JPH0518402B2 - - Google Patents
Info
- Publication number
- JPH0518402B2 JPH0518402B2 JP60143126A JP14312685A JPH0518402B2 JP H0518402 B2 JPH0518402 B2 JP H0518402B2 JP 60143126 A JP60143126 A JP 60143126A JP 14312685 A JP14312685 A JP 14312685A JP H0518402 B2 JPH0518402 B2 JP H0518402B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- secondary imaging
- optical system
- detection device
- focus detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000003384 imaging method Methods 0.000 claims description 50
- 230000003287 optical effect Effects 0.000 claims description 36
- 238000006243 chemical reaction Methods 0.000 claims description 15
- 238000001514 detection method Methods 0.000 claims description 11
- 210000001747 pupil Anatomy 0.000 claims description 5
- 238000003491 array Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 230000004907 flux Effects 0.000 description 3
- 230000011514 reflex Effects 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Landscapes
- Focusing (AREA)
- Automatic Focus Adjustment (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、光学系によつて形成される、一方向
につき２つの物体像のズレ量から焦点調節状態の
判別を行うための焦点検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a focus detection device for determining a focus adjustment state from the amount of shift between two object images in one direction formed by an optical system.
従来技術
従来より、一眼レフカメラ等において、撮影レ
ンズの瞳の異なる２つの部分からの夫々の光束に
基づいて２つの物体像を形成し、この物体像の相
対的な位置関係から撮影レンズの焦点状態を検出
するようなした所謂像ズレ方式の焦点検出装置は
周知である。Conventionally, in single-lens reflex cameras and the like, two object images are formed based on the respective light beams from two different parts of the pupil of the photographing lens, and the focal point of the photographing lens is determined from the relative positional relationship of the object images. A so-called image shift type focus detection device that detects the state is well known.
第９図はこのような像ズレ方式の焦点検出装置
の従来例を示すもので、この図において、Ｏは被
写体面、１は不図示の一眼レフカメラにおける撮
影レンズ、３は撮影レンズ１の予定結像面（カメ
ラにおける焦点面）２の近傍に設けられたフイー
ルドレンズ、４，５は撮影レンズ１の光軸Ｌを中
心にして対称に配置され、撮影レンズ１の瞳の異
なる部分１ａ，１ｂの夫々を通過する光束に基づ
いて２つの物体像を結像させるための２次結像レ
ンズ、６，７は２次結像レンズ４，５によつて結
像された各物体像を検出するための光電変換素子
列で、この素子列６，７は例えばCCD（チヤージ
カツプルド デバイス）（Charge Coupled
Devide）等で構成される。 FIG. 9 shows a conventional example of such an image shift type focus detection device. In this figure, O is the subject plane, 1 is a photographing lens in a single-lens reflex camera (not shown), and 3 is a schedule for the photographic lens 1. Field lenses 4 and 5 provided in the vicinity of the imaging plane (focal plane in the camera) 2 are arranged symmetrically with respect to the optical axis L of the photographic lens 1, and have different portions 1a and 1b of the pupil of the photographic lens 1. Secondary imaging lenses 6 and 7 detect each object image formed by the secondary imaging lenses 4 and 5, respectively, for forming two object images based on the light flux passing through each of the secondary imaging lenses 4 and 5. This element row 6 and 7 is a photoelectric conversion element row for, for example, a CCD (Charge Coupled Device).
Devide) etc.
８は２次結像レンズ近傍に設けられたマスク
で、フイールドレンズ３はマスク８の開口部８
ａ，８ｂを撮影レンズ１の異なつた瞳部分１ａ，
１ｂに結像させている。このような装置では、例
えば、撮影レンズ１が図示左方に繰り出されて所
謂前ピン状態となると、２次結像レンズ４，５に
よつて夫々の光電変換素子列６，７の受光面に結
像されていた被写体面位置の物体の像が夫々矢印
方向にずれるので、この像の相対的なズレに応じ
た光電変換素子列６，７の出力の変化により、前
ピン状態であること及びその量が検出されること
になる。また、後ピン状態の場合には、夫々の像
が前ピン状態の場合と逆方向にずれるので、後ピ
ン状態であること及びその量が検出される。 8 is a mask provided near the secondary imaging lens, and the field lens 3 is located in the opening 8 of the mask 8.
a and 8b are different pupil portions 1a of the photographing lens 1,
The image is focused on 1b. In such a device, for example, when the photographic lens 1 is extended to the left in the figure and becomes in a so-called front-focus state, the secondary imaging lenses 4 and 5 focus on the light-receiving surfaces of the respective photoelectric conversion element rows 6 and 7. Since the image of the object at the object plane position that was being imaged shifts in the direction of the arrow, the outputs of the photoelectric conversion element arrays 6 and 7 change in accordance with the relative shift of the images, thereby indicating that the object is in the front focus state and The amount will be detected. Furthermore, in the case of the rear focus state, each image shifts in the opposite direction to that in the front focus state, so that the rear focus state and its amount are detected.
以下、第１０図を使用して、測距精度を低下さ
せる原因の内、画角に依頼するものを説明する。
第１０図で各部材は前述の場合と同様とし、他
方、光軸Ｌと被写体面Ｏとの交点をＯ１、軸外の
１点をＯ２とする。また点Ｏ１を発した光束は２
次結像レンズ４，５の作用で光電変換素子列６，
７へ結像し、その点をＰ１とＱ１とする。 Hereinafter, using FIG. 10, among the causes of decreasing distance measurement accuracy, those that depend on the angle of view will be explained.
In FIG. 10, each member is the same as in the previous case, and the intersection of the optical axis L and the object plane O is O1, and one point off the axis is O2. Also, the luminous flux emitted from point O1 is 2
Next, by the action of the imaging lenses 4 and 5, the photoelectric conversion element array 6,
7, and let those points be P1 and Q1.
次に軸外の点Ｏ２を発した光束に着目すると、
この画角を持つた光束は予定結像面２又はその近
傍に一旦結像した後、２次結像レンズ６，７によ
り光電変換素子列６，７に再結像する。この点が
Ｐ２，Ｑ２である。Ｐ１とＰ２の間隔Ｚ１及び、
Ｑ１とＱ２の間隔Ｚ２は、Ｏ１Ｏ２を結ぶ像に当
るものであるから等しくなければならないのであ
るが、２次結像レンズの収差に依存して等しくな
らないことに気付いた。そのため同じ被写体距離
の物体であつても、測距視野中央域と周辺域とで
はレンズの焦点状態の判別が異なる不都合が起き
ていると考えられる。従つて、中央域と周辺域の
不一致を含んだまま信号処理がなされるため精度
は低下することになるわけである。 Next, if we focus on the light flux emitted from the off-axis point O2, we get
The light beam having this angle of view forms an image at or near the intended imaging plane 2, and then re-images on the photoelectric conversion element arrays 6, 7 by the secondary imaging lenses 6, 7. This point is P2, Q2. The distance Z1 between P1 and P2 and
The distance Z2 between Q1 and Q2 must be equal because they correspond to images that form O1O2, but it has been noticed that they are not equal depending on the aberration of the secondary imaging lens. Therefore, even for objects having the same subject distance, it is thought that there is a problem in that the lens focus state is determined differently in the center area and the peripheral area of the distance measurement field of view. Therefore, signal processing is performed while including the mismatch between the central region and the peripheral region, resulting in a decrease in accuracy.
以上とは別に、２次結像レンズの色収差が良好
に補正されていない場合、第１１図に示す通り、
波長によつて結像位置が相違して差異Ｚ３が発生
すると考えられる。そのため被写体の色相によつ
てレンズの焦点状態の判別が相違し、合焦精度の
低下の原因となる。 Apart from the above, if the chromatic aberration of the secondary imaging lens is not well corrected, as shown in Figure 11,
It is considered that the difference Z3 occurs because the imaging position differs depending on the wavelength. Therefore, the determination of the focal state of the lens differs depending on the hue of the subject, which causes a decrease in focusing accuracy.
目 的
本発明の目的は、上述した難点の少なくとも片
方、そして望ましくは双方を解決することにあ
り、検出精度を向上させることにある。Purpose The purpose of the present invention is to solve at least one, and preferably both, of the above-mentioned difficulties, and to improve detection accuracy.
この目的を達成するため、対物レンズによる像
を更に２次結像光学系で再結像させるに際し、対
物レンズの瞳の異なつた部分を通過する光束で
夫々物体像を光電変換手段上に形成し、殊に２次
結像光学系が、光電変換手段の像走査方向（但し
走査順序に係わらないものとする）に光束を屈折
するプリズム作用面を具えている。尚、後述する
実施例で、プリズム作用面は光電変換素子列の配
列方向に対して傾いた傾斜平面であるが、平面を
傾ける替わりに内部に屈折率の分布を持つた光学
ブロツクで代用することもできる。 In order to achieve this purpose, when the image formed by the objective lens is further re-imaged by the secondary imaging optical system, an object image is formed on the photoelectric conversion means by the light beams passing through different parts of the pupil of the objective lens. In particular, the secondary imaging optical system is provided with a prism surface that refracts the light beam in the image scanning direction of the photoelectric conversion means (independent of the scanning order). In the examples described later, the prism working surface is an inclined plane that is inclined with respect to the arrangement direction of the photoelectric conversion element array, but instead of inclining the plane, an optical block having an internal refractive index distribution may be used instead. You can also do it.
実施例
第１図は本発明の第１の実施例を示す図であ
る。Ｏは被写体面、１１は例えば一眼レフレツク
スカメラの撮影レンズ、２は撮影レンズの予定結
像面、３は予定結像面上もしくはその近傍に光軸
Ｌを一致させて配置したフイールドレンズであ
る。１４と１５は夫々２次結像レンズで、例えば
両レンズの側部を切除して接合した形態をしてい
てプラスチツクで一体成型される。夫々前面が球
面１４ａ，１５ａで、後面は傾斜した平面１４
ｂ，１５ｂであり、谷型を形成する。後平面の傾
斜は光電変換素子列１６，１７の素子の配列方向
（像走査方向）に平行な方向に決められている。
尚、光電変換素子列は一本の素子列の２つの領域
であつても良い。Embodiment FIG. 1 is a diagram showing a first embodiment of the present invention. O is a subject plane, 11 is a photographing lens of, for example, a single-lens reflex camera, 2 is a planned image forming plane of the photographing lens, and 3 is a field lens arranged with its optical axis L aligned on or near the planned image forming plane. be. Reference numerals 14 and 15 denote secondary imaging lenses, which are formed by, for example, cutting out the sides of both lenses and joining them together, and are integrally molded from plastic. The front surface is a spherical surface 14a, 15a, and the rear surface is an inclined plane 14.
b, 15b, forming a valley shape. The inclination of the rear plane is determined in a direction parallel to the arrangement direction (image scanning direction) of the photoelectric conversion element arrays 16 and 17.
Note that the photoelectric conversion element array may be two regions of one element array.
また１８は２孔マスクで、２次結像レンズ１
４，１５の直前に配され、各開口の中心は各２次
結像レンズ１４，１５の光軸と一致している。 18 is a two-hole mask, and the secondary imaging lens 1
4 and 15, and the center of each aperture coincides with the optical axis of each secondary imaging lens 14 and 15.
傾いた平面１４ｂ，１５ｂは光軸Ｌに関して対
称であるが、この角度の決定は次の方法による。
第２図Ａはプリズム角を横軸に、結像位置の差Ｚ
１−Ｚ２を縦軸に採つたときの特性図で、Ｂはプ
リズム角を横軸に、波長による結像位置の差２Ｚ
３を縦軸に採つたときの特性図である。プリズム
角を負にする方向が除去すべき諸量が正になる方
向である。また変化に対する敏感度は２次結像レ
ンズが短い程、高くなる。図は２次結像レンズの
焦点距離をｆ＝１に規格化し、長さを1.046に選
んだときのものである。 The inclined planes 14b and 15b are symmetrical with respect to the optical axis L, and this angle is determined by the following method.
Figure 2 A shows the difference Z in the imaging position with the prism angle as the horizontal axis.
This is a characteristic diagram when 1-Z2 is taken as the vertical axis, and B is the difference in imaging position due to wavelength, with the prism angle as the horizontal axis.
FIG. 3 is a characteristic diagram when 3 is plotted on the vertical axis. The direction in which the prism angle becomes negative is the direction in which the various quantities to be removed become positive. Furthermore, the shorter the secondary imaging lens is, the higher the sensitivity to changes becomes. The figure shows the focal length of the secondary imaging lens normalized to f=1 and the length chosen to be 1.046.
特性図からわかる様にＺ１−Ｚ２を０にするプ
リズム角及び２Ｚ３を０にするプリズム角が存在
するが、両値の値は一致しないから、Ｚ１−Ｚ２
の差の除去に比重を掛けた中間的な値を採用する
のが一法である。 As you can see from the characteristic diagram, there is a prism angle that makes Z1-Z2 0 and a prism angle that makes 2Z3 0, but since the two values do not match, Z1-Z2
One method is to adopt an intermediate value by multiplying the removal of the difference by the specific weight.
第１図に示す２次結像レンズの数値例は次の通
りである。表でＲ１は１４ａ，１５ａに相当し、
Ｒ２は１４ｂ，１５ｂに相当する。Ｒは曲率半
径、Ｄはレンズ厚、Ndはｄ線に対する屈折率、
νdはアツベ数。 A numerical example of the secondary imaging lens shown in FIG. 1 is as follows. In the table, R1 corresponds to 14a, 15a,
R2 corresponds to 14b and 15b. R is the radius of curvature, D is the lens thickness, Nd is the refractive index for the d-line,
νd is Atsube number.
表 １
Ｒ Ｄ Nd νd
１ 0.4917 1.046 1.49171 57.4
２ ∞〓
〓 但し、Ｒ２平面は谷型となる様に各4°傾い
ている（第１図）。 Table 1 R D Nd νd 1 0.4917 1.046 1.49171 57.4 2 ∞〓 〓 However, the R2 plane is tilted by 4 degrees each so as to form a valley shape (Fig. 1).
マスク１８の各開口の中心の間隔と、２次結像
レンズ１４，１５の２つの光軸の中心の間隔は共
に0.247である。２次結像レンズの材質はアクリ
ルで、結像倍率は0.35である。 The distance between the centers of each aperture of the mask 18 and the distance between the centers of the two optical axes of the secondary imaging lenses 14 and 15 are both 0.247. The material of the secondary imaging lens is acrylic, and the imaging magnification is 0.35.
以上の構成によつて、Ｚ１−Ｚ２＝−0.32μｍ
（予定結像面で２mm高に相当）、Ｚ＝＋0.63μｍ
（ｄ線とｇ線の差）まで抑制された。 With the above configuration, Z1-Z2=-0.32μm
(Equivalent to 2mm height at planned imaging plane), Z = +0.63μm
(difference between d-line and g-line).
第３図は別の実施例の要部を示している。 FIG. 3 shows the main part of another embodiment.
図中、２４と２５は夫々２次結像レンズで、２
４ａと２５ａは球面、２４ｂと２５ｂは傾斜平面
で、両面は光軸Ｌを対称軸として山型を成す。他
の構成部材は第１図の例と同様であるが、本例の
場合、各２次結像レンズの光軸２４Ｌ，２５Ｌは
２孔マスク１８の中心１８′，１８″に対して外側
に位置ズレする様に配置している。従つて、レン
ズ球面２４ａ，２５ａの円弧に沿つて夫々の２次
結像レンズを傾けたのと類似の作用を与えること
ができ、この作用が傾斜平面２４ｂ，２５ｂのプ
リズム作用と共同することになる。 In the figure, 24 and 25 are secondary imaging lenses, respectively.
4a and 25a are spherical surfaces, 24b and 25b are inclined planes, and both surfaces form a mountain shape with the optical axis L as the axis of symmetry. The other components are the same as those in the example shown in FIG. Therefore, an effect similar to that obtained by tilting each secondary imaging lens along the arc of the lens spherical surfaces 24a and 25a can be provided, and this effect can be applied to the inclined plane 24b. , 25b.
２次結像レンズの偏心の量と平面の傾角は次の
様にして決定する。 The amount of eccentricity of the secondary imaging lens and the inclination angle of the plane are determined as follows.
第４図で縦軸は平面の傾角（プリズム角）、横
軸はレンズの偏心量を表し、線ＡはＺ３＝０、線
ＢはＺ１−Ｚ２＝０の条件を満たす。２線ＡとＢ
の交点が解で、後述の数値データはこの解近傍に
採つたときのものである。この値よりプリズム角
が緩いか或いはレンズの偏心量が大きい場合、除
去すべき諸量は正となり、逆の場合、負となる。
この解は２次結像レンズの長さが長い程、原点に
近づき、公差も緩くなる。 In FIG. 4, the vertical axis represents the inclination angle of the plane (prism angle), and the horizontal axis represents the eccentricity of the lens, line A satisfies the condition Z3=0, and line B satisfies the condition Z1-Z2=0. 2 wires A and B
The intersection point is the solution, and the numerical data described below is taken near this solution. If the prism angle is looser than this value or the amount of eccentricity of the lens is greater than this value, the amounts to be removed will be positive, and in the opposite case, they will be negative.
The longer the length of the secondary imaging lens, the closer this solution is to the origin and the looser the tolerance.
第３図の２次結像レンズのＲ，Ｄ，Nd，νd，
材質，結像倍率、及び２孔マスク１８の２つの開
口の中心間隔は表１に等しいが、２次結像レンズ
の光軸の間隔は0.322mmで、平面２４ｂ，２５ｂ
は光軸に垂直な面に対し外向きに6°傾いている。 R, D, Nd, νd of the secondary imaging lens in Fig. 3,
The material, the imaging magnification, and the center distance between the two apertures of the two-hole mask 18 are the same as shown in Table 1, but the distance between the optical axes of the secondary imaging lens is 0.322 mm, and the distance between the optical axes of the secondary imaging lens is 0.322 mm, and the distance between the centers of the two apertures of the two-hole mask 18 is 0.322 mm.
is tilted outward by 6° with respect to the plane perpendicular to the optical axis.
Ｚ１−Ｚ２＝−0.084μｍ、Ｚ３＝＋0.042μｍま
で抑制されている。 It is suppressed to Z1-Z2=-0.084 μm and Z3=+0.042 μm.
第５図は第３実施例の要部を示しており、他は
第１図の構成と同様とする。本例では２次結像レ
ンズ２４，２５の平面（プリズム面）３４ｂ，３
５ｂと球面（収斂レンズ面）３４ａ，３５ａが転
置され、２孔マスク１８′は球面３４ａ，３５ａ
側に設けられている。この様に球面と平面の順序
は限定されない。 FIG. 5 shows the main part of the third embodiment, and the other parts are the same as the configuration shown in FIG. 1. In this example, the planes (prism surfaces) 34b, 3 of the secondary imaging lenses 24, 25
5b and the spherical surfaces (convergent lens surfaces) 34a, 35a are transposed, and the two-hole mask 18' has the spherical surfaces 34a, 35a.
It is located on the side. In this way, the order of the spherical and flat surfaces is not limited.
第６図は更に他の実施例で、以上の実施例では
１つの棒状レンズの一端をプリズム面にしていた
が、プリズム作用部４６を２次結像レンズ４４，
４５から分離した例であり、また２次結像レンズ
を複数枚の単レンズで構成した例である。尚、以
上の例で、２次結像レンズはいずれもレンズの側
部を削除して接合した形状をしているが、これは
光量を多く取り入れるための構成であり、もし光
量が足りれば、小さな直径のレンズを分離して配
置することもできる。 FIG. 6 shows still another embodiment. In the above embodiment, one end of one rod-shaped lens was made into a prism surface, but the prism action part 46 is replaced by a secondary imaging lens 44,
45, and an example in which the secondary imaging lens is composed of a plurality of single lenses. In addition, in the above examples, the secondary imaging lenses all have a shape in which the sides of the lenses are removed and joined together, but this is a configuration to take in a large amount of light, and if the amount of light is sufficient, , small diameter lenses can also be placed separately.
第７図の実施例は２重楔型プリズムで２次結像
する像を分離する光学系に本発明を適用した例の
要部である。第８図はその斜視形態を示してい
る。５０は２重楔型プリズムで、像分離用プリズ
ム５０ａ，５０ｂから成り、２重楔型プリズム５
０の左側には第１図と同様、撮影レンズやフイー
ルドレンズが在るものとする。５１は２次結像レ
ンズで、不図示の撮影レンズの光軸Ｌに光軸を一
致させて配置する。５１ａ，５１ｂは２等辺プリ
ズムの上述したと同様の傾斜平面であり、光電変
換素子列５２ａ，５２ｂの配列と平行な方向に傾
斜している。これら光電変換素子列は２重楔型プ
リズムの作用で上下に分離した像を受ける位置に
配置される。本例の場合もプリズム面の作用で結
像位置の差Ｚ１−Ｚ２と波長による結像位置のズ
レＺ３を抑制することができる。 The embodiment shown in FIG. 7 is a main part of an example in which the present invention is applied to an optical system that separates images formed secondary by a double wedge prism. FIG. 8 shows its perspective form. Reference numeral 50 denotes a double wedge prism, which consists of image separation prisms 50a and 50b.
It is assumed that on the left side of 0 there is a photographing lens and a field lens, as in FIG. Reference numeral 51 denotes a secondary imaging lens, which is arranged so that its optical axis coincides with the optical axis L of a photographic lens (not shown). 51a and 51b are inclined planes similar to those of the isosceles prism described above, and are inclined in a direction parallel to the arrangement of the photoelectric conversion element arrays 52a and 52b. These photoelectric conversion element arrays are arranged at positions where they receive vertically separated images due to the action of a double wedge prism. In this example as well, the difference Z1-Z2 in the imaging position and the deviation Z3 in the imaging position due to the wavelength can be suppressed by the effect of the prism surface.
効 果
以上述べた本発明によれば複数像の位置ズレか
ら焦点判別を行う装置で、検出視野内の物***置
或いは色相に依存することなく常に高精度の検出
を実現できる効果があり、また著しく簡単な構成
で達成できるから装置を大型化することもなく、
更に光学系内で問題を解決できるから電気処理系
の負担を軽減できる優れた発明である。Effects According to the present invention described above, the device performs focus discrimination based on the positional deviation of multiple images, and has the effect of always realizing highly accurate detection without depending on the object position or hue within the detection field of view, and has a remarkable effect. This can be achieved with a simple configuration, so there is no need to increase the size of the device.
Furthermore, since the problem can be solved within the optical system, it is an excellent invention that can reduce the burden on the electrical processing system.
第１図は本発明の第１実施例を示す光学断面
図。第２図はプリズム角と補正対象の関係図。第
３図は第２実施例の要部光学断面図。第４図は傾
角、偏心量、補正対象の関係図。第５図，第６
図，第７図は夫々、別の実施例の要部光学断面
図。第８図は斜視図。第９図は従来例を示す光学
断面図。第１０図，第１１図は夫々問題点を説明
するための光学断面図。
図中、Ｏは被写体面、１１は撮影レンズ、Ｌは
光軸、１２は予定結像面、１３はフイールドレン
ズ、１４と１５は２次結像レンズ、１４ａと１５
ａは球面（収斂レンズ面）、１４ｂと１５ｂは傾
斜平面（プリズム面）、１６と１７は光電変換素
子列、１８は２孔マスクである。
FIG. 1 is an optical sectional view showing a first embodiment of the present invention. FIG. 2 is a diagram showing the relationship between prism angle and correction target. FIG. 3 is an optical sectional view of the main part of the second embodiment. FIG. 4 is a diagram showing the relationship between inclination, eccentricity, and correction target. Figures 5 and 6
and FIG. 7 are optical sectional views of main parts of another embodiment, respectively. FIG. 8 is a perspective view. FIG. 9 is an optical sectional view showing a conventional example. FIGS. 10 and 11 are optical cross-sectional views for explaining the problems, respectively. In the figure, O is the object plane, 11 is the photographing lens, L is the optical axis, 12 is the intended imaging plane, 13 is the field lens, 14 and 15 are the secondary imaging lenses, 14a and 15
a is a spherical surface (convergent lens surface), 14b and 15b are inclined planes (prism surfaces), 16 and 17 are photoelectric conversion element arrays, and 18 is a two-hole mask.
Claims (1)
イールドレンズと、このフイールドレンズの後方
に配置される２次結像光学系とを有することによ
り、上記対物レンズの瞳の異なつた部分を通過す
る光束に基づいた対の物体像に形成すると共に、
上記物体像の夫々を上記２次結像光学系の後方に
配置された光電変換素子列で検出することによ
り、上記物体像の相対的なズレ量から上記物体レ
ンズの焦点状態を判別するようにした焦点検出装
置であつて、前記対の像の内一方の像の所定の２
点間の距離と他方の像の対応する２点間の距離の
差を抑制する為に前記光電変換素子の配列方向に
光束を屈折するプリズム作用面を前記２次結像光
学系に設けたことを特徴とする焦点検出装置。 ２ 前記２次結像光学系は、一端にレンズ作用面
を具え他端にプリズム作用のための傾斜面を具え
た光学素子を光軸を平行に配置して成る特許請求
の範囲第１項記載の焦点検出装置。 ３ 前記２次結像光学系は、光軸を平行に配置し
た２次結像レンズとプリズムから成る特許請求の
範囲第１項記載の焦点検出装置。 ４ 前記２次結像光学系は、一端に前記対物レン
ズの光軸に一致した光軸を持つレンズ作用面を具
え他端に逆傾斜の傾斜面を具えた光学素子と２重
楔型プリズムから成る特許請求の範囲第１項記載
の焦点検出装置。[Claims] 1. By having a field lens disposed near the intended image forming plane of the objective lens and a secondary imaging optical system disposed behind this field lens, the pupil of the objective lens can be Forming a pair of object images based on the light beams passing through different parts,
By detecting each of the object images with a photoelectric conversion element array arranged behind the secondary imaging optical system, the focal state of the object lens is determined from the relative shift amount of the object images. a focus detection device, wherein a predetermined two images of one of the pair of images are
In order to suppress the difference between the distance between the points and the distance between two corresponding points of the other image, the secondary imaging optical system is provided with a prism working surface that refracts the light beam in the arrangement direction of the photoelectric conversion elements. A focus detection device featuring: 2. The secondary imaging optical system comprises an optical element having a lens-working surface at one end and an inclined surface for prismatic action at the other end, arranged with optical axes parallel to each other. focus detection device. 3. The focus detection device according to claim 1, wherein the secondary imaging optical system includes a secondary imaging lens and a prism whose optical axes are arranged in parallel. 4. The secondary imaging optical system includes an optical element having a lens action surface having an optical axis coinciding with the optical axis of the objective lens at one end and a reversely inclined surface at the other end, and a double wedge prism. A focus detection device according to claim 1, comprising:
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14312685A JPS623216A (en) | 1985-06-28 | 1985-06-28 | Focus detecting device |
| US06/877,850 US4849782A (en) | 1985-06-28 | 1986-06-24 | Focus detecting device |
| GB8615463A GB2178621B (en) | 1985-06-28 | 1986-06-25 | Focus detecting device |
| DE19863621542 DE3621542A1 (en) | 1985-06-28 | 1986-06-27 | DEVICE FOR DETECTING THE FOCUSING STATE OF A LENS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14312685A JPS623216A (en) | 1985-06-28 | 1985-06-28 | Focus detecting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS623216A JPS623216A (en) | 1987-01-09 |
| JPH0518402B2 true JPH0518402B2 (en) | 1993-03-11 |
Family
ID=15331521
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14312685A Granted JPS623216A (en) | 1985-06-28 | 1985-06-28 | Focus detecting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS623216A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2770301B2 (en) * | 1987-05-08 | 1998-07-02 | ミノルタ株式会社 | Optical device for focus detection |
| JP2005195786A (en) * | 2004-01-06 | 2005-07-21 | Canon Inc | Focus detector and optical apparatus using the same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61284714A (en) * | 1985-06-10 | 1986-12-15 | Minolta Camera Co Ltd | Focus detecting device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55157220U (en) * | 1979-04-27 | 1980-11-12 |
-
1985
- 1985-06-28 JP JP14312685A patent/JPS623216A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61284714A (en) * | 1985-06-10 | 1986-12-15 | Minolta Camera Co Ltd | Focus detecting device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS623216A (en) | 1987-01-09 |
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| EXPY | Cancellation because of completion of term |