JPH0355951Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a reflective overhead projector, more specifically, a mirror Fresnel plate illuminates the mirror Fresnel plate from a light source located above the mirror Fresnel plate and reflects the light toward the light source. The present invention relates to a reflective overhead projector that projects the reflected light onto a screen via a projection mirror and a projection lens to enlarge and project an object.

[Technical background] The above reflective overhead projector is
A projector has been proposed in which a mirror Fresnel plate is arranged in the projector main body, and the illumination section and the projection section are supported by a lid, thereby making the projector foldable and convenient to carry.

The present invention has further improved the reflective overhead projector that has the above-mentioned advantages, allowing the optical system to be housed more efficiently within a fixed volume consisting of the projector body and the lid, and has improved operability. The purpose is to provide an overhead projector.

[Structure of the idea]

The above object of the present invention is to illuminate the mirror Fresnel plate from a light source located above the mirror Fresnel plate, reflect it toward the light source, and project this reflected light onto a screen via a projection mirror and a projection lens to display the object. This is a reflection type overhead projector that performs enlarged projection, and includes a projector body with a mirror Fresnel plate placed on the top surface, a projection unit section equipped with a light source, a projection mirror, and a projection lens at one end, and a projection unit section at the other end. and a lid body pivotally supported on the Ector main body, the projection unit portion being held movably substantially parallel to the opening/closing axis of the other end, and the projection lens protruding from the side surface of the lid body during projection. This is achieved by a reflective overhead projector characterized by the following.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a portable reflective overhead projector is comprised of a box-shaped projector main body 10 and a lid 12 supported by hinges 17 and 18.

As shown in FIGS. 2 and 3, the projector with the lid 12 in the open state is connected to the pin 4 of the stay 15, which is pivotally supported on the side surface of the main body 10 by a pin 32.
1 slides within the J-shaped guide groove 33 provided on the side surface of the lid body 12, and the pin 41 engages with the lock portion 34 of the J-shaped guide groove 33, thereby maintaining the open state of the lid body 12. .

Inside the housing 14 at the tip of the lid 12, as shown in FIGS. 2 and 3, there are two rails 21 parallel to the axes of the hinges 17 and 18 in order to slide the illumination projection unit 11. It is provided. Sliding plates 24 and 26 fixed to both ends of the projection unit frame 22 are slidably attached to the rail 21.

As shown in FIG. 2, an illumination mirror 28 is attached to the projection unit frame 22 via an illumination mirror fixing member 50, and a light source lamp 54 is attached via a light source fixing member 52. The projection unit frame 22 is further provided with a shaft 101, on which a lens barrel holding member 102 for holding the lens barrel 52 and a reflection mirror holding member 103 for holding the reflection mirror 30 are supported.

A sun gear 104 is attached to the reflective mirror holding member 103.
are integrally formed. The lens barrel holding member 102 is provided with an internal gear 106 and a planetary gear 109 via a pin 107. The angle change (projection angle setting) α° of the lens barrel 52 is transmitted as 1/2α° to the reflecting mirror 30 by the gear train. A compression spring member (not shown) is arranged on the shaft 101 between the projection unit frame 22 and the lens barrel holding member 102, so that the projection unit frame 22 and the lens barrel holding member 10
2, the lens barrel 52
An arbitrary tilt angle of is maintained. Light source lamp 54
A ventilation window 25 is provided in the side wall of the housing 14 in the vicinity.

On the inner surface of the housing 14 on the lens barrel 52 side, there is a stopper 55 for positioning the illumination projection unit 11 at a predetermined position for projection, and a stopper 55 for positioning the projection unit frame when the illumination projection unit 11 is stopped by the stopper 55. 22 comes into contact and turns ON
A light source power switch 56 is provided.

On the other inner surface of the housing 14, there is further provided a first spring member 58 for pressing and fixing the illumination projection unit 11 against the stopper 55 with a small force, and a first spring member 58 for pressing and fixing the illumination projection unit 11 against the stopper 55 with a small force. A second spring member 59 for fixing by force is provided.

The main body 10 has a mirror Fresnel plate 60 disposed on its upper surface, and a notch 62 into which the tip of the lid 12 fits is provided on one side opposite to the side to which the hinges 17 and 18 are attached. There is. On the other hand, no notch is provided on the other side so that the side of the main body 10 closes the opening 64 when the lid 12 is in the closed state. Furthermore, the hinge 1 of the projector main body 10
A stopper 16 is attached to the end opposite to 7 and 18, and acts to maintain the lid 12 in a closed state. Furthermore, a handle 13 for hanging is provided on the side surface of the projector main body 10.

Next, a method of operating the overhead projector having the above configuration will be explained. First, the lid body 12
The device can be placed in the closed state shown in FIG. 1 and carried using the handle 13. Then, when the overhead projector is installed in the desired position, the stopper 1
6 is opened to bring the lid member 12 into the open state shown in FIGS. 2 to 4. At this time, the illumination projection unit 11 is in the storage position shown in FIG. Subsequently, the illumination projection unit 11 is moved to the right as shown in FIG. 2 against the restraining force of the second spring member 59, and is positioned at a projection position where the sliding plate 26 abuts against the stopper 54. At this time, the power switch 56 is turned on by contact with the sliding plate 26, and the movement of the illumination projection unit 11 to the projection position is maintained by the restraining force of the first spring member 58.

By turning on the power switch 56, the light source lamp 5
4 is turned on, the illumination light from the light source lamp 54 is reflected by the illumination mirror 28 and reaches the mirror Fresnel plate 60, and the projection light reflected by the mirror Fresnel plate 60 is transmitted to the reflection mirror 30 and the projection lens 120.
is projected toward a screen (not shown) through the screen. Subsequently, the lens barrel is swung up and down to allow the projection light flux to reach the screen. Preparation for projection is now complete, and when a subject written on transparent paper with opaque or colored transparent ink is placed on the mirror Fresnel plate 60, the image is formed on the screen.

Note that in the above embodiment, the light source lamp 54
The heat emitted is radiated through the ventilation window 25, but in order to further enhance the heat radiation effect, it is desirable to provide a ventilation fan at a suitable location.

Further, in the above embodiment, since the mirror Fresnel plate 60 is fixed to the main body 10, when the diameter of the lens barrel 52 is large or when the back focus of the projection lens is short, the lens barrel 52 and the mirror Fresnel plate 60
The contact with 0 limits the miniaturization of the overhead projector in the closed state. However, the mirror Fresnel plate 60 is pivotally supported near the hinges 17 and 18 of the main body 10 so that it can swing downward, that is, into the interior of the main body 10, and the mirror Fresnel plate 60 is By swinging downward, the above-mentioned restrictions on miniaturization can be significantly reduced.

[Effect of idea]

According to the present invention configured as described above, the illumination section and the projection section can be moved to the storage position when carried, so the entire projector can be downsized, and the illumination section and the projection section can be moved to the center of the mirror Fresnel board during projection. The projection lens can protrude from the lid body even when moved to a projection position corresponding to the position, and long lenses and zoom lenses can also be used, providing an extremely large degree of freedom in designing the optical system. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a perspective view of an overhead projector with the lid closed, and FIG. 2 is a perspective view of the overhead projector with the lid open and the illumination projection unit in the projection position. 3 is a sectional view taken along the line - in FIG. 2, and FIG. 4 is a front view of the overhead projector with the lid open and the light source projection unit in the storage position. DESCRIPTION OF SYMBOLS 10... Projector main body, 11... Lighting projection unit, 12... Lid body, 15... Stay, 2
1...Rail, 22...Projection unit frame,
28...Illumination mirror, 30...Reflection mirror, 50
...Light source lamp, 56...Power switch, 58...
...First spring member, 59... Second spring member, 60...
...Mirror Fresnel board.

Claims (1)

[Claims for Utility Model Registration] A light source located above the mirror Fresnel plate illuminates the mirror Fresnel plate and reflects it toward the light source, and this reflected light is projected onto a screen via a projection mirror and a projection lens to create an object. A reflective overhead projector that enlarges and projects images includes a projector main body on which a mirror Fresnel plate is arranged, a projection unit section equipped with a light source, a projection mirror, and a projection lens at one end, and a projector unit section at the other end. and a lid pivotally supported on the main body, the projection unit portion being held movably substantially parallel to the opening/closing axis of the other end, and the projection lens protruding from the side surface of the lid during projection. A reflective overhead projector featuring: