JP3136849B2 - Color separation prism 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 color separation prism device used in an image pickup section of a video camera, a video movie camera or the like, in which unnecessary light rays are reduced.

[0002]

2. Description of the Related Art In recent years, color separation prism devices have begun to be used in small video movie cameras and the like, and have become synonymous with high image quality and high performance. -High performance and low cost have been strongly desired for color separation prism devices.

Hereinafter, a conventional color separation prism device will be described. FIG. 2 shows the configuration of a conventional color separation prism device. In FIG. 2, reference numeral 21 denotes a green solid-state imaging device, and reference numeral 22 denotes a green light receiving unit. Reference numeral 23 denotes a blue solid-state imaging device, and reference numeral 24 denotes a blue light receiving unit. 25
Is a red solid-state imaging device, and 26 is a red light receiving unit. Reference numeral 27 denotes a first prism, which guides light in a green region to the green light receiving unit 22. Reference numeral 28 denotes a second prism, which guides light in the blue region to the blue light receiving unit 24. Reference numeral 29 denotes a third prism which guides light in the red region to the red light receiving portion 26. Reference numeral 30 denotes an optical axis of an incident light beam. 31a, 31b, 32a and 32b are effective light rays incident on the color separation prism device. Reference numeral 33 denotes a first notch, which blocks unnecessary light in the prism 27. 34 is the second
Unnecessary light in the prism 28 is blocked by the notch. Reference numeral 35 denotes a third notch, which blocks unnecessary light rays in the prism 29.

The operation of the above-configured color separation prism device will now be described. First, the effective light beams 31 and 32 which are incident on the color separation prism device are guided by the prisms 27, 28 and 29 so that only the light beams in the necessary areas for the green light receiving portion 22, the blue light receiving portion 24 and the red light receiving portion 26 are guided. I will Unnecessary light rays other than the effective lines 31a, 31b, 32a, and 32b are emitted by the green light receiving section 22, the blue light receiving section 24, and the red light receiving section 2.
Notch A33, notch B34, and notch C35 block unnecessary light so as not to reach 6.

[0005]

However, in the above-mentioned conventional configuration, the notches 33, 34 and 35 are not
There is a problem that a notch is added to the basic shape of the prism by post-processing.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a low-cost color separation prism apparatus in which addition of a light-shielding portion by post-processing is reduced.

[0007]

In order to achieve the above object, a color separation prism device according to the present invention is designed to convert an incident light beam into green, blue and red light.
First, second, and third prisms that separate light into three primary colors
And light rays emitted from the first, second, and third prisms
, Second, and third solid-state imaging devices each of which converts an image into an electric signal.
A color separation prism device comprising:
The first, second, and third prisms in the order in which light is incident.
And the second prism is arranged in contact with the second prism.
A second prism adjacent to the joining surface of the third prism to be combined;
With a light-shielding part formed by the side of the
There is .

[0008]

With this configuration, a light shielding portion having the same performance as that of the light shielding portion provided by the post-processing can be formed at a reduced cost, irrespective of the post-processing.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a green solid-state image sensor, and reference numeral 2 denotes a green light receiving unit. Reference numeral 3 denotes a blue solid-state imaging device, and reference numeral 4 denotes a blue light receiving unit. Reference numeral 5 denotes a red solid-state imaging device, and reference numeral 6 denotes a red light receiving unit. 7 is the first
Green light receiving part 2
Leading to. Reference numeral 8 denotes a second prism, which guides light in the blue region to the blue light receiving unit 4. Reference numeral 9 denotes a third prism, which guides light in the red region to the red light receiving unit 6.
10 is the optical axis of the incident light beam. Numerals 11 and 12 are effective light rays incident on the color separation prism device. Reference numeral 13 denotes a first notch for blocking unnecessary light rays in the prism 7. Reference numeral 14 denotes a second notch, which blocks unnecessary light rays in the prisms 8 and 9.

As described above, according to the present embodiment, the prism 8
By providing the notch 14, which is a light-shielding portion formed by the outer surface of the lens and the joining surface of the prisms 8 and 9, unnecessary light can be shielded so as not to reach the blue light-receiving portion 4 and the red light-receiving portion 5. Can be reduced. At this time, the outer portion of the prism 8 forming the notch 14 needs to be set in a direction away from the blue light receiving portion 4 in order to avoid ghost flare due to light reflection of the outer portion.

[0012]

As described above, according to the present invention, a light-shielding portion for reducing unnecessary light is formed by the joint surface between the prisms and the outer shape of the prism. It is possible to realize a low-cost excellent color separation prism device in which the number of additional units is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a color separation prism device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a conventional color separation prism device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid-state image sensor for green 2 Solid-state image sensor for green 3 Solid-state image sensor for blue 4 Solid-state image sensor for blue 6 Solid-state image sensor for red 6 Red light receiver 7 Prism 8 Prism 9 Prism 10 Optical axis 11 Effective ray 12 Effective ray 13 Notch 14 notches

Claims (1)

(57) [Claims] 1. A green incident light, blue, and the first, second, third prism decomposed into three primary colors of red light, the first, second
2, a color provided with first, second, and third solid-state imaging devices that convert light beams emitted from the third prism into electric signals, respectively.
A separation prism device, in which the incident light beam is incident
The first, second, and third prisms are joined to each other in this order.
And a third prism joined to the second prism.
Formed by the joining surface of the rhythm and the side surface of the adjacent second prism
A color separation prism device comprising: a light-shielding portion to be formed .