JP2004085752A - Image projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily project a focused, undistorted image without performing adjusting operations on any plane whatever surface is selected for projection. <P>SOLUTION: An image projector 6 has an installation reference surface at a base part, and the installation reference surface is arranged to abut on the surface to be projected (screen 81). An image is projected onto the screen 81 which lies on the same plane as the installation reference surface. Projection luminous flux is emitted in the normal direction of the screen 81 from the opening 10 of the projector 6, and is projected from an oblique upper side to the screen 81 after its optical path is deflected by a reflection mirror 4 attached to an arm 3. The mirror 4 has a free curved surface shape so that the image 5 is projected without distortion. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image projection device that displays an image such as a character, a figure, and a photograph. Further, the present invention relates to an image projection system including an image projection device and a screen.
[0002]
[Prior art]
2. Description of the Related Art In recent years, projectors for projecting images created and processed by a computer or the like or images recorded on a recording medium such as an optical disk or a magnetic tape on a screen or the like and displaying them at a conference or presentation are actively used. It has become so.
[0003]
Such projectors can generally be classified into the following four when classified according to their usage patterns.
[0004]
(1) The projector is moved as necessary, and an image is projected on a screen provided or movable. In such a case, the installation location and installation state of the projector should be adjusted so that the projected image is projected in a desired size, without distortion on the screen, and in focus on the entire screen. Do. An example of a projector used in such a case is an image projection device described in Japanese Patent Application Laid-Open No. 10-206969.
[0005]
(2) The projector is installed and fixed in advance. This is a form often used in conference rooms and show rooms, etc., and the projector is adjusted and fixed in place so that the image is projected on the entire screen without distortion on the provided screen. ing. An example of such a projector is a video display system described in JP-A-2000-314847.
[0006]
(3) This is a so-called rear projection monitor, in which a transmission screen and a projector are housed in the same housing. The projector is adjusted and fixed in the housing so as to project an image focused on the entire screen without distortion on the transmissive screen.
[0007]
(4) A projector is built in the end of the screen, and the projector is pulled out and projected as needed. As such a projector, for example, there is a Wall Display of 3M Corporation in the United States. In the Wall Display, a projector is attached to the tip of a movable arm built in the frame of a whiteboard, and an image is projected on the board surface by pulling out the arm.
[0008]
[Problems to be solved by the invention]
In the case of projecting an image using a projector, in the case of the above (1), the installation location and the installation state of the projector are set so that the image is projected onto the screen in a state where the entire screen is focused without distortion. Needs to be adjusted, and it is not always possible to use it when turning on the power. In some cases, it is necessary to change the layout of a desk or the like in order to install the projector.
[0009]
In the case of (2), the projector is fixed in a predetermined place such as a conference room, and cannot be easily carried and used.
[0010]
Even in the case of (3), it is difficult to move and cannot be easily carried and used.
[0011]
In the projector built into the screen as in (4), the adjustment is relatively easy, but the projector and the screen are integrated, and an image can be projected on a surface other than the integrated screen. Can not.
[0012]
In view of the above problems, the present invention can easily project an in-focus, undistorted image on any plane without requiring adjustment for displaying the image. It is an object of the present invention to provide an image projection device that is easy to use.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a light source, an image display unit illuminated by the light source, an image projection unit for enlarging and projecting image light from the image display unit, and a housing for housing these. An image projection apparatus comprising: an installation reference plane for installing the image projection apparatus, wherein the image projection unit is configured to project an image from a side where the housing is present on a plane substantially the same as the installation reference plane. It is configured to project.
[0014]
With this configuration, a desired projected image can be easily obtained by merely installing the image projecting device on a plane on which an image is to be displayed without selecting a screen. In addition, since the image projection device is installed on the screen surface and is away from the image observer, the image can be observed without being affected by the noise of the cooling fan or the hot air generated by cooling.
[0015]
The invention according to claim 2 is characterized in that the image projecting means is arranged so as to form a predetermined angle with the surface to be projected and face the surface to be projected, and to reflect a projection light beam emitted from the housing toward the surface to be projected. And the reflection mirror has a free-form surface shape.
[0016]
With this configuration, the projection image is projected without distortion.
[0017]
The invention according to claim 3 is characterized by further satisfying the following conditional expression.
H ≦ 2d / 5
However,
H: Height of the image projection device from the projection target surface
d: diagonal length of the projected image
It is.
[0018]
With this configuration, even if the image is projected large, the height of the image projection device does not increase, and the image projection device does not hinder the projection. Further, the image projection device can be easily carried.
[0019]
In the invention according to claim 4, the reflection mirror is replaceable.
[0020]
With this configuration, when changing the size of the projection image, a projection image without distortion can be obtained only by changing the reflection mirror.
[0021]
The invention according to claim 5 has a heat conducting member for dissipating heat generated inside the housing to the surface to be projected.
[0022]
With this configuration, the heat generated by the light source and the like can be efficiently radiated to the outside, and as a result, the size of the fan for cooling can be reduced and the number of rotations can be reduced, so that noise and power consumption can be reduced. I can do it.
[0023]
According to a sixth aspect of the present invention, in the projection device, the imaging device is configured to capture an image of the projection surface, an imaging mirror that guides light from the projection surface to the imaging device, and an optical path that switches an optical path of the imaging mirror. A switching unit is provided, and an imaging mirror can be inserted into the optical path of the image projection unit by operating the optical path switching unit, so that an image of the projection surface can be captured.
[0024]
With this configuration, information (for example, a projected image or characters written on the screen) displayed on the screen can be captured and recorded.
[0025]
According to a seventh aspect of the present invention, in the image projection system including the image projection device and the reflection type screen, the image projection device enlarges and projects the image light from the image display device illuminated by the light source. It has an image projection means, a housing for accommodating them, and an installation reference plane for installation of the image projection apparatus, and the reflection type screen is made of a white Fresnel reflection mirror and a Fresnel reflection mirror made of a colorless and transparent material. The reflective screen is disposed on a plane substantially the same as the installation reference plane, and the image projection means is configured to form an image on the reflective screen from the side where the housing is present. Are projected.
[0026]
With this configuration, an image can be easily projected simply by disposing the image projection device on the reflection type screen, and the projected image is reflected by the reflection screen with a predetermined reflection characteristic, so that a bright projection image can be obtained. Further, since the screen surface is a smooth surface, writing can be performed with a felt pen or the like at the same time as displaying an image.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the following embodiments, the same portions or corresponding portions are denoted by the same reference numerals, and redundant description will be appropriately omitted.
[0028]
FIG. 1 is a diagram illustrating an example of a use state of the image projection device according to the first embodiment of the present invention. The upper part of the figure corresponds to the upper part of the screen or the like. FIG. 2 is a view of the projection state shown in FIG.
[0029]
1 and 2, an installation reference surface 11 for installing the image projection device 6 is provided on a housing main body 1 (hereinafter, referred to as a housing 1) of the image projection device 6, and the installation reference surface 11 is a screen. 81 (projected surface). The screen 81 is a reflection type screen in which a screen curtain material is stuck to a parallel plate material, and the curtain surface is a general curtain surface such as a mat surface or a bead surface. The image projection device 6 is fixed to the wall surface 2 by the fixing member 21 at a position above the screen 81 with the installation reference surface 11 in contact with the screen 81. Note that the image projection device 6 is removable from the wall surface 2.
[0030]
In this embodiment, the installation reference surface 11 is the same as the bottom surface of the housing 1 (in this embodiment, the installation reference surface side of the housing 1 is the bottom surface, and the arm 3 side is the top surface). The bottom surface is flat so as to contact the screen 81. In addition, the installation reference surface 11 is not limited to the bottom surface of the housing 1 and may be configured by other members. For example, a protrusion consisting of three or more points may be provided on the bottom surface of the housing 1 and a plane including the apex of the protrusion may be used as the installation reference plane.
[0031]
The housing for housing the optical member of the image projection device 6 includes the housing 1 and the arm 3 holding the reflection mirror 4. The arm 3 is attached to the housing 1 so as to protrude in the normal direction of the screen 81, and a reflection mirror 4 is housed and held at the tip of the arm 3. The reflection mirror 4 reflects the projection light flux emitted from the housing 1 onto the screen 81 and projects the same, so that the reflection surface is arranged to face the screen 81 downward at a predetermined angle.
[0032]
The projection light beam is emitted from the opening 10 of the housing 1 in a direction away from the screen 81, the optical path is bent by the reflection mirror 4 attached to the arm 3, and is projected obliquely onto the screen 81 from above. To generate a projection image 5.
[0033]
In FIG. 2, reference numeral 91 denotes the spread angle of the projection light beam, and 92 denotes the angle of incidence of the projection light beam on the screen surface 81. In order to suppress the height of the image projection device 6 from the screen surface and obtain a large projection image, it is necessary to increase the spread angle 91 of the projection light beam. However, if the divergence angle 91 of the projection light beam is increased, the projection light beam and the housing 1 interfere with each other. Therefore, it is necessary to increase the incident angle 92 in accordance with the divergence angle 91 of the projection light beam.
[0034]
In general, when the spread angle 91 of the projection light beam and the incident angle 92 of the projection light beam are large, the projected image 5 projected on the screen 81 is greatly distorted by a slight change in the attitude of the image projection device. When setting up, precise adjustment work is required. Specifically, the adjustment work is a focus work, and is a work of adjusting the inclination of the projection device 6 in the vertical direction with respect to the screen surface, the work of adjusting the tilt in the horizontal direction, and the rotation adjustment work using the screen normal as a rotation axis.
[0035]
In the image projection device of the present embodiment, the installation reference plane 11 of the image projection device 6 abuts on the screen surface and is mechanically positioned, so that accurate adjustment work is not required when installing the image projection device, and image projection is not performed. By simply placing the device 6 on the screen 81 (wall surface 2), a focused and undistorted projected image can be obtained. Further, if the image projection device 6 can be installed so as to be in contact with the surface to be projected, the image can be easily projected on any plane.
[0036]
Further, when the surface of the screen 81 is a glossy surface or when the screen 81 is a screen having a high directivity (such as a silver screen), in a general image projection device that projects from the front of the screen, specular reflection light on the screen surface is generated. A hot spot is generated directly in the eyes of an image observer, but in the case of the present embodiment, due to oblique projection, the specularly reflected light is reflected in the lower direction of the screen and does not generate a hot spot. Note that a hot spot is a high-luminance area generated in a part of the projection screen. When this occurs, luminance unevenness occurs in the projection screen, thereby impairing the image quality of the projected image. In severe cases, the image observer feels glare due to the reflected light.
[0037]
Furthermore, since the image projection device 6 is installed on the screen surface and is far away from the image observer, the image observer may feel uncomfortable due to noise from the cooling fan of the image projection device or hot air exhausted. I will not.
[0038]
Next, the configuration of the image projection device 6 will be described. FIG. 3 is a schematic configuration diagram of the inside of the image projection device 6, and mainly illustrates a configuration of the inside of the housing 1.
[0039]
Inside the housing, as an optical member for projecting an image, a light source 60, an illumination optical system 61, a liquid crystal panel 62, a projection optical system 63, and a folding mirror 64 are directed downward from above to the installation reference surface 11 in this order. Are arranged along.
[0040]
The light beam emitted from the light source 60 is converted by the illumination optical system 61 so as to efficiently and uniformly illuminate the liquid crystal panel 62, and illuminates the liquid crystal panel 62.
[0041]
The liquid crystal panel 62 is a transmissive light modulation element in which small apertures called “pixels” capable of electrically controlling the transmittance are two-dimensionally arranged, and by applying an electric signal corresponding to an image to each pixel. Display an image.
[0042]
The image light transmitted through the liquid crystal panel 62 is transmitted through the projection optical system 63, is then bent by the folding mirror 64 in the normal direction of the installation reference plane 11, and emerges from the opening 10 of the housing 1.
[0043]
Since the light source 60, the illumination optical system 61, the liquid crystal panel 62, the projection optical system 63, and the return mirror 64 are arranged on a plane parallel to the installation reference plane 11, the screen of the image projection device 6 (housing 1) is formed. The height from the surface is suppressed so as not to increase. In the embodiment shown in FIG. 3, the optical path from the light source 60 to the folding mirror 64 is on a straight line from above to below. For example, an optical path from the light source 60 to the folding mirror 64 is formed from the back of the paper to the front of the paper. And may be bent as appropriate.
[0044]
Projection light emitted from the opening 10 of the housing 1 is turned toward the screen 81 by the reflection mirror 4 held by the arm 3 to form a projection image on the screen 81.
[0045]
The reflection mirror 4 is a mirror having a free-form surface shape. Note that a free-form surface is a surface that includes a large eccentric aspherical surface and does not have a rotationally symmetric axis near the center of the effective area, and has an aspherical undulation (degree of freedom) instead of a spherical surface. . If the curvature of the reflecting surface is three-dimensionally controlled by using the aspherical undulation of the free-form surface shape, the non-axisymmetric aberration (distortion etc.) caused by oblique projection can be obtained by the inclination of the surface set for each location of the reflecting surface. ) Can be easily corrected. The projected image projected on the screen 81 generally has a trapezoidal distortion as shown in FIG. 5, and this trapezoidal distortion can be corrected by changing the surface shape of the reflection mirror 4 to a free-form surface shape. The free-form surface shape includes a rotating aspherical shape.
[0046]
In the present embodiment, the transmission type liquid crystal panel is used as the image display element. However, a reflection type liquid crystal panel or a reflection type angle modulation type element (for example, DMD (Digital Micromirror Device)) may be used. In FIG. 3, the number of liquid crystal panels is one (single-panel type liquid crystal system). However, for example, an image may be formed using three liquid crystal panels (three-panel type liquid crystal system).
[0047]
The illumination optical system 61 of the present embodiment uses the illumination optical system of the second embodiment described in JP-A-2001-324762. Further, for example, an illumination optical system described in JP-A-1999-64977 can be used for a three-panel liquid crystal system, and an illumination optical system described in JP-A-2001-109062 can be used when a DMD is used for an image display device. It is.
[0048]
The rear projection optical system of Example 1 described in JP-A-2001-264627 is used for the projection optical system 63, the turning mirror 64, and the reflection mirror 4 of the present embodiment. The projection optical system 63 is on the S0 to S16 surfaces of the optical system described in the above publication, the return mirror is on the S17 surface (M1) of the optical system described in the above publication, and the reflecting mirror 4 is on the S18 surface (M2) of the optical system described in the above publication. ). With a height of about 500 mm from the installation reference plane 11 to the tip of the arm 3, it is possible to project a projected image size of 50 inches (diagonal length 1270 mm). In addition, for example, a rear projection optical system described in JP-A-2001-264632 or a rear projection optical system described in JP-A-2001-264634 can be used.
Further, the illumination optical system 61 and the projection optical system 63 are not limited to the optical systems described in the above publication, and any of a refractive optical system, a reflective optical system, and a catadioptric optical system can be applied.
[0049]
Inside the housing 1, a light source drive circuit 65, a liquid crystal panel drive circuit 66, a signal processing circuit 67, a cooling fan 68, an external input circuit 69, a heat transfer member 12, and the like are housed in addition to the above-described optical members.
[0050]
The light source driving circuit 65 is a circuit that supplies a voltage and a current to the light source 60.
[0051]
The liquid crystal panel drive circuit 66 is a circuit that performs an operation for changing the transmittance of each pixel of the liquid crystal panel 62 or that samples an image signal and supplies it to each pixel.
[0052]
The signal processing circuit 67 is a circuit that performs signal processing such as scaling and gamma correction on an externally input image signal. For example, a process of inverting the image data vertically or inverting the image data horizontally is performed according to the projection direction of the image. As described above, the projected image generally has a trapezoidal distortion. However, in order to correct the trapezoidal distortion of the projected image 5 by the signal processing circuit 67, a distortion having a characteristic opposite to that at the time of the projection is given to the image signal in advance. The image signal may be converted.
[0053]
The external input circuit 69 is an interface circuit for transmitting image data created and processed by a computer or the like or image data recorded on a recording medium such as an optical disk or a magnetic tape to the signal processing circuit 67 of the image projection device 6. is there. The image data is received from the external device by a wired or wireless connection with the external device, and is sent to the signal processing circuit 67.
[0054]
The cooling fan 68 emits heat generated by the light source 60 to the outside, or cools the liquid crystal panel 62.
[0055]
The heat conducting member 12 is a metal member that conducts and radiates heat generated by the light source 60, and is made of, for example, a magnesium alloy, an aluminum alloy, copper, brass, iron, stainless steel, or the like. The heat conduction member 12 is arranged close to the light source 60 and is in contact with substantially the entire bottom inner wall surface of the housing 1. The heat conducting member 12 absorbs the heat radiated by the light source 60, conducts the absorbed heat, and radiates heat from the entire surface. Further, the heat conducting member 12 not only dissipates heat but also conducts heat to the projection surface of the image projection device 6 through the housing 1 and the installation reference surface 11, thereby obtaining a greater heat dissipation effect.
[0056]
By providing the heat conducting member 12, the size of the cooling fan 68 can be reduced or the number of rotations can be suppressed, so that noise generated by the cooling fan 68 and power consumption can be reduced. In this embodiment, the heat transfer member 12 is housed in contact with the inside of the housing 1. However, the heat transfer member 12 forms the bottom surface of the image projection device 6, and the outer wall surface may be used as the installation reference surface 11. Good.
[0057]
Next, the structure of the arm 3 will be described. FIG. 13 is a perspective view of the arm 3. The arm 3 includes an incidence part 31, a side part 32, and a reflection mirror support part 33. When viewed from the direction of A shown in FIG. 13, it has a “b-shape” shape, and a region surrounded by the incident part 31, the side part 32, and the reflection mirror support part 33 has a large opening both up and down. . The entrance section 31 is provided with an opening 31A for guiding the projection light reflected by the return mirror 64 (see FIG. 3) to the reflection mirror 4 without blocking.
[0058]
The reflection mirror 4 is attached to the inner surface of the reflection mirror support 33 so that the reflection surface faces the inner surface. The mounting angle of the reflection mirror 4 is set to a predetermined angle so that the projection light reflected by the return mirror 65 is projected onto the screen 81 without being blurred. The connection with the main body of the image projection device 6 is performed by screwing the side portion 32 (not shown).
[0059]
Part or all of the side portion 32 is formed of an elastic portion 32A. The elastic portion 32A is elastically deformed at the time of contact so that the arm 3 is not damaged by contact with a human body or the like at the time of using the image projecting device or the human body is not damaged. Return to the position.
[0060]
The arm 3 has a function of changing the size of the projection screen, and the distance between the housing 1 and the projection surface (the distance between the housing 1 and the reflection mirror 4 and the distance between the reflection mirror 4 and the projection surface). By changing the size, the size of the projection screen can be made variable. When the length of the arm 3 (side portion 32) is increased, a larger projected image can be obtained. The arm 3 can take two or more use positions corresponding to the size of the projection screen. In addition, it is possible to take a storage position that is compact when stored.
[0061]
FIG. 6 is a diagram illustrating an example of an attached state of the arm 3. (A) And (b) is a figure showing the state corresponding to two types of projection screens, (c) is a figure showing the storage state at the time of non-use.
[0062]
The state of (b) represents a state for projecting on a screen smaller than the state of (a). Therefore, the arm 3 is inserted further into the housing 1 than in the state shown in FIG. 3A, and the length of the projecting portion of the arm 3 from the housing 1 is shorter. When the arm 3 is inserted, the folding mirror 64 does not interfere with the arm 3 due to the opening 31A.
[0063]
In the state (c), the arm 3 is stored compactly while avoiding the overhang of the arm 3,
This represents a state in which the direction of insertion into the housing 1 is different from that in use. That is, the arm 3 is inserted into the housing 1 from the incident part 31 in a direction parallel to the installation reference plane 11. A cover (not shown) is provided at a portion of the housing 1 into which the arm is inserted, and when the cover is removed, an opening exists (not shown). The arm 3 is inserted from this opening. When the arm 3 is inserted, the folding mirror 65 and the projection optical system 64 pass through the opening 31A of the arm 3 and are housed in a space surrounded by the side portion 32.
[0064]
The arm 3 is not limited to the shape shown in FIG. 13, but holds the reflection mirror 4 in a predetermined state, does not block the projection light, and sets the projection state shown in (a) and (b) of FIG. Any shape may be used as long as it has a function of not interfering with the components inside the housing 1 in the storage state shown in ()). For example, when viewed from the viewpoint of A in FIG. 13 without the incident portion 31, the shape is a “U-shaped” shape, or a shape provided with a beam connecting two side portions.
[0065]
When changing the size of the projection screen, it is preferable to change not only the length of the arm 3 but also the shape of the reflecting surface of the reflecting mirror 4 to a shape suitable for the size of the projection screen. For example, in the state (b) projected onto a small screen, the reflection mirror 41 is used instead of the reflection mirror 4 used in the state (a). The reflection mirror 41 is a reflection mirror designed so as to be optimal for a projection screen corresponding to the state of FIG. By doing so, a projection image with less distortion can be obtained.
[0066]
Inside the housing 1 of the image projection device 6, an imaging unit 71, an optical path switching unit (not shown) indicated by an optical path switching operation 72, and an imaging mirror 73 for capturing and recording an image on the screen surface and the like are further provided. Have. For example, when an image is projected on a whiteboard and characters and figures are written over the projected image, characters and figures written on the whiteboard can be imaged.
[0067]
The imaging unit 71 specifically includes an imaging optical system including an imaging lens and an imaging element, a signal processing circuit that processes an image signal captured by the imaging element, a recording unit that records the signal-processed image signal, A member that includes an image sensor, a control circuit that controls a signal processing circuit, and the like, forms an image on a screen on the image sensor using an image pickup lens, and processes and records the formed image.
[0068]
The optical path switching unit is a member that switches the position of the imaging mirror 73. FIG. 14 is a diagram illustrating an example of the switching operation 72 of the optical path switching unit. (A) shows an example in which the optical path of the imaging mirror 73 is switched by a linear moving mechanism, and (b) shows an example in which the optical path of the imaging mirror 73 is switched by a rotary moving mechanism.
[0069]
In the case of (a), at the time of projecting an image, the imaging mirror 73 is arranged at a position 73A outside the optical path of the projection light. The optical path switching unit has a linear movement mechanism, and at the time of imaging, moves the imaging mirror 73 linearly from a position 73A outside the optical path of the projection light to a position 73B for imaging. The imaging position 73B is a position where the optical axis of the projection light and the optical axis of the imaging unit 71 (imaging lens) intersect on the imaging mirror 73, and is reflected by the optical axis of the projection light and the imaging mirror 73. The position is such that the optical axis of the imaging unit 71 matches. That is, the center of the image projected on the screen 81 is the position where the image is formed substantially at the center of the image sensor included in the imaging unit 71.
[0070]
In the case of (b), at the time of image projection, the imaging mirror 73 is arranged at a position 73A outside the optical path of the projection light. The optical path switching unit has a rotary movement mechanism, and when imaging, rotates the imaging mirror 73 from a position 73A outside the optical path of the projection light to a position 73B for imaging. The rotation center axis is an end of the imaging mirror 73 on the side of the reflecting mirror 64, and is an axis parallel to the reflection surface and perpendicular to the optical axis of the projection light and the optical axis of the imaging unit.
[0071]
The optical path switching unit is a member for moving the imaging mirror 73 from the outside of the optical path of the projection light to the inside of the optical path of the projection light, and the moving form may be any form. In other words, not only the movement form shown in FIGS. 14A and 14B but also a combination of, for example, a linear movement and a rotational movement may be used, and a rotation axis other than the rotation axis shown in FIG. It may be rotated and moved.
[0072]
To image the screen surface, the optical path switching unit is operated to place the imaging mirror 73 at the imaging position 73B in the projection optical path. When the imaging mirror 73 is arranged at the imaging position 73B in the projection optical path, the image on the screen surface is reflected by the reflection mirror 4 and the imaging mirror 73, and is imaged by the imaging device 71. Since the image captured in this way shares the free-form surface reflection mirror 4, it is captured without distortion.
[0073]
If the imaging mirror 73 is a 100% reflection mirror, characters and symbols written on the screen are imaged. If the reflection mirror is a half mirror, the characters and symbols written on the screen and the projected image are imaged simultaneously. The reflecting mirror may be any mirror.
[0074]
Even if the imaging mirror 73 is arranged at the imaging position 73B, the imaging mirror 73 and the arm 3 do not interfere with each other because an opening exists on the upper surface of the arm 3 as shown in FIG.
[0075]
In the present embodiment, the imaging device 71, the optical path switching unit 72, and the imaging mirror 73 are housed in the housing 1 of the image projection device 6, but as shown in FIG. The switching unit 72 and the imaging mirror 73 may be a detachable imaging unit 7, and the imaging unit 7 may be attached to the image projection device 6 and used when an imaging function is required.
[0076]
An opening is provided in the housing 70 so as not to block the projection light beam and interfere with the arm 3, and the opening is formed on the upper surface of the housing 1 of the image projection device 6 so as to coincide with the opening 10 of the image projection device 6. It is attached. At the time of imaging, the optical path switching unit is operated, and the imaging mirror 73 is moved to the imaging position 73B to capture an image of the projection surface.
[0077]
Next, the relationship between the height of the image projection device 6 and the size of the projection image will be described. FIG. 7 shows the relationship between the height of the image projection device 6 from the projection target surface (hereinafter, referred to as the height of the image projection device 6) and the size of the projection image. As shown in FIG. 7, the height of the image projection device 6 is H, and the diagonal length of the projection image is d.
[0078]
As the image projection device, it is desirable that the height of the image projection device be as small as possible, and that the size of the projected image be larger if the height of the image projection device is constant. Generally, to increase the size of a projected image,
(A) The projection optical system is a wider-angle optical system.
(B) Increase the distance (projection distance) between the projection lens and the screen surface.
However, in the method (A), the design of the projection optical system becomes difficult, and the cost of the projection optical system 63 is increased. In the case of the method (B), the height of the image projection device 6 is increased, so that the image projection device 6 enters the field of view of the observer at the time of observing the image and is an obstacle. In addition, the advantage of the present invention, which is an advantage of the present invention, is lost due to the size increase. Further, the increase in the size of the reflection mirror 4 makes it difficult to manufacture the reflection mirror 4 and increases the cost.
[0079]
Therefore, in the present embodiment, in order to avoid an increase in the size of the image projection device 6, the ratio of the height of the image projection device to the size of the projected image is limited.
[0080]
As a result of consideration, the present applicant has found a relational expression of the height of the image projection device with respect to the projection image size. The relational expression is shown in the following expression (1).
H ≦ 2d / 5 (1)
However,
H: Height of image projection device 6
d: diagonal length of projected image
It is.
[0081]
In equation (1), for example, when the projection size is 50 inches (diagonal length 1270 mm), there is a slight difference depending on the positional relationship between the projected image and the image observer, but when the height of the image projection device is 500 mm or more, the arm is used. Although 3 overlaps the projection image and hides a part of the projection image, no problem occurs when the number is less than 3. Further, the arm 3 having a length of 500 mm or more hinders the description, for example, when a presentation is performed in a meeting or the like. The relational expression of the expression (1) is mainly based on whether or not the presence of the arm 3 hinders the explanation in the image observation and the presentation. However, in the design of the projection lens, the expression (1) It is a reasonable relational expression to satisfy the expression. When the size of the projected image is other than 50, the result of Expression (1) can be derived from the result of the same consideration.
[0082]
Next, regarding the projection apparatus of the present embodiment, a projection method other than the projection method described with reference to FIG. 1 will be described. Each of the image projection devices is the same as the image projection device 6 described above.
[0083]
FIG. 8 is a diagram illustrating an example of a projection state of the image projection device 6 different from that in FIG. 1. The screen 82 is a roll-up cloth-like screen different from the case of FIG.
[0084]
Since the cloth projection screen 82 cannot be positioned by abutting the image projection device 6 on the screen surface, the installation auxiliary member 22 is fixed to the wall surface 2 above the screen 82, and the installation auxiliary member 22 is mounted on the installation reference surface of the image projection device 6. 11 is abutted and fixed. As a result, the installation reference plane 11 and the screen 82 are substantially in the same plane, and an in-focus, undistorted image can be projected on the screen 82 without performing adjustment work of the image projection device 6 in projecting the image.
[0085]
The installation assisting member 22 is made of a material having high thermal conductivity and has a large surface area. Thus, the cooling efficiency of the heat conductive member 12 inside the image projection device 6 can be increased.
[0086]
FIG. 9 is a diagram illustrating an example of a projection state of the image projection device 6 different from FIG. The image projection device 6 is placed on a top plate 84 of a table 83 such that the installation reference plane 11 abuts. The image projection device 6 does not need to be fixed on the top plate. The image projection device 6 projects an image using the top plate 84 as a screen. If the top plate 84 is light-colored, it may be used as it is, and if it is dark-colored, simply place light-colored paper or cloth on the top plate, and the top plate 84 functions as a screen. When the image projection device 6 is installed, it is only necessary to install the installation reference surface 11 so as to abut the top plate 84, and it is not necessary to perform focus adjustment, tilt adjustment of the image projection device 6, and the like. Further, regarding projecting an image using the image projection device 6, there is no restriction on the structure of the table 83, and a general table can be used.
[0087]
FIG. 10 is a diagram illustrating an example of a projection state of the image projection device 6 that is still different. In the arrangement shown in FIG. 10, the image projection device 6 is used as a rear projector. The image projection device 6 is attached so that the installation reference surface 11 abuts on the back surface of the top plate 85 of the table 83. The image projection device 6 projects an image using the top plate 85 as a rear screen. The top plate 85 is made of a light transmissive material. It is more preferable that the top plate 85 is made of a milky light diffusing material. In this case, the top plate 85 can be used as a rear projection screen as it is. When the top plate 85 is a transparent member such as glass, it can be used as a screen and an image can be projected simply by placing white paper or cloth on the top plate 85.
[0088]
As described above, since the image projection device 6 is easy to carry, as long as there is a flat surface on which the image projection device 6 can be installed, an image can be projected using the installation surface as a screen. Further, at the time of projection, it is not necessary to adjust the focus or adjust the inclination of the image projection device for projecting the image without distortion.
[0089]
Next, a projection system using the image projection device 6 and the reflection type screen will be described.
[0090]
FIG. 11 shows a projection system according to a second embodiment of the present invention, which comprises an image projection device and a reflective screen. The image projection device 6 has the same configuration as the image projection device described in the first embodiment. This embodiment will be described with reference to FIGS.
[0091]
The image projection device 6 is arranged so that the installation reference plane 11 is in contact with the screen 100, and is fixed to the upper portion of the screen 100 by a fixing member 21. An image is projected on a screen surface 100 which is the same plane as the installation reference surface 11.
[0092]
FIG. 12 shows a cross-sectional view of the screen 100. The screen is composed of a Fresnel member 101 and a transparent member 102. The projection light enters from the right side of FIG. 12, passes through the transparent portion 102, and is reflected by the Fresnel portion 101. The reflected projection light again passes through the transparent portion 102 and reaches the image observer.
[0093]
The Fresnel surface of the Fresnel member 101 is formed such that the light beam reflected by the reflection mirror 4 of the image projection device 6 has a predetermined reflection characteristic after being projected onto a screen. The reflection characteristic is a characteristic determined by the reflection direction of the light beam and the degree of diffusion of the reflected light beam. The Fresnel surface is made of a white member or is coated with white so as to diffuse light, and has a predetermined reflection direction and a predetermined degree of diffusion along with the action of the Fresnel surface shape. The predetermined reflection direction is, for example, the front direction of the screen where the image observer is located. By having such a reflection direction, the image observer can see a bright projected image.
[0094]
The reflection characteristics of the screen can be changed by changing the shape of the Fresnel surface, that is, the inclination of the reflection surface for each location of the screen surface so as to be optimum over the entire screen.
[0095]
The transparent member 102 is made of a colorless and transparent material, and coats the surface of the Fresnel member 101 so as to form a smooth surface on the screen. In order to increase the degree of diffusion of the screen 100, a small amount of a diffusing material may be mixed into the transparent member.
[0096]
In the screen configured as described above, since the projection light flux is diffused and reflected in the front direction of the screen, the projected image can be recognized brightly, and a hot spot due to regular reflection on the screen surface does not occur due to oblique projection. In addition, since the screen surface is formed of a smooth surface, writing can be performed with a felt pen 110 or the like, and the screen 100 can be used as a white board.
[0097]
The image projection device 6 is detachable from the screen 100, and only the screen can be used as a whiteboard. The detached image projection device 6 can be used as shown in FIGS. 1, 8, 9, and 10 described in the first embodiment.
[0098]
In the first embodiment and the second embodiment, the image projection device 6 projects an image from above the screen. However, as shown in FIG. 15A, the image is projected below the screen or as shown in FIG. It goes without saying that the image may be projected from the lateral direction of the screen as described above.
[0099]
As described above, according to the first aspect of the present invention, a projected image can be easily obtained only by installing an image projecting device on a plane on which an image is to be displayed without selecting a screen. Further, since the image projection device is installed on the projection surface and is away from the image observer, the image can be observed without being affected by noise of a cooling fan or hot air generated by cooling.
[0100]
According to the second aspect of the present invention, since a free-form surface is used for the reflection mirror, a projection image without distortion can be obtained.
[0101]
According to the third aspect of the present invention, since the height from the screen surface of the image projection device with respect to the size of the projection image is defined, the height of the image projection device does not increase even when the image is projected large, and the projection time is reduced. The image projection device does not get in the way. In addition, since the size of the image projection device does not increase, it is easy to carry the image projection device.
[0102]
According to the fourth aspect of the present invention, the reflection mirror can be replaced according to the size of the projection screen. Therefore, when changing the size of the projection image, a good projection image without distortion can be obtained simply by replacing the reflection mirror. can get.
[0103]
According to the fifth aspect of the present invention, since the heat generating member for radiating the heat generated inside the casing of the image projection device to the projection surface is provided, the heat generated by the light source or the like is efficiently radiated to the outside. As a result, it is possible to reduce the size and the number of revolutions of the fan for cooling, thereby reducing noise and power consumption.
[0104]
According to the sixth aspect of the present invention, since the image projection device has an imaging function for imaging the screen surface, the image projection device captures an image projected on the screen, a character written on the screen, and the like, and records the image. I can do it.
[0105]
According to the seventh aspect of the present invention, an image can be easily projected simply by arranging the image projection device on the reflective screen, and the projected image is reflected by the reflective screen with a predetermined reflection characteristic, so that a bright projected image can be obtained. Can be Further, since the screen surface is a smooth surface, writing can be performed with a felt pen or the like at the same time as displaying an image.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a use state of an image projection device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a projection state of the image projection apparatus shown in FIG. 1 as viewed from the side of a screen.
FIG. 3 is a schematic configuration diagram of the inside of the image projection device 6.
FIG. 4 is a diagram illustrating an image projection device 6 and an imaging unit 7.
FIG. 5 is a diagram illustrating trapezoidal distortion of a projected image caused by oblique projection.
FIG. 6 is a diagram illustrating a state where the arm 3 is attached to the housing body 1 of the image projection device 6.
FIG. 7 is a diagram illustrating a relationship between a height of the image projection device 6 from a projection target surface and a size of a projection image.
FIG. 8 is a diagram showing an example of a projection state of the image projection device 6.
FIG. 9 is a diagram illustrating an example of a projection state of the image projection device 6.
FIG. 10 is a diagram showing an example of a projection state of the image projection device 6.
FIG. 11 is a diagram illustrating an image projection system including an image projection device and a reflective screen according to a second embodiment of the present invention.
FIG. 12 is a cross-sectional view illustrating a structure of a reflective screen 100.
13 is a perspective view of the arm 3. FIG.
FIG. 14 is a diagram illustrating an example of an optical path switching operation 72 of the optical path switching unit.
FIG. 15 is a diagram illustrating an example of a projection state according to the first embodiment and the second embodiment.
[Explanation of symbols]
1 Case body
2 wall
3 arm
4, 41 Reflection mirror (free-form surface)
5 Projected images
6 Image projection device
7 Imaging unit
11 Installation reference plane
12 Heat transfer member
21 Fixing member
22 Installation auxiliary members
31 Incident part
32 side parts
32A elastic part
33 Reflection mirror support
60 light source
61 Illumination optical system
62 LCD panel
63 Projection optical system
64 folding mirror
65 Light source drive circuit
66 LCD panel drive circuit
67 signal processing circuit
68 Cooling fan
69 External input circuit
70 Housing of Imaging Unit 7
71 Imaging unit
72 Optical path switching unit
73 Imaging mirror
73A Projection position of imaging mirror 73
73B Image pickup position of image pickup mirror 73
81,100 screen
82 cloth screen
83 tables
84 Top plate (opaque)
85 Top plate (light transmissive)
91 Spread angle of projected light beam
92 Incident angle of projection light beam
101 Fresnel
102 Transparent part

Claims (7)

A light source, an image display unit illuminated by the light source, an image projection unit for enlarging and projecting image light from the image display unit, and a housing for housing the same.
It has an installation reference plane for installation of the image projection apparatus, and the image projection means is configured to project an image from a side where the housing exists on a plane substantially the same as the installation reference plane. Image projection device. The image projection means has a reflection mirror disposed at a predetermined angle to the projection surface and opposed to the projection surface, and reflecting a projection light beam emitted from the housing toward the projection surface,
The image projection device according to claim 1, wherein the reflection mirror has a free-form surface shape. The image projector according to claim 2, wherein the following conditional expression is satisfied;
H ≦ 2d / 5
However,
H: height from the projection target surface of the image projection device d: diagonal length of the projected image. The image projection device according to claim 2, wherein the reflection mirror is replaceable. The image projection device according to claim 1, further comprising a heat conducting member for radiating heat generated inside the housing to a projection surface. Imaging means for capturing an image of the projection surface;
An imaging mirror for guiding light from the projection target surface to imaging means,
An optical path switching unit that switches an optical path of the imaging mirror,
2. The image projection apparatus according to claim 1, wherein an imaging mirror is arranged in a projection optical path of the image projection unit by operating an optical path switching unit to capture an image of a projection target surface. In an image projection system including an image projection device and a reflective screen,
The image projection device includes a light source, image display means illuminated by the light source, image projection means for enlarging and projecting image light from the image display means, a housing for accommodating them, and a housing for installing the image projection device. Has an installation reference plane,
The reflection type screen is composed of a white Fresnel reflection mirror and a transparent member made of a colorless and transparent material, which coats the surface of the Fresnel reflection mirror and makes the screen surface a smooth surface,
The reflective screen is placed on the same plane as the installation reference plane,
An image projection system, wherein the image projection means is configured to project an image on a reflective screen from a side where a housing is present.

Images