JP3027798B2 - Projection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for enlarging and projecting a projection material on a distant screen using a transmission type overhead projector.

[0002]

2. Description of the Related Art There are two methods of using a transmission type overhead projector.
In general, a method of enlarging and projecting a material on a screen about 3 m away is used, and a projection lens of an overhead projector having a focal length of about 300 mm is provided as a standard lens so as to be suitable for such a method of use. .

[0003]

When an A4-size original is projected onto a screen at a projection distance of 2 m using a standard lens having a focal length of 300 mm, the screen is enlarged to a size of about 1.7 m. However, when projected from a projection distance of, for example, 7 m, the screen size is about 5.
As it is enlarged to 7m, the screen size is 1.7m
The image runs off the screen on the standard size screen. In contrast, the point of use is about 900 mm
If a long focal length lens is used, an A4-size original can be enlarged and projected to fill a standard screen of 1.7 m in screen size from a projection distance of 7 m. However, when equipped with a long focal length lens instead of the standard lens,
The projection distance of the overhead projector is too long for general use, and the usability is extremely poor. In view of the above, an object of the present invention is to provide a projection apparatus capable of easily performing both enlarged projection with a standard lens and enlarged projection with a long focus lens.

[0004]

According to a first aspect of the present invention, a standard lens Fresnel lens for condensing illumination light of a projection light source for illuminating a projection material on a standard lens of a projection head is detachably incorporated in a housing. And, a transmission overhead projector provided so that the projection head can be retracted from above the stage on which the projection material is mounted, a pedestal on which the transmission overhead projector is mounted, and a column standing on the pedestal, A long-focal length projection head having a long-focal length lens and supported by the support so as to be positioned above the pedestal by an arm; and a standard lens Fresnel lens for focusing the illumination light on the long-focal length lens And a Fresnel lens for a long focal length lens which can be mounted on the housing. According to a second aspect of the present invention, in the projection device of the first aspect, a storage unit for storing the standard lens Fresnel lens or the long focus lens Fresnel lens is provided on the pedestal.

[0005]

According to the first aspect of the present invention, the projection material mounted on the stage with the standard lens of the projection head attached to the transmission overhead projector is enlarged by using the transmission overhead projector alone. Can be projected. In addition, while replacing the Fresnel lens for the standard lens of the transmission type overhead projector with the Fresnel lens for the long focus lens, the overhead projector is set on the pedestal with the attached projection head retracted from the stage, and the projection of the overhead projector is performed. When the projection material mounted on the stage is illuminated by the light source, the projection material can be enlarged and projected using the long focus lens of the long focus projection head. As described above, according to the projection device of the present invention, it is possible to easily perform the enlarged projection by the standard lens and the enlarged projection by the long focal length lens of the projection lens. According to the second aspect of the invention,
Of the Fresnel lens for the standard lens and the Fresnel lens for the long focus, the unused Fresnel lens can be stored in the storage portion of the pedestal, so that the Fresnel lens can be prevented from being lost or damaged, and the usability is good.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show a projection apparatus 10 according to an embodiment of the present invention. The projection device 10 includes a long focus lens unit 20 and a transmission type overhead projector 40. The long focus lens unit 10 includes a pedestal 21 on which the overhead projector 30 is installed,
Post 2 fixed on pedestal 21 by bracket 22
3. An arm 2 having a base end mounted on a column 23 so as to be movable up and down.
4. The arm 24 is positioned above the center of the pedestal 21.
And a long-focus projection head 25 attached to the tip of the camera. A rotation knob 26 is attached to a base end of the arm 24 by a pivot 27. The guide roller 2 is attached to the pivot 27.
8 are integrally fixed, and are pressed against the column 23 by a leaf spring 29. When the rotation knob 26 is operated, the guide roller 28 rotates while being pressed against the column 23, and the arm 24 is moved to the column 23.
Up and down along The long focus projection head 25 has a single focus type, a long focus lens 30 having a focal length of 900 mm, and a projection mirror 31. The long focus lens 30 has an optical axis
It is installed so that it intersects perpendicularly. The front end face of the pedestal 21 has a storage port 33 for storing a long focus Fresnel lens 32 or a standard lens Fresnel lens 55 described later.
Are formed.

[0007] Transmission overhead projector 40
Is a housing 41, a housing 41, as shown in FIG.
At the rear corner, there is provided a column 43 whose base end is rotatably mounted on a pivot 42, and a projection head 45 supported at the upper end of the column 43 by an arm 44. The projection head 45 has a focal length of 300.
A standard lens 46 of mm and a projection mirror 47 are provided. A lock mechanism for selectively locking the base end of the support column 43 to either a position standing up from the housing 41 as shown in FIG. 3 or a position falling down on the side surface of the housing 41 as shown in FIGS. Is built-in. When the column 43 is in the upright position, the optical axis of the standard lens 46 vertically intersects the center of the stage 48 formed on the upper surface of the housing 41. On the other hand, if the support column 43 falls on the side surface of the housing 41, the projection head 45 can be retracted from above the stage 48.

FIG. 4 schematically shows the internal structure of the housing 41. As shown in FIG.
1a is formed, and a transparent stage glass 49 is fitted into the window opening 41a to constitute a stage 48 on which a projection material 50 such as a film is placed. Inside the housing 41, a metal halide lamp 51, a spherical reflecting mirror 52 for reflecting illumination light of the lamp 51 toward the stage 48, and a condenser lens 5 for condensing the illumination light on the stage 48.
3. Fresnel lens for standard lens 5 for condensing illumination light on two heat ray reflection filters 54 and standard lens 46
5. A blower 56 that sucks outside air from a ventilation hole 41b formed on the right side surface of the housing 41 and exhausts heated air inside the housing 41 from a ventilation hole 41c on the left side surface.
b, 41c, a louver 5 for preventing the light of the metal halide lamp 51 from leaking out of the housing 41.
7 is built-in. Fresnel lens 55 for standard lens
Is detachably attached to an engaging portion 58 provided in the housing 41, and the Fresnel lens 32 for a long focal length lens can be attached to the engaging portion 58 instead of the Fresnel lens 55 for a standard lens. The focal length of the Fresnel lens 55 for a standard lens is such that the standard lens 46 has a focal length of 300 mm.
When the support 43 is erected as shown in FIG.
Is set so that the light of the metal halide lamp 51 can be condensed on the standard lens 46 located at a height of about 300 mm above. In contrast, the long focus Fresnel lens 32
Since the long focal lens 30 has a focal length of 900 mm, when the overhead projector 40 is installed on the pedestal 21 as shown in FIGS. 1 and 2, the focal length is about 900 mm above the stage 48. The focus lens 30 is set so that light from the metal halide lamp 51 can be collected.

The configuration of the projection apparatus 10 according to the present embodiment is as described above. The transmission overhead projector 40 is used as a single unit separately from the long focus lens unit 20 so that the transmission overhead projector 4 can be used.
A projection material 50 of A4 size placed on the stage 48 by the standard lens 46 of the projection head 45 attached to
Screen size 1.7m on a screen at a projection distance of 2m
Can be enlarged and projected in the size of. On the other hand, the projection material 50 is placed on a screen at a projection distance of 7 m, for example, with a screen size of 1.7.
In order to enlarge and project with a size of m, the Fresnel lens 55 for a standard lens of the transmission type overhead projector 40 is used.
Is replaced by a Fresnel lens 32 for a long focal length lens,
3 is retracted, the attached projection head 45 is retracted from the stage 48, the overhead projector 40 is set on the pedestal 21, and the stage 4 is moved by the metal halide lamp 51.
The projection material 50 placed on the lens 8 is illuminated, and the rotation knob 26 is operated to raise and lower the long focus projection head 25 to adjust the focus of the long focus lens 30. As described above, the projection device 10 according to the present embodiment can easily perform the enlarged projection by the standard lens 46 and the enlarged projection by the long focus lens 30. The Fresnel lens 3 not used among the standard lens Fresnel lens 55 and the long focus Fresnel lens 32
2 and 55 can be stored in the storage opening 33 of the pedestal 21, so that the Fresnel lenses 32 and 55 can be prevented from being lost or damaged without being mounted on the overhead projector 40, and the usability is good. In the projection device 10 according to the present embodiment, the focus adjustment of the long focus lens 30 is performed by the manual operation of the rotary knob 26. However, a motor is built in the base end of the arm 24 so that the motor can be driven. If configured,
Usability is further improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a projection device according to an embodiment of the present invention.

FIG. 2 is a front view showing the projection device.

FIG. 3 is a perspective view showing a transmission type overhead projector constituting the projection apparatus.

FIG. 4 is a cross-sectional view schematically showing an internal structure of the transmission overhead projector.

[Explanation of symbols]

10 Projection device, 20 Long focus lens unit, 21
Pedestal, 23 ... Support, 24 ... Arm, 25 ... Long focus projection head, 26 ... Rotation knob, 30 ... Long focus lens, 32 ...
Fresnel lens for long focal length lens, 33 ... storage port, 40 ...
Transmission overhead projector, 41 housing, 48 stage, 45 projection head, 46 standard lens, 55 Fresnel lens for standard lens.

Continuation of the front page (56) References Japanese Utility Model Showa 49-110639 (JP, U) Japanese Patent Publication No. 51-44406 (JP, B1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03B 21 / 132

Claims (2)

(57) [Claims] 1. A standard lens Fresnel lens for focusing illumination light of a projection light source for illuminating a projection material on a standard lens of a projection head is detachably built in a housing, and the projection head mounts the projection material. A transmission overhead projector provided so as to be able to retreat from above the stage to be mounted, a pedestal for mounting the transmission overhead projector, a support standing on the pedestal, a long focal length lens, and an arm having an arm above the pedestal. A long focus projection head supported by the support so as to be positioned, and a long focus lens fresnel mountable on the housing by exchanging with the standard lens fresnel lens to focus the illumination light on the long focus lens. A projection device comprising a lens. 2. The projection apparatus according to claim 1, wherein a storage unit for storing the standard lens Fresnel lens or the long focus lens Fresnel lens is provided on the pedestal.