JPS62242925A - Projecting machine - Google Patents

Abstract

PURPOSE:To enlarge and project the image of an object to be inspected, and to obtain brightly and distinctly the image by an optional enlargement ratio it, by irradiating the object to be inspected by parallel rays, making transmission light or reflected light which is obtained transmit through a square-law refractive index distribution cylindrical lens, and emitting it at a prescribed angular aperture through a beam waist. CONSTITUTION:Parallel rays 5 are emitted from a light source 1 such as a laser and halogen lamp, etc., transmit through a square-law refractive index distribution cylindrical lens 2, emitted at an annular aperture 2theta through a beam waste in its focal position, and irradiated to a screen being in a position separated by a distance L from the beam waist 6. The square-law refractive index distribution cylindrical lens 2 which is used in such a case is a small-sized one whose length and diameter are 2-3mm, and about a little under 2mm, respectively, and having a focal distance of about 1-2mm is suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a projector that projects an image of an object on a screen.

<Prior art> There are two types of projectors: non-telecentric 1-ric type and telecentric 1-ric type. In non-telecentric 1-ric type, when the focus shifts, the magnification of the image on the screen changes and the image is distorted. It has the characteristic of blurring.

Focusing becomes difficult when there is depth to the focus.
Generally, telecentric systems are often used.

In other words, the telesend link system is designed so that the focal point behind the projector lens is the pupil position.
Even if pins 1 and 2 shift, the size of the image displayed on the screen does not change much. For this reason, it is necessary to install an aperture at the focal point of the objective lens or the focal point of the condenser system of the illumination device, or to use a light source with a small filament that is close to a point light source. It is used.

<Problems to be solved by the invention> However, in the conventional telecentric 1-rick system, the aperture ratio is small and the 1-resolution decreases accordingly, so the resolution limit is 0.4μ [[1] On the other hand, in a projector, the thickness is on the order of 4 μnt even at the center, and there is a certain limit to how clearly the enlarged image can be projected on a large screen. Furthermore, the magnification of the image is limited to a certain range by the magnification of the projection lens, which is set to project onto the screen in a fixed position, and the magnification cannot be changed arbitrarily. There was a problem.

The present invention has been made in view of these problems, and aims to provide a projector that has high resolution and can arbitrarily change the magnification of the image.

<Means for Solving the Problems> In order to achieve the object stated in -1-, the projector of the present invention has the following features:
Using a light source that emits parallel light rays and a square gradient index cylindrical lens, the test object is irradiated with the parallel light rays from this light source, and the resulting transmitted or reflected light from the test object is transmitted through the square gradient index cylindrical lens. The image of the object to be examined is enlarged and projected onto a screen by transmitting the beam and emitting it through a beam waste at a predetermined aperture angle.

<Function> As described above, in the present invention, the object to be examined consisting of parallel light beams is irradiated in a magnified manner through a square gradient index cylindrical lens, without using an aperture to restrict the light beam to the focal point position.
Moreover, like a pinhole camera, it does not use a lens-based imaging system, so it can project a bright and clear image onto a screen located far away, and the image will not blur even if the screen position is changed. This makes it possible to freely change the magnification rate by changing the position.

<Example> Next, the basic configuration and principle will be explained using an example shown in the drawing.

In Figure 1, (1) is a light source that emits parallel rays, (
2) is a square gradient index cylindrical lens, (3) is a screen, and (4) is a test object. As the light source (1), for example, a laser light source or a halogen lamp light source can be used, and the parallel light beam (5) passes through the square gradient index cylindrical lens (2), passes through the beam uniformity h (G) at its focal position, and changes the aperture angle. The beam is emitted at 20 and is irradiated onto a screen (3) located as far away as the beam uniice 1-(6).

The square gradient index cylindrical lens (2) used in the present invention is small, for example, 2 to 3 meters long and a little less than 21 mm in diameter. Rather than something with an extremely short focal length close to zero.

A lens with a slightly larger focal length of about 1 to 2 um is suitable. Here, if the refractive index at the center is ng, the radius is ``, and the constant is A, then the refractive index at any position within a cylindrical lens is n.
(r) is.

n(r)=ng (1-Ar') The radius r is sufficiently small.

If the influence of the refractive index change related to the fourth power of the radius term can be ignored, the optical path lengths of both the meridional ray and the helical ray can be made to be the same. In addition, when we examine the phase velocity of the transmission mode as wave optics when the square gradient index cylindrical lens (2) is considered as an optical fiber, we find that the relative phase velocity of the waves is almost the same up to the waves of the 10th order or higher order. It turns out that they are equal. Therefore, when the parallel light beam from the light source (1) passes through the square gradient index cylindrical lens (2) and exits, and spreads at an aperture angle of 20, the wavefront has a uniform phase. This opening angle 20
However, it is much larger than, for example, an objective lens with a magnification of 50 times in a conventional microscope.

Now, assuming that the size of the spora 1 in the beam waste (6) is 2w and the wavelength is λ, the relationship between the aperture angle 2θ and the spot size 2w is approximately 20=λ/πW. Therefore, in the case where the aperture angle 2θ=ta@=0.314 radian and the wavelength λ=0.6 μm, the spot size 2w is determined to be 2w=1.2 μm.

In this way, since the spot size is very small, it is essentially equivalent to placing a very small pinhole at the position of the beam unicornice 1-(6).

Like a pinhole camera, it is possible to obtain a projected image on the screen (3) without using an imaging system using a lens. Moreover, the resolution is higher than that of a square gradient index cylindrical lens (
It is determined by the numerical aperture of 2).

The resolution is much improved compared to the conventional telecentric system, and a resolution limit of 1 μm or less can be easily obtained, and furthermore, there is no actual pinhole placed at the beam waist (6). Therefore, the amount of light is not limited, and is more than 1,000 times more! A sufficiently bright and clear projected image can be obtained even when the image is enlarged to -.

The magnification of the projected image at this time is determined by the aperture angle 20 and the distance ML to the screen (3).
- will not shift and the image will not be blurred. Therefore, the distance 1IllL to the screen (3) can be freely changed, making it possible to obtain a clear projected image enlarged at any magnification.

Therefore, the square gradient index cylindrical lens (2) and the light source (1)
If the test object (4) is placed between the cylindrical lens (2) and the distance 1111d between the square gradient index cylindrical lens (2) and the test object (4) is approximately equal to the focal length f of the cylindrical lens (2), then the aperture angle is A projected image (7) of the object (4) to be examined is obtained, which is magnified at a magnification determined by the distance between the test object (4) and the screen (3). At this time, the position of the test object (4) is adjusted so that the distance d between the square gradient index cylindrical lens (2) and the test object (4) is approximately equal to the focal length f of the cylindrical lens (2). Although it is necessary, the adjustment range is quite flexible. In other words, for example, to obtain a clear image with a normal microscope, it is necessary to keep the position of the object to be examined within an error of more than 1 μm, and if the magnification is 1,000 times, an order of magnitude higher precision is required. However, in the present invention, an accuracy of several tens of micrometers is sufficient, making it possible to adjust the Fj of the object (4) extremely easily.

Figure 1 is an example of projecting the transmitted light of the test object (4) onto the screen (3), but as shown in Figure 2, the test object (4)
It is also possible to project reflected light. That is, in this case, the parallel light beam (5) from the light source (1) is reflected by the object (4) and enters the square gradient index cylindrical lens (2),
It passes through the beam waste (6) and is enlarged and projected onto the screen (3) at an aperture angle of 20.

The principle is exactly the same as that shown in FIG.

<Effects of the Invention> As is clear from the above description, in the present invention, parallel light rays from the object to be examined are emitted at a predetermined aperture angle through a square gradient index cylindrical lens, and an imaging system using the lens is used. First, the image of the object to be examined is projected onto the screen without using an aperture that would limit the amount of light. Therefore, the resulting projected image is bright and does not go out of focus even if the screen position changes, making it possible to project a clear image at any magnification, and it is also easy to adjust the position of the subject. It has features such as easy focusing.

This makes it possible to obtain a high-performance, easy-to-use projector.

[Brief explanation of drawings]

FIG. 1 is a schematic structural diagram of one embodiment of the present invention, and FIG. 2 is a schematic structural diagram of another embodiment. (1)...Light source, (2)...Square refractive index gradient cylindrical lens. (3)...screen, (4)...test object, (5)
...Parallel rays. (6)...Beam waste, (7)...Projected image.

Claims (1)

[Claims] (1) By irradiating the test object with parallel light beams, and transmitting the transmitted light or reflected light from the test object through a square gradient index cylindrical lens, and emitting it through the beam waste at a predetermined aperture angle. , a projector characterized by projecting an enlarged image of an object to be examined on a screen.