【０００１】
【発明の属する技術分野】
各々独立した受光光路を有する測距装置と測光装置を備えたカメラ等の撮影装置及び一対の受光素子と受光光路を備えた測距装置に関する。
【０００２】
【従来の技術】
独立した受光光路を備えた測距装置や独立した受光光路を備える測光装置を有するカメラ等の撮影装置、一般的にはコンパクトカメラと呼ばれるものでは、ファインダーも独立した光路を備えていて、撮影者はその受光光路から被写体を観測して撮影を行う。従って、例えば撮影者がカメラを構えた時の指先が受光装置の受光光路を遮っていても気付かずにシャッターを切ってしまい、露出が合わない写真となる恐れがある。また、測距装置の受光光路が遮られるとピントがずれた写真となってしまうことになる。
【０００３】
そのような問題に対する対策として、従来は指掛りによる撮影ミスを防止するための手法が提案されていて、例えば特開平７−２１９０１４号公報では「指の接触を検知するタッチセンサーを設け、このタッチセンサーからの検知信号により警告手段を作動させるようにする」ことが提案されている。
【０００４】
【発明が解決しようとする課題】
しかしながら、上記従来例では受光部が遮られることを検出するためのタッチセンサーを複数個カメラに設ける必要があることから、其の為のスペースを用意する必要があり、カメラが其の分大きくなる。また、タッチセンサーのコストが上乗せされることになり、カメラの価格が高くなってしまうことになる。また、タッチセンサーはそのごく近傍に指が在る時には検出可能であるが、例えば車窓から屋外を撮影する際、窓枠が測距装置や測光装置の光路を遮ってしまいピント合わせや露出制御が正確に行われないなど、カメラ本体から離れた所に存在する受光光路を遮る障害物に対しては役立たない。
【０００５】
本発明は上記問題点を鑑みて為されたもので、測距装置や受光装置の光路が遮られたことを専用のセンサー等を用いることなく検出し、警告を行って撮影ミスを防止することにある。
【０００６】
【課題を解決するための手段】
上記目的を達成するため本出願の発明は、被写体や其の周囲の明るさを測定しする測光手段と、被写体までの距離を測距する測距手段が備える受光素子からの出力信号から被写体付近の明るさに関する信号を得る明るさ検出手段を有するカメラで、測光手段の出力信号と明るさ検出手段の出力信号とを比較し、其の比較結果から測光手段の受光光学系、測距手段の受光光路の何れかが遮られたことを検出する遮光検出手段を備えたことである。
【０００７】
【作用】
上記構成により、測距装置で得た被写体の明るさと測光装置で得た被写体の明るさを比較する遮光検出手段の出力信号から、何れかの受光光路が遮られたことを検出することが可能になる。
【０００８】
本出席に係る第二の発明は、独立した受光光路から信号光を得て其の信号光を光電変換する受光素子一対を備え、各受光素子の出力信号の大きさを比較し、其の比較結果より何れかの受光素子の受光光路が遮られたことを検出する遮光検出手段を備えた測距装置若しくは其の測距装置を搭載したカメラ等の撮影装置であるもの。
【０００９】
上記構成で測距装置の一対の受光素子の出力信号の大きさが異なることを検出することにより、何れかの受光素子の受光光路が遮られたことを検出することが可能になる。
【００１０】
本出願に係る第三の発明は、警告手段を備えたカメラで、遮光検出手段が測距手段若しくは測光手段の受光光路が遮られたことを検出すると該警告手段にて警告するものであり、警告手段はカメラのシャッターレリーズを禁止するもの、発音手段より警告音、音声等を発するもの、表示手段に警告表示を為すもの等である。
【００１１】
警告手段で撮影者に警告することにより、測距手段、測光手段の何れかの受光光路が遮られて失敗写真を撮ることを防ぐことが可能となる。
【００１２】
【発明の実施の形態】
（実施形態１）
図１は本発明を具備した３５ｍｍフィルムを用いるカメラの外形を示す。図１において１はそのカメラの前面パネルを示す。２は撮影レンズで其の焦点距離は３８ｍｍであるものとする。
【００１３】
３はシャッターレリーズボタンで、第一のストロークまで押込むとＳＷ１がＯＮ、更に深く第二のストロークまで押込むとＳＷ２がＯＮ状態となる。４はファインダーの対物レンズ、５は測距装置の一対のセンサーアレイのうち右側のセンサーアレイ上に被写体の像を形成する為の受光レンズで６は左側のセンサーアレイ上に被写体の像を形成する為の受光レンズである。何れも焦点距離７．６ｍｍの凸レンズである。７は測光装置の測光素子前面に設置したＡＥ受光レンズで撮影範囲内の適切な領域を測光範囲に設定する焦点距離３．８ｍｍの凸レンズである。
【００１４】
図２は図１に示したカメラのブロック図で、１は図１で説明したようにカメラの前面パネル、５、６は測距装置の受光レンズ、７は測光装置のＡＥ受光レンズである。１０はカメラの動作シーケンスを制御する制御回路で、ＣＰＵと制御ソフトを書込んだマスクＲＯＭ、ＲＡＭ、不揮発性で書換え可能なＥＥＰＲＯＭ等のメモリ回路、更にはＡ／Ｄコンバータ等の周辺回路から成るものであり、本実施例では測距手段が備える受光手段からの信号出力から被写体付近の明るさに関する信号を得る明るさ検出手段及び何れかの受光光路が遣られたことを検出する為の遮光検出手段としても作用する。１１Ｒは測距手段が備える受光素子の一つで撮影者から見て右側に配置されるものである。１１Ｌは同じく測距手段が備える受光素子の一つで左側に配置されるものである。この一対の受光素子上に形成される被写体像の相対的な距離から被写体までの距離を算出する為のものであり、どちらも複数（本実施例では１９個）の光電変換素子と、其の光電変換素子で光電変換された信号電荷を出力端へ転送するための電荷転送手段であるＣＣＤから成るセンサーアレイで、其の光電変換素子部の形状を図３（Ａ）に示す。１２は測光手段を構成する測光素子で形状を図３（Ｂ）に示す。測光素子は３分割されていて、撮影範囲の中央のみの明るさを測光する１２Ｓ、撮影範囲の大半部を測光する１２Ｃ、撮影範囲の周辺部４点を測光するための１２Ｐからなる。測光素子各部の出力信号は独立して取出すことが出来るもので、例えば１２Ｓと１２Ｐから得た被写体の明るさの情報から、中央が暗く周辺部が明るいことを検出して「逆光」と判定させることなどが可能である。１３は一対の受光素子１１Ｒと１１Ｌの信号を受けて被写体までの距離を算出する測距回路で、測距結果は制御回路１０へ伝える。１４は測光素子の信号出力を受けて被写体の明るさを算出する測光回路で、測光結果を制御回路１０へ伝える。１５はレンズ駆動装置で、測距回路１３から得た被写体までの距離に応じて被写体にピントを合わせるよう制御回路１０の指示に基づいて撮影レンズの合焦用レンズを駆動する。１６はシャッター制御装置で、測光回路１４から得た被写体の明るさに応じてフィルムに適正な露光量を与えるよう制御回路１０の指示に基づいて適切なシャッター速度と絞り値でシャッターを駆動する。１７はフィルム給送装置で、制御回路１０の指示に基づいてフィルムの巻上げ、巻戻し動作を行う。１８は表示装置で、液晶などの表示部を備え、そこに制御回路１０の指示に基づいてカメラの状態等の情報を表示する。１９は発音体で、スピーカ等から構成され、制御回路１０の指示に基づき警告音等を発するものである。２０はＳＷ１で、シャッターレリーズボタン３が第一のストロークまで押込まれるとＯＮ状態となる。２１はＳＷ２で、シャッターレリースボタン３が第一のストロークよりも深い第二のストロークまで押込まれるとＯＮ状態となる。２２は電池やＤＣ／ＤＣコンバータより構成される電源回路で、制御回路１０や其の他の回路に所定の電圧、電流を供給する。
【００１５】
本構成のカメラの測距回路１３は、一般にパッシブ測距といわれる測距方法を用いたもので、其の原理は広く知られているものであり、本出願人からも特開平９−２２９６７４号公報等の中で述べていることから其の詳細は省略するが、受光素子の信号出力から被写体の明るさを知ることも可能である。即ち、受光素子を構成する複数の光電変換素子が其の表面に当たる光量に応じて発生する信号電荷を所定時間Ｔ１だけ蓄積した後、電荷転送手段であるＣＣＤに転送し、ＣＣＤは其の転送クロックに応じて先の信号電荷を出力段まで順次転送する。出力段で其の信号電荷は信号電圧Ｖｓに変換されて測距回路１３に入力される。測距回路１３では各光電変換素子の信号電圧Ｖｓを用いて測距演算を行い被写体までの距離を求めるものである。ここで信号電圧Ｖｓは
Ｖｓ＝Ｋ＊Ｔ１＊光の強さ （但し、Ｋ：比例定数）…▲１▼
である。よって、比例定数Ｋを事前に求めておくことで光の強さ即ち被写体の明るさは、蓄積する時間Ｔ１と信号電圧Ｖｓから求めることが可能である。
【００１６】
ところで図４は図１に示したカメラの測光装置の受光光路と測距装置の受光光路を模式的に表したものであり、この図面において８は被写体であってこの被写体の一点が測光素子１２、受光素子１１Ｒ、１１Ｌに投影されることを示している。即ち、測距装置は被写体８までの距離を測距し、測光装置は被写体８の周辺の明るさを測定している状態を表している。撮影範囲に対して各測光素子、受光素子が検出する範囲の概略を図６に示す。この光学系から被写体８上に測光素子１２Ｓ、受光素子１１Ｌ、１１Ｒを逆投影した投影像が図５に示す図面である。各々１２ＳＰ、１１ＬＰ、１１ＲＰで示す。１１ＬＰと１１ＲＰがＹ方向にずらしているのは説明の便宜上であり、実際にはＹ方向は一致するよう合せ込まれるものである。この図５に於いて１２ＳＰと１１ＬＰの光電変換素子３〜６、１１ＲＰの６〜９はほぼ同じ領域に存在する。即ち、測光素子１２Ｓが検出している領域と、受光素子１１Ｌの光電変換素子３〜６が検出する領域、受光素子１１Ｒの光電変換素子６〜９が検出する領域はほぼ等しいことになる。よって測光素子１２Ｓが検出する明るさ、受光素子１１Ｌの光電変換素子３〜６が検出する明るさ及び受光素子１１Ｒの光電変換素子６〜９が検出する明るさは、各受光光路が遮られていない限り概略等しくなる。一方何れかの光路が遮られると其の光路の受光素子若しくは測光素子が検出する明るさが、他の二つの明るさより暗いものとなる。
【００１７】
以上述べた構成を備えた図１に示すカメラの一駒撮影時のシーケンスを図７を用いて説明する。
【００１８】
Ｓ１：シャッターレリーズボタン３が第一ストロークまで押込まれてＳＷｌがＯＮになるのを待つ。
【００１９】
Ｓ２：受光素子１１Ｌと１１Ｒの各光電変換素子からの信号電荷を所定時間Ｔ１だけ蓄積し、測距回路１３にてその蓄積された電荷を電圧に変換した信号で１１Ｌ上の被写体像と１１Ｒ上の被写体像間の相関演算を行い、三角測量の原理から被写体までの距離を求める。
【００２０】
Ｓ３：Ｓ２で蓄積した信号電荷の中の所定の光電変換素子、１１Ｌの３〜６、１１Ｒの６〜９の信号電荷量を変換した電圧値を制御回路１０は測距回路１３を介して取込み、その平均値を演算し、其の演算結果を式▲１▼に代入して被写体の明るさを求める。即ち、制御回路１０は明るさ検出手段として作用する。更に１１Ｌで求めた被写体の明るさと１１Ｒで求めた被写体の明るさを比較する。二つの受光素子はほぼ同じ範囲を見ていることからその明るさに差異（例えば１段以上）があれば、蓄積された電荷量が少ない側の受光素子の受光光路が何らかの障害物に遮られていると判断する。即ち、制御回路１０は遮光検出手段として作用する。従って１１Ｒと１１Ｌの所定の位置の信号電荷から算出した明るさの差が所定の範囲以内であればＳ４へ移行し、差が所定の範囲より大きければＳ１０へ移行する。
【００２１】
Ｓ４：測光回路１４は測光素子１２を用いて被写体と其の周辺の明るさを測定して、制御回路１０へ明るさの測定値を送る。先に述べたように測光素子１２は三分割されたもので、１２Ｓは撮影範囲の中央付近を測光し、１２Ｃは撮影範囲の中央部付近を広く測光し、１２Ｐは撮影範囲の周辺部のみを測光する。制御回路１０はこれらの測光結果から被写体の順光、逆光状態などを判定して、適切な露光条件を算出する。
【００２２】
Ｓ５：制御回路１０はＳ４で得た１２Ｓの測光結果とＳ３で求めた測距装置の受光素子から求めた被写体の明るさとを比較する。先に述べたように１２Ｓの測光範囲と測距装置の所定の光電変換素子とは被写体のほぼ同じ範囲を見ていることから、同じ明るさが得られる筈であり、明るさの差異が所定値（例えば２段）以上であれば、何れかの受光光路が何らかの障害物によって遮られていると判断してＳ１０へ移行する。
【００２３】
Ｓ６：シャッターレリーズボタン３が第二のストロークまで押込まれて、ＳＷ２がＯＮとなるのを待つ。
【００２４】
Ｓ７：制御回路１０はＳ２で求めた被写体の距離に応じて、合焦用レンズの移動量を算出し、レンズ駆動装置１５で撮影レンズの合焦用レンズを算出された移動量だけ動かす。
【００２５】
Ｓ８：制御回路１０はＳ４で求めた露光条件でシャッター駆動装置を動かし、フィルムに露光させる。
【００２６】
Ｓ９：制御回路１０はフィルム駆動装置を駆動してフィルムを一助分巻き上げる。
【００２７】
Ｓ１０：測距装置の受光光路若しくは測光装置の受光光路が遮られるとこのステップに移行してくることから、表示装置１８の表示部に警告のマークを点滅させるとともに、発音体１９を駆動して警告音を発する。また、シャッターレリーズは行えない、即ちシャッターレリーズが禁止されることになる。
【００２８】
以上説明したごとく、一対の測距用の受光素子の明るさに関する情報を比較することにより、何れかの受光光路が遮られたことを検知することが可能で、其の場合には警告表示、警告音、レリーズの禁止等により撮影者に警告し、失敗写真が撮られることを防止できる。
【００２９】
また、測距用の受光素子の明るさに関する情報と、測光素子の明るさに関する情報とを比較することにより、何れかの受光光路が遮られたことを検知することが可能で、上記と同様な処理により失敗写真が撮られることを防止できる。
【００３０】
尚、被写体までの距離が変わると視差により測光素子が検出する範囲と測距用の受光素子が検出する範囲がずれてくる。この場合、測距結果に応じて測距用受光素子で被写体の明るさを検出する受光素子の位置を変更することで解決する。
【００３１】
【発明の効果】
以上説明したように本出願に係る発明によれば。被写体や其の周囲の明るさを測定する測光手段と、被写体までの距離を測距する測距手段が備える受光素子からの出力信号から被写体付近の明るさに関する信号を得る明るさ検出手段を有するカメラで、測光手段の出力信号と明るさ検出手段の出力信号とを比較し、其の比較結果から測光手段の受光光学系、測距手段の受光光路の何れかが遮られたことを検出する遮光検出手段を備えることにより、失敗写真を防止するための手段を講ずることが可能となる。
【００３２】
更に、一対の受光素子を備え、各受光素子の出力信号の大きさを比較し、其の比較結果より何れかの受光素子の受光光路が遮られたことを検出する遮光検出手段を備えたことを特徴とする測距装置では誤った測距結果を出力する為の手段を講ずることが可能となる。
【００３３】
更に、警告手段を備えることで、遮光検出手段が測距手段若しくは測光手段の受光光路が遮られたことを検出すると該警告手段にて警告するカメラとすることにより撮影者に注意を促すことが可能となる。
【００３４】
更に、測光手段の受光光学系、測距手段の受光光路の何れかが遮られた場合にカメラのシャッターレリーズを禁止することにより、失敗写真が撮影されることを防止することが可能になる。
【図面の簡単な説明】
【図１】本発明を具備するカメラの外観図。
【図２】本発明を具備するカメラのブロック図。
【図３】受光素子と測光素子。
【図４】測光光路と測距光路。
【図５】被写体上の測光素子、受光素子の投影像。
【図６】撮影範囲に対する受光素子、測光素子の検出範囲。
【図７】本発明を具備するカメラの撮影時のシーケンス図。
【符号の説明】
１ カメラの前面パネル
２ 撮影レンズ
３ シャッターレリーズボタン
４ ファインダー対物レンズ
５ 測距装置の受光レンズ
６ 測距装置の受光レンズ
７ ＡＥ受光レンズ
８ 被写体
１０ カメラの制御回路
１１Ｒ 測距装置の受光素子
１１Ｌ 測距装置の受光素子
１２ 測光素子
１３ 測距回路
１４ 測光回路
１５ レンズ駆動装置
１６ シャッター駆動装置
１７ フィルム駆動装置
１８ 表示装置
１９ 発音体
２０ ＳＷ１
２１ ＳＷ２
２２ 電源回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a distance measuring device having an independent light receiving optical path, a photographing device such as a camera having the light measuring device, and a distance measuring device having a pair of light receiving elements and a light receiving optical path.
[0002]
[Prior art]
In a photographing device such as a distance measuring device having an independent light receiving optical path or a camera having a photometric device having an independent light receiving optical path, generally called a compact camera, the finder also has an independent optical path, and Performs photographing while observing the subject from the light receiving optical path. Therefore, for example, even if the fingertip of the photographer holding the camera blocks the light receiving optical path of the light receiving device, the shutter is released without being noticed, and there is a possibility that the photograph may not be properly exposed. Further, if the light receiving optical path of the distance measuring device is interrupted, the photograph will be out of focus.
[0003]
As a countermeasure against such a problem, there has been conventionally proposed a method for preventing a photographing error caused by finger-holding. For example, Japanese Patent Application Laid-Open No. Hei 7-219014 discloses that "a touch sensor for detecting finger contact is provided. The warning means is activated by a detection signal from a sensor. "
[0004]
[Problems to be solved by the invention]
However, in the above conventional example, since it is necessary to provide a plurality of touch sensors for detecting that the light receiving unit is blocked, it is necessary to provide a space for the touch sensor, and the camera becomes larger accordingly. . In addition, the cost of the touch sensor is added, and the price of the camera is increased. In addition, the touch sensor can detect when the finger is in the immediate vicinity, but for example, when photographing the outdoors from the car window, the window frame blocks the optical path of the distance measuring device or the photometric device, and focus adjustment and exposure control are performed. It is not useful for obstacles that block the light receiving optical path that exists at a location distant from the camera body, such as being not accurately performed.
[0005]
The present invention has been made in view of the above problems, and it is an object of the present invention to detect that an optical path of a distance measuring device or a light receiving device is interrupted without using a dedicated sensor or the like, and to issue a warning to prevent a photographing error. It is in.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention of the present application provides a photometric device for measuring the brightness of a subject and its surroundings, and a subject near the subject based on an output signal from a light receiving element provided for the distance measuring device for measuring a distance to the subject. A camera having a brightness detection means for obtaining a signal relating to the brightness of the camera, comparing the output signal of the photometry means and the output signal of the brightness detection means, from the comparison result of the light receiving optical system of the photometry means, the distance measurement means That is, a light-blocking detecting means for detecting that any one of the light-receiving optical paths is blocked is provided.
[0007]
[Action]
With the above configuration, it is possible to detect that any of the light receiving optical paths has been blocked from the output signal of the light blocking detection unit that compares the brightness of the subject obtained by the distance measuring device with the brightness of the subject obtained by the photometric device. become.
[0008]
The second invention according to the present attendance includes a pair of light receiving elements that obtain signal light from independent light receiving optical paths and photoelectrically convert the signal light, compare the magnitudes of output signals of the respective light receiving elements, and perform the comparison. A distance measuring device provided with a light shielding detecting means for detecting that the light receiving optical path of any of the light receiving elements is blocked from the result, or a photographing device such as a camera equipped with the distance measuring device.
[0009]
With the above configuration, it is possible to detect that the light receiving optical path of any one of the light receiving elements is blocked by detecting that the output signals of the pair of light receiving elements of the distance measuring device are different.
[0010]
A third invention according to the present application is a camera provided with a warning unit, wherein when the light blocking detection unit detects that the light receiving optical path of the distance measuring unit or the light measuring unit is blocked, the warning unit warns. The warning means includes a means for prohibiting the shutter release of the camera, a means for generating a warning sound or voice from the sounding means, a means for displaying a warning on the display means, and the like.
[0011]
By giving a warning to the photographer with the warning means, it is possible to prevent any of the light receiving optical paths of the distance measuring means and the light measuring means from being interrupted and to take a failed photograph.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
FIG. 1 shows an outline of a camera using a 35 mm film provided with the present invention. In FIG. 1, reference numeral 1 denotes a front panel of the camera. Reference numeral 2 denotes a photographing lens whose focal length is 38 mm.
[0013]
Reference numeral 3 denotes a shutter release button. When the shutter release button is pressed down to the first stroke, SW1 is turned on. When the shutter release button is pressed further down to the second stroke, SW2 is turned on. Reference numeral 4 denotes an objective lens of a finder, and reference numeral 5 denotes a light receiving lens for forming an image of a subject on the right sensor array of a pair of sensor arrays of the distance measuring device. Reference numeral 6 forms an image of the subject on the left sensor array. For receiving light. Each is a convex lens having a focal length of 7.6 mm. Reference numeral 7 denotes an AE light receiving lens installed on the front surface of the photometric element of the photometric device, which is a convex lens having a focal length of 3.8 mm for setting an appropriate area in the photographing range to the photometric range.
[0014]
FIG. 2 is a block diagram of the camera shown in FIG. 1. Reference numeral 1 denotes a front panel of the camera as described in FIG. 1, reference numerals 5 and 6 denote light receiving lenses of a distance measuring device, and reference numeral 7 denotes an AE light receiving lens of the photometric device. Reference numeral 10 denotes a control circuit for controlling an operation sequence of the camera. The control circuit 10 includes a CPU, a memory circuit such as a mask ROM and a RAM in which control software is written, a nonvolatile and rewritable EEPROM, and a peripheral circuit such as an A / D converter. In the present embodiment, the brightness detection means for obtaining a signal relating to the brightness near the subject from the signal output from the light receiving means provided in the distance measuring means, and the light shielding for detecting that any of the light receiving optical paths have been sent. It also acts as a detecting means. 11R is one of the light receiving elements included in the distance measuring means, and is arranged on the right side as viewed from the photographer. 11L is one of the light receiving elements similarly provided in the distance measuring means and is arranged on the left side. This is for calculating the distance to the subject from the relative distance between the subject images formed on the pair of light receiving elements. Both of them are a plurality of (19 in this embodiment) photoelectric conversion elements and FIG. 3A shows the shape of a photoelectric conversion element portion of a sensor array including a CCD which is a charge transfer means for transferring signal charges photoelectrically converted by the photoelectric conversion element to an output terminal. Reference numeral 12 denotes a photometric element that constitutes photometric means, the shape of which is shown in FIG. The photometric element is divided into three parts, and includes 12S for measuring the brightness only at the center of the photographing range, 12C for measuring the majority of the photographing range, and 12P for measuring the light at four points around the photographing range. The output signal of each part of the photometric element can be extracted independently. For example, based on the brightness information of the subject obtained from 12S and 12P, it is detected that the center is dark and the peripheral part is bright, and the backlight is determined as “backlit”. It is possible. Reference numeral 13 denotes a distance measuring circuit that receives a signal from the pair of light receiving elements 11R and 11L and calculates a distance to a subject. Reference numeral 14 denotes a photometry circuit that receives the signal output of the photometry element and calculates the brightness of the subject, and transmits the photometry result to the control circuit 10. Reference numeral 15 denotes a lens driving device that drives the focusing lens of the photographing lens based on an instruction from the control circuit 10 to focus on the subject in accordance with the distance to the subject obtained from the distance measurement circuit 13. Reference numeral 16 denotes a shutter control device that drives a shutter at an appropriate shutter speed and aperture value based on an instruction from the control circuit 10 so as to give an appropriate amount of exposure to the film according to the brightness of the subject obtained from the photometry circuit 14. Reference numeral 17 denotes a film feeding device which performs film winding and rewinding operations based on instructions from the control circuit 10. Reference numeral 18 denotes a display device, which includes a display unit such as a liquid crystal and displays information such as the state of the camera on the basis of an instruction from the control circuit 10. Reference numeral 19 denotes a sounding body, which is constituted by a speaker or the like, and emits a warning sound or the like based on an instruction from the control circuit 10. Reference numeral 20 denotes a switch SW1, which is turned on when the shutter release button 3 is pressed down to the first stroke. Reference numeral 21 denotes a switch SW2, which is turned on when the shutter release button 3 is pressed down to a second stroke deeper than the first stroke. A power supply circuit 22 includes a battery and a DC / DC converter, and supplies a predetermined voltage and current to the control circuit 10 and other circuits.
[0015]
The distance measuring circuit 13 of the camera having this configuration uses a distance measuring method generally called passive distance measuring, and its principle is widely known. Although the details are omitted from the description in the gazette and the like, it is also possible to know the brightness of the subject from the signal output of the light receiving element. That is, after a plurality of photoelectric conversion elements constituting a light receiving element accumulate signal charges generated according to the amount of light impinging on the surface thereof for a predetermined time T1, the signal charges are transferred to a CCD which is charge transfer means, and the CCD receives the transfer clock. , The previous signal charges are sequentially transferred to the output stage. At the output stage, the signal charge is converted into a signal voltage Vs and input to the distance measurement circuit 13. The distance measuring circuit 13 calculates the distance by using the signal voltage Vs of each photoelectric conversion element to obtain the distance to the subject. Here, the signal voltage Vs is Vs = K * T1 * light intensity (however, K is a proportional constant).
It is. Therefore, by obtaining the proportionality constant K in advance, the light intensity, that is, the brightness of the subject, can be obtained from the accumulation time T1 and the signal voltage Vs.
[0016]
FIG. 4 schematically shows a light receiving optical path of the photometric device of the camera shown in FIG. 1 and a light receiving optical path of the distance measuring device. In FIG. , Are projected on the light receiving elements 11R and 11L. That is, the distance measuring device measures the distance to the subject 8 and the photometric device measures the brightness around the subject 8. FIG. 6 shows an outline of the range detected by each photometric element and light receiving element with respect to the photographing range. FIG. 5 shows a projected image obtained by back-projecting the photometric element 12S and the light receiving elements 11L and 11R onto the subject 8 from the optical system. These are indicated by 12SP, 11LP, and 11RP, respectively. The reason why 11LP and 11RP are shifted in the Y direction is for convenience of explanation, and in fact, the Y direction is matched so as to match. In FIG. 5, the photoelectric conversion elements 3 to 6 of 12SP and 11LP and 6 to 9 of 11RP exist in substantially the same region. That is, the area detected by the photometric element 12S, the area detected by the photoelectric conversion elements 3 to 6 of the light receiving element 11L, and the area detected by the photoelectric conversion elements 6 to 9 of the light receiving element 11R are substantially equal. Therefore, each of the light receiving optical paths is blocked for the brightness detected by the photometric element 12S, the brightness detected by the photoelectric conversion elements 3 to 6 of the light receiving element 11L, and the brightness detected by the photoelectric conversion elements 6 to 9 of the light receiving element 11R. Unless otherwise approximately equal. On the other hand, when one of the optical paths is blocked, the brightness detected by the light receiving element or the photometric element in that optical path becomes darker than the other two brightnesses.
[0017]
A sequence for photographing one frame of the camera shown in FIG. 1 having the above-described configuration will be described with reference to FIG.
[0018]
S1: Wait until the shutter release button 3 is pressed down to the first stroke and SWl is turned on.
[0019]
S2: The signal charge from each of the photoelectric conversion elements of the light receiving elements 11L and 11R is accumulated for a predetermined time T1, and the signal obtained by converting the accumulated charge into a voltage by the distance measuring circuit 13 is a signal on the subject 11L and on the 11R. The distance between the subject and the subject is calculated from the principle of triangulation.
[0020]
S3: The control circuit 10 takes in the voltage value obtained by converting the signal charge amount of the predetermined photoelectric conversion element, 3L to 6L of 11L, and 6 to 9 of 11R in the signal charges accumulated in S2 via the distance measuring circuit 13. The average value is calculated, and the calculated result is substituted into equation (1) to determine the brightness of the subject. That is, the control circuit 10 functions as a brightness detecting unit. Further, the brightness of the subject obtained in 11L is compared with the brightness of the subject obtained in 11R. Since the two light receiving elements look at substantially the same range, if there is a difference in the brightness (for example, one or more steps), the light receiving optical path of the light receiving element on the side where the accumulated charge amount is small is blocked by some obstacle. Judge that That is, the control circuit 10 functions as light-shielding detection means. Therefore, if the difference between the brightness calculated from the signal charges at the predetermined positions of 11R and 11L is within the predetermined range, the process proceeds to S4, and if the difference is larger than the predetermined range, the process proceeds to S10.
[0021]
S4: The photometric circuit 14 measures the brightness of the subject and its surroundings using the photometric element 12, and sends the measured brightness value to the control circuit 10. As described above, the photometric element 12 is divided into three parts, 12S measures light near the center of the photographing range, 12C measures light widely near the center of the photographing range, and 12P measures only the peripheral part of the photographing range. Perform photometry. The control circuit 10 determines the subject's forward light, back light state, and the like from the photometric results, and calculates an appropriate exposure condition.
[0022]
S5: The control circuit 10 compares the 12S photometry result obtained in S4 with the subject brightness obtained from the light receiving element of the distance measuring device obtained in S3. As described above, since the photometry range of the 12S and the predetermined photoelectric conversion element of the distance measuring device look at substantially the same range of the subject, the same brightness should be obtained. If it is equal to or more than the value (for example, two steps), it is determined that any of the light receiving optical paths is blocked by some obstacle, and the process proceeds to S10.
[0023]
S6: Wait until the shutter release button 3 is pressed down to the second stroke and SW2 is turned ON.
[0024]
S7: The control circuit 10 calculates the amount of movement of the focusing lens according to the distance to the subject obtained in S2, and moves the focusing lens of the photographing lens by the calculated amount of movement by the lens driving device 15.
[0025]
S8: The control circuit 10 operates the shutter driving device under the exposure conditions obtained in S4 to expose the film.
[0026]
S9: The control circuit 10 drives the film driving device to wind up the film by one part.
[0027]
S10: When the light receiving optical path of the distance measuring device or the light receiving optical path of the light measuring device is interrupted, the process shifts to this step. Therefore, the warning mark is blinked on the display unit of the display device 18 and the sounding body 19 is driven. Emit a warning sound. Further, the shutter release cannot be performed, that is, the shutter release is prohibited.
[0028]
As described above, it is possible to detect that any of the light receiving optical paths has been blocked by comparing information regarding the brightness of the pair of distance measuring light receiving elements, in which case a warning display, The photographer is warned with a warning sound, release prohibition, and the like, thereby preventing a failed photograph from being taken.
[0029]
Further, by comparing the information on the brightness of the light receiving element for distance measurement and the information on the brightness of the light measuring element, it is possible to detect that any of the light receiving optical paths has been blocked. It is possible to prevent a failed photograph from being taken by an appropriate process.
[0030]
When the distance to the subject changes, the range detected by the photometric element and the range detected by the light receiving element for distance measurement differ due to parallax. In this case, the problem is solved by changing the position of the light receiving element for detecting the brightness of the subject with the light receiving element for distance measurement according to the distance measurement result.
[0031]
【The invention's effect】
According to the invention according to the present application as described above. It has photometric means for measuring the brightness of the subject and its surroundings, and brightness detecting means for obtaining a signal relating to brightness near the subject from an output signal from a light receiving element provided in the distance measuring means for measuring the distance to the subject. The camera compares the output signal of the light measuring means with the output signal of the brightness detecting means, and detects from the comparison result that either the light receiving optical system of the light measuring means or the light receiving optical path of the distance measuring means has been blocked. The provision of the light-blocking detecting means makes it possible to take measures for preventing a failed photograph.
[0032]
Furthermore, a light-shielding detecting means for providing a pair of light-receiving elements, comparing the magnitudes of the output signals of the respective light-receiving elements, and detecting that the light-receiving optical path of one of the light-receiving elements is blocked based on the comparison result. In a distance measuring apparatus characterized by the above, it is possible to take a means for outputting an incorrect distance measurement result.
[0033]
Furthermore, by providing a warning means, when the light blocking detection means detects that the light receiving optical path of the distance measuring means or the light measuring means is interrupted, a warning is issued by the warning means so that the photographer can be alerted. It becomes possible.
[0034]
Further, when either the light receiving optical system of the light measuring means or the light receiving optical path of the distance measuring means is blocked, the shutter release of the camera is prohibited, so that a failure photograph can be prevented from being taken.
[Brief description of the drawings]
FIG. 1 is an external view of a camera provided with the present invention.
FIG. 2 is a block diagram of a camera equipped with the present invention.
FIG. 3 shows a light receiving element and a photometric element.
FIG. 4 shows a photometric optical path and a distance optical path.
FIG. 5 is a projection image of a photometric element and a light receiving element on a subject.
FIG. 6 is a detection range of a light receiving element and a photometric element with respect to an imaging range.
FIG. 7 is a sequence diagram at the time of photographing by a camera equipped with the present invention.
[Explanation of symbols]
Reference Signs List 1 front panel of camera 2 photographing lens 3 shutter release button 4 finder objective lens 5 light receiving lens of distance measuring device 6 light receiving lens of distance measuring device 7 AE light receiving lens 8 subject 10 camera control circuit 11R light receiving element 11L of distance measuring device Light receiving element 12 of distance device 12 Photometric device 13 Distance measuring circuit 14 Photometric circuit 15 Lens driving device 16 Shutter driving device 17 Film driving device 18 Display device 19 Sounding body 20 SW1
21 SW2
22 Power supply circuit
