JPH0432671Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a three-dimensional image reproducing device that obtains a three-dimensional image by inputting images of an object photographed from different directions to the right eye and the left eye, respectively.

BACKGROUND ART Conventional three-dimensional image reproduction devices include, for example, a device as shown in FIG. This device is constructed by arranging rectangular images A and B under a lenticular sheet 1 made up of a collection of semicylindrical minute lenses.

Images A and B are images of the same subject taken from different directions and cut into rectangular shapes, and are provided in pairs corresponding to the semicylindrical lenses of the lenticular sheet. In addition, the positional relationship between images A and B and the lenticular sheet is such that when the observer's right eye ER and left eye EL are at the planned observation positions shown in the diagram, the right eye ER is moved from image A to the right eye ER due to the refractive power of the lens. The luminous flux from image B is set to be input to the left eye EL,
This allows the viewer to view an image with a three-dimensional effect.

Problems to be Solved by the Invention However, in the conventional three-dimensional image reproduction device described above, the visible range of images A and B is limited by the refractive power of the lens of the lenticular sheet, so the position of the eye is slightly Even if the two images are shifted, the two images will appear to be duplicated, resulting in a problem that the range that can be observed as a three-dimensional image is narrow. Note that this observation range corresponds to the width of each image, and it is possible to widen the range by narrowing the width, but if the width is narrowed too much, the brightness of the image will naturally decrease, so it is necessary to maintain a certain image quality. As mentioned above, the tolerance for misalignment between the device and the eye is inherently small and limited.

By the way, the present inventor has already proposed a three-dimensional image reproducing device that utilizes two prisms 2 and 3 to input light beams from two images to the right eye ER and the left eye EL, respectively, as shown in FIG. are doing. This device uses the critical angle of the prism to limit the exit angle of the luminous flux from the two images, so even if the eye and the device are misaligned, the right eye ER will receive image A, and the left eye EL will receive image A. The luminous flux from image B is input,
The range that can be observed as a three-dimensional image is wider than that using the lenticular sheet described above.

However, since a prism corresponding to the size of the image is required, there is a problem that the device becomes thick and it is impossible to observe an image wider than the interpupillary distance.

Purpose of the invention This invention was created in view of the above-mentioned problems, and the positional relationship between the eye and the device allows for a wide range of stereoscopic images to be observed, and the overall thinness allows for the observation of images wider than the width of the eyes. The purpose of the present invention is to provide a stereoscopic image reproducing device that can reproduce images.

Means for Solving the Problems The three-dimensional image reproducing device according to this invention, when a line segment connecting both eyes at a scheduled observation position is defined as a base line, is configured to set the center of the base line as the focal point in the cross section of the base line including the base line. A lens section is provided, and below this positive lens section,
A plurality of prism parts each consisting of a pair of prisms are provided in parallel along the base line direction, and the first prism is
A first input surface facing the image and a first slope that internally reflects a part of the luminous flux from the first image in contact with the air layer toward the positive lens side are formed, and the second prism faces the second image. a second input surface that faces the first slope with an air layer in between, and a second slope that allows a part of the light beam from the second image to pass through and enter the positive lens via the first prism. and the critical angles of the first and second slopes are set so that the light flux from the first image and the light flux from the second image are positive at different angles with the optical axis direction of the positive lens as the boundary within the baseline cross section. It is characterized by being set so that it enters the lens.

Examples This invention will be explained below based on the drawings. 1 to 3 show an embodiment of this invention.

First, as shown in FIG. 1, a line segment connecting the right eye ER and left eye EL of the observer at the planned observation position is defined as a base line l, and the midpoint thereof is defined as M.

This three-dimensional image reproducing device includes a thin Linder Fresnel lens FL as a positive lens portion whose focal point in a base line cross section including the base line l coincides with the midpoint M, and a generatrix direction b of this Fresnel lens FL (see Fig. 3). Seven long prism parts arranged in parallel along the base line direction
It consists of PR, PR,...

As shown in the enlarged view in Fig. 2, each prism part PR has a first,
It is composed of second prisms 10 and 20, and first and second images A and B that are rectangular in shape and long in the generatrix direction b.

Further, the first prism 10 is a Fresnel lens.
It is a right-angle prism having an oblique angle of 45° and having an observation surface 11 facing the FL, a first input surface 12 facing the first image A, and a first slope 13 in contact with the air layer AI.

The second prism 20 has a second input surface 21 facing the second image B and parallel to the observation surface 11, and a first slope 1.
3 and a second slope 22 facing parallel to each other.
This is a right-angled prism that is symmetrical to the prism 10.

Note that both prisms 10 and 20 are arranged so that the critical angle at the d-line is 45°, that is, the refractive index nd=
It is made of a glass material such that 1/sin45°=1.41421.

Images A and B are stereo images taken of the subject from different positions, such as photographs cut into strips, and one pair is provided for each prism section. However, as will be described later, the light flux from the first image A is reflected once and enters the Fresnel lens FL, whereas the light flux from the second image B is incident without being reflected, so both images are reversed. It must be a statue.

Next, the operation of the stereoscopic image reproducing device with the above configuration will be explained.

FIG. 1 is an explanatory diagram along a baseline cross section that includes the baseline l and is orthogonal to the generatrix b of the Fresnel lens FL,
Below, explanation will be given within this baseline cross section.

Since the Fresnel lens FL is configured such that the focal point within the baseline cross section coincides with the midpoint M of the baseline l, the light ray passing through the midpoint M becomes parallel to the optical axis of the Fresnel lens FL, and the first prism 20 observation planes 1
It is perpendicular to 1.

The part of the light flux from the first image A that has an incident angle larger than the critical angle due to the first slope 13, that is, the part that has an incident angle larger than the ray passing through the midpoint M indicated by the dashed line, is on the Fresnel lens FL side. reflected to. The reflected light beam exits from the observation surface 11 and reaches only the right side in the figure from the midpoint M of the base line l via the Fresnel lens FL.

On the other hand, the light flux from the second image B is
Accordingly, a portion having an incident angle smaller than the critical angle, that is, a portion having an incident angle smaller than the light ray indicated by the dashed line is transmitted through the second slope 22.
The transmitted light flux enters the first slope again, exits from the observation surface 11, and reaches only the left side in the figure from the midpoint M via the Fresnel lens FL.

Therefore, the light flux from the first image A is input only to the right eye ER, and the light flux from the second image B is input only to the left eye EL, so the observer sees different images with both eyes, and both images By converting the image into a stereo image as described above, a three-dimensional image can be observed.

In addition, because the configuration uses the critical angle of the prism to limit the light flux that enters each eye of the observer, even if the observer's eyes are slightly shifted from the intended observation position, the two images will not appear duplicated. , it is possible to continue observing 3D images.

In addition, in the above embodiment, only an example in which the positive lens part was provided independently of the prism part was described, but the observation surface 11 of the first prism may have an upwardly convex shape and be integrated with the positive lens. In addition, although a cylinder Fresnel lens was used as the positive lens part,
The present invention is not necessarily limited to this, and it goes without saying that a normal non-Fresnel lens may be used, and a spherical lens may also be used.

Effects of the Invention As explained above, the three-dimensional image reproducing device of this invention has a structure in which the individual prism parts emit light beams from the images for the right eye and the image for the left eye at different angles by utilizing the critical angle of the prism. In addition, the system is configured so that these light beams are input to the observer's right and left eyes through the positive lens, making the range of observation positions wider than before, and even if the observation positions are slightly shifted, the images appear to overlap. In addition, it is possible to visually recognize images that are wider than the distance between the eyes.

Furthermore, since there are a plurality of prism parts, the thickness of the device can be kept small.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram within a baseline cross section showing an embodiment of the three-dimensional image reproducing device according to this invention, FIG. 2 is an enlarged view of the prism section shown in FIG. 1, and FIG.
A top view of the cylinder Fresnel lens shown in the figure,
FIGS. 4 and 5 are explanatory diagrams of a conventional stereoscopic image reproduction device. FL...Fresnel lens (positive lens part), PR...
... Prism section, 10... First prism, 12...
First input surface, 13...first slope, 20...second prism, 21...second input surface, 22...second slope, A...first image, B...second image, l... ...baseline, M...midpoint.

Claims (1)

[Scope of utility model registration request] A positive lens part whose focal point is the center of a baseline connecting both eyes at a scheduled observation position in a baseline cross section including the baseline, and a first prism and a second prism, which are arranged in parallel along the baseline direction. the first prism has a first input surface facing the first image, and the first prism in contact with an air layer.
The second prism has a first slope that internally reflects a part of the light flux from the image toward the positive lens, and the second prism has a second input surface facing the second image, and the first slope.
a second slope facing the slope with an air layer in between, and transmitting a part of the luminous flux from the second image to enter the positive lens via the first prism; 1. The critical angle of the second slope is set so that the light flux from the first image and the light flux from the second image enter the positive lens at different angles with the optical axis direction of the positive lens as a boundary within the baseline cross section. A stereoscopic image reproduction device characterized by: