JPH08152663A - Photometry device - Google Patents

Abstract

PURPOSE: To switch a photometry range to the prescribed-sized photometry range (spot photometry area, average photometry area and the like) while a photometry device is made compact and inexpensive. CONSTITUTION: The photometry device is provided with a focus varying means changing a focusing state by changing a relative position between a single photometry sensor 1 and a photometry lens 2 in an optical axis direction as for the size of the selected photometry range. Then, the focusing state on the sensor 1 is changed by changing the relative position between the sensor 1 and the lens 2 in the optical axis direction so as to project an image coinciding with the size of the selected photometry range on the sensor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a photometric device mounted on electronic equipment such as a camera.

[0002]

2. Description of the Related Art In a conventional camera, spot photometry and average photometry are performed by using a plurality of divided sensors or a plurality of sensors. In addition, JP-A-57-3
As disclosed in Japanese Patent No. 2426, there is also a structure in which the form of photometric sensitivity distribution is varied by using an electrically diffusive variable focusing screen.

[0003]

However, in the above-mentioned conventional example, in the case where the sensor divided into a plurality of parts is used,
The chip area of the sensor is large, and in the case of using a plurality of sensors, this is a factor of cost increase.

Further, in Japanese Patent Laid-Open No. 57-32426, an electrically diffusive variable focusing plate is required, which increases cost and is applicable to lens shutter cameras and the like, which are desired to be further downsized. It was difficult.

(Object of the Invention) The object of the present invention is to reduce the size,
An object of the present invention is to provide a photometric device capable of switching to a photometric range of a predetermined size while achieving cost reduction.

[0006]

In order to achieve the above object, the present invention according to claims 1 to 5 provides an optical axis of a single photometric sensor and a photometric lens in a selected photometric range. The focus variable means for changing the relative position in the direction to change the focus state is provided, and the relative position in the optical axis direction between the single photometric sensor and the photometric lens is changed to change the focus state on the photometric sensor. An image matching the size of the photometric range is projected on the photometric sensor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a diagram showing a photometric optical system of a photometric device according to a first embodiment of the present invention. Reference numeral 1 is an SPD (silicon photodiode) which is a photometric sensor for detecting subject brightness. Reference numeral 2 denotes a photometric lens for condensing on the SPD1, and the photometric lens 2 is arranged so that an object located at a finite distance with respect to the SPD1 is in focus, and 2a is from the position of the photometric lens 2. Length L
The figure shows a state in which the subject image is blurred with respect to the SPD 1 at this time.

FIG. 2 is a block diagram showing the electrical construction of the photometric device having the photometric optical system shown in FIG. 1. 1 is the SPD, which is the above-mentioned photometric sensor, 2 is a photometric lens for collecting light, and 3 is a photometric lens. Is a CPU that controls the operation of the camera, and 4 is the SP
A received light signal processing means for amplifying a signal received from D1,
Reference numeral 5 is a lens driving means including a drive motor for moving the photometric lens in the focus direction, 6 is a motor driver for driving the motor in the lens driving means 5, and 7 is a gain resistor for changing the amplification factor of the received light signal processing means 4. , 8 is CPU3
An activation switch for activating the, and a portrait switch 9 for selecting whether or not to take a picture at a portrait.

In the above configuration, when the activation switch 8 is turned on, the CPU 3 is activated and step 101 in FIG.
To start the operation from. [Step 101] It is checked whether or not the portrait switch 9 is turned on, and if it is turned on, step 102 is performed.
Go to. [Step 102] The photometric lens 2 is driven via the motor driver 6 and the lens driving means 5 in order to bring the SPD 1 into focus at a designated finite distance. As a result, a focused subject image is formed on the SPD 1.

At this time, since the light receiving range is in focus, it becomes a narrow photometric area as shown by 21 in FIG. 4A, which is so-called spot photometry. [Step 103] The received light signal output from the SPD 1 is amplified by the received light signal processing means 4, and this signal is fetched and the CPU 3 calculates photometric data.

If the portrait switch 9 is off in step 101, step 1
Move to 04. [Step 104] The photometric lens 2 is driven via the motor driver 6 and the lens driving means 5 so that the focus is out of focus on the SPD 1. As a result, the subject image on the SPD1 becomes a blurred image.

At this time, since the light receiving range is out of focus, a wide photometric region as shown by 22 in FIG. 4A is obtained, which is so-called average photometry. [Step 105] Since the brightness of the sensor surface changes after the spot photometry, the resistance value of the gain resistor 7 is changed to correct the amplification degree of the received light signal processing means. [Step 106] The received light signal output from the SPD 1 is amplified by the received light signal processing means 4 whose amplification degree is corrected, and the CPU 3 takes in this signal and calculates the photometric data.

With the above, a series of operations is completed.

(Second Embodiment) FIG. 5 is a block diagram showing the electrical construction of a photometric device according to the second embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals.

The difference from the first embodiment described above is that the position of the photometric lens 2 is not changed according to the state of the portrait switch 9 but the SP is driven by the sensor driving means 10.
The only difference is that the position of D1 (in the optical axis direction) is changed.

The state at this time is shown in FIG.

In the above configuration, when the activation switch 8 is turned on, the CPU 3 is activated and step 201 in FIG.
To start the operation from. [Step 201] It is checked whether the portrait switch 9 is turned on, and if it is turned on, step 202
Go to. [Step 202] The SPD 1 is driven through the motor driver 6 and the sensor driving means 10 to a predetermined position on the SPD 1 where the subject image is in focus.

At this time, since the light receiving range is in focus, a narrow photometric region as shown by 21 in FIG. 4A is obtained, which is so-called spot photometry, as in the first embodiment. [Step 203] The received light signal output from the SPD 1 is amplified by the received light signal processing means 4, and this signal is fetched and the CPU 3 calculates photometric data.

If the portrait switch 9 is off in step 201, step 2
Move to 04. [Step 204] The motor driver 6 and the sensor drive means 10 are used to move the S so that the focus is out of focus on the SPD 1.
The PD1 is driven (position 1a in FIG. 7).

At this time, since the light receiving range is out of focus, as in the first embodiment, as shown in FIG.
A wide photometric range as shown by No. 22 is obtained, which is so-called average photometry.

After that, the process proceeds to the previous step 203, the photometric data is calculated, and the series of operations is ended.

(Third Embodiment) FIG. 8 is a block diagram showing the electrical construction of a photometric device according to the third embodiment of the present invention. The same parts as those in FIGS. 2 and 5 are designated by the same reference numerals. is there.

In this embodiment, the photometric lens 12 is a lens such as a liquid lens whose focal length can be varied, and the focal length varying means 11 changes the focal length of the photometric lens 12 according to the state of the portrait switch 9. Spot photometry and average photometry (in this case, as in the first embodiment, the gain resistance is used to correct the amplification degree).

FIG. 9 is a diagram showing a state in which the focal length of the photometric lens 12 is switched according to the state of the portrait switch 9.

According to each of the above embodiments, SPD1 and S
A means for changing the optical relative focus relationship with the photometric lens 2 (12) for condensing on the PD 1 is provided, and the means is driven according to the state of the portrait switch 9 to focus and spot photometry. Since it is possible to put it in a state or make the focus out of focus to obtain average photometry, it is not necessary to divide the sensor surface into multiple parts or to require multiple sensors as in the past, and the sensor surface is large. Become
The cost will not increase.

(Correspondence between Invention and Example) In this example, the SPD 1 corresponds to the photometric sensor of the present invention, and the photometric lens 2 and the photometric lens 12 correspond to the photometric lens of the present invention.
The lens driving unit 5, the sensor driving unit, and the focal length changing unit 11 correspond to the focus changing unit of the present invention.

The above is the correspondence relationship between each structure of the embodiments and each structure of the present invention, but the present invention is not limited to the structures of these embodiments, and the functions or embodiments shown in the claims or the embodiments It goes without saying that any structure may be used as long as it can achieve the function of.

(Modification) In this embodiment, the case where the SPD is used as the photometric sensor is described, but it may be CSD or the like.

Further, although the spot metering and the average metering are switched by the portrait switch,
However, the present invention is not limited to this, and even if the photographer can arbitrarily select it, it may be switched according to another photographing mode. Further, it may be switched to an area other than spot metering or average metering (for example, an intermediate partial metering area).

Further, although the present invention has been described as applied to a camera such as a single-lens reflex camera, a lens shutter camera, a video camera, etc., it can also be applied to other optical devices and other devices, and further as a constituent unit. Is something that can be done.

Furthermore, the present invention may be constructed by appropriately combining the above-described embodiments or their techniques.

[0033]

As described above, according to the present invention,
In the size of the selected photometry range, focus changing means for changing the relative position of the single photometry sensor and the photometry lens in the optical axis direction to change the focus state is provided, and the single photometry sensor and the photometry lens are provided. The relative position in the optical axis direction is changed to change the focus state on the photometric sensor so that an image matching the size of the selected photometric range is projected on the photometric sensor.

Therefore, it is possible to switch to a photometric range of a predetermined size (spot photometric area, average photometric area, etc.) while achieving miniaturization and cost reduction.

[Brief description of drawings]

FIG. 1 is a diagram showing a position of a photometric lens when a photometric area is variable in a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a photometric device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the CPU of FIG.

FIG. 4 is a diagram showing states on the screen during spot photometry and average photometry in each embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a photometric device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing the position of the SPD when the photometric area is changed in the second embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the CPU of FIG.

FIG. 8 is a block diagram showing a configuration of a photometric device in a third embodiment of the present invention.

FIG. 9 is a diagram showing a state of a photometric lens when a photometric region is variable in a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 SPD 2, 12 Photometric lens 3 CPU 4 Light receiving signal processing means 5 Lens driving means 10 Sensor driving means 11 Focal length varying means

Claims (5)

[Claims] 1. A photometric device comprising a single photometric sensor and a photometric lens for converging light on the photometric sensor, wherein the photometric sensor and the photometric lens are selected within a selected photometric range. A photometric device comprising focus changing means for changing a relative position in the optical axis direction to change a focus state. 2. The photometric device according to claim 1, wherein the focus changing unit is a unit that changes a distance in the optical axis direction between the photometric sensor and the photometric lens. 3. The photometric device according to claim 1, wherein the focus changing means is means for changing a focal length of the photometric sensor. 4. The photometric device according to claim 1, wherein the photometric sensor is a photoelectric sensor. 5. The photometric device according to claim 1, wherein the photometric sensor is a semiconductor position detector.