JP2007183384A - Rear projector and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear projector where a reflection mirror is easily arranged. <P>SOLUTION: A turntable 35 is attached to a base 33 by fitting a supporting shaft 34 in a through hole 35d, and further an adjusting member 36 is attached to the turntable 35 by fitting a through hole 36a to the supporting shaft 34. In such a state that the turntable 35 and the adjusting member 36 are attached, the center of the supporting shaft 34 is positioned at the intersection of the respective reflection surfaces 31a and 32a of first and second plane mirrors 31 and 32. The turntable 35 and the adjusting member 36 can turn with the supporting shaft 34 as center, and the adjusting member 36 is fixed on the turntable 35 by a fixing tool 37b, and the turntable 35 is fixed on the base 33 by a fixing tool 37a after the turntable 35 and the adjusting member 36 are properly turned to be in desired states respectively. Furthermore, the second plane mirror 32 is fixed to the adjusting member 36 by a fixing tool 37c after it is properly slid to a desired position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rear projector and a manufacturing method thereof.

  2. Description of the Related Art A rear projector is known in which image light is enlarged and projected from the optical engine unit to a rear surface of a transmissive screen via a plurality of reflecting mirrors so that the image can be visually recognized from the front side of the screen. In such a rear projector, it is necessary to precisely arrange the reflecting mirror with respect to the screen so that the image light is not projected with a deviation from the screen.

  In the projection apparatus described in Patent Document 1, in order to facilitate the arrangement of a plurality of reflection mirrors (reflection optical elements) constituting the projection optical system, the respective reflection mirrors are not fixed directly to the main body of the projection apparatus, but temporarily. After being attached to the holding member (housing) and fixing the relative positions thereof, the holding member is arranged on the main body. According to this projection apparatus, it is possible to adjust each reflection mirror integrally when assembling the main body, and thus it is possible to suppress the complexity of position adjustment for each reflection mirror.

JP 2002-55306 A

  However, in the projection apparatus described in Patent Document 1, when the holding member is attached to the main body, it is still necessary to place the holding member precisely with respect to the screen.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a rear projector capable of easily arranging reflecting mirrors.

  The rear projector of the present invention includes an optical engine unit that projects image light, a planar reflection surface, a first reflection mirror that reflects the image light projected from the optical engine unit, and a planar reflection. A second reflection mirror that reflects the image light reflected by the first reflection mirror, and receives the image light reflected by the second reflection mirror on the back side, The first reflection mirror and the second reflection mirror are centered on the intersection of the screen that is transmitted and displayed as an image, and the reflection surface of the first reflection mirror and the reflection surface of the second reflection mirror. And an angle adjusting means for adjusting an angle formed by the two reflecting surfaces by rotating at least one of the first and second reflecting surfaces.

  The optical path of the light reflected by the two plane mirrors (reflection mirrors having a planar reflecting surface) is at an angle (relative angle) formed by the two reflecting surfaces if the position of the intersection of the reflecting surfaces is fixed. Depending on the angle (absolute angle) of each reflecting surface itself. That is, if the relative angle between the two reflecting surfaces is fixed, the reflected light from the second reflecting mirror always travels on the same optical path even if the absolute angles of the two reflecting surfaces are shifted. For this reason, according to the rear projector of the present invention, it is possible to relax the accuracy of the installation angle of each reflection mirror itself by adjusting the relative angle by the angle adjustment means, so that the installation of the reflection mirror is easy. Can be done.

  In the present specification, the intersection of two reflection surfaces is the intersection of one reflection surface or its extension surface and the other reflection surface or its extension surface, in other words, a plane including one reflection surface, The point of intersection with the plane including the other reflecting surface shall be said. For this reason, even when the two reflecting mirrors are separated from each other, there can be an intersection of the reflecting surfaces.

  The rear projector of the present invention includes an optical engine unit that projects image light, a first reflection mirror that reflects the image light projected from the optical engine unit, and the image that is reflected by the first reflection mirror. A rear projector comprising: a second reflecting mirror that reflects light; and a screen that receives the image light reflected by the second reflecting mirror on the back side and transmits the image light to the front side and displays it as an image. One of the first and second reflecting mirrors is a plane mirror having a planar reflecting surface, and the other is a curved mirror having a curved reflecting surface, and the reflecting surface of the plane mirror is , By rotating at least one of the plane mirror and the curved mirror around an intersection with a tangent at a predetermined position on the reflection surface of the curved mirror, the reflection surface of the plane mirror, Characterized by comprising an angle adjusting means for enabling adjustment of the angle between the tangent plane mirror.

  According to this rear projector, by adjusting the relative angle of the reflecting surface by the angle adjusting means, the optical path of the light reflected in the vicinity of the predetermined position is greatly shifted even when the installation angles of the reflecting mirrors themselves are deviated. Nothing will happen. For this reason, since it becomes possible to ease the accuracy of the installation angle of each reflection mirror, the reflection mirror can be easily installed. In addition, since one of the reflecting mirrors is a curved mirror, the image light can be reflected at a wide angle. As a result, it is possible to display a large image without increasing the optical path length, so that the main body (rear projector) can be reduced in size or thickness.

  In the present specification, the intersection of the reflecting surface and the tangent means the intersection of the reflecting surface or its extended surface and the tangent, in other words, the intersection of the plane including the reflecting surface and the tangent. To do.

  In this rear projector, it is desirable that the predetermined position on the reflection surface of the curved mirror is a position corresponding to the center of the image.

  According to this rear projector, even when the installation angles of the reflecting mirrors themselves are deviated, it is possible to suppress the positional deviation of the center of the image.

  In this rear projector, it is preferable that the first and second reflecting mirrors are integrally held, and a mirror holding unit including the angle adjusting unit is provided.

  According to this rear projector, the first and second reflecting mirrors are integrally held and the mirror holding part having the angle adjusting means is provided, so that the relative angle of the reflecting surface is adjusted on the mirror holding part. After performing the above operation, the mirror holder can be attached to the main body. In other words, since the relative angle that requires precise work can be adjusted before the main body is mounted, the reflection mirror can be installed more easily.

  In this rear projector, it is preferable that at least one of the first and second reflection mirrors is held movably along each of the reflection surfaces.

  According to this rear projector, since at least one of the reflecting mirrors is held so as to be movable along the reflecting surface, even when the dimension margin of the reflecting mirror is reduced, the mirror is moved according to the installation state. Thus, it is possible to suppress the displacement (the projection of image light) at the end of the mirror.

  The method of manufacturing a rear projector according to the present invention is a rear projector that projects image light projected by an optical engine unit on a transmissive screen by sequentially reflecting the first and second reflecting mirrors having a planar reflecting surface. And at least one of the first reflection mirror and the second reflection mirror centering on the intersection of the reflection surface of the first reflection mirror and the reflection surface of the second reflection mirror. And an angle adjusting step of adjusting an angle formed by the two reflecting surfaces by rotating the lens.

  The optical path of the light reflected by the two plane mirrors (reflection mirrors having a planar reflecting surface) is at an angle (relative angle) formed by the two reflecting surfaces if the position of the intersection of the reflecting surfaces is fixed. Depending on the angle (absolute angle) of each reflecting surface itself. That is, if the relative angle between the two reflecting surfaces is fixed, the reflected light from the second reflecting mirror always travels on the same optical path even if the absolute angles of the two reflecting surfaces are shifted. For this reason, according to the manufacturing method of the rear projector of the present invention, it is possible to relax the accuracy of the installation angle of each reflection mirror itself by adjusting the relative angle in the angle adjustment step. Installation can be performed easily.

  A method for manufacturing a rear projector according to the present invention is a method for manufacturing a rear projector in which image light projected by an optical engine unit is sequentially reflected by first and second reflecting mirrors and projected onto a transmissive screen, One of the first and second reflecting mirrors is a plane mirror having a planar reflecting surface, and the other is a curved mirror having a curved reflecting surface, the reflecting surface of the plane mirror, By rotating at least one of the flat mirror and the curved mirror around the intersection with a tangent at a predetermined position on the reflective surface of the curved mirror, the reflective surface of the flat mirror and the curved mirror An angle adjusting step for adjusting an angle formed with the tangent line is provided.

  According to this method of manufacturing a rear projector, the relative angle of the reflecting surface is adjusted in the angle adjusting step, so that the light reflected in the vicinity of the predetermined position can be obtained even when the installation angle of each reflecting mirror itself is deviated. The optical path is not greatly shifted. For this reason, since it becomes possible to ease the accuracy of the installation angle of each reflection mirror, the reflection mirror can be easily installed.

(First embodiment)
Hereinafter, a rear projector according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a schematic configuration of a rear projector according to the first embodiment. The rear projector 1 includes an optical engine unit 10 that projects image light, a projection optical system 20, a mirror holding unit 30 that holds first and second plane mirrors 31 and 32 as reflecting mirrors, and a substantially vertical arrangement. A transmission-type screen 40 is provided, and a housing 50 that holds each of the parts 10, 30, 40. The image light projected from the optical engine unit 10 is sequentially reflected by the first plane mirror 31 and the second plane mirror 32, and then irradiated to the back surface of the screen 40. From the front side of the screen 40 to the observer as an image. Visible.

  The optical engine unit 10 is disposed on the back side of the screen 40 (inside of the housing 50) and in the vicinity of the bottom surface of the housing 50, and the light modulated in accordance with the image signal is provided above the first Projection is performed from the projection optical system 20 toward the flat mirror 31.

  FIG. 2 is a configuration diagram illustrating the configuration of the optical engine unit 10 with the projection optical system 20 attached. The ultra-high pressure mercury lamp 101 serving as a light source unit includes red light (hereinafter referred to as “R light”), green light (hereinafter referred to as “G light”), and blue light (hereinafter referred to as “B light”). Is emitted toward the integrator 102. The integrator 102 is an optical system that makes the illuminance distribution of the light from the ultra-high pressure mercury lamp 101 substantially uniform, and the light that has passed through the integrator 102 is polarized light having a specific polarization direction by the polarization conversion element 103, for example, s Converted to polarized light.

  The light converted into the s-polarized light is bent 90 degrees in the optical path by the plane mirror 104 and then enters the R light transmitting dichroic mirror 105R. The R light transmitting dichroic mirror 105R transmits R light and reflects G light and B light. The R light transmitted through the R light transmitting dichroic mirror 105R is bent 90 degrees in the optical path by the plane mirror 105 and enters the liquid crystal light valve 107R.

  The G light and B light reflected by the R light transmitting dichroic mirror 105R are incident on the B light transmitting dichroic mirror 105B after the optical path is bent 90 degrees. The B light transmitting dichroic mirror 105B reflects the G light and transmits the B light. The G light reflected by the B light transmitting dichroic mirror 105B enters the liquid crystal light valve 107G.

  The B light transmitted through the B light transmitting dichroic mirror 105B enters the liquid crystal light valve 107B via the two relay lenses 106 and the two plane mirrors 105. The reason for passing the B light through the relay lens 106 is that the path of the B light becomes longer than the paths of the other color lights, so that the illumination efficiency to the liquid crystal light valve 107B decreases due to the divergence of the light. It is for suppressing. Since the polarization direction of the light does not change even after passing through the dichroic mirrors 105R and 105B, each color light incident on the liquid crystal light valves 107R, 107G, and 107B remains in the state of s-polarized light.

  Each of the liquid crystal light valves 107R, 107G, and 107B includes a liquid crystal panel in which liquid crystal is sealed between a pair of transparent substrates. On the inner surface of the liquid crystal panel, a driving voltage for each minute region (pixel) with respect to the liquid crystal. Transparent electrodes (pixel electrodes) to which can be applied are formed in a matrix. An incident-side polarizing plate is provided on the incident-side surface of the liquid crystal panel so as to transmit s-polarized light, and most of each color light incident on each liquid crystal light valve 107R, 107G, 107B is transmitted through the incident-side polarizing plate. Then, it enters the liquid crystal panel. Further, an exit-side polarizing plate is provided on the exit-side surface of the liquid crystal panel so as to transmit p-polarized light.

  Here, when a driving voltage corresponding to an image signal is applied to each pixel of the liquid crystal panel, the light incident on the liquid crystal panel is modulated according to the driving voltage and polarized light having a different polarization direction for each pixel. It becomes. Of this polarized light, only the p-polarized light component that can be transmitted through the output-side polarizing plate is emitted from the respective liquid crystal light valves 107R, 107G, and 107B. That is, the liquid crystal light valves 107R, 107G, and 107B transmit incident light with different transmittances for each pixel according to the image signal, so that image light having gradation is formed for each color light. The image light composed of each color light emitted from each of the liquid crystal light valves 107R, 107G, and 107B enters the cross dichroic prism 108.

  The cross dichroic prism 108 which is a color synthesis optical system is configured by arranging two dichroic films 108a and 108b so as to be orthogonal to the X shape. The dichroic film 108a reflects B light and transmits R light and G light. The dichroic film 108b reflects R light and transmits B light and G light. Thereby, the image light composed of the respective color lights modulated by the liquid crystal light valves 107R, 107G, and 107B is synthesized and enlarged and projected by the projection optical system 20.

  Returning to FIG. 1, the mirror holding unit 30 further reflects the first plane mirror 31 that reflects the projection light from the optical engine unit 10 and the reflected light from the first plane mirror 31 toward the screen 40. The second flat mirror 32 is held in an eight-letter shape.

Here, the mirror holding | maintenance part 30 is demonstrated in detail using FIGS. 3-5.
3 is an exploded perspective view for explaining the structure of the mirror holding unit 30 in detail, FIG. 4 is a side view showing a holding state of the second plane mirror 32, and FIG. It is a top view.
As shown in FIG. 3, the mirror holding unit 30 includes a flat base 33, a columnar support shaft 34 that stands vertically from the base 33, and a rotary base 35 that holds the first flat mirror 31. , And an adjustment member 36 that slidably holds the second plane mirror 32.

  The turntable 35 is a substantially fan-shaped flat plate having an arcuate end 35a and two linear ends 35b, 35c, and the first plane mirror 31 is not shown in the vicinity of the linear end 35b. It is held vertically by a fixture. A through hole 35d is provided in the vicinity of the intersection of the linear end portions 35b and 35c so that the shaft 34 can be fitted. Here, the through hole 35d is arranged so that the center thereof is located on the extension line of the reflection surface 31a of the first plane mirror 31 (see FIG. 5).

  The adjustment member 36 extends from the side surface of the fitting portion 36b provided with a through hole 36a for fitting with the support shaft 34 and the fitting portion 36b so that the second plane mirror 32 can slide. And holding part 36c for holding. As shown in FIG. 4, the holding portion 36c is formed with a groove 36d having an L-shaped cross section, and the groove 36d protrudes from the second plane mirror 32 and one side of the peripheral portion thereof. A fixed auxiliary member 32b is fitted.

  Further, as shown in FIG. 5, the length Ld of the groove 36d is longer than the width (holding length) Lm of the second plane mirror 32, so that the second plane mirror 32 extends along the groove 36d. Can be slid. Since the second plane mirror 32 is held so that the reflection surface 32a thereof is parallel to the groove 36d, the sliding along the groove 36d can be rephrased as the sliding along the reflection surface 32a. it can. Here, the through hole 36a and the groove 36d are provided so that the center of the through hole 36a is located on the extension line of the reflecting surface 32a of the second plane mirror 32, and the second plane mirror 32 is formed in the groove 36d. As long as it slides along, the extension line of the reflective surface 32a passes through the center of the through hole 36a.

  The turntable 35 is mounted on the base 33 by fitting the support shaft 34 to the through hole 35d, and the adjustment member 36 is mounted on the turntable 35 by fitting the through hole 36a to the support shaft 34. It is attached to. As shown in FIG. 5, in the state where the turntable 35 and the adjustment member 36 are mounted, the center of the support shaft 34 is at the intersection of the reflecting surfaces 31a and 32a of the first and second plane mirrors 31 and 32, respectively. Will be located. Further, the turntable 35 and the adjustment member 36 are rotatable about the support shaft 34, and the adjustment member 36 is rotated by a fixture 37b after being appropriately rotated so as to be in a desired state. The turntable 35 is fixed to the base 33 by a fixture 37a. Further, the second flat mirror 32 is appropriately slid to a desired position and then fixed to the adjustment member 36 by a fixing tool 37c. In addition, since each of the turntable 35 and the adjusting member 36 rotates around the support shaft 34, the angle formed by the two reflecting surfaces 31a and 32a can be adjusted. And the adjustment member 36 functions as an angle adjustment means of the present invention.

Next, a procedure for attaching the first and second flat mirrors 31 and 32 to the casing 50 when manufacturing the rear projector 1 of the present embodiment will be described.
FIG. 6 is a flowchart showing a procedure for attaching the flat mirrors 31 and 32 to the casing.
As shown in FIG. 6, first, the base 33 having the support shaft 34 is fixed at a predetermined position of the casing 50 to which the screen 40 and the optical engine unit 10 are fixed (step S101). The turntable 35 and the adjustment member 36 holding the second plane mirrors 31 and 32 are mounted on the base 33 (step S102).

  Next, while projecting image light from the optical engine unit 10, the turntable 35 is rotated so that the first flat mirror 31 is aligned in a direction in which image light can be received substantially, and then the turntable 35 is temporarily fixed. Thereafter, the adjustment member 36 is rotated so that the image light reflected by the second plane mirror 32 is appropriately projected onto the screen 40. Specifically, the center of the projection image is set at the center of the screen 40. After the orientation is adjusted so as to be displayed, the adjustment member 36 is fixed to the turntable 35 by the fixture 37b (step S103). Thereby, the angle (relative angle) formed by the reflection surface 31a of the first plane mirror 31 and the reflection surface 32a of the second plane mirror 32 is determined.

  Thereafter, the temporarily fixed turntable 35 is rotated together with the adjusting member 36 so that the image light emitted from the optical engine unit 10 (image light to be displayed as an image) does not protrude from the first flat mirror. After adjusting the direction so that the first flat mirror 31 does not block the reflected light from the second flat mirror 32, the turntable 35 is fixed to the base 33 by the fixture 37a. (Step S104).

  Then, after sliding the second plane mirror 32 and moving its position so that the image light reflected by the first plane mirror 31 is reflected by the second plane mirror 32 without protruding, The second plane mirror 32 is fixed to the adjustment member 36 by the fixing tool 37c (step S105). Thereby, the optical image emitted from the optical engine unit 10 is projected to an appropriate position of the screen 40. As described above, in the present embodiment, since the adjustment member 36 slidably holds the second plane mirror 32, even if the dimensional margin of the second plane mirror 32 is reduced, the adjustment member 36 depends on the installation state. By sliding the mirror, it is possible to suppress displacement (excess of image light) at the end of the mirror.

  As described above, in the present embodiment, after the angles (relative angles) formed by the reflecting surfaces 31a and 32a of the two plane mirrors 31 and 32 are determined, the support provided at the intersection of the reflecting surfaces 31a and 32a is provided. The rotary table 35 is rotated about the shaft 34, and the absolute angles of the first and second plane mirrors 31 and 32 are determined.

  Theoretically, the optical path of the light sequentially reflected by the two plane mirrors 31 and 32 is the angle (relative angle) formed by the two reflection surfaces 31a and 32a if the position of the intersection of the reflection surfaces 31a and 32a is fixed. ) And does not depend on the angles (absolute angles) of the respective reflecting surfaces 31a and 32a themselves. That is, if the relative angle between the two reflecting surfaces 31a and 32a is fixed, the reflected light from the second plane mirror 32 always travels on the same optical path regardless of the absolute angle. For this reason, when each flat mirror 31 and 32 is arrange | positioned in the housing | casing 50, it becomes possible to ease the precision calculated | required by each arrangement angle (absolute angle), and installation of the flat mirrors 31 and 32 becomes easy. Can be done.

Next, the theory described above, that is, the fact that the light reflected by the two reflecting mirrors travels on the same optical path will be described geometrically with reference to the drawings.
FIG. 7 is an explanatory diagram that geometrically represents the optical path from the optical engine unit 10 to the screen 40. In this figure, the optical path from the optical engine unit 10 toward the first plane mirror 31 is the Y axis (straight line L0), and a straight line that passes through an arbitrary position on the Y axis (set to the origin O) and is perpendicular to the Y axis is X. The axis. A straight line representing the reflecting surface 31a of the first flat mirror 31 is M1, and a straight line representing the reflecting surface 32a of the second flat mirror 32 is M2, and the second flat mirror is reflected by the first flat mirror 31. An optical path toward 32 is a straight line L1, and an optical path reflected by the second plane mirror 32 and toward the screen 40 is a straight line L2. Further, the intersection of the straight line M1 and the straight line M2, that is, the center of the support shaft 34 is the point P (L, H), the intersection of the Y axis and the straight line M1 is the point Q, and the intersection of the straight line L1 and the straight line M2 is the point S. To do.

  Assuming that the angle of the reflecting surface 31a of the first plane mirror 31 with respect to the X axis is α, the straight line M1 passes through the point P (L, H) and is expressed by the following equation (1) as a straight line having an inclination of tan α. The

  In equation (1), when x = 0, y = HL · tan α, and the coordinates of the point Q are (0, HL · tan α). Since the incident angle and the reflection angle at the first plane mirror 31 are both equal to α, the angle of the straight line L1 with respect to the X axis is − (π / 2-2α), and the straight line L1 passes through the point Q and has an inclination. It is represented by the following formula (2) as a straight line of −tan (π / 2-2α).

  When this is rearranged, the following equation (3) is established.

  If the angle between the reflecting surface 31a of the first plane mirror 31 and the reflecting surface 32a of the second plane mirror 32, that is, the angle between the straight line M1 and the straight line M2, is φ, the angle of the straight line M2 with respect to the X axis is − Since it is (π−α−φ), the straight line M2 passes through the point P (L, H) and is represented by the following equation (4) as a straight line having an inclination of −tan (π−α−φ).

Here, assuming that the coordinates of the intersection S of the straight line L1 and the straight line M2 are (x _S , y _S ), x _S is solved by the following equations (3) and (4) as simultaneous equations. It is expressed as 5).

By substituting the above equation (5) into the equation (4), y _S becomes the following equation (6).

  Further, since the angle of the straight line L2 with respect to the X axis is 2φ−π / 2, the straight line L2 is expressed by the following equation (7) as a straight line passing through the point S and having an inclination of tan (2φ−π / 2). The

Here, assuming that the intersection of the Y axis and the straight line L2 is T and the coordinates are (x _T , y _T ), since x _T = 0, the following equation (8) is established from equation (7).

  Substituting Equation (5) and Equation (6) into Equation (8) and rearranging leads to the following Equation (9).

  As described above, the light reflected by the two plane mirrors 31 and 32 travels on the straight line L2 represented by the following equation (10).

  As shown in Expression (10), if the position (L, H) of the point P, which is the intersection of the reflecting surfaces 31a, 32a, is fixed, the straight line L2 has an inclination tan (2φ−π / 2), Y Both the intercept HL and tan φ are not dependent on the absolute angle α of the first plane mirror 31 and are determined only by the relative angle φ. For this reason, as shown in FIG. 8, the first and second plane mirrors 31 and 32 are rotated by rotating the two plane mirrors 31 and 32 around the point P while keeping the relative angle φ constant. Even if the reflection point of 32 changes from point Q and point S to point Q ′ and point S ′, the reflected light from the second plane mirror 32 always travels on the same straight line (straight line L2). Become.

(Second Embodiment)
Hereinafter, a rear projector according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 9 is a cross-sectional view illustrating a schematic configuration of the rear projector according to the present embodiment, and FIG. 10 is a plan view of the mirror holding unit 30 according to the present embodiment.
As shown in FIGS. 9 and 10, the rear projector 1 according to the present embodiment includes a curved mirror 38 instead of the second flat mirror 32 in the first embodiment as a reflection mirror included in the mirror holding unit 30. . The curved mirror 38 includes a primary curved reflecting surface 38a that is curved in a convex shape, can reflect image light at a wide angle, and can display a large projected image even with a short optical path length.

  Further, as shown in FIG. 10, the curved mirror 38 is arranged such that a tangent at a predetermined position on the reflecting surface 38a passes through the center of the through hole 36a. In the present embodiment, by design, that is, when each reflecting mirror (the first flat mirror 31 and the curved mirror 38) is ideally arranged, the position corresponding to the center of the projected image (toward the center C of the screen 40). A tangent line (a tangent line parallel to the paper surface in FIG. 10) at a position A where light should be reflected is arranged so as to pass through the center of the through hole 36a. That is, each of the reflection mirrors 31 and 38 is rotatable about the intersection between the reflection surface 31a of the first plane mirror 31 and the tangent at the position A on the reflection surface 38a of the curved mirror 38.

  According to the rear projector 1 of the present embodiment, the optical path of the reflected light from the curved mirror 38 strictly depends on the absolute angle of each reflecting mirror (the first flat mirror 31 and the curved mirror 38). Although the positional deviation of the projected image may occur due to the deviation of the absolute angle, it is possible to relax the accuracy required for each arrangement angle (absolute angle) as compared with the case where the reflection mirrors 31 and 38 are individually arranged. The reflection mirrors 31 and 38 can be easily installed. In particular, in this embodiment, each reflection mirror 31 is centered on the intersection of the tangent line at the position A corresponding to the center of the projection image on the reflection surface 38a of the curved mirror 38 and the reflection surface 31a of the first plane mirror 31. , 38 is rotated, it is possible to suppress the displacement of the projected image due to the variation in the absolute angles of the reflecting mirrors 31, 38 toward the center of the projected image.

  Note that the mirror holding unit 30 shown in FIGS. 9 and 10 is different from the mirror holding unit 30 in the first embodiment and moves the reflecting mirror (the second flat mirror 32 or the curved mirror 38) along the reflecting surface. Although no means for suppressing the protrusion of the image light is provided, the means can be provided even when the curved mirror 38 is used. For example, as shown in FIG. 11, a support arm 39 that can be rotated about the center of curvature B at the position A is fixed to the back surface of the curved mirror 38, and the curved mirror 38 is rotated on the adjustment member 36. By doing so, it is possible to realize movement along the reflecting surface 38a in the vicinity of the position A.

  Further, the curved mirror 38 is not limited to a primary curved surface, and may be a secondary curved surface. In any case, the tangent at the position A means a tangent that passes through the position A and is parallel to the paper surface in FIG. 10, that is, a tangent that passes through the position A and perpendicularly intersects the support shaft 34.

(Modification)
In addition, you may change embodiment of this invention as follows.
The base 33 in the embodiment is not an essential configuration, and the support shaft 34 may be directly fixed to the housing 50.

  In the first embodiment, after the base 33 is fixed to the housing 50, the first and second flat mirrors 31 and 32 are mounted and the relative angles of the reflecting surfaces 31a and 32a are determined. A jig (angle adjusting device) in which the arrangement of the optical engine unit 10 and the optical engine unit 10 are set to be the same as those of the actual rear projector 1 is used. The orientation of the turntable 35 with respect to the position may be determined, and then the mirror holding unit 30 may be fixed to the housing 50.

  According to this, it becomes possible to adjust the relative angle that requires precise work before mounting on the main body (rear projector 1). Since the jig does not need to be covered with a cover member such as the housing 50 and can be installed in an easy-to-work direction, the relative angles of the plane mirrors 31 and 32 can be easily set. It becomes possible. If the arrangement of the members (the screen 40 and the optical engine unit 10) varies between the jig and the main body, the relative angle may be finely adjusted after mounting on the housing 50.

  In the above-described embodiment, only the second plane mirror 32 or the curved mirror 38 of the two reflection mirrors is movable along the reflection surfaces 32a and 38a, but only the first plane mirror 31 is shown. The first and second plane mirrors 31 and 32, or both the first plane mirror 31 and the curved mirror 38 may be movable.

  In the embodiment, the configuration in which only two reflection mirrors are present in the optical path from the projection optical system 20 to the screen 40 is shown, but other optical elements or the like may be interposed before and after the two reflection mirrors. Good.

  In the embodiment, the light source light is modulated using the transmissive liquid crystal light valves 107R, 107G, and 107B. However, a reflective light modulator such as a reflective liquid crystal light valve can also be used. . In addition, it is possible to use a micromirror array device that modulates the light emitted from the light source by controlling the emission direction of the incident light for each micromirror as a pixel. Further, the light source unit is not limited to a discharge type light source lamp such as the ultra-high pressure mercury lamp 101, and other light sources such as an LED light source composed of an LED (light emitting diode) may be used.

1 is a cross-sectional view showing a schematic configuration of a rear projector according to a first embodiment. The block diagram explaining the structure of the optical engine part of the state to which the projection optical system was attached. The disassembled perspective view for demonstrating in detail the structure of a mirror holding | maintenance part. The side view which shows the holding state of a 2nd plane mirror. The top view of a mirror holding part. The flowchart which shows the procedure at the time of attaching a plane mirror to a housing | casing. Explanatory drawing which geometrically represented the optical path from an optical engine part to a screen. Explanatory drawing which shows that an optical path does not depend on the absolute angle of a reflective mirror. Sectional drawing which shows schematic structure of the rear projector which concerns on 2nd Embodiment. The top view of the mirror holding part which concerns on 2nd Embodiment. The top view of the mirror holding part which hold | maintains a curved mirror so that a movement along a reflective surface is possible.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rear projector, 10 ... Optical engine part, 20 ... Projection optical system, 30 ... Mirror holding part, 31 ... 1st plane mirror, 32 ... 2nd plane mirror, 31a, 32a ... Reflective surface, 32b ... Auxiliary member , 33 ... base, 34 ... support shaft, 35 ... rotating base, 35d ... through hole, 36 ... adjustment member, 36a ... through hole, 36b ... fitting part, 36c ... holding part, 36d ... groove, 37a, 37b, 37c ... Fixing tool, 38 ... Curved mirror, 38a ... Reflecting surface, 40 ... Screen, 50 ... Case, 101 ... Super high pressure mercury lamp, 102 ... Integrator, 103 ... Polarization conversion element, 104,105 ... Plane mirror, 105B ... B light transmission dichroic mirror, 105R ... R light transmission dichroic mirror, 106 ... relay lens, 107R, 107G, 107B ... liquid crystal light valve, 108 ... cross die Roikkupurizumu.

Claims (7)

An optical engine for projecting image light;
A first reflecting mirror that includes a planar reflecting surface and reflects the image light projected from the optical engine unit;
A second reflecting mirror that includes a planar reflecting surface and reflects the image light reflected by the first reflecting mirror;
A screen that receives the image light reflected by the second reflecting mirror on the back side, transmits the image light to the front side, and displays it as an image;
By rotating at least one of the first reflecting mirror and the second reflecting mirror around the intersection of the reflecting surface of the first reflecting mirror and the reflecting surface of the second reflecting mirror, An angle adjusting means capable of adjusting an angle formed by the two reflecting surfaces;
A rear projector characterized by comprising: An optical engine for projecting image light;
A first reflection mirror that reflects the image light projected from the optical engine unit;
A second reflecting mirror that reflects the image light reflected by the first reflecting mirror;
A screen that receives the image light reflected by the second reflecting mirror on the back side, transmits the image light to the front side, and displays it as an image;
A rear projector comprising:
One of the first and second reflecting mirrors is a plane mirror having a planar reflecting surface, and the other is a curved mirror having a curved reflecting surface,
By rotating at least one of the flat mirror and the curved mirror around the intersection of the reflective surface of the flat mirror and a tangent at a predetermined position on the reflective surface of the curved mirror, A rear projector comprising an angle adjusting means for adjusting an angle formed between a reflecting surface and the tangent to the curved mirror.   The rear projector according to claim 2, wherein the predetermined position on the reflection surface of the curved mirror is a position corresponding to a center of the image.   The rear projector according to any one of claims 1 to 3, further comprising a mirror holding unit that integrally holds the first and second reflecting mirrors and includes the angle adjusting unit. A featured rear projector.   5. The rear projector according to claim 1, wherein at least one of the first and second reflection mirrors is held movably along each of the reflection surfaces. A featured rear projector. A method of manufacturing a rear projector in which image light projected by an optical engine unit is sequentially reflected by first and second reflecting mirrors having a planar reflecting surface and projected onto a transmissive screen,
By rotating at least one of the first reflection mirror and the second reflection mirror around the intersection of the reflection surface of the first reflection mirror and the reflection surface of the second reflection mirror, A method of manufacturing a rear projector, comprising an angle adjusting step of adjusting an angle formed by the two reflecting surfaces. A method of manufacturing a rear projector in which image light projected by an optical engine unit is sequentially reflected by first and second reflecting mirrors and projected onto a transmissive screen,
One of the first and second reflecting mirrors is a plane mirror having a planar reflecting surface, and the other is a curved mirror having a curved reflecting surface,
By rotating at least one of the flat mirror and the curved mirror around the intersection of the reflective surface of the flat mirror and a tangent at a predetermined position on the reflective surface of the curved mirror, A method of manufacturing a rear projector, comprising: an angle adjusting step of adjusting an angle formed between a reflecting surface and the tangent of the curved mirror.

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