JP2014238432A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the positional deviation of an optical element by preventing the deformation of an optical element holding member.SOLUTION: An image projection device includes a light source, an image display element forming an image, an illumination unit illuminating the image display element by using light from the light source, and a projection unit projecting the image formed by the image display element onto a surface to be projected. The illumination unit includes a plurality of optical elements (a relay lens 7, a plane mirror 8, and a concave mirror 9) for illuminating the image display element, an optical element holding member 11 positioning and holding the plurality of optical elements, and an illumination optical housing 12 covering the optical element holding member 11 from a side where the optical element holding member 11 holds the plurality of optical elements. The optical element holding member 11 comprises a plurality of holding parts 11b holding each optical element and a base material part 11a supporting the plurality of holding parts 11b. At least one place of the plurality of holding parts 11b is fixed to the illumination optical housing 12 from the outside of the illumination optical housing 12.

Description

  The present invention relates to an image projection apparatus.

  Recently, projectors widely known as image projection apparatuses have been improved in the resolution and the cost of the liquid crystal panel due to the high resolution, the efficiency of the light source lamp, and the like. In addition, small and light image projection devices using DMD (Digital Micro-mirror Device) or the like as an image display element have become widespread, and these image projection devices are widely used not only in offices and schools but also at home. ing. In particular, front-type projectors have improved portability and have been used for small meetings of several people.

  In an image projection device, an image forming element such as a liquid crystal panel or DMD is illuminated by light from a lamp as a light source, and light modulated by the image forming element is projected onto a projection surface such as a screen. With respect to the image quality to be projected, an image quality with a limited size and high brightness and high resolution is required, and it is desired that the image quality be kept constant depending on the projection time.

  In response to such a demand for higher image quality, for example, in Patent Document 1, in order to achieve a high-brightness and high-definition image, a plurality of lamps are used, and an image adjustment process is provided for alignment. A method of manufacturing a projector that performs the above is disclosed.

  Also, for example, Patent Document 2 includes a pixel profile deforming unit that transforms a light intensity profile of a pixel into a non-rectangular pixel profile, thereby reducing the relative light intensity near the edge of the pixel and shifting the optical axis. In this case, a projection image display apparatus that reduces the influence of overlapping between adjacent pixels and realizes “sharpness” and “surface and edge smoothness” of an image is disclosed.

  After starting the image projection device, the optical element holding member holding the optical element such as the lens and mirror is thermally expanded due to heat from the light from the lamp, etc., and the deformation of the optical element position such as the lens and mirror is displaced. As a result, there is a risk that a slight positional shift on the image or a luminance drop or luminance unevenness occurs in a part of the image.

  In the techniques of Patent Documents 1 and 2 described above, image adjustment is performed on the initial state and the initial image, but it has not been possible to cope with fluctuations after activation.

  Therefore, the present invention prevents deformation of the optical element holding member after activation of the image projection apparatus, suppresses the positional deviation of the optical element, and suppresses the occurrence of positional deviation on the image, luminance reduction, and luminance unevenness. An object of the present invention is to provide an image projection apparatus capable of performing the above.

  In order to achieve the above object, an image projection apparatus according to the present invention includes a light source that emits light, an image display element that forms an image, and an illumination unit that illuminates the image display element using light from the light source. A projection unit that projects an image formed by the image display element onto a projection surface, wherein the illumination unit includes a plurality of optical elements for illuminating the image display element; An optical element holding member that positions and holds the plurality of optical elements; and an illumination optical housing that covers the optical element holding member from a side where the optical element holding member holds the plurality of optical elements. The optical element holding member includes a plurality of holding portions that hold the optical elements and a base material portion that supports the holding portions, and at least one of the plurality of holding portions is the illumination optical housing. From outside the body In which it is fixed to the illumination optical housing.

  According to the present invention, it is possible to prevent the optical element holding member from being deformed, to suppress the positional deviation of the optical element, and to suppress the positional deviation on the image, the luminance decrease, and the luminance unevenness.

(A) External appearance perspective view which shows one Embodiment of the image projection apparatus which concerns on this invention, (B) It is the side view of an image projection apparatus, Comprising: It is the figure which showed the projection state to a to-be-projected surface. (A) The perspective view which shows the state which removed the exterior cover of the image projector, (B) It is an enlarged block diagram of the encircled part of (A). It is sectional drawing of an illumination unit, a projection unit, and a light source unit. (A) The expansion perspective view of an optical engine, (B) The expansion perspective view of an illumination unit, (C) The expansion perspective view of a projection unit. (A) is an enlarged perspective view of an irradiation unit, (B) an enlarged perspective view of an illumination optical housing portion, and (C) an enlarged perspective view of an optical element holding member portion. (A) The perspective view of the optical element holding member holding the optical element, (B) The perspective view which looked at the optical element holding member holding the optical element from a different direction from (A). (A) Perspective view of optical element holding member, (B) Side view of optical element holding member. (A) Explanatory drawing of the assembly | attachment of the optical element holding member and illumination optical housing which hold | maintained the optical element, (B) The perspective view of the illumination optical housing after the assembly | attachment of an optical element holding member, (C) (B) It is an enlarged view of the circled part. (A) is explanatory drawing at the time of fixing the optical element holding member holding the optical element to the illumination optical casing by a fixing member, (B) perspective view of the illumination optical casing at the time of fixing by the fixing member of the optical element holding member (C) It is an enlarged view of the encircled part of (B). (A) The perspective view of the optical element holding member holding the optical element, (B) It is an enlarged view of the encircled part of (A). (A) Explanatory drawing of assembly of optical element holding member holding optical element and illumination optical housing, (B) Enlarged view of circled portion of (A), (C) After assembly of optical element holding member It is a perspective view of an illumination optical housing | casing, and is an enlarged view of the encircled part of (D) (C). (A) Explanatory drawing at the time of fixing the optical element holding member holding the optical element to the illumination optical casing by a fixing member, (B) is a perspective view of the illumination optical casing at the time of fixing by the fixing member of the optical element holding member It is.

  Hereinafter, a configuration according to the present invention will be described in detail based on the embodiment shown in FIGS.

<First Embodiment>
The image projection apparatus according to the present embodiment uses a light source that emits light (a light source of the light source unit 4), an image display element that forms an image (a DMD element 10a of the image display element unit 10), and light from the light source. An image projection apparatus comprising: an illumination unit (illumination unit 3a) that illuminates the image display element; and a projection unit (projection unit 3b) that projects an image formed by the image display element onto a projection surface (screen 15). In the image projection apparatus 1, the illumination unit positions a plurality of optical elements (relay lens 7, plane mirror 8, concave mirror 9) for illuminating the image display element, and the plurality of optical elements. An optical element holding member (optical element holding member 11) to be held, and an illumination optical housing (illumination light) that covers the optical element holding member from the side on which the optical element holding member holds a plurality of optical elements. The optical element holding member includes a plurality of holding portions (holding portions 11b) that hold the optical elements, and a base material portion (base material portion 11a) that supports the plurality of holding portions. And at least one of the plurality of holding portions is fixed to the illumination optical casing from the outside of the illumination optical casing. In addition, the code | symbol in embodiment and the example of application are shown in a parenthesis.

  FIG. 1A is an external perspective view showing an embodiment of an image projection apparatus. FIG. 1B is a side view of the image projection apparatus, and shows a projection state on a screen that is a projection surface.

  The image projection device 1 is a device (projector) that generates a video based on video data input from an information processing device such as a personal computer or an imaging device such as a video camera, and projects and displays the video on the screen 15. .

  FIG. 2A is a perspective view showing a state in which the exterior cover 2 of the image projection apparatus 1 is removed. FIG. 2B is an enlarged configuration diagram of the optical engine 3 and the light source unit 4 indicated by a circled portion in FIG. As shown in FIG. 2, the image projection apparatus 1 includes an optical engine 3 and a light source unit 4. FIG. 3 is a cross-sectional view of the illumination unit 3 a provided with the irradiation optical system constituting the optical engine 3, the projection unit 3 b provided with the projection optical system, and the light source unit 4.

  In the image projection apparatus 1, light (white light) from the light source of the light source unit 4 is irradiated to the illumination unit 3 a of the optical engine 3. In the illumination unit 3a, the irradiated white light is split into RGB and guided to the image display element unit 10 by the irradiation optical system, and the image display element unit 10 that forms an image according to the modulation signal and the image thereof are projected to the projection unit 3b. The projection optical system projects the image on the screen 15 in an enlarged manner.

  As a light source of the light source unit 4, for example, a high-pressure mercury lamp can be used. The illumination unit 3a of the optical engine 3 includes a color wheel 5 that splits light emitted from a light source, a light tunnel 6 that guides light emitted from the color wheel 5 to an irradiation optical system, and a relay lens as an irradiation optical system. 7, a plane mirror 8 and a concave mirror 9. An image display element unit 10 is provided in the illumination unit 3a.

  In the illumination unit 3a, first, white light from the light source is converted into light that repeats each color of RGB by a disc-shaped color wheel 5 per unit time and emitted. Next, the light emitted from the color wheel 5 is guided and transmitted to the light tunnel 6 that is formed in a cylindrical shape by laminating plate glasses.

  Next, the light emitted from the light tunnel 6 is condensed by correcting a longitudinal chromatic aberration of the light by a relay lens 7 formed by combining two lenses. The light emitted from the relay lens 7 is reflected by the plane mirror 8 and the concave mirror 9 to have a substantially rectangular mirror surface composed of a plurality of micromirrors, and each micromirror is time-divided based on video data. By being driven, the projection light is processed and reflected so as to form a predetermined image, and is focused on an image display element unit 10 including a DMD element 10a as an image display element that reflects the image.

  Based on the video data in a time division manner, the DMD element 10a reflects light used by the plurality of micromirrors to the projection lens, and discards light to the OFF light plate. The light used in the image display element unit 10 is reflected to the projection unit 3b, and the image light enlarged through the plurality of projection lenses in the projection unit 3b is enlarged and projected onto the screen 15.

  Such an image projection apparatus is desired to have high brightness and high resolution in a limited size and space. For this reason, even when the same light source (lamp) is used, it is required to irradiate the image display element by collecting and uniforming the light from the lamp as much as possible. In order to satisfy the above requirements, a slight shift in the optical path from the light source to the image display element may cause a positional shift on the image, a partial reduction in brightness, and uneven brightness. The positional accuracy of optical elements such as lenses and mirrors is important, and it is necessary to suppress these positional fluctuations during projection.

  4A is an enlarged perspective view of the optical engine 3, FIG. 4B is an enlarged perspective view of the illumination unit 3a, and FIG. 4C is an enlarged perspective view of the projection unit 3b. As shown in FIG. 4, the optical engine 3 is a combination of an illumination unit 3a and a projection unit 3b.

  5A is an enlarged perspective view of the irradiation unit 3a, FIG. 5B is an enlarged perspective view of the illumination optical housing 12 portion of the irradiation unit 3a, and FIG. 5C is an optical element holding member 11 of the irradiation unit 3a. It is an expansion perspective view of a part. As shown in FIG. 5, the irradiation unit 3a is a combination of the illumination optical housing 12 portion and the optical element holding member 11 portion.

  An optical element holding member 11 shown in FIG. 5C includes a holding part 11b having a shape for holding each optical element (illumination optical system), and a substrate having a plate shape and supporting a plurality of holding parts 11b. It is a member composed of a portion 11a, and each optical element is attached to each holding portion 11b for holding and positioning. In the present embodiment, four optical elements of two relay lenses 7, a plane mirror 8, and a concave mirror 9 are held as optical elements.

  Since the optical element holding member 11 is a member that requires high positioning accuracy of each optical element, for example, a resin member such as LCP (liquid crystal polymer) is used to integrally form the base material portion 11a and each holding portion 11b. It is a member formed by molding.

  The illumination optical housing 12 is a housing that surrounds the exterior of the illumination unit 3a, and houses the optical element holding member 11 that holds each optical element. Further, a color wheel 5 and a light tunnel 6 provided on the optical path between the light source and the illumination optical system are accommodated. The illumination optical housing 12 is a member made of a metal member such as a magnesium alloy, for example. The illumination optical housing 12 is a portion excluding the color wheel 5 and its holding portion, the light tunnel 6 (not shown), and the heat sink 14 in FIG.

  The illumination optical housing 12 shown in FIG. 5B accommodates and is fixed with the optical element holding member 11 holding the optical elements shown in FIG. For example, the hole portions provided at the four corners of the base material portion 11a are fixed by attachment members (screws or the like) from the illumination optical housing 12 side. In addition, the protrusion part 12a is an attachment part to the main body of the image projection apparatus 1 of the illumination unit 3a.

  6A and 6B are perspective views of the optical element holding member 11 holding the optical elements as viewed from two directions. In this embodiment, the optical element holding member 11 is configured such that at least one of the plurality of holding portions 11b can be fixed to the illumination optical housing 12 from the outside of the illumination optical housing 12.

  In the example shown in FIGS. 6 to 9, three boss-shaped portions 11 c are provided on the holding portion 11 b at a position where the plane mirror 8 is mainly held. As described above, the interior of the lighting unit 3a is equivalent to room temperature at the time of startup, but the temperature rises to about 70 ° C. to 80 ° C. during operation. Therefore, the optical element holding member 11 mainly composed of resin expands thermally during operation.

  FIG. 7A is a perspective view of the optical element holding member 11, and FIG. 7B is a side view of the optical element holding member 11. A portion surrounded by a dotted line in FIG. 7 indicates a portion that is easily deformed in the arrow direction due to thermal expansion when the holding portion 11b of the optical element holding member 11 is not fixed from the outside of the illumination optical housing 12.

  The holding portion 11 b surrounded by the dotted line is a place for holding a part of the flat mirror 8 and the concave mirror 9. The location is likely to be deformed due to thermal expansion because the height of the holding portion 11b is high, and if thermal expansion occurs in this portion, the positions of the plane mirror 8 and the concave mirror 9 may be shifted during operation.

  Therefore, in this embodiment, a boss-shaped portion 11c that protrudes upward is provided on the support portion 11b of the optical element holding member 11 that is easily deformed. In the example of FIG. 7, the boss-shaped portion 11 c is provided at three locations, and has a length that protrudes from a hole provided in the illumination optical housing 12 when the illumination optical housing 12 is assembled.

  FIG. 8A is an explanatory view showing a state of assembling the optical element holding member 11 holding each optical element and the illumination optical housing 12. FIG. 8B is a perspective view of the illumination optical housing 12 after the optical element holding member 11 is assembled. FIG. 8C is an enlarged view of a circled portion in FIG.

  As shown in FIG. 8C, the illumination optical housing 12 is provided with a through hole 12b. After the boss-shaped portion 11c provided in the holding portion 11b of the optical element holding member 11 is assembled, the illumination optical The structure protrudes to the outside of the housing 12. In the example of FIG. 8, the illumination optical housing 12 is provided with through holes 12b through which three boss-shaped portions 11c are inserted, and screw holes 12c on both sides thereof.

  FIG. 9A is an explanatory diagram when the optical element holding member 11 holding each optical element is fixed to the illumination optical housing 12 by the fixing member 13. FIG. 9B is a perspective view of the illumination optical housing 12 when the optical element holding member 11 is fixed by the fixing member. FIG. 9C is an enlarged view of a circled portion in FIG.

  Next, as shown in FIG. 9, the fixing member 13, which is a plate-like member provided with a fitting hole 13 a for inserting the boss-shaped portion 11 c and a screw hole (fastening hole) 13 b, is fixed to the illumination optical housing 12. To do. That is, with the boss-shaped portion 11c protruding from the illumination optical housing 12 inserted through the fitting hole 13a of the fixing member 13, the screw 13c serving as a fastening member is stopped in the screw hole 13b, whereby the optical element holding member 11 The boss-shaped portion 11 c is fixed from the outside of the illumination optical housing 12. The fixing member 13 may be a member made of a metal member such as a magnesium alloy, for example.

  As described above, the optical element holding member 11 is made of a resin having a high coefficient of thermal expansion, and the illumination optical housing 12 is made of a metal having a low coefficient of thermal expansion. Therefore, the optical element holding member has a high coefficient of thermal expansion and is easily deformed. 11 is fixed to the illumination optical housing 12 that has a low coefficient of thermal expansion and is difficult to be deformed, so that deformation due to thermal expansion of the optical element holding member 11 can be suppressed, and position variation of the optical element can be suppressed.

  Therefore, it is possible to suppress the occurrence of image misalignment during operation, and the occurrence of luminance reduction and luminance unevenness in part of the image. Moreover, since the fixing member 13 is comprised from a sheet metal and a screw | thread, it can implement | achieve at low cost.

  The fixing position of the holding portion 11b from the outside of the illumination optical housing 12 is not limited to the location surrounded by the dotted line shown in FIG. 7, and the holding portion 11b holding the relay lens 7 and the concave mirror 9 has a boss. The shape portion 11c may be provided and fixed. Further, the fixing location is not limited, and it is also preferable to fix at a plurality of positions of the holding portion 11b.

  In the present embodiment, the fixing direction by the fixing member 13 is opposite to the direction (from the lower side in FIG. 8A) in which the base material portion 11a is attached to the illumination optical housing 12 by the attachment member (see FIG. 8A). However, the fixing direction is not limited to this. For example, even if the holding portion 11b is fixed from the side surface side of the illumination optical housing 12, the fixing direction is not limited to this. good. In this case, it is also preferable to fix at a plurality of positions.

<Second Embodiment>
Hereinafter, other embodiments of the image projection apparatus according to the present invention will be described. In addition, description about the same point as the said embodiment is abbreviate | omitted suitably.

  FIG. 10A is a perspective view of the optical element holding member 11 holding each optical element, and FIG. 10B is an enlarged view of the encircled portion of FIG. As shown in FIG. 10B, a screw hole (fastening hole) 11e is provided at the center of the three boss-shaped parts 11d provided in the holding part 11b.

  FIG. 11A is an explanatory diagram showing the state of assembly of the optical element holding member 11 holding each optical element and the illumination optical housing 12. FIG. 11B is an enlarged view of a circled portion in FIG. FIG. 11C is a perspective view of the illumination optical housing 12 after the optical element holding member 11 is assembled. FIG. 11D is an enlarged view of a circled portion in FIG.

  As shown in FIG. 11, the boss-shaped portion 11 d of the optical element holding member 11 has a length that fits without protruding when assembled in the fitting hole 12 d that is a hole provided in the illumination optical housing 12. It has become.

  FIG. 12A is an explanatory diagram when the optical element holding member 11 holding each optical element is fixed to the illumination optical housing 12 by a fixing member. FIG. 12B is a perspective view of the illumination optical housing 12 when the optical element holding member 11 is fixed by the fixing member.

  Next, as shown in FIG. 12, the optical element holding member 11 is held by fastening a screw (fastening member) 13 c as a fixing member into a screw hole 11 e provided in the center of the fitted boss-shaped portion 11 d. The part 11 b is fixed from the outside of the illumination optical housing 12. As a result, it is possible to suppress the occurrence of image misalignment during operation and the occurrence of luminance reduction and luminance unevenness in part of the image. Further, since only the screw 13c is used as the fixing member, the cost can be further reduced.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Image projection apparatus 2 Exterior cover 3 Optical engine 3a Illumination unit 3b Projection unit 4 Light source unit 5 Color wheel 6 Light tunnel 7 Relay lens 8 Plane mirror 9 Concave mirror 10 Image display element unit 10a DMD element 11 Optical element holding member 11a Base material Part 11b Holding part 11c, 11d Boss shape part 11e Screw hole 12 Illumination optical housing 12a Projection part 12b Through hole 12c Screw hole 12d Fitting hole 13 Fixing member 13a Fitting hole 13b Screw hole 13c Screw 14 Heat sink 15 Screen

JP 2011-221380 A JP 2003-259255 A

Claims (8)

A light source that emits light;
An image display element for forming an image;
An illumination unit that illuminates the image display element using light from the light source;
A projection unit for projecting an image formed by the image display element onto a projection surface;
The lighting unit is:
A plurality of optical elements for illuminating the image display element;
An optical element holding member that positions and holds the plurality of optical elements;
An illumination optical housing that covers the optical element holding member from a side on which the optical element holding member holds the plurality of optical elements;
The optical element holding member comprises a plurality of holding portions for holding each optical element, and a base material portion for supporting the plurality of holding portions,
At least one of the plurality of holding portions is fixed to the illumination optical casing from the outside of the illumination optical casing. The optical element holding member holds at least a relay lens, a plane mirror, and a concave mirror as the plurality of optical elements,
The image projection apparatus according to claim 1, wherein the holding unit of the flat mirror is fixed from the outside of the illumination optical housing.   In the optical element holding member, the base portion is attached to the illumination optical casing by an attachment member, and the holding portion is fixed to the illumination optical casing from the opposite side of the attachment position by the attachment member. The image projection apparatus according to claim 1, wherein the image projection apparatus is an image projection apparatus.   The image projection according to any one of claims 1 to 3, wherein the optical element holding member is fixed to the illumination optical casing from the outside of the illumination optical casing by a plurality of holding portions, respectively. apparatus.   The image projection apparatus according to claim 1, wherein the illumination optical housing is made of a material having a lower coefficient of thermal expansion than the optical element holding member. The holding portion has a boss shape portion,
The image projection apparatus according to claim 1, wherein the boss-shaped portion is fixed by a fixing member in a state where the boss-shaped portion is inserted or fitted into a hole provided in the illumination optical housing. . The boss-shaped portion protrudes through the hole provided in the illumination optical housing,
The image projection apparatus according to claim 6, wherein the fixing member includes a plate-like member having a through hole and a fastening hole that are inserted through the boss-shaped portion, and a fastening member that stops the fastening hole. The boss-shaped part has a fastening hole in the center part, and fits into the hole part provided in the illumination optical casing,
The image projection apparatus according to claim 6, wherein the fixing member is a fastening member that stops the fastening hole.