JP2720133B2 - Collimator device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collimator apparatus used for checking whether a predetermined in-focus state is obtained by a zoom lens to be inspected.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, an illuminating device including a collimating lens 1, a light source 2, an adjusting device 3 for adjusting an illuminating light amount of the light source, a diffusion plate 4, and the like, and an illuminating device. A test chart 5 movably provided along the optical axis of the collimating lens 1.
A video signal of the test chart 5 as a subject obtained from a video camera (not shown) via the zoom lens in a state where a test zoom lens (not shown) is temporarily provided in alignment with the optical axis of the collimator lens 1. 2. Description of the Related Art There is known a collimator device used for detecting the level of a high-frequency component and inspecting whether a predetermined in-focus state is obtained by the zoom lens to be inspected. In FIG. 2, 6 is an optical bench, 7 is a case, and 8 is a knob for adjustment of the adjusting device 3. The shaded portions of the test chart 5 are painted black, and the test chart 5 is evenly proved through the diffusion plate 4.

In general, focusing inspection of a zoom lens is often performed using an object at a distance of several meters to infinity, but by using the above-described collimator device, focusing inspection can be performed even in a narrow place. .

By the way, as shown in FIG. 3, the angle of view of the zoom lens 9 is wider at a wide angle than at a telephoto angle (shown at β) as indicated by α, and is transmitted through the collimating lens described in FIG. The image of the test chart 5 obtained is shown in FIG.
As shown in (b), the image is in a small area at the center of the screen. Incidentally, FIG. 4A shows an image of the test chart 5 at the time of telephoto, and covers the entire screen. Since the periphery of the test chart 5 is shielded from external light, the screen shown in FIG. 4B has a dark periphery and a bright central portion, but the amount of light incident on the video camera is as shown in FIG. Compared to the telephoto case shown in FIG.

As described above, when detecting the level of the high frequency component of a video signal, an AGC circuit is used to increase the accuracy of the detection. That is, when the average level of the video signal is low, the overall level of the video signal is raised. In the case shown in FIG. 4B, since the average level of the video signal is low, the entire level of the video signal is raised by the AGC circuit. As described above, when the overall level of the video signal is raised, the image portion shown in FIG. 4B has a sufficiently high video signal level as compared with the other portions, so that this image portion is clipped. Sometimes. If this clipping phenomenon occurs, it becomes impossible to correctly inspect whether or not the camera is in focus. In order to avoid the above-mentioned clipping phenomenon, in the related art, the level of the image signal shown in FIG. 4B may be reduced by reducing the amount of light applied to the test chart.

[0006]

However, when the level of the image portion of the video signal shown in FIG. 4B is reduced, the S / N of the video signal is reduced. As a result, it is difficult to correctly inspect whether or not the camera is in focus. The present invention eliminates the above-mentioned disadvantages, and reduces the possibility of clipping of the image portion of the subject of the video signal without reducing the amount of illumination on the test chart during focus inspection at a wide angle. It is an object of the present invention to provide a collimator device configured as described above.

[0007]

In order to solve the above-mentioned problems, a collimator device according to the present invention includes a collimating lens, an illuminating device, and an illumination device illuminated by the illuminating device, which moves along the optical axis of the collimating lens. A test chart provided so as to be capable of being obtained, and a height of a video signal having the test chart as a subject, which is obtained through the zoom lens in a state where the zoom lens to be measured is temporarily set to match the optical axis of the collimator lens. In a collimator device used to detect whether a predetermined in-focus state has been obtained by the test zoom lens by detecting the level of the band component, between the collimator lens and a test chart,
The light emitting surface of the collimating lens is within a range that does not substantially hinder the light reaching the collimating lens from the test chart, and within a wide angle of view of the test zoom lens via the collimating lens. A light-emitting body is provided in a direction toward the head. Here, the luminous body is not limited to a luminous body that emits light itself, but may be a luminous body that appears to be luminous, for example, a reflector that diffusely reflects light from the light source, transmits light from the light source, and This also includes things such as frosted glass that diffuses this light. It is desirable that the luminous body emits light uniformly,
Further, it is desirable that the brightness is substantially the same as that of the test chart when viewed from outside the collimating lens.

[0008]

The level of the whole video signal in the wide-angle inspection of the zoom lens to be inspected is increased by the light from the light emitter, and the AGC gain in the AGC circuit is reduced. Therefore, the above-described clipping phenomenon of the video signal is reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1A is a schematic sectional view of a collimator device,
FIG. 1B is a perspective view of a main part. 1, the same reference numerals as those in FIG. 2 denote the same parts, and a detailed description thereof will be omitted. Reference numeral 10 denotes a high-reflectance reflector having a hole 11 in the center thereof, which reflects light from the light source 12 uniformly. 13 is an adjusting device for adjusting the amount of illumination of the light source 12, and 14 is a knob for adjusting the adjusting device 13. By providing the light source 12 and the reflector 10, the amount of light incident on the video camera in a wide-angle inspection of the zoom lens to be inspected is increased, and thus the level of the entire video signal is increased.

In the above embodiment, the reflection plate 10 for reflecting the light from the light source 12 is provided. However, instead of these, a luminous body having a light emitting function by itself may be used. A plate such as frosted glass that transmits and diffuses light may be used. Further, in the above embodiment, when the reflection plate 10 moves the test chart 5 to a position for inspection of the zoom lens to be inspected at a wide angle, the light from the test chart 5 to the collimating lens 1 is prevented. Although the hole 11 is provided so as not to be substantially formed, a portion corresponding to the hole 11 of the reflection plate 10 may be made transparent instead of the hole 11.

[0011]

As described above, according to the present invention, the portion of the image of the subject of the video signal is clipped without reducing the amount of illumination on the test chart at the time of wide-angle focusing inspection. That is alleviated.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, in which (a)
FIG. 2 is a schematic sectional view of a collimator device, and FIG. 2B is a perspective view of a reflector.

FIG. 2 is an exploded perspective view showing a conventional example.

FIG. 3 is a schematic diagram for explaining a conventional one.

FIG. 4 is a schematic view for explaining a conventional one.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Collimating lens 2 Light source 3 Adjuster 4 Diffusion plate 5 Test chart 10 Reflector 11 Hole 12 Light source 13 Adjuster

Claims (1)

(57) [Claims] 1. A collimating lens, an illuminating device, and a test chart illuminated by the illuminating device and movably provided along an optical axis of the collimating lens. The level of a high-frequency component of a video signal with the test chart as a subject, which is obtained through this zoom lens in a state temporarily set in accordance with the optical axis, is detected, and a predetermined in-focus state is set by the test zoom lens. In a collimator device used for inspecting whether or not it is obtained, between the collimating lens and a test chart, in a range that does not substantially hinder light from the test chart to the collimating lens, and The collimating lens has a light emitting surface within the range of the wide-angle field of view of the zoom lens to be inspected. Collimator device which is characterized by providing a light emitter in a direction toward the lens.