JPH0521064Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention [Field of industrial application] The invention relates to a television camera for close-up photography that is equipped with a lighting device. The object of the present invention is to provide a television camera for close-up photography that is integrated with an illumination device that can provide uniform illumination.

[Conventional technology]

In close-up photography, high-intensity illumination is required, so the high-intensity illumination light is focused by an appropriate optical system to illuminate the field.

[Problem that the invention attempts to solve]

Conventional illumination devices for close-up television cameras have the following problems.

In other words, the field of view for close-up photography is small, and therefore it is not possible to obtain illumination with uniform illuminance depending on the direction using conventional relatively large illumination devices, making it difficult to obtain uniform images. It was difficult to obtain.

B. Structure of the invention [Means for solving the problems] The close-up television camera of the present invention uses a ring illumination device in which a large number of optical fibers are used as light guide members and the emission ends of each are arranged in a cylindrical shape. integrated, the diffused light uniformly emitted from the circumferential emission end of the illumination device is condensed by a ring-shaped lens disposed adjacently in front to form a substantially cylindrical parallel light beam; The light flux is reflected on the inner surface of the support frame of the ring-shaped lens and the outer side of the objective lens housing to illuminate the object field, and it is possible to uniformly illuminate the object with high illuminance from all directions. Problems can be resolved.

[Effect]

The light emitted from a single optical fiber is diffused into a conical shape with an apex angle of 50 to 60° with the exit end as the apex, and a cone with an apex angle of 50 to 60° is placed in front of the exit end, approximately radially away from the rear principal point. If a spherical lens is placed at the same position, a substantially parallel beam of light can be obtained. Applying this principle, a ring-shaped lens placed in front of a ring-shaped lens placed in front of the light emitted from a ring illumination consisting of a large number of optical fibers with their ends forming a circle can be used to diffuse components in the diametrical direction. By condensing light substantially in parallel, it is possible to obtain a cylindrical light beam over the entire circumference.

The present inventor has obtained a close-up television camera that can obtain high-intensity illumination using this ring lighting device, and in front of the circular exit end of the ring lighting device, a diameter of approximately the same size as the diameter of the exit end circle is installed. Ring-shaped lenses each having a diameter with a substantially circular cross-section are arranged coaxially so that their central axes overlap, and the diffused light from the ring illumination device is made into a cylindrical light beam consisting of parallel light rays as much as possible, Further, the light flux is reflected by the inverted conical surface of the lower inner surface of the support frame that fixes the ring-shaped lens and the inverted conical outer surface of the objective lens housing,
The illumination light is used to illuminate the field of a television camera formed integrally with the illumination device.

FIG. 3 is a perspective view schematically illustrating how light is focused by a ring-shaped lens. It is considered to be a planar light beam.

Note that g is a single optical fiber that is arranged in large numbers in the same direction as the axis O so that the ends thereof are circumferential, and the optical fiber g (not shown) is converged from the other end and serves as a light source (also not shown). For example, the ring illumination device 1 is obtained by introducing light from a halogen lamp whose infrared component is removed by a filter.

Embodiment FIGS. 1 and 2 are an enlarged side sectional view of a main part of an embodiment of the present invention as a small pen-shaped television camera, and a perspective view showing how it is actually used.

Reference numeral 1 denotes a ring illumination device attached to the entire length of the cylindrical main body tube of the television camera C, and an optical fiber bundle G in which optical fibers G are focused is led out from the upper end and connected to a light source (not shown). ing.

The optical fiber g extends toward the lower end of the ring illumination device 1, and is held in such a way that the lower end forms a circumference coaxial with the optical axis of the camera C, and the optical fiber g is oriented in the same direction as the optical axis. It is arranged to form a circular light exit end.

The ring-shaped lens 2 is arranged in succession near the front surface of the exit end of the ring illumination device 1, and has a circular shape and a circular cross-section.

In the ring-shaped lens 2, the diameter r of the circle formed by connecting the centers of the cross-sectional circles is equal to the diameter R of the exit end circle,
In addition, since the ring illumination device 1 is arranged in series at a distance of 2/3 of the radius of the cross-sectional circle from the exit end circle, the light emitted from the ring illumination device 1 passes through the ring-shaped lens 2 and is condensed into a cylindrical surface. Ru.

In front of the ring-shaped lens 2, there is a support frame F that has a conical mirror surface whose lower inner surface forms an angle of 45° in the optical axis direction and fixes the ring-shaped lens 2 to the ring lighting device. 1, the focused light is reflected on the mirror surface and reflected and deflected in the horizontal direction, and the housing accommodates the objective lens system L of the camera C. The reflected light is reflected again at the light-reflective inverted conical outer surface formed to have an angle of 55° with respect to the optical axis as an angle corresponding to the angle (45°) of the inner surface of the support frame F, It is possible to reach the part of the field indicated by the small circle and illuminate that part uniformly and with high illuminance from the entire circumferential direction forming an angle of 20 degrees from the optical axis.

The optical path of the main components of the light diffused and emitted from the optical fiber g is shown by the dashed-dotted line in FIG.

S is a spacer screwed onto the side of the support frame F, and its lower end surface is positioned at the same distance as the subject, and the end surface is directly pressed against the subject as shown in the perspective view of the used state in Figure 2. This makes it easy to take photographs in focus.

A charge-coupled device is incorporated inside the television camera C, and is connected to a suitable television monitor via a cable W to display a captured image.

Although specific examples are not shown, the illumination direction (in the example, 20° with respect to the optical axis) can be varied by simple design changes such as the angle and combination of the reflecting surfaces. .

C. Effect of the invention As explained above, the close-up television camera of the present invention is an integrated lighting device that can provide uniform and high-intensity illumination, making it possible to easily take pictures with high image quality without unevenness. It is what it is.

[Brief explanation of the drawing]

Fig. 1 is an enlarged side sectional view showing the main parts of the embodiment of the television camera of the present invention, Fig. 2 is a perspective view showing its usage, and Fig. 3 schematically shows how light is collected by a ring-shaped lens. FIG. DESCRIPTION OF SYMBOLS 1... Ring illumination device, 2... Ring-shaped lens, g... Optical fiber, G... Optical fiber bundle, C... Television camera, F... Support frame, S...
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Claims (1)

[Scope of utility model registration request] In a television camera for close-up photography, a ring illumination device is attached to the outer peripheral side of the television camera C coaxially with the optical axis, and a ring illumination device is installed close to the front of the illumination device with a diameter that is approximately the same as the diameter of the circumference formed by the illumination light exit end. A ring-shaped lens having a substantially circular diameter cross section is coaxially arranged by a support frame F whose lower inner surface is an inverted conical light reflecting surface,
On the other hand, a close-up television camera with an illumination device is characterized in that the outer surface of the housing of the objective lens L of the television camera C is an inverted conical light reflecting surface corresponding to the inverted conical shape of the inner surface of the support frame F.