JPS6148825A - Slanting projecting device - Google Patents

Abstract

PURPOSE:To project a distortion-free image on a projection surface slantingly by providing the optical axis of a projection lens system slantingly at a specific angle to the projection surface, and arranging a positive image behind the intersection of the optical axis and the perpendicular from the center of the projection lens system to the projection surface. CONSTITUTION:When the optical axis 2 is at 45 deg. to the projection surface 3, acute angleBCA is 45 deg., so acute angleBAC is 90 deg., so that a sharp image is obtained by the projection of a positive film on which a subject is photographed at 45 deg.. Further, a positive image 5 is arranged slantingly at the specific angle to the optical axis to obtain a sharper image having no defocusing up to corners of the image plane. For the purpose, the tilt angle beta is equalized to the angle that the optical axis 2 and a straight line 6 extended from the symmetrical point C on the projection surface 3 to the positive image 5 contain; tan(acute angleDCA)=AD/AC=gamma and beta=90 deg.-gamma, where tan (acute angleDCA) is an angle calculated from a distance AC on the straight line 6 and distance AD on the optical axis 2. Further, 90 deg.=acute angleBAC, so we have beta=acute angleBAC-gamma.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oblique projection device that projects an image onto a projection surface from an oblique direction.

For example, when drawing a pattern on a cake using chocolate, cream, etc., it would be very convenient to be able to project the image using a projector, but if you place the projector directly above the cake, the projector will get in the way, and you will also have to place your hands. In some cases, there is a problem that shadows are formed and the projected image cannot be used.

The present invention has been made to solve these problems, and its purpose is to provide an oblique projection device that projects an image without distortion onto a projection plane from an oblique direction.

That is, in the present invention, the optical axis of the projection lens system is inclined by a predetermined angle α with respect to the projection surface, and the optical axis is provided at a position rearward from the intersection of the perpendicular line descending from the center of the projection lens system to the projection surface and the optical axis. The tilting device in which the positive 1iTii image is arranged and the optical axis of the projection lens system are tilted at a predetermined angle α with respect to the projection plane, and Posi II in the rear position! ii [, and from a symmetrical position on the projection plane centering on the perpendicular line,
The tilt projection apparatus is characterized in that a positive image is arranged on a straight line extending to the rear positive image.

Such a projection device can be used for general one-to-one-to-one processing operations on cakes, T-sheets, and other objects, and especially when configured as in the second invention, it can be used for one minute projection even though it is an oblique projection. Blur around the image can be minimized.

The present invention will be explained in detail below. FIG. 1 is a principle diagram of an oblique projection device according to the present invention, in which 1 indicates a projection lens system;
2 is the optical axis of the projection lens system, 3 is the projection plane, 4 is a perpendicular line descending from the center A of the projection lens system 1 to the projection plane 3, B is the intersection of the optical axis 2 of the projection lens system 1 and the projection plane 3, C is a symmetrical point on the projection plane 3 of the intersection B centered on the perpendicular line 4, and the positive image 5 from the positive film is placed behind the projection lens system 1, and its position is changed again by focus adjustment.

In the above, if the angle at which the light 1lIllI2 intersects with the projection plane 3 is 45 degrees, LBCA is 45 degrees, and the angle to LB8 is 90 degrees (α = 45 degrees), so 45 degrees
A clear image (projected image) can be obtained by projecting a cocoon-shaped positive film of the subject from a degree angle.

Therefore, in the present invention, in addition to the above-mentioned (16-format image), by arranging the positive image 5 at a predetermined angle with respect to the optical axis, it is possible to obtain a sharp image without blur in every corner of the screen. The inclination angle β is the symmetry point C on the projection plane 3.
The straight line 6 extended from to the positive image 5 intersects the optical axis 2, and this angle β is tan(L DC8) = to 〇/toC = 7β-90
°−γ...■.

Well, 90° here = LB8C, so β-L B to C
−γ...■ is obtained.

According to the invention, the best projection effect can be obtained by setting the positive image 5 at β degrees or tilting it by 1 degree with respect to the optical axis 2.

2 to 6 relate to an embodiment of the second invention, in which 10 is a projection device body, 11 is a light source, 12 is a heat shielding filter, and 13 is a positive image 5 tilted by 1 degree with respect to the optical axis 2. 14 is a lens barrel of a projection lens system, 15 is a holding tool for inserting and removing the positive image 5 from above into the holder 13, and 15' is not showing a holding tool for inserting and removing the positive image from the side. Further, the projection device main body 10 is attached to a support 16 such that its height and angle can be adjusted, and the support 16 is erected on a base 17 having a built-in transformer and the like. Reference numeral 18 denotes a column attachment, 19 an elastic fixing portion interposed between the attachment 18 and the column 16, 20 a power cord, 21 a switch, and 2
2 is an outlet, 23 is a socket, and 24 is a cord 25 is a fuse material.

In the above configuration, the positive image 5 to be projected can be a slide film, an image drawn on a transparent film, or an image drawn on glass, but the angle at which the image is viewed and the projection angle are different. Must match. For example, when projecting a positive film photographed from above at an angle of 45 degrees, the inclined projection device is installed 45 degrees above and to the left of the user.
When the image is projected from there onto the projection surface 3, an undistorted image exactly as the original image can be projected in front of the user. In that case, the size of the image P is adjusted by adjusting the projection distance. Therefore, the user can trace the IP projected on the projection surface 3 using the projection light from the left with his/her right hand, allowing the user to proceed with the work smoothly without having his hands or face get in the way. Of course, in the case of a person who works with his left hand, it is sufficient to use a film that has been copied from the upper right and to project from the upper right.

Therefore, according to the present invention, since a positive image placed behind the center of the projection lens system is projected onto the projection plane from the same angle α at which it is drawn or imitated, an image without distortion can be obtained. Since the image is tilted with respect to the optical axis of the projection lens system, it is possible to project a sharp image without blur to every corner.

[Brief explanation of the drawing]

The drawings show an embodiment of the oblique projection device according to the present invention, in which Fig. 1 is a diagram explaining the principle, Fig. 2 is a vertical cross-sectional view, Fig. 3 is a cross-sectional view of main parts, and Fig. 4 is a positive image. FIG. 5 is an explanatory view showing the relationship between the support and the elastic fixing device, and FIG. 6 is a perspective view of the device in use. 1... Projection lens system, 2... Tip axis, 3... Projection surface, 4... Perpendicular line descending from the center of the projection lens system to the projection surface, 5... Positive image, A... - Center of the projection lens system. Patent applicant Century Enterprise Co., Ltd. Figure 2 Figure G

Claims (3)

[Claims] (1) The optical axis of the projection lens system is set at a predetermined angle α with respect to the projection plane.
1. An inclined projection apparatus, characterized in that the positive image is arranged at a position rearward from the intersection of the optical axis and a perpendicular line descending from the center of the projection lens system to the projection surface. (2) The optical axis of the projection lens system is set at a predetermined angle α with respect to the projection plane.
A positive image is placed at a position behind the intersection of the optical axis with a perpendicular line descending from the center of the projection lens system to the projection plane, and from a symmetrical position on the projection plane about the perpendicular line, An oblique projection device characterized in that a positive image is arranged on a straight line extending to the rear positive image. (3) The tilt projection device according to claim 2, wherein the positive image is a positive film obtained by photographing from a direction tilted by a predetermined angle α with respect to the surface on which the subject is placed.