JPH0432672Y2 - - 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 obtained by cutting images of the same subject taken from different directions 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 from each other, 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 you narrow the width too much, the brightness of the image will naturally decrease, so it is necessary to maintain a certain image quality. In order to achieve this, the tolerance for misalignment between the device and the eye is essentially small and limited as described above.

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, a prism corresponding to the size of the image is required, and the images cannot be arranged on the same plane, so there is a problem that the device becomes thick. Another problem was that it was not possible to observe images 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 is provided, and under this positive lens, a plurality of columnar prisms each having upper and lower surfaces perpendicular to the optical axis in the baseline cross section of the positive lens and slopes parallel to each other are placed with the slopes facing each other with an air layer interposed therebetween. These columnar prisms are arranged in parallel, and the upper surfaces of every other columnar prism are shielded, and a first image is placed facing on the lower surface of the shielded columnar prisms, and a second image is placed on the lower surface of the unshielded columnar prisms. The images are placed facing each other, and the slopes of the columnar prism are arranged so that the light beam from the first image that has passed through the two slopes and the light beam from the second image that has been reflected by the two slopes are the light of the positive lens within the baseline cross section. This is characterized in that the critical angle is set so that the light enters the positive lens at different angles with respect to the axial direction.

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 a base line l coincides with a midpoint M, and a generatrix direction of this Fresnel lens FL (direction perpendicular to the paper surface).
14 in this example, long and parallel along the baseline direction.
It is equipped with book-shaped prisms PR ₁ , PR ₂ , ... PR ₁₄ .

Each columnar prism PR ₁ , PR ₂ , ...PR ₁₄
As shown enlarged in FIG. 3, the Fresnel lens FL has an upper surface 10 and a lower surface 11 perpendicular to the optical axis AX, and slopes 12 and 13 parallel to each other. These prisms are arranged with their slopes facing each other with an air layer AI in between.
As shown in FIG. 2, the upper surface 10 is shielded by a shielding film 20 every other line.

In this example, the angle of the slope 13 with respect to the optical axis AX is set to 42°, and the columnar prism is
It is formed from a glass material that has a critical angle of 42° at the d-line, that is, a refractive index of nd = 1/sin42° = 1.49448, and satisfies the condition that the slope angle and critical angle are equal. Other glass materials may also be selected.

Further, on the lower surface of the columnar prism whose upper surface 10 is shielded, a first image A having a long rectangular shape in the generatrix direction b is arranged to face the columnar prisms PR ₁ , PR ₃ , . . . whose upper surfaces are not shielded. The bottom of PR ₁₃ has the first
A second image B in the form of a strip similar to image A is placed opposite to it. These images are stereo images of the subject photographed from different directions, and may be photographs, television images, or the like. In particular, since both images are located in the same plane, it is suitable for liquid crystal televisions and the like. Note that, as described later, the light beam from the first image A is reflected twice and passes through the Fresnel lens.
Since the light flux from the second image B enters the FL without being reflected, there is no need to make both images inverted images, unlike the conventional example shown in FIG.

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 columnar prism PR It is perpendicular to the upper surface 10 of ₁ to ₁₄ .

The light flux from the first image A enters from the lower surface 11 of the columnar prism PR ₇ whose upper surface 10 is shielded as shown in FIG. A portion having an incident angle smaller than the optical axis AX shown by the dashed line is transmitted, and the rest is reflected. The transmitted light flux passes through the slope 12 and top surface 10 of the columnar prism PR ₈ and enters the Fresnel lens FL.
It reaches only the right side in the figure from the midpoint M of the base line l via FL.

On the other hand, the light beam from the second image B enters from the lower surface 11 of the unshielded columnar prism PR ₈ , and is blocked by the slope 13 at a portion having an incident angle larger than the critical angle, that is, an incident angle larger than the optical axis AX. The part that has the light is reflected and the rest is transmitted. The reflected light beam is reflected again by the slope 12 of the columnar prism PR ₈ , passes through the upper surface 10, and passes through the Fresnel lens.
The light enters the FL side and reaches only the left side in the figure from the midpoint M of the base line l via the Fresnel lens FL.

These effects apply not only to the two prisms shown in FIG. 3, but to all columnar prisms. Therefore, as shown in FIG.
The luminous flux from the second image B is input only to the right eye ER, and the luminous flux from the second image B is input only to the left eye EL, so
The viewer sees different images with both eyes, and by converting both images into stereo images 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 the above embodiments, a cylindrical Fresnel lens is used as the positive lens portion, but the present invention is not necessarily limited to this, and a normal non-Fresnel lens may be used, as well as a spherical lens.

Effects of the Invention As explained above, the three-dimensional image reproducing device of this invention has a configuration in which the light beams from the images for the right eye and the left eye are emitted at different angles by utilizing the critical angle of the prism. Since the light flux is input to the observer's right and left eyes through the positive lens section, the range of observation positions is wider than before.
Even if the viewing position is slightly shifted, the images will not overlap, and images wider than the eye width can be viewed.

Furthermore, since the prism is divided into a plurality of parts and the images are provided on the same plane, 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 a plan view of the cylinder Fresnel lens shown in Fig. 1, and Fig. 3 is the same as Fig. 1. 4 and 5 are explanatory diagrams of a conventional three-dimensional image reproduction device. FL……Fresnel lens (positive lens), PR……
Prism, 10...Top surface, 11...Bottom surface, 12,
13... Slope, A... First image, B... Second image, l... Baseline, M... Midpoint.

Claims (1)

[Scope of utility model registration request] a positive lens whose focal point is the center of a baseline that connects both eyes at a scheduled observation position in a baseline cross section that includes the baseline;
a plurality of columnar prisms having upper and lower surfaces perpendicular to the optical axis in the baseline cross section of the positive lens and a pair of mutually parallel slopes, the slopes facing each other with an air layer interposed therebetween; The upper surface of every other prism is shielded, a first image is disposed facing the lower surface of the shielded columnar prism, and a second image is disposed opposite to the lower surface of the columnar prism that is not shielded, The slopes of the columnar prism are such that the light beam from the first image that has passed through the two slopes and the light beam from the second image that has been reflected by the two slopes are at different angles with respect to the optical axis direction within the baseline cross section. A stereoscopic image reproducing device characterized in that a critical angle is set so that the incident light enters a positive lens.