JPH06201905A - Color separating prism and method for assembling color separating prism - Google Patents

Abstract

PURPOSE:To reduce the thickness of an air layer and to assure sufficient parallelism by adhering first and second prisms with an adhesive into which fine spacers are incorporated, thereby forming the air layer of the thickness determined by these spacers. CONSTITUTION:The color separating prism 10 is constituted by adhering the first and second prisms 2, 3 with the prescribed adhesive 11 while averting optical paths, thereby the first and second prisms 2, 3 are directly adhered and held and the air layer is formed between the first and second prisms 2 and 3. The adhesive 11 is so prepd. in this case, that fiber materials 13 are incorporated at a prescribed ratio as the fine spacers in the adhesive 12 of a UV curing type and further that black pigments are incorporated therein at a prescribed ratio. Namely, a third prism 4 is adhered to the second prism 3 and thereafter, the adhesive 11 is applied on the incident surface of the second prism 3 and the first prism 2 is pressed. Then, the first and second prisms 2, 3 eye held these prisms apart by the spacing determined by the fiber materials 13.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color separation prism applied to a television camera or the like, and more particularly to a method for assembling the color separation prism.

[0002]

2. Description of the Related Art Conventionally, for example, in a television camera or the like, after incident light entering from a lens is separated into red, blue and green components by a color separation prism, each component is received by a predetermined image pickup device. It has become.

As shown in FIG. 6, in this type of color separation prism 1, incident light L1 from a lens is guided to a first prism 2. In the first prism 2, the entrance surface and the exit surface are formed perpendicularly and obliquely with respect to the optical axis of the incident light L1, and a plurality of vapor deposition films having a predetermined thickness are formed on the exit surface. It is like this.

As a result, in the first prism 2,
The vapor deposition film is used to form a mirror MB having wavelength selectivity, and reflects the blue component light LB of the incident light L1 and transmits the non-blue component light.
As a result, in the color separation prism 1, the first prism 2 separates the blue component light LB from the incident light L1.

On the other hand, in the color separation prism 1, the second prism 3 is arranged on the back surface of the first prism 2,
The transmitted light of the mirror MB is guided to the second prism 3. Here, in the second prism 3, a mirror MR having wavelength selectivity is formed on the exit surface in the same manner as the first prism, whereby the red component of the light emitted from the first prism 2 is formed by this mirror MR. Light LR is reflected, and light LG other than the red component is transmitted.

Accordingly, in the color separation prism 1,
After the blue component light LB is separated by the first prism 2, the red component light LR is separated by the second prism 3D, and the third prism arranged on the back surface of the second prism 3 is arranged.
The remaining green component light LG is emitted through the prism 4. Therefore, for example, in a television camera, the light emitted from the third prism 4 is received by a predetermined light receiving element and a green color signal is generated.

On the other hand, in the color separation prism 1, the separated lights LB and LR are totally reflected by the incident surfaces of the prisms 2 and 3, whereby the lights LB and LR of the blue and red components are separated by the color separation prism. Eject from 1. That is, in the first prism 2, the lenses are arranged on the incident surface side at a predetermined distance from each other, so that the inclination of the exit surface is selected and the incident angle of the light LB with respect to this incident surface is maintained at a critical angle or more. Then, the separated blue component light LB is totally reflected on the incident surface and emitted to the outside. As a result, in the television camera, the emitted light LB is received by the image pickup element and a blue color signal is generated.

Further, in the second prism 3, the first prism 2 is arranged on the incident surface side, so that the first prism 2
In order to totally reflect the separated light LR in the same manner as in the prism 2 and to emit it to the outside, it is necessary to form an air layer between it and the first prism 2. For this reason, as shown in FIG. 7, in the color separation prism 1, the first and second prisms 2 and 3 are held with the spacer 5 interposed therebetween, whereby the space between the first and second prisms 2 and 3 is held. An air layer having a predetermined thickness is formed on the optical axis, so that the red component light LR separated at the exit surface of the second prism 3 can be received by a light receiving element arranged outside.

That is, in the color separation prism 1, a spacer 5 formed by thinly rolling stainless to form a frame is inserted between the first and second prisms 2 and 3, and in this state, the first and second prisms are formed. Press 2 and 3. As a result, in the color separation prism 1, the space between the first and second prisms 2 and 3 is maintained at a space determined by the thickness of the spacer 5, and in this state the upper and lower side plates 6 and 7 are adhered to each other. Is designed to hold.

[0010]

By the way, in such a color separation prism 1, when the distance between the first and second prisms 2 and 3 becomes large, aberration occurs, so that the distance between them becomes 10 [. [μm] or less is desirable. Furthermore, if the parallelism between the exit surface of the first prism 2 and the entrance surface of the second prism is disturbed at this time, the image quality of the captured image deteriorates.

However, according to the structure of the conventional color separation prism 1, since the distance between the first and second prisms 2 and 3 is maintained at the distance determined by the thickness of the spacer 5, the spacer 5 is made thin. Even if the distance between them is 10 [μm]
There is a problem that it is difficult to set below, and as the interval between them becomes smaller, it becomes difficult to maintain the parallelism and the assembling work becomes complicated.

The present invention has been made in view of the above problems, and the thickness of the air layer formed between the first and second prisms can be reduced by a simple assembling work, and sufficient parallelism can be secured. An object of the present invention is to provide a color separation prism that can be used and a method for assembling the color separation prism.

[0013]

According to the present invention, the above objects are achieved by forming mirror surfaces having wavelength selectivity on the exit surfaces of the first prism and the second prism, respectively, so that predetermined incident light can be emitted. In a color separation prism that sequentially transmits the first prism and the second prism to separate the light of a wavelength that allows the wavelength selectivity of the mirror surface from the incident light, the exit surface of the first prism and The incident surface of the second prism is bonded with an adhesive containing fine spacers, and air having a thickness determined by the fine spacers is provided between the exit surface of the first prism and the incident surface of the second prism. Achieved by layered color separation prisms.

Preferably, a fiber material or beads is used for the fine spacers.

The adhesive may be mixed with a black pigment in addition to the fine spacers.

Preferably, the exit surface of the first prism or the entrance surface of the second prism has an escape groove outside the optical path of the incident light, and the adhesive is provided outside the escape groove. When applied, the exit surface of the first prism and the second surface of the second prism
It is configured by adhering the incident surface of the prism.

Further, the above-mentioned object is to provide the first prism and the second prism.
A mirror surface having wavelength selectivity is formed on the exit surface of each prism, and predetermined incident light is sequentially transmitted through the first prism and the second prism to select the wavelength of the mirror surface from the incident light. In a method of assembling a color separation prism for separating light of a wavelength that can be achieved, the exit surface of the first prism and the entrance surface of the second prism are bonded with an adhesive containing a fine spacer, The exit surface of the prism and the entrance surface of the second prism are held at intervals determined by the fine spacers, and the thickness determined by the spacer is set between the exit surface of the first prism and the entrance surface of the second prism. It can also be achieved by a method of assembling the color separation prism that forms the air layer of the roof.

[0018]

According to the above-mentioned structure, the distance between the exit surface of the first prism and the entrance surface of the second prism can be maintained at a highly accurate interval determined by the fine spacers by a simple operation. Thus, by selecting the size of the fine spacer, the thickness of the air layer formed between the first and second prisms can be reduced and sufficient parallelism can be secured.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The examples described below are
Since it is a preferred specific example of the present invention, various technically preferable limitations are attached, but the scope of the present invention is, unless otherwise stated to limit the present invention, in the following description.
It is not limited to these modes.

FIG. 1 is a schematic perspective view showing a color separation prism according to the present invention. In the figure, the color separation prism 10
Adheres the first and second prisms 2 and 3 with a predetermined adhesive 11 while avoiding the optical path to directly adhere and hold the first and second prisms 2 and 3, and
And an air layer is formed between the second prisms 2 and 3.

Here, in the adhesive 11, as shown in FIG. 2, the fiber material 13 is mixed as a fine spacer into the ultraviolet curable adhesive at a mixing ratio of 10% or less, and a black pigment is further added. Is mixed in a predetermined amount. In this fiber material 13, the diameter is selected according to the thickness of the air layer formed between the first and second prisms 2 and 3, and in the case of this embodiment, the diameter is 10 [μ
m] glass fiber is selected as the fiber material.

That is, in the color separation prism 10, after adhering the third prism 4 to the second prism 3, the adhesive 11 is applied to the incident surface of the second prism 3 to form the first prism 2. Press. As a result, the first and second prisms 2 and 3 are held at a distance determined by the fiber material 13. Therefore, in the first and second prisms 2 and 3, the thickness of the first and second prisms 2 and 3 can be easily adjusted by simply applying an adhesive and pressing the same.
An air layer of [μm] can be formed.

Further, when the fiber material 13 is mixed into the adhesive 12 in this way to form an air layer between the first and second prisms 2 and 3, the first and second prisms 2 and 3 face each other. It is also possible to hold the surfaces to be parallel to each other with high accuracy. Further, the diameter of the mixed fiber material 13 can be changed to select the desired thickness of the air layer, and in this case as well, high parallelism can be secured.

Further, in the color separation prism 10, by mixing a black pigment in the adhesive 11, it is possible to reduce the penetration of stray light with a simple structure.

Further, as shown in FIG. 3, preferably, in the color separation prism 10, an escape groove 14 is formed on the incident surface of the second prism 3 so that the adhesive 11 does not stick out on the optical path. It has become. That is, when the adhesive is applied in this way, if the first and second prisms 2 and 3 are directly adhered, there is a risk that they will stick out in the optical path. For this reason, in this embodiment, the excess adhesive 11 that may protrude from the optical path is allowed to escape into the escape groove 14 so that the adhesive 11 does not enter the optical path.

That is, as shown in FIG. 4, in the color separation prism 10, the adhesive 11 is applied to the outside of the escape groove 14 by using a dispenser or the like, and then the first prism 2 is pressed and adhered. As a result, the color separation prism 1
At 0, the thickness of the air layer formed between the first and second prisms can be reduced and sufficient parallelism can be secured by a simple assembling work, and at the same time, the penetration of stray light is also reduced. be able to. Further, in the color separation prism 10, after adhering the respective prisms 2 to 4 in this manner,
The side plates 6 and 7 are adhered to form the whole.

That is, in the conventional color separation prism, it is difficult to secure sufficient strength only by the side plates 6 and 7 by adhesively holding the prisms 2 to 4 through the side plates 6 and 7. In the conventional color separation prism 1, a reinforcing plate is provided outside the side plates 6 and 7 to secure the strength. However, if the prisms 2 to 4 are directly bonded and held as in this embodiment, the overall strength can be improved and the reinforcing plates provided outside the side plates 6 and 7 can be omitted. Therefore, the assembling work and the entire structure can be simplified accordingly, and the overall shape can be reduced.

As described above, in the above-described embodiment, the first and second prisms 2 and 3 are directly adhered to each other with the adhesive agent in which the fiber material and the black pigment are mixed, and then adhered to the side plate to color separation prism 10. By assembling, the space determined by the fiber material can be secured between the first and second prisms 2 and 3 with a simple assembling work, and sufficient strength can be secured. Therefore, by selecting the size of this fiber material, the thickness of the air layer can be reduced and sufficient parallelism can be secured.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where the escape groove is formed in the vertical direction and the adhesive is applied to the outer side thereof has been described, but the present invention is not limited to this, and as shown in FIG. Alternatively, an escape groove may be formed and an adhesive may be applied. By doing so, it is possible to further improve the overall strength and further reduce the entry of stray light.

Furthermore, in the above-mentioned embodiment, the case where the adhesive agent in which the fiber material is mixed is used as the fine spacer has been described, but the present invention is not limited to this, and the adhesive agent in which beads such as glass are mixed is used. You may do it.

Further, in the above-mentioned embodiments, the case where the black pigment is mixed into the adhesive has been described, but the present invention is not limited to this, and can be widely applied to the case where a black pigment such as brown is mixed. Further, when the stray light can be sufficiently prevented by other mechanical parts or the like, the mixing of the pigment may be omitted.

Further, in the above-mentioned embodiment, the case where the ultraviolet curing type adhesive is used has been described, but the present invention is not limited to this, and various adhesives such as epoxy type can be widely applied. .

[0033]

As described above, according to the present invention, the thickness of the air layer formed between the first and second prisms can be reduced by a simple assembling work, and sufficient parallelism can be secured. can do.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a color separation prism according to the present invention.

FIG. 2 is a diagram showing a fiber material mixed in an adhesive used in the assembling work of FIG.

3 is a perspective view showing a first work procedure of the assembly work of FIG. 1. FIG.

4 is a perspective view showing a second work procedure of the assembling work of FIG. 1. FIG.

FIG. 5 is a perspective view of a second embodiment of the color separation prism according to the present invention.

FIG. 6 is a schematic diagram for explaining the principle of a color separation prism.

FIG. 7 is an exploded perspective view showing a conventional color separation prism.

[Explanation of symbols]

 1, 10 color separation prism 2, 3, 4 prism 5 spacer 6, 7 side plate 11, 12 adhesive 13 fiber material 14, 15 escape groove

Claims (5)

[Claims] 1. A mirror surface having wavelength selectivity is formed on each of the exit surfaces of the first prism and the second prism, and predetermined incident light is sequentially transmitted through the first prism and the second prism. Then, in a color separation prism that separates light having a wavelength that allows the wavelength selectivity of the mirror surface from the incident light, fine spacers are mixed in the exit surface of the first prism and the entrance surface of the second prism. A color separation prism characterized in that an air layer having a thickness determined by the fine spacers is formed between the exit surface of the first prism and the entrance surface of the second prism with an adhesive. 2. The color separation prism according to claim 1, wherein the fine spacers are made of fiber material or beads. 3. The color separation prism according to claim 1, wherein the adhesive contains a black pigment in addition to the fine spacers. 4. The exit surface of the first prism or the entrance surface of the second prism has a clearance groove outside the optical path of the incident light, and the adhesive is applied to the outside of the clearance groove. The color separation prism according to claim 1, wherein the exit surface of the first prism and the entrance surface of the second prism are adhered to each other. 5. A mirror surface having wavelength selectivity is formed on each of the exit surfaces of the first prism and the second prism, and predetermined incident light is sequentially transmitted through the first prism and the second prism. In the method of assembling a color separation prism that separates light having a wavelength that is sufficient for the wavelength selectivity of the mirror surface from the incident light, the exit surface of the first prism and the entrance surface of the second prism are provided with fine spacers. Are adhered with an adhesive mixed with the above, and the exit surface of the first prism and the entrance surface of the second prism are held at intervals determined by the fine spacers, and the exit surface of the first prism and the second prism A method for assembling a color separation prism, comprising forming an air layer having a thickness determined by the spacer between the incident surfaces of the prism. [0001]