JP3015158U - Reflective real projector - Google Patents

Abstract

(57) [Summary] [Purpose] The mechanism and structure of a reflection type real projector are simplified, the number of parts is reduced, and the cost is reduced. A light source, a stage 24 through which light from the light source is transmitted and on which an object to be projected can be placed, a reflection mirror 22a (22b) that reflects reflected light from the object to be projected,
The present invention relates to a reflection-type real projector including a projection lens 23 that collects reflected light from the reflection mirror and forms a projection image of a projection object on an external screen. The reflection mirror 22a (22b) is formed so as to be rotatable about an axis O ₁ parallel to the projection lens surface, and the virtual image projection surface of the projection object through the reflection mirror, the projection lens surface, and the connection on the screen. The reflection mirror 22a (22b) is rotated so that the image plane and the Scheimpflug condition are satisfied.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a reflection-type real projector for projecting reflected light from a projection object placed on a stage onto a screen via a reflection mirror and a projection lens.

[0002]

[Prior art]

 As a conventional reflection type real projector of this type, there is a reflection type real projector according to U.S. Pat. This reflection type real projector has a so-called positional relationship among a virtual image of an object to be projected (a surface where a virtual image exists), a projection lens surface (a surface orthogonal to the optical axis of the projection lens), and an image forming surface on a screen. A mechanism equipped with a mechanism for changing the stage angle so as to satisfy the Scheimpflug condition (the above three surfaces are parallel or their extended surfaces intersect on the same straight line) The purpose of this is to easily obtain a projected image with no out-of-focus on the screen surface when the projection direction and the screen surface are not orthogonal.

FIG. 3 is a principle diagram of the above conventional technique. In the figure, 21 is a casing, 22 is a reflection mirror, 23 is a projection lens, C is its focal point, and 24a is a transparent stage on which an object to be projected is placed. A light source for irradiating the projection target with light from below the stage 24a is provided in the casing 21, but is not shown for convenience. Due to the relationship with the height of the screen, this type of real projector is usually installed at an elevation angle θ _{0 with} respect to the horizontal plane. The virtual image of is like 25a shown by the solid line.

Therefore, in order to obtain a projection image without blurring in the vertical direction, the image plane of the projection object on the screen through the projection lens 23 needs to be set to S _{1. In} other words, It is necessary to install the screen so that it coincides with the image plane S ₁ . However, if the projection direction and the screen surface are not orthogonal, the virtual image projection surface, the projection lens surface, and the actual image formation surface are not parallel to each other, and these extension surfaces do not intersect on the same straight line. , The Scheimpflug condition is not met, and the top or bottom of the projected image becomes out of focus.

Therefore, in the above-mentioned conventional technique, the stage 24a is rotatable about the axis O parallel to the projection lens surface to the position shown by the broken line. Assuming that the rotation angle of the stage 24b at this time is θ ₁ , the virtual image 25b of the projection target becomes the position of the broken line rotated by the angle θ ₂ (= θ ₁ ) from the original virtual image 25a, and the projection lens 23 is moved. The image plane of the projected image through is S ₂ and coincides with the screen plane (vertical plane). Therefore, the virtual image projection surface, the projection lens surface, and the respective extended surfaces of the image formation surface (vertical surface) on the screen intersect on the same straight line, which satisfies the Scheimpflug condition and eliminates the out-of-focus image of the projection image. be able to.

[0006]

[Problems to be solved by the device]

 However, the above conventional technique has the following problems. First, if the structure is such that a gap is created between the rotating stage and the casing 21, the cooling efficiency by the cooling fan arranged inside the casing 21 will be reduced, so that a machine that does not leak cooling air will be used. It is necessary to take a physical structure. In addition, since the stage is rotatable, a mechanism to hold the projection target on the stage so that it does not slide down is required, and the structure is complicated, including the mechanism that supports the stage to rotate. However, the number of parts increased and the cost increased.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a simple structure and low cost by making a reflecting mirror rotatable instead of a stage. It is to provide a reflection-type real projector that has made possible.

[0008]

In order to achieve the above-mentioned object, the present invention provides a light source, a stage through which light from the light source is transmitted, and a projection object can be placed, and a projection object. In a reflection-type real projector equipped with a reflection mirror for reflecting the reflected light of and a projection lens for condensing the reflected light from the reflecting mirror to form a projection image of the projection object on an external screen , A reflecting mirror is formed so as to be rotatable about an axis parallel to the projection lens surface, and the virtual image projection surface of the projection object through this reflection mirror, the projection lens surface, and the image formation surface on the screen. Is to rotate the reflecting mirror so as to satisfy the Scheimpflug condition.

[0009]

[Action]

 In the present invention, by adopting a structure in which the reflecting mirror is rotated, it is possible in principle to satisfy the Scheimpflug condition and eliminate the out-of-focus image of the projected image as in the prior art. Further, since the structure for rotating the stage is not adopted, it is not necessary to consider the structure for closing the gap that may occur between the stage and the casing and the mechanism for holding the projection target on the stage. As a result, the structure can be simplified, the number of parts can be reduced, and the cost can be reduced.

[0010]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram showing an embodiment, and the same components as those in FIG. 3 are designated by the same reference numerals. In this embodiment, the stage 24 is fixed, while the reflecting mirror in the casing 21 is rotatable about an axis O ₁ parallel to the projection lens surface. The rest of the structure is the same as the conventional one and is not the main part of the present invention, so the description is omitted.

A structure for rotating the reflection mirror is, for example, as shown in FIG. In FIG. 2, O ₁ is an axis that serves as the center of rotation of the reflection mirror, and a guide pin 30 is fixed to the rear surface of the tip of the reflection mirror 22a shown by the solid line. On the other hand, 29 is a semi-circular reflecting mirror drive cam which is rotatable about an axis O ₂ parallel to the axis O ₁ . The drive cam 29 is a kind of eccentric cam, and is rotatable in the direction of arrow a in the figure along a guide pin 30 slidably engaged with the peripheral portion thereof.

That is, as the drive cam 29 rotates in the direction of arrow a, the length between the shaft O ₂ and the peripheral portion of the drive cam 29 gradually increases and engages with this peripheral portion. As the guide pin 30 gradually moves away from the axis O _{2, the} free end of the reflection mirror rotates as shown by arrow b in the figure. Accordingly, the reflection mirror 22a shown by the solid line can be rotated to the position of 22b shown by the broken line.

Therefore, by rotating the drive cam 29 from the outside of the casing 21 by a known means such as a dial operation, the reflecting mirror 22a can be rotated by a desired angle. In FIG. 2, reference numeral 26 is a cover for holding the projection object on the stage 24, 27 is a cooling fan for blowing air inside the casing 21 to cool it, and 28 is an extendable leg for adjusting the elevation angle. .

In FIG. 1, it is assumed that the actual projector is installed at an elevation angle θ ₀ with respect to the horizontal plane. At this time, if the reflection mirror is located at the position indicated by the solid line, the virtual image of the object projected on the stage 24 (illustrated as a straight line corresponding to the stage 24 in the figure) by the reflection mirror 22a is indicated by the solid line. It becomes 25a shown.

At this time, in order to prevent the projected image on the screen from being out of focus, the virtual image projection surface (the surface where the virtual image 25a exists), the projection lens surface (the optical axis of the projection lens 23 are orthogonal to each other, depending on the Scheimpflug condition. Surface) and the screen surface must be parallel to each other. That is, the screen surface and the image forming surface S ₁ need to coincide with each other. However, as long as the screen is installed vertically, for example, when the screen is on the image forming plane S ₂ in the figure, the image forming position I _{2 at} the lower end of the projected image is in focus, but the upper end is at the upper end. The focus will be out of focus in the vicinity of part I ₃ .

Therefore, in the present embodiment, with the structure shown in FIG. 2, the reflecting mirror is rotated by the angle θ ₁ about the axis O ₁ as shown in FIG. The reflecting mirror after this rotation is indicated by 22b by a broken line. At this time, the virtual image of the projection object by the reflection mirror 22b becomes 25b shown by a broken line, and the rotation angle θ _{2 of the} virtual image is doubled with respect to the rotation angle θ ₁ of the reflection mirror (θ ₂ = 2θ ₁ ).

At this time, the projected image through the projection lens 23 is imaged on the vertical image plane S ₂ as in FIG. Therefore, since the focus position of the image formation at the upper end moves to I ₃ , the virtual image projection surface (the surface where the virtual image 25b exists), the projection lens surface, and each extension surface of the image formation surface S ₂ on the screen are on the same straight line. Therefore, the Scheimpflug condition is satisfied and the upper and lower image forming positions I ₃ and I ₂ of the projected image are in focus.

In the above embodiment, the axis O ₁ is provided at the upper end of the reflecting mirror, but this axis may be provided at the back or the lower end of the reflecting mirror, and in any case, the axis is parallel to the projection lens surface. It suffices to rotate the reflection mirror about.

According to the present embodiment, since it is not necessary to rotate the stage 24 as in the conventional case, a structure for closing a gap that may occur between the stage and the casing 21, and a projection object on the stage 24 are held. A mechanism for doing so is unnecessary. Further, since the mechanism for rotating the reflecting mirror need only be as simple as shown in FIG. 2, it can be manufactured easily and can be provided at a low cost. In particular, compared with the structure in which the stage is rotated as shown in FIG. 3, in order to make the rotation angle of the virtual image the same, the rotation angle of the reflection mirror is half of the rotation angle of the stage in FIG. It will be. Therefore, it is suitable when there is a restriction on the space, and the amount of operation for rotating is small.

[0020]

[Effect of device]

 As described above, according to the present invention, the structure of the actual projector is simplified, the mechanism is simplified, the number of parts is reduced, and the cost is reduced by adopting a structure in which the reflection mirror is rotated to prevent the out-of-focus image of the projected image. Will be possible.

[Brief description of drawings]

FIG. 1 is a principle view showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

FIG. 3 is a principle diagram showing a conventional technique.

[Explanation of symbols]

21 casing 22a, 22b reflection mirror 23 projection lens 24 stage 25a, 25b virtual image 26 cover 27 cooling fan 28 leg 29 reflection mirror drive cam 30 guide pin C focus I ₁ , I ₂ , I ₃ image formation position S ₁ , S ₂ Image plane O ₁ and O ₂ axes

Claims (1)

[Scope of utility model registration request] 1. A light source, a stage through which light from this light source is transmitted and on which a projection object can be mounted, a reflection mirror which reflects light reflected from the projection object, and reflection from this reflection mirror. In a reflection type actual projector equipped with a projection lens that collects light and forms a projected image of the projection object on an external screen, the reflection mirror can be rotated around an axis parallel to the projection lens surface. It is characterized in that the reflecting mirror is rotated so that the virtual image projection surface of the projection object, the projection lens surface, and the image forming surface on the screen through this reflecting mirror satisfy the Scheimpflug condition. Reflective real projector.