mode setting unit 301 sets the output mode of the light source 101 according to the image projection mode or the like by the image projection device 1. Examples of the projection mode include a high-luminance mode that emphasizes the brightness of an image, a tint mode that emphasizes the tint of an image, and an eco-mode that emphasizes power consumption. The projection mode is set by the user of the image projection device 1 via the operation unit 308 and stored in the RAM.

The output mode setting unit 301 detects the projection mode with reference to the RAM, and for example, in the case of the high luminance mode, the output mode is set to the first mode in which the output of the light source 101 is large. Further, in the case of the color tint mode or the eco mode, the second mode in which the output of the light source 101 is suppressed is set as compared with the first mode. The projection mode is not limited to the setting by the user, and may be configured to be automatically set according to the ambient brightness of the image projection device 1.

The output mode detection unit 302 detects the output mode set by the output mode setting unit 301. Specifically, the output mode setting unit 301 stores the output mode in the RAM, and the output mode detection unit 302 detects the output mode with reference to the RAM. The output mode detecting unit 302 is an example of the output mode detecting means.

The phosphor wheel control unit 303 controls the drive unit 107m of the phosphor wheel 107 according to the detected output mode. Specifically, the rotation speed of the phosphor wheel 107 by the drive unit 107m is set or changed. The phosphor wheel control unit 303 is an example of "rotation speed control means for changing the rotation speed of the first light conversion means". Further, the rotation speed of the phosphor wheel 107 is an example of "the rotation speed of the first rotating body".

The phosphor wheel synchronization detection unit 304 detects the timing of rotation of the phosphor wheel 107. Specifically, for example, the timing of the rotation origin of the phosphor wheel 107 and the rotation speed are detected by the drive unit 107m.

For example, the phosphor wheel synchronization detection unit 304 monitors the number of drive pulses of the drive unit 107m when the phosphor wheel 107 is rotating, and detects the timing of the rotation origin of the phosphor wheel 107. For example, when the number of pulses per rotation of the drive unit 107m is 3600 pulses, the timing of the rotation origin is when the number of drive pulses is a multiple of 3600 pulses.

However, the present invention is not limited to this, and the timing of the rotation origin may be detected by the origin sensor provided in the drive unit 107m. Further, a mark may be provided in a part of the circumferential direction of the phosphor wheel 107, and the reflected light when the mark is irradiated with light may be detected to detect the rotation origin. A notch may be provided instead of the mark, and the transmitted light when the notch is irradiated with light may be detected. Further, an angle sensor such as a rotary encoder may be provided in the drive unit 107 m and detected by the rotary encoder output.

Further, the phosphor wheel synchronization detection unit 304 receives the rotation speed data of the phosphor wheel 107 from the phosphor wheel control unit 303, and detects the rotation speed of the phosphor wheel 107.

The timing of each segment of the phosphor wheel 107 with respect to the origin of rotation is known from the origin of rotation and the arrangement of each segment. Therefore, by detecting the timing of the rotation origin of the phosphor wheel 107 and the rotation speed, the timing of light conversion by the phosphor wheel 107 can be detected. The phosphor wheel synchronization detection unit 304 is an example of "means for detecting the rotation timing of the first rotating body". The detection of the rotation origin of the phosphor wheel 107 is an example of "detection of a predetermined position of the first rotating body".

The color wheel synchronization control unit 305 controls the timing of rotation of the color wheel 109, and synchronizes the rotation of the color wheel 109 with the rotation of the phosphor wheel 107. Specifically, for example, the timing and the number of rotations of the rotation origin of the color wheel 109 are controlled by the drive unit 109m, and the timing and the number of rotations of the rotation origin of the color wheel 109 and the phosphor wheel 107 are matched.

For example, the color wheel synchronization control unit 305 receives a signal indicating the timing of the rotation origin of the phosphor wheel 107 from the phosphor wheel synchronization detection unit 304. Further, the color wheel synchronization control unit 305 monitors the number of drive pulses of the drive unit 109m when the color wheel 109 is rotating, and detects the timing of the rotation origin of the color wheel 109. For example, when the number of pulses per rotation of the drive unit 109m is 3600 pulses, the timing of the rotation origin is when the number of drive pulses is a multiple of 3600 pulses. Then, the timing of the rotation origin of the color wheel 109 is adjusted so that the timing of the rotation origin of the color wheel 109 and the phosphor wheel 107 are matched.

However, the detection of the timing of the rotation origin of the color wheel 109 is not limited to the above. It may be configured by the origin sensor provided in the drive unit 109m. Further, a mark may be provided in a part of the color wheel 109 in the circumferential direction, and the reflected light when the mark is irradiated with light may be detected to detect the rotation origin. A notch may be provided instead of the mark, and the transmitted light when the notch is irradiated with light may be detected. Further, an angle sensor such as an encoder may be provided in the drive unit 109 m, and detection may be performed by the output of the encoder.

Further, the color wheel synchronization control unit 305 receives the rotation speed data of the phosphor wheel 107 from the phosphor wheel control unit 303, and matches the rotation speed of the color wheel 109 with this.

The timing of each segment of the color wheel 109 with respect to the origin of rotation is known from the origin of rotation and the arrangement of each segment. Therefore, by controlling the timing of the rotation origin of the color wheel 109 and the number of rotations, the light conversion by the phosphor wheel 107 can be synchronized with the light conversion by the color wheel 109. The color wheel synchronization control unit 305 is an example of "a second synchronization means for synchronizing the rotation of the first rotating body and the rotation of the second rotating body".

The image forming element synchronization control unit 306 controls the timing of image formation of each color by the image forming element 113, and synchronizes the image formation by the image forming element 113 with the rotation of the phosphor wheel 107. Specifically, for example, the start timing of image formation by the image forming element 113 and the frame rate are controlled so that the rotation origin of the drive unit 107m and the timing of starting image formation by the image forming element 113 are matched.

For example, the image forming element synchronization control unit 306 receives a signal indicating the timing of the rotation origin of the phosphor wheel from the phosphor wheel synchronization detection unit 304. By starting the image formation in accordance with this, the rotation origin of the phosphor wheel 107 and the timing of the start of the image formation are matched.

Further, the image forming element synchronization control unit 306 receives the rotation speed data of the phosphor wheel 107 from the phosphor wheel control unit 303, and matches the frame rate of the image forming element 113 with this. To adjust the frame rate, for example, measure the time from the number of clocks of the CPU and the clock cycle, and change the pixel clock cycle of image formation so that the time corresponding to the reciprocal of the frame rate, that is, the frame cycle becomes a predetermined value. Do it at.

Thereby, the image formation by the image forming element 113 can be synchronized with the light conversion by the phosphor wheel 107. The image forming element synchronization control unit 306 is an example of "a first synchronization means for synchronizing the rotation of the first rotating body and the image formation by the image forming element".

The image control unit 307 acquires image data from an external I / F or the like, and controls the gradation of the image forming element 113 for each pixel according to the image data to form an image.

An example of the processing by the control device 300 of the present embodiment will be described with reference to FIG. 7.

First, in step S701, the output mode setting unit 301 detects the projection mode and sets the output mode.

Subsequently, in step S703, the output mode detection unit 302 detects the set output mode.

Subsequently, in step S705, the phosphor wheel control unit 303 sets or changes the rotation speed of the phosphor wheel 107 according to the detected output mode.

Subsequently, in step S707, the phosphor wheel 107 rotates at a set or changed rotation speed.

Subsequently, in step S709, the phosphor wheel synchronization detection unit 304 detects the timing of rotation of the phosphor wheel 107.

Subsequently, in step S711, the color wheel synchronization control unit 305 rotates the color wheel 109 in synchronization with the rotation of the phosphor wheel 107 based on the timing detected by the phosphor wheel synchronization detection unit 304.

Subsequently, in step S713, the image forming element synchronization control unit 306 synchronizes with the rotation of the phosphor wheel 107 based on the timing detected by the phosphor wheel synchronization detecting unit 304, and forms an image by the image forming element 113. Let's get started.

Subsequently, in step S715, the image forming element 113 forms an image by controlling the gradation for each pixel according to the image data.

Subsequently, in step S717, the projection optical unit 200 projects an image of a predetermined color on a screen or the like.

The functions and effects of the functional configuration and the processing flow exemplified above will be described.

If the output of the light source 101 is large, the phosphor provided on the phosphor wheel 107 may be damaged by heat generation or the like due to the excitation light. Therefore, for example, when the output mode is the first mode in which the output of the light source 101 is high, the phosphor wheel control unit 303 sets the rotation speed so that the phosphor wheel 107 is rotated at high speed. By rotating the phosphor wheel 107 at high speed, the period during which the excitation light hits the phosphor is shortened, so that damage to the phosphor due to the excitation light is suppressed. This makes it possible to prevent the phosphor from being damaged and the luminous efficiency of the fluorescence from being lowered.

Further, for example, when the output mode is the second mode in which the output of the light source 101 is suppressed, the phosphor wheel control unit 303 rotates the phosphor wheel 107 at a lower speed than in the first mode. Set. As a result, power consumption and noise associated with the rotation of the phosphor wheel 107 are suppressed.

On the other hand, the output of the light emitted from the light source 101 may be detected, and the rotation speed of the phosphor wheel 107 may be changed according to the detected output. For example, a part of the light emitted from the light source 101 is taken out by a half mirror or the like, and the taken out light is received by a PD (Photo Diode) to detect the output of the light emitted from the light source 101. Since the light taken out by the half mirror or the like is a part of the light emitted from the light source 101, the detected output does not show the output of the light emitted from the light source 101 as it is. However, since the two have a substantially linear relationship, the output of the light source 101 can be detected from the output of the PD by grasping this relationship in advance.

Further, the output of the light emitted from the light source 101 may be detected by referring to the current value or the voltage value applied to cause the light source 101 to emit light.

As described above, the phosphor wheel control unit 303 detects the output of the light emitted from the light source 101, and the phosphor wheel control unit 303 rotates the phosphor wheel 107 at a higher speed as the output of the light source 101 increases. To change. By rotating the phosphor wheel 107 at high speed, the period during which the excitation light hits the phosphor is shortened, so that damage to the phosphor due to the excitation light is suppressed. This makes it possible to prevent the phosphor from being damaged and the luminous efficiency of the fluorescence from being lowered.

Further, not limited to the above, the temperature change of the air around the phosphor when the light from the light source 101 is applied to the phosphor of the phosphor wheel 107 is detected, and the phosphor wheel 107 is detected according to the detected output. You may change the number of rotations of. For example, a temperature sensor is provided in the vicinity of the phosphor wheel 107 to detect a temperature change in the air around the phosphor wheel 107 due to irradiation of the phosphor of the phosphor wheel 107 with light from the light source 101. In addition, "around the phosphor" is synonymous with "around the phosphor wheel 107". Further, the "periphery of the phosphor" is "a space within a range in which the temperature change of the air caused by the irradiation of the phosphor from the light source 101 with light can be detected". As long as the temperature change of the air can be detected, the temperature sensor may be provided at a position away from the phosphor wheel 107, not limited to the vicinity of the phosphor wheel 107.

The phosphor wheel control unit 303 changes the rotation speed of the phosphor wheel 107 so that the temperature change around the phosphor wheel 107 is detected and the phosphor wheel 107 is rotated at a higher speed as the temperature change is larger. Since the phosphor wheel 107 rotates at high speed, the period during which the excitation light hits the phosphor is shortened, so that the temperature rise of the phosphor due to the excitation light is suppressed, and the damage of the phosphor is suppressed. This makes it possible to prevent the phosphor from being damaged and the luminous efficiency of the fluorescence from being lowered.

On the other hand, when the rotation speed of the phosphor wheel 107 is changed according to the output mode of the light source 101 or the like as described above, the timing of light conversion by the phosphor wheel 107 is changed. As a result, the predetermined segment of the color wheel 109 may not be arranged at the incident position of the light from the lens 108 at the timing when the light converted by the phosphor wheel 107 is incident. Then, the segment of the phosphor wheel 107 and the segment of the color wheel 109 do not form a desired combination, and the illumination light having a desired color cannot be obtained.

Further, when the rotation speed of the phosphor wheel 107 is changed, the color of the light illuminated by the image forming element 113 and the image formed by the image forming element 113 do not match, and an image having a desired tint is obtained. You will not be able to obtain it.

In the present embodiment, as described above, the rotation of the color wheel 109 is synchronized with the rotation of the phosphor wheel 107 based on the timing detected by the phosphor wheel synchronization detection unit 304. In other words, the light conversion by the phosphor wheel 107 and the light conversion by the color wheel 109 are synchronized.

Further, based on the timing detected by the phosphor wheel synchronization detection unit 304, the image formation by the image forming element 113 is synchronized with the rotation of the phosphor wheel 107. In other words, the light conversion by the phosphor wheel 107 and the image formation by the image forming element 113 are synchronized.

As a result, the segment of the phosphor wheel and the segment of the color wheel 109 can be made into a desired combination, and the light of a desired color can be illuminated on the image forming element 113. Further, the image forming element 113 can form an image matching the color of the illuminated light and irradiate the projection optical unit 200 with the image forming element 113.

Therefore, by changing the rotation speed of the phosphor wheel 107, it is possible to prevent damage to the phosphor wheel 107 and decrease in the luminous efficiency of fluorescence, and to suppress power consumption and noise associated with the rotation of the phosphor wheel 107, as desired. An image of color can be obtained. In other words, it is possible to prevent the destruction of the phosphor and the decrease in the fluorescence efficiency due to the excitation light without disturbing the formed image.

FIG. 8 shows an example of the operation specifications of the image projection device 1 in the present embodiment. FIG. 8 shows specifications of "light source output mode", "light source output", "fluorescent wheel rotation speed", "color wheel rotation speed", "fan rotation speed", and "noise" according to the "light source output mode". An example is shown.

In FIG. 8, the “light source output mode” is an item set by the output mode setting unit 301. For example, the first mode is a high-luminance mode, and the second mode is a mode in which color is emphasized.

The "light source output" is the output of the light source 101 corresponding to the "light source output mode". Since high brightness is required in the first mode, a large output is set for the second mode.

This "light source output" is a typical value, and the unit is watts. The output of the light source 101 actually obtained is obtained by multiplying this "light source output" by the ratio shown in the item "ratio of light source output" in FIG. In both the first mode and the second mode, the "ratio of light source outputs" can be switched in chronological order according to the settings such as the hue of the image.

The "fluorescent wheel rotation speed" is the rotation speed of the phosphor wheel 107. Since the light source output is large in the first mode, the rotation speed of the phosphor wheel 107 is set high.

The "color wheel rotation speed" is the rotation speed of the color wheel 109, which is the same as the rotation speed of the phosphor wheel 107. In the above, the method of receiving the rotation speed data of the phosphor wheel 107 and matching the rotation speed of the color wheel 109 is shown. In this way, the rotation speed of the color wheel 109 is set in advance according to the "light source output mode". You may decide.

As for the frame rate of image formation by the image forming element 113, as described above, the data of the rotation speed of the phosphor wheel 107 is received and the frame rates are matched. However, the frame rate may be determined in advance according to the "light source output mode". For example, it is 120 fps in the first mode and 60 fps in the second mode.

The "fan rotation speed" is the rotation speed of the fan for cooling the light source 101, the phosphor wheel 107, or the color wheel 109. The details of the "fan rotation speed" will be described later.

"Noise" is an allowable value of loudness generated by the rotation of the phosphor wheel 107, the color wheel 109, or the fan. In the first mode, since the phosphor wheel 107 and the like are rotated at high speed, a large noise is allowed as compared with the second mode.

In the above, the high-luminance mode, the tint mode, and the eco-mode are shown as the projection modes, but the projection mode is not limited to these, and more modes may be set. Further, although the first and second modes are shown as the light source output modes, more output modes may be provided.

<Second embodiment>
Next, an example of the image projection device according to the second embodiment will be described with reference to FIGS. 9 to 11. In the second embodiment, the description of the same components as those in the above-described embodiment may be omitted.

FIG. 9 is a schematic diagram illustrating the image projection device 1a of the second embodiment. The image projection device 1a has an optical sensor 114 in addition to the device configuration of the first embodiment.

The optical sensor 114 is provided at a position where a part of the substantially parallel light flux from the lens 103 can receive the light reflected by the wavelength selective polarization separating element 104. The optical sensor 114 detects the intensity of the reflected light by the wavelength selective polarization separating element 104. The output of the light source 101 is detected based on the output of the optical sensor 114. Since the light reflected by the wavelength selective polarization separating element 104 is a part of the substantially parallel luminous flux from the lens 103, the detected output does not show the output of the light emitted from the light source 101 as it is. However, since the two have a substantially linear relationship, the output of the light source 101 can be detected from the output of the optical sensor 114 by grasping this relationship in advance.

The optical sensor 114 is, for example, a PD. The output of the optical sensor 114 is A / D (Analog / Digital) converted and input to the control device 300a.

An example of the functional configuration of the control device 300a will be described with reference to FIG. The control device 300a has a light source output detection unit 309 and a storage unit 310 in addition to the functional configuration of the control device 300. Further, the control device 300a has a phosphor wheel control unit 303a in which some functions are added to the phosphor wheel control unit 303 in the control device 300.

The light source output detection unit 309 is realized by, for example, an optical sensor 114. The storage unit 310 is realized by, for example, an external storage device such as a ROM or a USB (Universal Serial Bus). The phosphor wheel control unit 303a is realized, for example, by the CPU collaborating with the RAM to execute a program stored in the ROM.

The light source output detection unit 309 detects the output of the light source 101 and outputs the detected light source output data to the phosphor wheel control unit 303a. The light source output detection unit 309 is an example of "output mode detection means for detecting the output of the first light".

The storage unit 310 stores data showing the relationship between the output of the light source 101 and the rotation speed of the phosphor wheel 107. This relationship is the relationship between the output of the light source 101 and the rotation speed of the phosphor wheel 107 so that the phosphor of the phosphor wheel 107 is not damaged or the luminous efficiency of the fluorescence is not lowered by the excitation light. Obtained in advance by an experiment or simulation, and stored in the storage unit 310.

The phosphor wheel control unit 303a receives the light source output data from the light source output detection unit 309 and refers to the storage unit 310. Then, the rotation speed of the phosphor wheel 107 according to the light source output data is acquired, and the rotation speed of the phosphor wheel 107 is set or changed.

FIG. 11 shows an example of processing by the control device 300a of the present embodiment.

First, in step S1101, the light source output detection unit 309 detects the output of the light source 101 and outputs the light source output data to the phosphor wheel control unit 303a.

Subsequently, in step S1103, the phosphor wheel control unit 303a refers to the storage unit 310 and acquires the rotation speed of the phosphor wheel 107 according to the light source output data.

Subsequently, in step S1105, the phosphor wheel control unit 303a sets or changes the rotation speed of the phosphor wheel 107.

Subsequently, in step S1107, the phosphor wheel 107 rotates at a set or changed rotation speed.

Subsequently, in step S1109, the phosphor wheel synchronization detection unit 304 detects the timing of rotation of the phosphor wheel 107.

Subsequently, in step S1111, the color wheel synchronization control unit 305 rotates the color wheel 109 in synchronization with the rotation of the phosphor wheel 107 based on the timing detected by the phosphor wheel synchronization detection unit 304.

Subsequently, in step S1113, the image forming element synchronization control unit 306 starts image formation on the image forming element 113 in synchronization with the rotation of the phosphor wheel 107 based on the timing detected by the phosphor wheel synchronization detecting unit 304. Let me.

Subsequently, in step S1115, the image forming element 113 forms an image by controlling the gradation for each pixel according to the image data.

Subsequently, in step S1117, the projection optical unit 200 projects an image of a predetermined color on a screen or the like.

According to this embodiment, the rotation speed of the phosphor wheel 107 can be controlled in more detail according to the output of the light source 101. As a result, it is possible to perform more detailed control for suppressing the destruction of the phosphor due to the excitation light and the decrease in the fluorescence efficiency, and suppressing the noise and the power consumption without disturbing the formed image. The other effects are the same as those described in the first embodiment.

Further, in the above, the storage unit 310 stores data showing the relationship between the output of the light source 101 and the rotation speed of the phosphor wheel 107, but the present invention is not limited to this. For example, the threshold value of the light source output for switching the above-mentioned output mode to the first mode or the second mode may be obtained in advance and stored in the storage unit 310. In this case, the phosphor wheel control unit 303a refers to the storage unit 310 and acquires an output mode based on the detected light source output. Then, the rotation speed of the phosphor wheel 107 is set or changed according to the output mode.

Further, in the above, the optical sensor 114 is provided at a position where a part of the substantially parallel luminous flux from the lens 103 can receive the light reflected by the wavelength selective polarization separating element 104, and the output of the light source 101 is detected. Not limited. As long as the output of the light source 101 can be directly or indirectly detected, the position where the optical sensor 114 is installed may be arbitrary.

Further, in the above, an example in which the light source output detection unit 309 is realized by the optical sensor 114 is shown, but by grasping the drive voltage or the drive current of the light source 101 from the control signal of the light source 101, the light source output detection unit 309 can be used. It may be realized.

<Third embodiment>
Next, an example of the image projection device according to the third embodiment will be described with reference to FIGS. 12 to 14. In the first and second embodiments, the description of the same components as those of the embodiments already described may be omitted.

FIG. 12 is a schematic diagram illustrating the image projection device 1b of the third embodiment. The image projection device 1b has a fan 101a in addition to the device configuration of the second embodiment.

The fan 101a is a device for flowing air by rotating an impeller provided inside. Hereafter, the rotation of the impeller is simply displayed as the rotation of the fan. A drive unit 101am such as a stepping motor for rotating the fan 101a is provided at the axis of the fan 101a. The fan 101a rotates at a predetermined rotation speed by being driven by the driving unit 101am.

The air blown by the rotation of the fan 101a gives a flow to the air in the vicinity of the light source 101, and the light source 101 is cooled by heat exchange using the air as a medium. The amount of air blown by the fan 101a can be controlled by the rotation speed.

Here, the light source 101 changes its calorific value according to the output of the emitted light. When the amount of heat generated becomes large, the output of the light emitted from the light source 101 may become unstable, the temperature inside the image projection device 1b may rise, and the phosphor of the phosphor wheel 107 may be easily damaged. be. The fan 101a has a function of cooling the generated light source 101 by blowing air to prevent these problems.

An example of the functional configuration of the control device 300b that controls the image projection device 1b will be described with reference to FIG. The control device 300b has a fan control unit 311 and a storage unit 312 in addition to the functional configuration of the control device 300a.

The storage unit 312 is realized by, for example, an external storage device such as a ROM or USB. The fan control unit 311 is realized by the CPU collaborating with the RAM to execute a program stored in the ROM.

The storage unit 312 stores data showing the relationship between the output of the light source 101 and the rotation speed of the fan 101a. This relationship is the relationship between the output of the light source 101 and the rotation speed of the fan 101a so as not to cause instability of the output of the light emitted from the light source 101 or damage to the phosphor of the phosphor wheel 107. Obtained in advance by an experiment or simulation, and stored in the storage unit 312.

The fan control unit 311 receives the light source output data from the light source output detection unit 309 and refers to the storage unit 312. Then, the rotation speed of the fan 101a corresponding to the light source output data is acquired, and the rotation speed of the fan 101a is set or changed.

FIG. 14 shows an example of processing by the control device 300b of the present embodiment.

First, in step S1401, the light source output detection unit 309 detects the output of the light source 101 and outputs the light source output data to the fan control unit 311.

Subsequently, in step S1403, the fan control unit 311 refers to the storage unit 312 and acquires the rotation speed of the fan 101a according to the light source output data.

Subsequently, in step S1405, the fan control unit 311 sets or changes the rotation speed of the fan 101a.

Subsequently, in step S1407, the fan 101a rotates at a set or changed rotation speed.

According to the present embodiment, by controlling the rotation speed of the fan 101a according to the output of the light source 101 and appropriately cooling the light source 101, the output of the light emitted from the light source 101 becomes unstable or fluorescence. It is possible to prevent a problem that the phosphor of the body wheel 107 is easily damaged. The other effects are the same as those described in the first and second embodiments.

Further, in the above, the fan 101a for cooling the light source 101 is shown as an example, but a fan for cooling the phosphor wheel 107 and the color wheel 109 may be provided. The phosphor wheel 107 and the color wheel 109 also generate heat due to rotation. As a result, the temperature inside the image projection device 1b rises, and the phosphor of the phosphor wheel 107 may be easily damaged. By appropriately cooling the phosphor wheel 107 and the color wheel 109 with a fan, such a problem can be prevented.

Here, FIGS. 15 to 16 show an example of the relationship between the output of light emitted from the light source 101, the rotation speed of the phosphor wheel 107, and the rotation speed of the fan 101a. The horizontal axis shows the output of the light source 101, and the output on the left side is large, and the output becomes smaller toward the right side.

The two-dot chain line shows a case where the rotation speed of the phosphor wheel 107 is linearly changed according to the output of the light source 101. On the other hand, the solid line shows a case where the rotation speed of the phosphor wheel 107 is changed in a non-linear, that is, discontinuous stepwise step according to the output of the light source 101. In actual control, the change in the rotation speed of the phosphor wheel 107 is often stepwise, so the relationship between the output of the light source 101 and the rotation speed of the phosphor wheel 107 is non-linear as shown by the solid line. That is, it often becomes discontinuous and stepwise. The dotted line shows the rotation speed of the fan.

In FIG. 15, when the rotation speed of the fan 101a is linearly changed with respect to the output of the light source 101, the phosphor wheel 107 is overcooled in the portion where the solid line is above the two-dot chain line (the rotation speed is high). become. Further, in the portion where the solid line is below the two-dot chain line (the rotation speed is low), the phosphor wheel 107 is in a state of insufficient cooling.

FIG. 16 shows a case where the rotation speed of the fan 101a is discontinuously changed in a sawtooth shape with respect to the output of the light source 101. By changing the rotation speed of the fan 101a discontinuously in a sawtooth shape in this way, it is possible to prevent the phosphor wheel 107 from being overcooled or undercooled. This makes it possible to appropriately cool the phosphor wheel 107 and prevent an increase in power consumption and noise in an overcooled state.

<Fourth Embodiment>
Next, an example of the image projection device according to the fourth embodiment will be described with reference to FIGS. 17 to 20. In the first to third embodiments, the description of the same components as those of the above-described embodiments may be omitted.

The image projection device 1c according to the fourth embodiment has a temperature sensor that detects the temperature around the image forming unit.

FIG. 17 is a schematic view showing a state in which the image projection device 1c of the fourth embodiment is observed from the outside. In FIG. 17, the image projection device 1c projects the image P on the screen S. The image projection device 1c has a temperature sensor 116 on the outside of the housing 115 constituting the image projection device 1c. The temperature sensor 116 detects the temperature around the image forming unit included in the image projection device 1c. The temperature sensor 116 is an example of "temperature detection means".

FIG. 18 is a schematic diagram illustrating the image projection device 1c of the fourth embodiment. The image projection device 1c has a fan 107a in addition to the device configuration of the third embodiment.

Like the fan 101a, the fan 107a is a device that allows air to flow by rotating an impeller provided inside. It rotates at a predetermined rotation speed by driving a drive unit 107am such as a stepping motor. The air blown by the rotation of the fan 107a gives a flow to the air in the vicinity of the phosphor wheel 107, and the phosphor wheel 107 is cooled by heat exchange using the air as a medium.

By the way, the temperature inside the image projection device 1c changes according to the temperature around the image forming unit. Therefore, the phosphor of the phosphor wheel 107 may be easily damaged due to an increase in the ambient temperature of the image forming unit. In the present embodiment, the temperature sensor 116 detects the temperature around the image forming unit, and the rotation speed of the fan 107a is changed according to the detected temperature. This appropriately cools the phosphor wheel 107 and prevents the above-mentioned problems.

An example of the functional configuration of the control device 300c that controls the image projection device 1c will be described with reference to FIG. The control device 300c has a temperature detection unit 313 and a storage unit 314 in addition to the functional configuration of the control device 300b. Further, the control device 300c has a fan control unit 311a to which some functions are added to the fan control unit 311 in the control device 300b.

The storage unit 314 is realized by, for example, an external storage device such as a ROM or USB. The fan control unit 311a is realized by the CPU collaborating with the RAM to execute a program stored in the ROM.

The storage unit 314 stores data showing the relationship between the output of the temperature sensor 116 and the rotation speed of the fan 101a. This relationship is the relationship between the output of the temperature sensor 116 and the rotation speed of the fan 101a so as not to cause damage to the phosphor of the phosphor wheel 107. Obtained in advance by an experiment or simulation, and stored in the storage unit 314.

The fan control unit 311a receives the temperature data from the temperature detection unit 313 and refers to the storage unit 314. Then, according to the temperature data, the rotation speed of the fan 107a satisfying the above conditions is acquired, and the rotation speed of the fan 107a is set or changed.

FIG. 20 shows an example of processing by the control device 300c of the present embodiment.

First, in step S2001, the temperature detection unit 313 detects the temperature around the image forming unit and outputs the temperature data to the fan control unit 311a.

Subsequently, in step S2003, the fan control unit 311a refers to the storage unit 314 and acquires the rotation speed of the fan 107a according to the temperature data.

Subsequently, in step S2005, the fan control unit 311a sets or changes the rotation speed of the fan 107a.

Subsequently, in step S2007, the fan 107a rotates at a set or changed rotation speed.

According to the present embodiment, the rotation speed of the fan 107a is controlled according to the temperature around the image forming unit detected by the temperature sensor 116, and the phosphor wheel 107 is appropriately cooled to fluoresce the phosphor wheel 107. It is possible to prevent problems such as the body being easily damaged. The other effects are the same as those described in the first to third embodiments.

Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various aspects are described within the scope of the gist of the present invention described in the claims. It can be transformed and changed.

The image forming unit of each embodiment can be used for a projector which is an example of an image projection device, but is not limited to this, and may be used for, for example, a head-up display, a head-mounted display, or the like.

1,1a, 1b, 1c Image projection device 100, 100a, 100b, 100c Image forming unit 101 Light source 101a, 107a Fan 102, 103, 108 Lens 104 Wavelength selective polarization separation element 105 1/4 wave plate 106, 111 Lens group 107 Fluorescent wheel (an example of the first light conversion means)
107m, 109m, 101am, 107am Drive unit 109 color wheel (example of second optical conversion means)
110 Light tunnel 112 Mirror group 113 Image forming element 114 Optical sensor (an example of output mode detection means)
115 Housing 116 Temperature sensor (an example of temperature detection means)
200 Projection optical unit 300, 300a, 300b, 300c Control device 301 Output mode setting unit 302 Output mode detection unit 303 Fluorescent wheel control unit 304 Fluorescent wheel synchronization detection unit 305 Color wheel synchronization control unit 306 Image forming element synchronization control unit 307 Image control unit 308 Operation unit 309 Light source output detection unit 310, 312, 314 Storage unit 311 311a Fan control unit 313 Temperature detection unit 1071, 1072 Yellow (Y) phosphor, Green (G) phosphor 1073 Reflective surface area 1091 Red (R) region 1092 Green (G) region 1093 Transparent region 1094 Diffusion region

Japanese Unexamined Patent Publication No. 2011-215332

Claims (12)

A light source that emits the first light,
A first rotating body having a phosphor region and a region without a phosphor, wherein the fluorescent light fluorescent from the first light in the phosphor region and the first rotating body passing through the region without the phosphor. A first light conversion means for converting one light into a second light containing at least one.
An image forming element that modulates the second light to form an image,
Rotation that changes the rotation speed of the first rotating body according to the output of the first light emitted from the light source or the temperature change of the air around the phosphor region due to the irradiation of the first light. Number control means and
Based on the timing of rotation of the first rotating body detected based on the detection of a predetermined position in the first rotating body, the rotation of the first rotating body and the image formation by the image forming element are synchronized. An image forming unit characterized by having a first synchronization means. A light source that emits the first light,
A first rotating body having a phosphor region and a region without a phosphor, wherein the fluorescent light fluorescent from the first light in the phosphor region and the first rotating body passing through the region without the phosphor. A first light conversion means for converting one light into a second light containing at least one.
A second rotating body having a wavelength selection region and a region having no wavelength selection function, the wavelength selection light having the wavelength selection of the second light in the wavelength selection region and the region having no wavelength selection function. A second light conversion means for converting the second light that has passed through the process into a third light containing at least the above-mentioned second light.
An image forming element that modulates the third light to form an image,
The rotation speed that changes the rotation speed of the first rotating body according to the output of the first light emitted from the light source or the temperature change of the air around the phosphor due to the irradiation of the first light. Control means and
Based on the timing of rotation of the first rotating body detected based on the detection of a predetermined position in the first rotating body, the rotation of the first rotating body and the image formation by the image forming element are synchronized. The first synchronization means and
Based on prior Symbol timing, the image forming unit and having a second synchronizing means for synchronizing the rotation of the rotary and the second rotary member of said first rotating body. The second light conversion means is a color wheel in which a rotating body is provided with a wavelength selection region and a region having no wavelength selection function in the circumferential direction, and is converted into the third light by rotation. The image forming unit according to claim 2, wherein the image forming unit is characterized in that. The first light conversion means is a phosphor wheel in which a rotating body is provided with a phosphor region and a region not provided with the phosphor in the circumferential direction, and is converted into the third light by rotation. The image forming unit according to claim 2 or 3 , wherein the image forming unit is characterized in that. It has an output mode detecting means for detecting the output mode of the light source, and has an output mode detecting means.
The image forming unit according to claim 4, wherein the phosphor wheel changes the rotation speed of the phosphor wheel according to the detected output mode. The output mode detecting means detects the output of the first light.
The image forming unit according to claim 5. It has a fan that cools at least one of the light source, the first light conversion means, or the second light conversion means by rotating at a predetermined rotation speed and blowing air.
The image forming unit according to any one of claims 2 to 6, wherein the fan changes the rotation speed of the fan according to the output of the first light. It has a fan that cools at least one of the light source, the first light conversion means, or the second light conversion means by rotating at a predetermined rotation speed and blowing air.
One of claims 4 to 6, wherein the fan changes the rotation speed of the fan according to the output of the first light or the rotation speed of the first light conversion means. The image forming unit described in. The image forming unit according to claim 7, wherein the fan changes the rotation speed of the fan discontinuously. It has a temperature detecting means for detecting the temperature around the image forming unit.
The image forming unit according to any one of claims 7 to 9, wherein the fan changes the rotation speed of the fan based on the detected temperature. An image projection apparatus having the image forming unit according to any one of claims 1 to 10. The process of emitting the first light by the light source and
The first rotating body having a phosphor region and a region without a phosphor is used, and the fluorescent light obtained by fluorescing the first light in the phosphor region and the first one passing through the region without the phosphor. And the process of converting to a second light containing at least
Using a second rotating body having a wavelength selection region and a region having no wavelength selection function, a wavelength selection light in which the second light is wavelength-selected in the wavelength selection region and a region having no wavelength selection function are separated. A step of converting the second light that has passed through the process into a third light containing at least the second light.
A step of modulating the third light by an image forming element to form an image,
A step of changing the number of rotations of the first rotating body according to the output of the first light emitted from the light source or the temperature change of the air around the phosphor region due to the irradiation of the first light. When,
The rotation of the first rotating body and the rotation of the second rotating body are synchronized based on the timing of the rotation of the first rotating body detected based on the detection of the predetermined position in the first rotating body. Process and
Based on prior Symbol timing, an image forming method characterized by comprising the a step of synchronizing the image formation by rotation and the image forming device of the first rotating body.

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