JPH0593846A - Automatic focusing device for camera - Google Patents

Abstract

PURPOSE:To facilitate adjustment for the deviation of range-finding in automatic focusing as to an automatic focusing camera. CONSTITUTION:At the stage of completing the camera, the camera and an object to which range-finding is performed are faced to each other spaced by a distance coincident with a specified distance value apart, and a writing requirement is given so that a correction amount writing means 300 is driven. The correction amount writing means drives a range-finding means 100, so that an observed value to the object to which range-finding is performed from the range-finding means is inputted to calculate correction amount for correcting the value to the specified distance value, then the calculated correction amount is written in an E<2>PROM 200. When a release switch 400 is operated, the observed value to the object from the range-finding means is corrected with the correction amount by a correction means 500 and range-finding information is given.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera autofocus adjusting device.

[0002]

2. Description of the Related Art In an auto-focus camera, even if the auto-focus part is adjusted in a unit state before being attached to the camera body, distortion or variation in the attachment due to attachment to the camera body or the like may cause an error in distance measurement. Occurs. Therefore, in the conventional autofocus camera, when the camera is completed, mechanical adjustment of the light receiving element and the light emitting element is used to adjust the deviation of the distance measurement, and the method of fixing the adjustment state by adhesion is used. It was

[0003]

In such a conventional method, there is a possibility that the distance may be misaligned again due to a deviation in curing at the time of bonding, and in addition to the mechanical adjustment time, the bonding time Was required, and there was a problem that adjustment took time.

The present invention has been made based on the above viewpoint, and an object of the present invention is to provide a camera which is effective for facilitating the adjustment for the deviation of the distance measurement without requiring the mechanical adjustment work of the light receiving element and the light emitting element. It is to provide an autofocus adjustment device.

[0005]

In the present invention, as shown in FIG.
Distance measuring means 1 for measuring the distance to the subject, as shown in FIG.
00 and electrically rewritable nonvolatile memory E ² PR
In response to the OM 200 and a write request from the outside, the distance measuring means 100 is driven, a correction amount for correcting the actual measurement value from the distance measuring means 100 to a predetermined distance value is calculated, and the calculated correction amount. Is a correction amount writing means 300 for writing into the E ² PROM 200, and when the camera is completed, the camera and the distance-measuring object prepared for writing the correction amount are separated by a distance equal to the predetermined distance value. In response to the operation of the correction amount writing means 300 for calculating the correction amount and writing the correction amount in the E ² PROM 200 when the write request is given in a state where they are separated from each other and the release switch 400 is operated, The distance measuring means 100 is driven to drive the distance measuring means 10
The above object is achieved by an autofocus adjusting device for a camera having a correction unit 500 that gives distance measurement information by correcting a measured value from 0 with the correction amount written in the E ² PROM 200.

In a so-called multi-beam autofocus camera having a plurality of light projecting elements, the correction amount writing means 300 gives the E ² PROM 200 a correction amount for each measured value obtained by projecting light from each light projecting element. And the correction means 500 corrects the actual measurement values obtained by the projection of each light projecting element by the corresponding correction amounts written in the E ² PROM 200, thereby measuring the distance measurement information corresponding to each light projecting element. give.

[0007]

When the camera is completed, the correction amount writing means 30 sets the camera and the object to be measured prepared for writing the correction amount.
The correction amount writing means 300 is driven by giving a writing request by facing them by a distance corresponding to a predetermined distance value of 0. The correction amount writing unit 300 drives the distance measuring unit 100, inputs a measured value up to the object to be measured by the distance measuring unit 100, and calculates a correction amount for correcting the measured value to the predetermined distance value, This correction amount is written in the E ² PROM 200. When the photographer operates the release switch 400, the correction means 500 outputs the measured value from the distance measuring means 100 to the subject to the E ² PROM.
Distance measurement information is given by correcting the correction amount written in 200. In the multi-beam autofocus camera, the correction amount for each actual measurement value given by the projection of each projecting element is calculated and written in the E ² PROM 200,
The correction means 500 corrects the actual measurement values obtained by the light projection of the respective light projecting elements by the corresponding correction amounts to give the distance measurement information corresponding to the respective light projecting elements.

[0008]

2 is a block diagram showing an embodiment of the present invention.

In FIG. 2, reference numeral 1 is a microcomputer.
The photometric unit 3, the focus adjustment unit 4, and the shutter control unit 5 are controlled, and writing / reading of the electrically rewritable nonvolatile memory E ² PROM 6 is controlled.

The distance measuring section 2 has a light projecting means 7 and a light receiving means 8. The light projecting means 7 has three light projecting elements 10, 11 and 12 arranged in a line for projecting light through the same light projecting lens 9. The light projecting elements 10 to 12 are provided so as to form a horizontal row when the camera is held in a normal position, and the central projecting element 10 is provided on the optical axis of the light projecting lens 9. The beam of the central light projecting element 10 travels on the optical axis of the light projecting lens 9, and the beams of the left and right light projecting elements 11 and 12 open to the beam of the central light projecting element 10 as the distance increases. It is like this. The central light projecting element 10 is driven by a drive circuit 13 controlled by the microcomputer 1, the left light projecting element 11 is driven by a drive circuit 14 controlled by the microcomputer 1, and the right light projecting element 12 is driven by a microcomputer. It is adapted to be driven by a drive circuit 15 controlled by the computer 1. The light receiving means 8 reflects the light from the subject and returns to receive the light emitted by the light projecting means 7, and provides the microcomputer 1 with the measured value information of the distance to the subject.

The photometric section 3 performs photometry under the control of the microcomputer 1 and gives photometric information to the microcomputer 1. Under the control of the microcomputer 1, the focus adjusting section 4 extends the photographing lens 16 to the in-focus position and returns it to a predetermined position. The shutter controller 5 opens and closes the shutter 17 under the control of the microcomputer 1. 1
Reference numeral 8 denotes a release switch having a two-stage configuration including a first-stage SP1 and a second-stage SP2, which gives a start signal to the microcomputer 1 when the first-stage SP1 is turned on and releases it to the microcomputer 1 when the second-stage SP2 is turned on. Give a signal.
Reference numeral 19 denotes a correction amount write request switch, which turns on to give a correction amount write start signal to the microcomputer 1. The correction amount write request switch 19 is provided, for example, in a recess of the camera body so that it cannot be operated by simply touching it normally. For example, after completion of writing the correction amount to the E ² PROM 6 which will be described later, a label is attached. For example, it is hidden so that the camera user cannot operate it.

When the distance measuring unit 2 is attached to the camera body, the distance measuring unit 2 may be distorted due to distortion or variation in the attachment of the light projecting means 7 and the light receiving means 8 to the camera body. Occurs. That is, when the camera and the distance-measuring object are faced apart by a predetermined distance at the stage of completion of the camera and the distances to the distance-measuring object are measured by the respective light-projecting elements 10 to 12, each light-projecting element is measured. An error occurs between each measured value by the light projections of 10 to 12 and the predetermined distance. The microcomputer 1 calculates correction amounts A ₁ , A ₂ and A ₃ for correcting an error in distance measurement by the light projecting elements 10 to 12 according to a flowchart of FIG. 3 described later to calculate E ² PR.
In addition to having a function of writing to the OM 6, each of the light projecting elements 10 to 1 is used during distance measurement calculation according to the flowchart of FIG. 4 described later.
2 has a function of correcting the actual measurement value by the light projection of 2 with the correction amounts A _{1 to} A ₃ written in the E ² PROM 6. Correction amount A
The writing of _{1 to} A ₃ is carried out when the camera is completed by setting the camera and the object to be measured prepared for writing the correction amount into a predetermined distance value for writing the correction amount which is stored in advance in the microcomputer 1. The correction amount write request signal is sent to the microcomputer 1 by the correction amount write request switch 19 so that they are opposed to each other by a matching distance. The microcomputer 1 has well-known automatic focus adjustment function and automatic exposure function in addition to these functions.

FIG. 3 is a flow chart showing the writing of the correction amounts A _{1 to} A ₃ by the microcomputer 1.

When the camera is completed, the camera and the object to be measured prepared for writing the correction amount are separated by a distance corresponding to a predetermined distance value for writing the correction amount stored in the microcomputer 1 in advance. Then, the correction amount write request switch 19 is turned on in this state. When the correction amount writing request switch 19 is turned on, a correction amount writing start signal is given to the microcomputer 1, and the microcomputer 1 starts the control of FIG. First, in step 20, the microcomputer 1 drives the central light projecting element 10 to take in the measured value up to the object to be measured by the central light projecting element 10 from the light receiving means 8, and then in step 21.
Then, by driving the left light projecting element 11, the actually measured value of the left light projecting element 11 up to the object to be measured is fetched from the light receiving means 8, and in the next step 22, the right light projecting element 12 is driven. As a result, the actually measured value up to the object to be measured by the light projecting element 12 on the right side is taken in from the light receiving means 8. Each light emitting element 10
After taking in the measured values up to the object to be measured by .about.12, in step 23, the measured value by the light projection of the central light projecting element 10 is stored in advance and the above-mentioned predetermined distance value for writing the correction amount is stored. By subtracting from
The correction amount A ₁ for the distance measurement by the left side light emitting element 11 is calculated by subtracting the measured value by the light projection element 11 on the left side from the predetermined distance value in the next step 24. calculates a correction amount a ₂ for, at the next step 25, the actual measurement value measured by the light projecting the right of the light projecting element 12 by subtracting from the predetermined distance value, the correction amount for the distance measurement by the right side of the light emitting element 12 Calculate A ₃ . Correction amount A ₁ to actual measurement value by each light projecting element 10 to 12
After calculating A ₃ , the correction amounts A _{1 to} A ₃ are written in the E ² PROM 6 in step 26, and the writing of the correction amount is completed.
After the writing is completed, the correction amount writing request switch 1 is set by the camera user by attaching a label or the like as described in the configuration description.
9 is disabled.

FIG. 4 is a flowchart showing the exposure control by the microcomputer 1.

When the first stage SP1 of the release switch 18 is turned on, the microcomputer 1 enters the photometric processing of step 30, fetches the photometric information from the photometric section 3, and then executes the distance measuring processing of step 31. to go into. Step 3
The distance measuring process of No. 1 includes steps 310 to 316. First, in step 310, by driving the central light projecting element 10, the measured value up to the subject by the central light projecting element 10 is fetched from the light receiving means 8, In step 311, the left-side light projecting element 11 is driven to take in the measured value up to the subject by the left-side light projecting element 11 from the light receiving means 8, and in the next step 312, the right-side light projecting element 12 is driven. As a result, the actually measured value up to the subject by the right light projecting element 12 is taken in from the light receiving means 8. After capturing the measured values up to the subject by each of the light projecting elements 10 to 12, in step 313, the measured value up to the subject by the central projecting element 10 is set to E ² PR.
The measured value by the central light projecting element 10 is corrected by adding the correction amount A ₁ written in the OM 6, and in the next step 314, E ² is added to the actual measured value up to the subject by the left projecting element 11. Correction amount A ₂ written in PROM ₆
Is corrected to correct the actually measured value by the left light projecting element 11, and in the next step 315, the right light projecting element 1
By adding the correction amount A ₃ written in the E ² PROM 6 to the actually measured value up to the subject by 2, the actually measured value by the light projecting element 12 on the left side is corrected. Each light emitting element 10 to 1
After correcting the actually measured values by 2 with the corresponding correction amounts A _{1 to} A ₃ , in step 316, the distance to the object is determined by selecting the closest distance information from these three corrected distance information. Then, the distance measuring process is completed. Next, in step 32, the exposure calculation is performed based on the photometric information, and then the next step 33 is entered. In step 33, it is determined whether or not the second stage SP2 of the release switch 18 has been turned on. If not turned on, step 34 is entered, and if turned on, step 35 is entered. In step 34, the first step S of the release switch 18
Whether P1 is turned on or off is determined, and if the first stage SP1 remains on, the process returns to step 33, and if it is off, the standby state, which is the shooting standby state, is entered. In step 35, the exposure processing is performed by controlling the focus adjustment section 4 and the shutter control section 5 according to the distance measurement information to the subject obtained in step 31 and the exposure calculation result in step 32.

In the embodiments described above, the so-called multi-beam autofocus camera having three light projecting elements has been described as an example, but a so-called single-beam autofocus camera using a single light projecting element, or this It is needless to say that the present invention can be applied to a multi-beam autofocus camera having a plurality of light projecting elements different in number from.

[0018]

As described above, according to the present invention, at the stage when the camera is completed, the distance-measuring object arranged at a distance corresponding to the predetermined distance value is actually measured by the distance measuring means,
A correction amount for correcting the measured value to the predetermined distance value is calculated and written in the E ² PROM, and when the release switch is operated, the measured value up to the subject by the distance measuring means is calculated by the correction amount. Since it is configured to adjust the deviation of the distance measurement by correcting, the mechanical adjustment work of the light receiving element and the light projecting element becomes unnecessary, and the complexity associated with the mechanical adjustment work can be eliminated. It is possible to provide an auto-focus adjusting device for a camera, which has effects such as facilitating adjustment for misalignment of distance measurement.

[Brief description of drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

3 is a flowchart showing writing of a correction amount by a microcomputer in FIG.

FIG. 4 is a flowchart showing exposure control by the microcomputer in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Distance measuring means 6 E ² PROM 18 Release switch 19 Correction amount writing request switch 100 Distance measuring means 200 E ² PROM 300 Correction amount writing means 400 Release switch 500 Correction means

Claims (2)

[Claims] 1. A distance measuring means for measuring a distance to an object and an electrically rewritable nonvolatile memory E ² PROM.
In response to a writing request from the outside, the distance measuring means is driven, a correction amount for correcting the measured value from the distance measuring means to a predetermined distance value is calculated, and the calculated correction amount is the E value. ²
Compensation amount writing means for writing in the PROM, and when the camera is completed, the camera and the distance-measuring object prepared for writing the compensation amount are faced apart by a distance corresponding to the predetermined distance value. In response to the write request in the above state, the correction amount is calculated and the correction amount is written in the E ² PROM, and the distance measuring device is driven in response to the operation of the release switch. An autofocus adjusting device for a camera, comprising: a correction unit that gives distance measurement information by correcting a measured value from the distance measurement unit with a correction amount written in the E ² PROM. 2. The distance measuring means has a plurality of light projecting elements,
The correction amount writing means writes a correction amount for each measured value obtained by the light projection of each light projecting element into the E ² PROM,
The correction means corrects the actual measurement values obtained by the projection of the respective light projecting elements by the corresponding correction amounts written in the E ² PROM to give distance measurement information corresponding to the respective light projecting elements. The autofocus adjusting device for a camera according to claim 1.