JP2006229563A - Fixing structure of color separation prism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the registration error of a color separation prism due to temperature variation. <P>SOLUTION: When the color separating prism is fixed to a base 13, a spacer 15 and a fixing member 16 made of a thin metal plate bent in an L shape are put one over the other while being fitted onto a positioning pin 19 on the base 13 so that the bending root of the fixing member 16 is pressed by a pressure plate 17, and positioning is made by the positioning pin 19 provided to the base 13 and the hole portion 16a of the fixing member 16. Then a fixing means 14 is fixed to the base 13 with an unillustrated fixing screw and the other surface of the fixing member 16 is bonded to the flank 12e of the prism 12a finally by using an adhesive, so that the color separation prism is precisely held on the base 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fixing structure for a color separation prism used in a photographing apparatus such as a television camera.

  FIG. 6 is a front view of a state in which a color separation prism used in many current television camera photographing systems is attached, and FIG. 7 is a side view thereof. A general color separation prism 1 is composed of three prisms 2a, 2b, and 2c, and separates incident light L from the direction of an arrow into three color components B, G, and R, and is represented by a CCD. The incident light is incident on each of the image sensors that do not.

  The prism base 3 is bonded and fixed to the side portions of these three prisms 2a, 2b, and 2c, and the prism base 3 is aligned with the base 5 by positioning pins 4 and further fixed. It is fixed with screws 6.

  Thereafter, so-called registration adjustment is performed by superimposing the subject images of the respective color components to be imaged by advanced positioning using the image sensor. After this adjustment, ceramic, titanium, or the like is used as the material of the prism base 3 so that the registration does not change greatly due to a temperature change or the like, and its linear expansion coefficient is close to that of the prism material glass.

JP 2000-270340 A

  As described above, the linear expansion coefficients of the prisms 2a, 2b, and 2c and the prism base 3 adhered and fixed to the prisms 2a and 2b are close to each other. However, when a sudden temperature change occurs, the subject image of each color component captured by the image sensor is captured. There is a possibility of causing a so-called registration error in which the overlay is shifted.

  Further, since the prism base 3 is bonded to the prisms 2a, 2b, and 2c, it is necessary to perform high-precision surface processing on the bonding surfaces of the prisms 2a, 2b, and 2c bonded to the prism base 3 and the prism base 3 itself. Further, since the prism base is made of a material that is generally difficult to process, such as ceramics or titanium, the prisms 2a, 2b, 2c and the prism base 3 are both expensive parts.

  An object of the present invention is to solve the above-described problems and provide an inexpensive color separation prism fixing structure that does not require high-precision processing on a fixing adhesive surface.

  In order to achieve the above object, the technical feature of the color separation prism fixing structure according to the present invention is that when a color separation prism that separates an incident light beam into a plurality of colors by a plurality of prisms is fixed to a base, One surface of the fixing member is attached to a side surface through which light flux of one prism among the prisms does not pass, and the other surface of the fixing member is fixed to the base.

  According to the color separation prism fixing structure according to the present invention, the fixing member for fixing the prism to the base is bonded to only one of the plurality of prisms, and therefore the accuracy of the pasting surface of the other prisms is taken into consideration. In addition, even when the dimensions of the prism and the fixing member change due to temperature changes, the spacing between the prisms and the attachment position do not shift, and registration errors can be prevented.

  Further, if a gap is provided between the members and used as an adhesive reservoir, it is possible to prevent the adhesive from flowing around the incident surface of the prism, and it is possible to prevent malfunction of the function.

  In addition, if the fixing member is a metal plate, processing is easy and dimensional errors can be absorbed by bending when adhering to the prism and fixing to the base, improving yield and reducing processing costs. Both the prism and the fixing member are inexpensive.

  The present invention will be described in detail with reference to the embodiments shown in FIGS.

  FIG. 1 is an overall perspective view of the first embodiment, and FIG. 2 is a side view. In the color separation prism 11, the prisms 12 a and 12 b, 12 b and 12 c are firmly fixed by an optical adhesive on the surfaces through which the light beams pass, and the incident surface 12 d of the prism 12 a is connected to the mounting surface 13 a of the base 13. It touches.

  Fixing means 14 for fixing the color separation prism 11 to the base 13 is attached to both sides of the triangular shape of the prism 12a. In these fixing means 14, a spacer 15, a fixing member 16, and a pressing plate 17 are laminated from the base 13 side as shown in FIG.

  As shown in the sectional view of the fixing portion in FIG. 3, the fixing member 16 is made of a thin metal plate bent into an L shape, and one surface of the L shape orthogonal to the laminated portion uses an adhesive on the side surface 12e of the prism 12a. An air gap 18 is formed between the spacer 15 and the side surface 12e of the prism 12a.

  Positioning pins 19 project upward from the base 13, and holes 15 a, 16 a, and 17 a are provided in the spacer 15, the fixing member 16, and the pressing plate 17 corresponding to the positioning pins 19, respectively. Is larger than the outer diameter of the positioning pin 19, and the inner diameter of the hole 16 a substantially matches the outer diameter of the positioning pin. Further, holes 15b, 16b, and 17b (16b and 17b are not shown) are provided in the spacer 15, the fixing member 16, and the presser plate 17, and can be fixed to the base 13 by the fixing screw 20. .

  When the color separation prism 11 is fixed to the base 13, the base of the bending of the fixing member 16 is pressed by the pressing plate 17 while the spacer 15 and the fixing member 16 are inserted into the positioning pins 19 on the base 13. The positioning is determined by positioning pins 19 provided on the base 13 and the holes 16 a of the fixing member 16. Next, if the fixing means 14 is fixed to the base 13 with the fixing screw 20, and the prism 12a is finally adhered to the fixing member 16 with high accuracy, the positioning accuracy between the color separation prism 11 and the base 13 can be maintained. .

  When the fixing member 16 is attached to the side surface 12e of the prism 12a, the adhesive S to be used may protrude, but the gap 18 is provided between the end surface of the spacer 15 and the side surface 12e of the prism 12a. The gap 18 serves as a reservoir for the adhesive S, and the excessive adhesive S does not go around the incident surface 12d of the prism 12a.

  Further, by making the fixing member 16 a metal plate, it is possible to absorb attachment errors by bending.

  The fixing member 16 can be bonded to the prism 12a in the previous step of fixing the color separation prism 11 to the base 13. In this case, the fixing member 16 is bonded using a jig instead of the base 13. Then, it may be fixed to the base 13 thereafter.

  FIG. 4 is a cross-sectional view of the fixing portion of the second embodiment. The spacer 15 in the first embodiment is omitted, and one surface of the fixing member 16 made of a metal plate is in contact with the base 13. A sticking spacer 31 for adhering to the side surface 12e of the prism 12a is fixed in advance to the surface by means such as adhesion or screwing. A lower end surface 31a of the sticking spacer 31 is attached so as to form a gap 32 between the base 13 and the sticking spacer 31 and the prism 12a are bonded by an adhesive S.

  When the side surface 12e of the prism 12a and the sticking spacer 31 are stuck, the used adhesive S may protrude, but the gap corresponding to the thickness of the sticking spacer 31 provided below the sticking spacer 31. Since 32 serves as an adhesive reservoir, excess adhesive S does not enter the prism incident surface 12d.

  Positioning when the color separation prism 11 is fixed to the base 13 is performed in the same manner as in the first embodiment, and the pressing plate 17 is placed so as to press the bending base of the fixing member 16, and the fixing member 16 on the base 13 is placed. The holding plate 17 is fixed using a fixing screw 20 (not shown).

  FIG. 5 shows a third embodiment, which is fixed using only the fixing member 41, and the fixing member 41 is made of a block-like highly rigid part made of an arbitrary material. A gap 42 formed of a chamfer or a step is provided at the lower end of the prism 12a on the side surface 12e side, and serves as an adhesive reservoir for the adhesive S used when the fixing member 41 is bonded to the side surface 12e of the prism 12a. ing. After the prism 12 a and the fixing member 41 are bonded and fixed, the fixing member 41 is positioned using a positioning pin (not shown), and the fixing screw 20 is inserted into the hole 41 a formed in the fixing member 41 and fixed to the base 13.

  Also in the third embodiment, the adhesive S does not enter the incident surface 12d of the prism 12a, and the positioning of the color separation prism 11 and the base 13 can be maintained with high accuracy. In order to increase the surface accuracy and angle accuracy, it is necessary to perform high-precision processing, and the price of the components increases.

1 is an overall perspective view of Example 1. FIG. It is a side view. It is sectional drawing of a fixing | fixed part. FIG. 6 is a cross-sectional view of a fixing part of Example 2. FIG. 6 is a cross-sectional view of a fixing part of Example 3. It is a front view of a prior art example. It is a side view of a prior art example.

Explanation of symbols

11 Color separation prism 12a, 12b, 12c Prism 13 Base 15 Spacer 15a, 15b, 16a, 17a, 41a Hole 16, 41 Fixing member 17 Holding plate 18, 32, 42 Space 19 Positioning pin 20 Fixing screw 31 Spacer for pasting

Claims (8)

  When fixing a color separation prism that separates an incident light beam into a plurality of colors by a plurality of prisms on a base, a surface of a fixing member is attached to a side surface through which the light beam of one of the plurality of prisms does not pass, A fixing structure of a color separation prism, wherein the other surface of the fixing member is fixed to the base.   The color separation prism fixing structure according to claim 1, wherein the fixing member includes an alignment mechanism for the base.   The adhesive reservoir for preventing the adhesive for adhering the fixing member to the prism from entering the surface through which the luminous flux of the prism passes is provided between the fixing member and the prism. Item 3. A fixing structure of a color separation prism according to item 1 or 2.   The color separation prism fixing structure according to any one of claims 1 to 3, wherein the fixing member is a metal plate bent in an L shape.   The structure for fixing a color separation prism according to claim 4, wherein when the metal plate is fixed to the base, the metal plate is pressed using a pressing plate.   6. The color separation prism according to claim 4, wherein the adhesive reservoir is a step portion corresponding to a thickness of the spacer when the metal plate is fixed to the base via a spacer. Fixed structure.   6. The color separation prism according to claim 4, wherein the adhesive reservoir is a step portion corresponding to a thickness of the spacer when the metal plate is attached to the prism via a spacer. Fixed structure.   An image pickup apparatus using the color separation prism fixing structure according to claim 1.

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