JPS63285090A - Image pickup device - Google Patents

Abstract

PURPOSE:To reduce the deviation of registration due to thermal fluctuation by selecting the thermal expansion coefficient of an auxiliary plate to allow the image pickup element to follow up emitted light position changed due to the thermal expansion/contraction for a prism group or the like and selecting the adhering position between the auxiliary plate and the prism group or between the prism base and the image pickup element. CONSTITUTION:Each auxiliary plate 14, with respect to the adhering length (l) and the thermal expansion coefficient alpha, is selected to keep the relation of position between the emitted pieces of light 20-22 of the prisms 2-4 and the solid-state image pickup elements 11-13 to be constant by moving an optional amount of the solid-state image pickup elements 11-13 with respect to the prism bases 5a, 5b at thermal expansion/contraction. By selecting properly the thermal expansion coefficient alpha and the length (l) of the plate 14 in this way, the quantities of expansion of the prism group 1 and the prism bases 5a, 5b are varied to place the center of the solid-state image pickup element 11 on the position a' thereby reducing the deviation of the registration between the solid-state image pickup elements 11 and 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a color video camera in which incident light is divided into a plurality of optical paths by a group of prisms, and each light emitted from the group of prisms is received by a plurality of image sensors. The present invention relates to an imaging device.

2. Description of the Related Art As a general imaging device used in a conventional color video camera, the configuration shown in FIGS. 5 and 6 is known. The above conventional example will be explained below with reference to FIGS. 5 and 6.

As shown in FIGS. 5 and 6, the prism group 101 has three
prisms 102. 103. A spacer 106 is inserted between the prisms 102 and 103 to form an air gap 105.
and 104 are bonded with adhesive. Furthermore, a filter for color separation is formed on each light passing surface.

This prism group 101 is placed on a prism base plate 107 and fixed with adhesive.

A lens system 109 is arranged on the entrance surface 108 side of the prism 102, and the prism 102. 103. A solid-state image pickup device (or image pickup tube) 113, 114. 115 is adhesive 116
It is glued well.

Next, the operation of the above conventional example will be explained. In FIG. 6, incident light 117 from the lens system 109 enters from the entrance surface 108 of the prism 102 and enters the air gap 10.
One of the reflected lights 118 is reflected again at the entrance surface 108 of the prism 102 and enters the solid-state imaging device (or imaging tube) 113 from the exit surface 110. The other transmitted light 119 is the adhesive surface 1 of the prisms 103 and 104.
20, one reflected light 121 is reflected again at the air gap section 105, and enters the solid-state image sensor (or image sensor) 114 from the output surface 111. The other transmitted light 122 enters the solid-state imaging device (or imaging tube) 115 from the exit surface 112 of the prism 104 . In this way, the incident light 117 is divided into three parts, and each of the divided lights at this time is color-separated by filters provided on each reflection and transmission surface.

Therefore, each solid-state image sensor (or image sensor) 113
A color image can be obtained by combining the ~115 output signals.

Problems to be Solved by the Invention However, in the conventional imaging device described above, when affected by heat, each component of the imaging device undergoes thermal expansion and contraction, which causes the emitted light from each of the prisms 102 to 104 to The position where the light enters the image pickup device (or image pickup tube) 113 to 115 is the same as that of each solid-state image pickup device (or image pickup tube) 113 to 11.
It will be different between 5. As a result, each solid-state image sensor (
(or an image pickup tube) 113 to 115), a registration shift occurs on an image that is a composite of the outputs of the image pickup tubes 113 to 115, and the resolution of the image is significantly degraded. One of the reasons for this is that the elements that make up the imaging device have different coefficients of thermal expansion, and the amount of change in the refractive index due to heat of each prism 102 to 104 that makes up the prism group 101 differs depending on the wavelength of light. .

Conventionally, in devices using an image pickup tube, a chart or the like is periodically projected, and the resist between each channel is By detecting the amount of deviation in the ration and electrically correcting it, control can be performed to maintain a high-resolution image.

In contrast, in recent years, the number of color cameras using solid-state image sensors 113 to 115 has increased;
115, but when using a plurality of solid-state image sensors 113 to 115, it is very difficult to control the image pickup tube to maintain a high-resolution image using electrical correction as in the case of the image pickup tube. Therefore, an example is JP-A-60-272.
Like the solid-state imaging camera described in Publication No. 78, a wedge-shaped glass plate is inserted on the optical axis, and the optical path is mechanically adjusted by controlling the rotation of this plate to match the registration. . However, this method requires a highly precise glass plate and a circuit system to control it, and the complexity of the structure poses a problem of its own thermal influence.

Therefore, the present invention has a simple structure that can maintain a constant positional relationship between the emitted light that is displaced by thermal expansion and contraction and the image sensor, prevent misregistration due to the influence of heat, and improve image resolution. The present invention aims to provide an imaging device that can perform the following functions.

Means for solving the problems and the technical means of the present invention for solving the above problems include a prism group that divides incident light into a plurality of optical paths and emits it, and a prism base plate that holds this prism group. a plurality of image pickup devices that receive each of the output lights that are divided and emitted from the prism group; and an auxiliary plate that connects at least two of these image pickup devices and the prism group or the prism base plate; The coefficient of thermal expansion of the auxiliary plate is selected so that the image sensor follows changes in the position of the emitted light due to thermal expansion and contraction, and the bonding positions of the auxiliary plate and the prism group, or the prism base plate and the image sensor are set. It is something.

action The effect of this technical means is as follows.

That is, when components having different coefficients of thermal expansion thermally expand and contract, the position of each emitted light from the prism group changes. expands and contracts thermally, causing the image sensor to follow changes in the position of the emitted light. Therefore, even if the position of the emitted light changes due to thermal expansion and contraction, the position of the light incident on the image sensor does not change.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a first embodiment of the present invention will be described.

1 to 3 show an imaging device according to a first embodiment of the present invention, in which FIG. 1 is a perspective view, FIG. 2 is an enlarged view of essential parts, and FIG. 3 is a plan sectional view for explaining the operation.

In FIGS. 1 and 2, ■ is a prism group, consisting of three prisms 2. 3. 4, a spacer (not shown) is inserted between the prisms 2 and 3 to form an air gap (not shown) as in the conventional example, and the prisms 3 and 4 are bonded together with an adhesive. Furthermore, a filter for color separation is formed on each light passing surface. Reference numerals 5a and 5b denote a pair of prism base plates, which are an entrance surface 6 and an exit surface 7 in the prism group 1. 8. The adhesive 1 is arranged so as to sandwich the prism group 1 from both sides in the right angle direction of the
It is connected to prism group 1 with a magnitude of 0. 11. 12 and 13 are each output surface 7 of the prism group 1. 8. The solid-state imaging device 14 is placed on the 9 side, and is an auxiliary plate for joining the prism base plates 5a, 5b and the solid-state imaging device 11.1.2.13. Each auxiliary plate 14 has a width that follows the base plates 5a and 5b, and joint portions 15 and 16 are slightly protruded on opposite sides. One joint] 5 is the prism base plate 5a, 5b
The other bonded portion 16 is bonded to the solid-state image sensor 11, 12, 13 using an adhesive 17 or the like. Each auxiliary plate 14 has a joint portion 14a.

14bQ Length t and coefficient of thermal expansion α, as described later, allow the solid-state imaging devices 11, 12, 13 to be moved by any amount with respect to the prism base plates 5a, 5b during thermal expansion and contraction, and the prism 2. 3. The positional relationship between the emitted light 20.21° 22 of No. 4 and the solid-state image sensor 11, 12, 13 can be maintained constant. 18 is a lens system installed on the entrance surface 6 side.

Next, the operation of the above embodiment will be explained. In FIG. 3, incident light 19 from the lens system 18 enters from the entrance surface 6 of the prism 2, and the outgoing light 20.2 is similar to the above conventional example.
The light is divided into 1.22 parts, exits from the exit surface 7.8°9, and enters the solid-state image sensor 11, 12, and 13. therefore,
A color image can be obtained by combining the output signals of each solid-state image sensor 1.1.12.13.

Next, a case where the imaging device undergoes thermal fluctuation will be described using FIG. 3. In FIG. 3, solid lines indicate each component and the optical axis before thermal deformation, and broken lines indicate each component and optical axis after thermal deformation.

The incident light 19 enters the prism group 1 from the entrance surface 6, and the emitted light 22, which is a part of the transmitted light, passes through the prism group 1 as it is and enters the solid-state image sensor I3 from the exit surface 9. Here, with the transmitted light 22 as a reference, the output light 2 which is other reflected light is
0.21, first, the reflected light 20 reflected between the prisms 2 and 3 is reflected again at the entrance surface 6 and enters the solid-state image sensor 11 at position a from the exit surface 7. Here, when thermal expansion occurs, conventionally, the reflected light 20 is displaced and becomes the reflected light 20', and the position a of the solid-state image sensor 11 is
′ is reached. However, in the present invention, at this time, by appropriately setting the thermal expansion α and length t of the auxiliary plate 14 as described above, the prism group 1 and the prism base plates 5a, 5b are
The center of the solid-state image sensor 11 can be located at position a' by changing the amount of expansion for the solid-state image sensor 11 and 13.
It is possible to prevent misregistration between the two. On the other hand, the light is reflected between the prisms 3 and 4, and further reflected on the surface of the prism 3 on the air gap side, and is transmitted to the solid-state image sensor 12 as the emitted light 21. In this case, as well, the auxiliary plate 14 By selecting , it is possible to prevent misregistration. As a result, even during thermal expansion and contraction, the optical axes that enter the fixed image pickup elements 11, 12, and 13 are not relatively displaced, and deterioration in image resolution can be suppressed.

Next, a second embodiment of the present invention will be described. FIG. 4 is a perspective view showing a second embodiment of the present invention.

In this embodiment, only the parts different from the configuration of the first embodiment will be explained, and the same members will be given the same reference numerals and the explanation thereof will be omitted.

As shown in FIG. 4, the auxiliary plate 14 is arranged along the edges of the prisms 2, 3 and 4, and one joint 15 is attached to the prism 2. 3. 4 with an adhesive 17 or the like, the other joint 16 is the solid-state image sensor If, and the adhesive 1 is attached to 12.13.
7 or the like, and the same effects as in the first embodiment can be obtained in this embodiment as well.

Note that in each of the above embodiments, all the solid-state image sensors 11.
12.13 and prism base plate 5a, 5b or prism 2. 3. 4 are joined by the auxiliary plate 14, but since it is sufficient to prevent misregistration of the remaining two solid-state image sensors with respect to one solid-state image sensor as described above, at least two The solid-state image sensors may be joined together using the auxiliary plate 14.

Effects of the Invention As described above, according to the present invention, at least two image sensors and a prism group or a prism base plate are joined via an auxiliary plate, and changes in the position of emitted light due to thermal expansion and contraction of the prism group, etc. can be avoided. The coefficient of thermal expansion of the auxiliary plate is selected so that the image sensor follows the image sensor, and the bonding position between the auxiliary plate and the prism group, or the prism plywood and the image sensor is set, so that the image sensor is subject to thermal fluctuations. Even in this case, the image sensor moves according to the deviation of the optical axis, and the position of incidence on the image sensor can be kept relatively constant. Therefore, with a simple configuration, misregistration due to thermal fluctuations can be suppressed to a minimum, and image resolution can be improved.

[Brief explanation of drawings]

1 to 3 show an imaging device according to a first embodiment of the present invention, in which FIG. 1 is a perspective view, FIG. 2 is an enlarged view of main parts, FIG. 3 is a plan sectional view for explaining operation, and FIG. This figure is a perspective view showing a second embodiment of the present invention, and FIGS. 5 and 6 show a conventional imaging device, with FIG. 5 being a perspective view and FIG. 6 being a plan view. 1... prism group, 2. 3. 4...prism,
5a. 5b... Prism base plate, 6... Incident surface, 7. 8.
9... Output surface, 11.12.13... Solid-state image sensor, 14... Auxiliary plate, 18... Lens system, 19...
-Incoming light, 20.21.22... Outgoing light. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 21. - Lens system A1J7J, Yoyo stopcock right b
74 Inasuke Board No. 3 Figure 14 Pattern n Skin, 67J I+

Claims (1)

[Claims] a prism group that splits incident light into multiple optical paths and emits it;
A prism base plate that holds this prism group, a plurality of image pickup devices that receive each of the emitted light beams divided and emitted from the prism group, and at least two of these image pickup devices and the prism group or the prism base plate are joined together. The coefficient of thermal expansion of the auxiliary plate is selected so as to make the imaging device follow the change in the position of the emitted light due to thermal expansion and contraction of the prism group, etc., and the auxiliary plate and the prism group or the prism base plate and An imaging device characterized in that a joining position with an imaging element is set.