JP2001337263A - Range-finding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a TTL system range-finding device capable of realizing accurate focusing on a main subject. SOLUTION: This range-finding device is provided with a 1st sensor part 2 having an infrared cutting part 4, a 2nd sensor part 3 having a visible light cutting part 5, and a focusing part 6 performing focusing based on output from the 1st and the 2nd sensor parts 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device usable for an image pickup device such as a camera.

[0002]

2. Description of the Related Art Conventionally, a passive AF system and an active A
2. Description of the Related Art A ranging device that performs ranging by switching to an F system is known. For example, a distance measuring device disclosed in Japanese Patent Application Laid-Open No. 11-337815 has a passive AF light-receiving element array and an active AF light-receiving element array.
A black filter is arranged on the surface of the light receiving element for cutting visible light and transmitting infrared light. In the case of the active AF, the object is irradiated with infrared light and the reflected light is received.

[0003]

The so-called TTL
In a distance measuring apparatus of the system, an infrared cut filter for removing infrared light is generally arranged in an optical path to reduce an error due to chromatic aberration. Therefore, when performing active AF (auxiliary light), the visible light wavelength is set so as not to be affected by the infrared cut filter, and infrared light cannot be used. Therefore, it is greatly affected by the visible light component of the stationary light, which is not preferable as the S / N.

[0004] Such a problem is described in the above-mentioned Japanese Patent Application Laid-Open No. 11-33.
Even if the distance measuring sensor disclosed in Japanese Patent No. 7815 is adopted, the same problem occurs.

That is, when the above-described apparatus is applied to the TTL system, the effect of the black filter (visible light cut filter) becomes very thin because the infrared cut filter is used, and the infrared light radiated to the subject is reduced. The reflected light is cut off, and the S / N is reduced, so that the distance measurement accuracy is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a TTL type distance measuring apparatus capable of accurately focusing on a main subject. It is to provide a device.

[0007]

In order to achieve the above object, according to a first aspect of the present invention, a first sensor having an infrared cut means, a second sensor having a visible light cut means, A distance measuring device is provided, comprising: focus adjusting means for adjusting a focus based on outputs of the first sensor means and the second sensor means.

According to a second aspect, in the first aspect, there is further provided a light projecting means for projecting light of a predetermined wavelength to the subject, and the focus adjustment means is provided when the light projecting means is not operated. The output of the first sensor means and the second signal when the light emitting means operates.
There is provided a distance measuring device for performing focus adjustment based on an output of a sensor means.

According to a third aspect, in the first aspect, the second sensor means further includes a stationary light removing means for removing a stationary light component from the amount of light received. A distance measuring device is provided.

According to a fourth aspect, in the first aspect, the first sensor means and the second sensor means are the same IC.
There is provided a distance measuring device formed on a chip.

According to the above-described first to fourth aspects, the following operations are provided.

That is, in the first aspect of the present invention, the focus adjusting means focuses on the basis of the output of the first sensor having the infrared cut means and the output of the second sensor having the visible light cut means. Adjustments are made.

[0013] In a second aspect, in the first aspect, the focus adjustment means controls the output of the first sensor means when the light emitting means is not operating and the second sensor when the light emitting means is operating. Focus adjustment is made based on the output of the means.

According to a third aspect, in the first aspect, the second sensor means removes a steady light component from the amount of light received by the steady light removing means.

According to a fourth aspect, in the first aspect, the first sensor means and the second sensor means are the same IC.
Formed on a chip.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram of a distance measuring apparatus according to the present invention.

As shown in FIG. 1, a first sensor section 2 having an infrared cut section 4 and a second sensor section having a visible light cut section 5 are provided.
Each output of the sensor unit 3 is connected to an input of the focus adjustment unit 6. The focus adjustment unit 6 performs focus adjustment based on the output of the first sensor unit 2 when the light projecting unit 7 is not operating and the output of the second sensor unit 3 when the light projecting unit 7 is operating. Further, an output of the focus adjusting unit 6 is connected to an input of a light projecting unit 7 for projecting light of a predetermined wavelength to a subject.

FIG. 2 is a further conceptual diagram of the distance measuring apparatus of the present invention.

As shown in FIG. 1, inside a sensor unit 1 for receiving reflected light from a subject, a first sensor unit 2 having a part of the sensor unit 1 and an infrared cut unit 4 on the front surface is provided.
And a second sensor unit 3 having a visible light cut filter 5 on a front surface of a part of the sensor unit 1. The output of the first sensor unit 2 and the output of the second sensor unit 3 are connected to the input of a focus adjustment unit 6 that performs focus adjustment based on the output, and the output of the focus adjustment unit 6 is applied to the subject. On the other hand, it is connected to the input of a light projecting unit 7 for projecting light having a predetermined wavelength distribution.

FIG. 3 is a further conceptual diagram of the distance measuring apparatus of the present invention.

As shown in FIG. 2, in this configuration, in addition to the configuration of FIG. 2, the steady light component is removed from the light receiving component of the second sensor unit 3 in synchronization with the light projection of the light projecting unit 7. Further, a stationary light removing unit 8 is provided. Then, the distance measuring unit 6
Focus adjustment is performed based on the output of the second sensor unit 3 that has activated the stationary light removal unit 8.

Hereinafter, a first embodiment of the present invention will be described.

FIG. 4 is a block diagram showing a configuration of a camera employing the distance measuring apparatus according to the first embodiment. In FIG. 1, a microcomputer (hereinafter, referred to as a microcomputer) 11 is a camera system controller.

Inside the microcomputer 11, a central processing unit (hereinafter, referred to as CPU) 11a, a read-only memory (hereinafter, referred to as ROM) 11b, and a random access memory (hereinafter, referred to as RAM) are provided. 11c,
Analog / digital (A / D) converter (hereinafter referred to as AD
11d). CPU 11
a performs a series of operations according to a sequence program stored in the ROM 11b. The microcomputer 11 further includes an EEPROM 11e therein.
The EPROM 11e stores correction data for AF, photometry, exposure calculation, and the like for each camera. Furthermore, this EE
The PROM 11e also stores various parameters and the like for detecting a main subject in a shooting screen described later.

The output of the microcomputer 11 is connected to the input of the AF area sensor 12.

The AF area sensor 12 captures a subject image formed by a distance measuring optical system 36, which will be described later, and converts the captured image into sensor data, which is an electrical signal. The AF area sensor 12 includes light receiving elements 12a and 12b, which are two-dimensionally arranged in a horizontal direction and a vertical direction, and a processing circuit 12c.

The charge generated by the light incident on the light receiving element (photodiode) is converted into a voltage by a pixel circuit for each pixel, and is amplified and output.

The microcomputer 11 controls the integration operation of the AF area sensor 12, controls the reading of sensor data, processes the sensor data output from the AF area sensor 12, and performs distance measurement calculation, main subject detection, and the like. . Also,
The AF area sensor 12 has a stationary light removing unit for each pixel, and the microcomputer 11 can switch whether or not to remove the stationary light. In other words, under such a steady light removing operation, by performing while performing auxiliary light described later, it is possible to detect a light receiving signal corresponding to only the subject reflected light due to the projected component.

The output of the microcomputer 11 is also connected to the input of the focus lens driving unit 13. The focus lens driving unit 13 drives the focusing lens 14 which is a part of the photographing lens 130. A focus encoder 15 connected to the focus lens 14 generates a pulse signal corresponding to the amount of movement of the focusing lens 14.

The microcomputer 11 outputs a drive signal to the focus lens drive unit 13 based on the distance measurement calculation result,
The output of the focus encoder 15 is monitored and the position of the focus lens 14 is controlled to adjust the focus.

A photometric unit 16 is also connected to the microcomputer 11. The photometric unit 16 processes a photocurrent signal generated by the photometric light-receiving element 16a divided into a plurality of sections, corresponding to a shooting screen, and generates a photometric output. The microcomputer 11 performs A / D conversion of the photometric output by the ADC 11d,
Perform exposure calculation.

The microcomputer 11 includes a shutter driving unit 1
7. The flash circuit 20 and the display unit 21 are also connected. That is, the shutter driving unit 17
A shutter (not shown) is driven based on the command 1 to expose the film. The strobe circuit section 20 is a block that emits a strobe light 20a as an auxiliary light source during photographing. The microcomputer 11 controls charging and light emission of the strobe circuit unit 20. Further, the strobe circuit unit 20 is also operated as AF auxiliary light at the time of the distance measuring operation. The display unit 21 displays information inside the camera as L
The information is displayed by a display element such as a CD, and is controlled by the microcomputer 11.

Further, the microcomputer 11 has a first relays switch (hereinafter referred to as 1RSW) 18 and a second release switch (hereinafter referred to as 2RSW) 19
Is also connected. These 1RSW18, 2RSW19
Is a switch interlocked with the release button. The 1RSW 18 is turned on when the release button is depressed in the first stage, and the 2RSW 19 is subsequently turned on when depressed in the second stage. The microcomputer 11 performs AF and photometry operations when the 1RSW 18 is turned on, and performs an exposure operation and a film winding operation when the 2RSW 19 is turned on.

In addition to the above, the film driving section 22 performs a film driving operation of auto-loading, winding one frame, and rewinding under the command of the microcomputer 11.

The zoom lens driving section 23 performs a zoom operation of the photographing lens 130 under the command of the microcomputer 11. The zoom drive unit 23 is provided with the microcomputer 11
To output focal length information of the photographing lens 130. Further, the infrared light emitting diode 131 is a light projecting element as AF auxiliary light, and has an irradiation angle corresponding to the entire photographing screen together with a light projecting optical system arranged on the front surface thereof.

Hereinafter, referring to the flowchart of FIG.
A main routine of the microcomputer 11 of the camera according to the first embodiment will be described.

When the power switch (not shown) is turned on or a battery is inserted, the microcomputer 11 starts operating and the ROM 11
Execute the sequence program stored in b.

First, the microcomputer 11 initializes each block in the camera (step S101). At this time,
The microcomputer 11 develops adjustment / correction data such as AF and photometry in the EEPROM 11e in the RAM 11c.

Subsequently, the microcomputer 11 detects the state of the 1RSW 18 (step S102). When the 1RSW 18 is turned on, the microcomputer 11 performs an AF operation (step S103), performs photometry / exposure calculation (step S104), and executes 2RSW1.
9 is detected (step S105). Where 2
When the RSW 19 is turned on, the film is exposed by the shutter operation (step S106), and the film is wound up by one frame (step S107).
Return to 02.

On the other hand, in step S102, 1RSW
If 18 is not turned on, 1RSW18, 2R
Inputs of switches other than SW19 are detected (step S1).
08), a process corresponding to a switch input, for example, zoom-up / down processing is performed in response to a zoom switch up / down input (step S109), and the above-described step S1 is performed.
02 will be returned.

FIG. 6 is an optical path diagram of the camera according to the first embodiment.

In the figure, a photographing lens 130 has a focus lens 14.

The subject light beam passing through the photographing lens 130 is partially reflected and partially transmitted by the main mirror 30 which is a half mirror.

A part of the subject light beam reflected by the main mirror 30 passes through the focus plate 31 and the condenser lens 32 to become an erect image by the pentaprism 33, and the subject image is observed by the photographer through the eyepiece lens 34.

On the other hand, a part of the luminous flux transmitted through the main mirror 30 is reflected by a sub-mirror 35 which is a total reflection mirror, and is guided to a distance measuring optical system 36.

The distance measuring optical system 36 includes a field mask 37, a field lens 38, a total reflection mirror 39, a pupil mask 40,
The image forming apparatus includes a re-imaging lens 41 and re-images the distance measuring light beam on the AF area sensor 12.

When a subject image is photographed, the main mirror 30 and the sub-mirror 35 are retracted to the positions indicated by the dotted lines in FIG.

FIG. 7A is a sectional view showing the structure of the distance measuring optical system (phase difference detecting optical system) 36, and FIG.
(B) is a perspective view showing a configuration of the distance measuring optical system.

7 (a) and 7 (b), reference numeral 130 denotes a photographing lens, reference numeral 37 denotes a field mask, reference numeral 38.
Is a field lens, reference numeral 40 is a pupil mask having openings 40a, 40b arranged substantially symmetrically with respect to the optical axis of the photographing lens 130, and reference numerals 41a, 41b are pupil masks 40.
a and 40b are reimaging lenses arranged rearward thereof. In FIG. 7A, the above-described main mirror 33, sub-mirror 35, total reflection mirror 39, and the like are not shown for simplicity.

The area Ha of the exit pupil H of the photographing lens 130,
The luminous flux of the subject that has passed through Hb is applied to the field mask 3
7. Field lens 38, aperture 40 of pupil mask 40
a, 40b and re-imaging lenses 41a, 41b,
Corresponding area 12 within the light receiving area of AF area sensor 12
a and 12b.

When the taking lens 130 is focused, that is, when the subject image I is formed on the image forming plane G, the subject I is perpendicular to the optical axis O by the field lens 38 and the re-imaging lenses 41a and 41b. The image is re-imaged on the image pickup areas 12a and 12b of the AF area sensor 12, which is the secondary image forming plane, to become a first image I1 and a second image I2.

The photographing lens 130 is positioned at the front focus, that is, the image plane G
The subject image F is formed in front of the subject image F
Are re-imaged perpendicularly to the optical axis O closer to the optical axis O by each other, and become a first image F1 and a second image F2.

The photographing lens 130 is positioned at the rear focus, that is, the image plane G
The subject image R is formed behind the subject image R
Are re-imaged perpendicularly to the optical axis O, away from the optical axis O by each other, to become a first image R1 and a second image R2.

By detecting the distance between the first image and the second image, it is possible to detect the in-focus state of the imaging lens 130 including the front focus and the rear focus. Specifically, the light intensity distribution of the first image and the second image is obtained from the image data output of the AF area sensor 12, and the interval between the two images is measured.

Next, FIG. 8A shows the AF area sensor 1.
8 shows the state of the light receiving unit, FIG. 8B shows an overview of the AF area sensor 12, FIG. 8C shows a cross section of the AF area sensor 12, and FIG. Twelve configurations are shown and will be described in detail.

As shown in FIG. 8A, the light receiving sections 12a, 1 corresponding to the two images separated by the distance measuring optical system 36.
A plurality of pixels are arranged in 2b. Light receiving units 12a, 1
In 2b, a plurality of pixels are divided into an infrared cut sensor region 101 and a visible light cut region 102, which are two groups, and are arranged every other row.

As shown in FIG. 8B, the IC chip 103 of the AF area sensor 12 is housed in a clear mold package 104.

In the cross-sectional view of the AF area sensor IC 12 shown in FIG. 8C, the photodiodes 105 and 106 as light receiving elements in a plurality of pixels are located in the infrared cut sensor area 101 and the visible light cut sensor area 102, respectively. Yes, it is.

On the front surface of the photodiode 105, the surface of the clear mold package 104 in a region through which the received light beam of the photodiode 105 passes is coated with a dielectric coating multilayer film constituting the infrared cut filter 107.

As shown in FIG. 15B, the spectral sensitivity characteristics of the infrared cut filter 107 are cut off at wavelengths of 700 nm or more.

The visible light cut filter 108 is applied to the surface of the IC chip at the photodiode 106. This visible light cut filter 108 is normally used as an anti-reflection film for suppressing the reflection of the AF area sensor 12 on the surface of the IC chip. As shown in FIG. 15A, the spectral sensitivity characteristic of the visible light cut filter 108 hardly transmits light in a visible light region having a wavelength of 400 to 700 nm, but transmits light in an infrared light region having a wavelength of 800 nm or more. I do.

The visible light cut filter 108 is applied on the photodiode to cut the visible light component and receive only the infrared light component.

Here, the emission intensity wavelength distribution of the infrared light emitting diode 131 is also shown in FIG. 15A, and is located in the transmission region of the visible light cut filter 108.

As shown in FIG. 9, the infrared cut region 1
The configuration of the pixel 50 in 01 includes a photodiode 51 as a light receiving element, a storage capacitor 52 for storing signal charges output from the photodiode 51, and an amplifier circuit for detecting a storage voltage stored in the storage capacitor 52. 53.

The pixel 6 in the visible light cut region 102
The configuration of 0 includes a photodiode 61 as a light receiving element,
It comprises a storage capacitor 62 for storing the signal charge output from the photodiode 61, an amplification circuit 63 for detecting the storage voltage stored in the storage capacitor 62, and a stationary removal circuit 64 for removing the stationary light component. .

The AF area sensor control circuit 54 controls the operation of each part inside the AF area sensor 12 by inputting the integration control signal and the read clock from the microcomputer 11.

The monitor selection circuit 65 creates a monitor signal indicating a peak accumulation amount within a predetermined pixel range according to a command from the microcomputer 11, and outputs the monitor signal from the output unit 66. The microcomputer 11 controls the accumulation operation based on the monitor signal. The read selection circuit 67 controls the horizontal shift register 68 and the vertical shift register 69 according to a command from the microcomputer 11 to set an area from which sensor data is read.

The horizontal shift register 68 and the vertical shift register 69 select a signal output of each pixel via a switch V70 and a switch H71 and output the selected signal from an output unit 72.

The fixed pattern noise removing circuit 73 is a circuit for removing fixed pattern noise contained in the signal output of each pixel. For example, the monitor selection circuit 65 and the readout selection circuit 66 can switch and select both the infrared cut region 101 and the visible light cut region 102.

Here, the flowchart of FIG. 10 and the flowchart of FIG.
The flow of the AF operation will be described in detail with reference to the timing chart of FIG.

First, the AF auxiliary light is projected and the visible light cut area 1 in the AF area sensor 12 is removed while removing the steady light.
02, an integration operation is performed (step S201).

That is, when the integration is started by the integration control signal (see FIG. 11 (b)), the AF auxiliary light is intermittently emitted a plurality of times (see FIG. 11 (d)), and the steady light removing circuit for each pixel. The integration operation is performed while removing the steady light by the operation 64. Then, the monitor selection area is set to the visible light cut area 1
02 (see FIG. 11A), and when the integration monitor signal reaches a predetermined level (see FIG. 11C), the integration operation and the emission of the AF auxiliary light are stopped (see FIG. 11B).

Subsequently, the read area is set as the visible light cut area 102 (see FIG. 11A), and a read clock is output to the AF area sensor 12 (FIG. 11A).
(D), the sensor data (pixel data) of the visible light cut area 102 is output to the ADC 11d (FIG. 11).
(Refer to (e)), perform A / D conversion, and read and store it in RAM 11c (step S202).

The read out visible light cut area 102
Based on the sensor data, a subroutine "main subject detection process", which will be described in detail later, is executed. Then, one or a plurality of ranging areas are set for the area determined as the main subject (step S203).

Then, an integration operation is performed for the infrared cut area 101 in the AF area sensor 12. The monitor selection area and the read area are set as the infrared light cut area 101 (see FIG. 11A), and the integration operation using the steady light is performed (see FIG. 11B) (step S204).

Next, a read clock is output to the AF area sensor 12 (see FIG. 11F), and sensor data of the infrared cut area is read (FIG. 11E).
(See step S205).

Then, the infrared cut area 1 for the plurality of distance measurement areas set in step S203 is set.
The distance measurement calculation is performed using the sensor data No. 01 (step S206).

Here, FIG. 14C shows the distance measurement areas 403 to 403 set in the photographing screen 400 in an area determined as a main subject as a result of main subject detection described later.
405 is shown. The distance measurement calculation is based on a known phase difference detection, and a description thereof will be omitted.

A predetermined condition (presence or absence of reliability) in the selected one or a plurality of selected distance measurement areas (distance measurement data)
Is satisfied, and one or a plurality of distance measurement data are selected from the highly reliable distance measurement data based on a predetermined algorithm (step S207). As the predetermined algorithm, for example, various methods such as close selection using the closest distance measurement data can be considered. Then, the determined distance measurement data is adopted as final distance measurement data.

In this way, it is determined whether or not the subject is in focus (step S208). If the subject is in focus, the process returns. If the subject is out of focus, the process proceeds to step S209. This step S
In step 209, the focusing lens is driven based on the adopted distance measurement data, and the process returns to step S204.

The subroutine "main subject detection" executed in step S203 in FIG. 10 will now be described with reference to the flowchart in FIG.

In the main subject detection process, the detection process is performed particularly assuming a person as the main subject. Although two images are obtained in the visible light cut area 102 by the AF area sensor 12, the image data (sensor data) used for detecting the main subject may be either one of the images or both images. Good.

The sensor data of the AF area sensor 12 is
It is stored in the RAM 11c in the microcomputer 11, and performs the following processing based on the sensor data.

First, a smoothing process is performed (step S30).
1). Here, in the process of removing random noise in the image, the image data (sensor data) is removed by performing a filtering process or a Fourier transform.

Next, difference processing is performed (step S30).
2). Here, a known image edge detection method is used. An edge portion is detected by calculating a difference between adjacent image data (sensor data).

Subsequently, a binarization process is performed (step S3).
03). Here, a binary image is obtained by extracting a portion equal to or more than a predetermined threshold value from the image signal after the difference processing.

Next, a labeling process is performed (step S304). Here, labeling is performed on a cluster of connected portions where pixels having the same luminance value (0, 1) are connected to each other in the binary image. In other words, different labels are attached to different connection portions to distinguish and separate the label regions (connection regions) (see FIG. 14B).

Next, a subroutine "shape determination processing" described later in detail is executed (step S305). Here, the main subject is extracted by determining the shape of the image.

Then, it is determined whether or not the shape determination processing has been performed for one or a plurality of the set label areas (step S306).
Returning to step 305, the process is performed for another label area.

Next, the subroutine "shape determination processing" executed in step S305 in FIG. 12 will be described with reference to the flowchart in FIG.

The area of the label area is the number of pixels belonging to the connected area. The perimeter is the number of pixels located at the boundary around the label area. However, the angle in the oblique direction is corrected to √2 times the horizontal and vertical directions.

To determine the shape of an image, the following coefficient e (shape determination value) is used.

E = (perimeter) ² / (area) In the above equation, e indicates a minimum value when the shape is circular.
The value becomes larger as the shape becomes more complicated. Since the person's face is considered to be almost circular, it is determined whether or not the target image is a person's face by comparing the above e with a predetermined value.

The label area is also compared with a predetermined value to determine whether or not the target image is a person's face. here,
As the predetermined value, a numerical value obtained statistically including individual differences and age is adopted. Hereinafter, the processing flow will be described in detail.

First, the area S of the extraction area (label area) is determined (step S401), and it is determined whether the area S is within a predetermined range (step S402). Next, when the extraction region area S is within the predetermined range, the process proceeds to S403, and when not, the process proceeds to step S406. In step S403, the shape determination value e is calculated. Subsequently, it is determined whether the shape determination value e is within a predetermined range (Step S).
404).

If it is within the predetermined range, step S
The process proceeds to 405, and if it is out of the range, the process proceeds to step S406. In step S405, it is determined that the person is a person, and the result is stored in the memory. Then, step S40
In 6, the subject is determined as a subject other than a person, and the result is stored in the memory.

Thus, the process returns to step S306 in FIG.

FIG. 14 is a diagram showing an example of a photographing scene and a process of detecting a main subject.

When the main subject is detected in the photographing scene of FIG. 14A, steps S301 to S301 of FIG.
As a result of the process 304 (until the labeling process) and the shape determination process (steps S401 to S402 in FIG. 13),
4 (b) is obtained. At this time, label areas 1 to 4 whose areas are within a predetermined range are extracted.

When the processing (steps S403 to S404) relating to the shape determination value e is performed on the image data of FIG. 14B, the label area 1 that matches the main subject 401 (person's face) is determined to be circular. You. That is, in step S405, it is determined that the person (main subject). Further, since the rough subject 402 is not circular, it is determined that it is not a person (main subject). As a result, within the obtained main subject area (label 1), a plurality of ranging areas 403 to
405 is set. The distance measurement results of the plurality of distance measurement areas are combined into one distance measurement data by processing such as averaging processing and closest selection (corresponding to S207 in FIG. 10).

In the above main subject detection, a circular image is detected as a person's face. However, this is only an example, and the present invention is not limited to this, and various methods can be considered.
For example, shape data and image data of a person shape prepared in advance may be detected by a known template matching method.

Alternatively, the movement of the subject may be detected from a plurality of images at different times, and the moving object may be detected as the main subject. As described above, since infrared light is projected for main subject detection, there is an advantage that a person who is a subject is not dazzled because infrared light cannot be seen.

Here, a modification of the first embodiment will be described.

Although the infrared cut filter is formed on the clear mold package by coating in the above embodiment, the infrared cut filter may be attached. Further, instead of the clear mold type, a ceramic package or a glass epoxy substrate type package may be formed on the cover glass by coating or the like. Further, in the AF area sensor 12, the integration operation of the infrared cut region 101 and the visible light cut region 102 is performed separately, but the integration operation may be performed simultaneously. The subject reflected light by the light emission of the infrared light emitting diode 131 is sufficiently blocked in the infrared cut area 101, and does not affect the distance measuring operation of the infrared cut area 101. Thus, the time lag required for the integration operation can be reduced. Further, the main subject may be detected using not only the visible light cut region 102 but also the sensor data of the infrared cut region 101. In this case, there is an advantage that the main subject can be detected even on a long distance side where the emission of the infrared light emitting diode 131 (auxiliary light) does not reach.

Next, the areas of the photodiodes 51 and 61 in the infrared cut area 101 and the visible light cut area 102 of the AF area sensor 12 can be made different.

That is, for example, the visible light cut region 10
By making the photodiode 61 inside 2 larger than the area of the photodiode 51 inside the infrared cut region 101,
Infrared light emitting diode 133 with the same IC chip size
By making the reaching distance of the (auxiliary light) longer, the main subject can be detected with higher accuracy.

A third sensor area having neither an infrared cut filter nor a visible light cut filter in addition to the infrared cut area 101 and the visible light cut area 102 (see FIG. 16).
Will be described. The third sensor region is arranged every two lines together with the infrared cut region 101 and the visible light cut region 102. This third sensor area
Since both visible light and infrared light have sensitivity, the steady light (external light) is the largest, so that distance measurement with low luminance is most advantageous.

Next, a second embodiment of the present invention will be described.

FIG. 17 is an optical path diagram of the optical system of the camera according to the second embodiment.

Here, the description of the common parts with the first embodiment (FIG. 6) will be omitted, and the description will proceed focusing on the characteristic parts.

As shown in FIG. 17, the distance measuring optical system 36
An infrared cut filter 132 is arranged between the field mask 37 and the field lens 38. The infrared cut filter 132 is formed by coating a multilayer film of a dielectric coat on glass.

The finder system includes a beam splitter 13.
A finder light beam 4 is arranged to split the finder light beam, one of which is guided to the eyepiece 34, and the other of which is guided to the second distance measuring optical system 137. The second ranging optical system 137 includes a re-imaging lens 136,
The second AF
The second AF light beam is guided to the area sensor 135.

The structure of the second AF area sensor 135 is such that all the pixels are replaced by the pixels 60 in FIG. However, the visible light cut filter 133 is the second
Since it is arranged in the distance measuring optical system 137, it is not necessary to form a visible light cut filter on the photodiode of the second AF area sensor 135. Visible light cut filter 1
33 is a plastic plate mixed with black dye. Also, since the infrared cut filter 132 is disposed in the distance measuring optical system 36 for the AF area sensor 12,
There is no need to form an infrared cut filter on the package.

The configuration of the AF area sensor 12 is such that all pixels are replaced with pixels 50 in FIG. AF area sensor 12 and second AF area sensor 13
The fields of view 5 are matched, and the pixel positions of both are associated.

Parameters such as the size and pitch of the photodiodes 51 and 61 of each of the AF area sensors 12 and 135 can be independently set, and need not always be the same. Further, the distance measuring optical system 36 and the second distance measuring optical system 13
7, the optical parameters such as the re-imaging magnification can be set independently, and the space and the corresponding AF can be set.
It may be changed according to the area sensor.

Hereinafter, with reference to the flow chart of FIG. 18, the camera distance measuring device A according to the second embodiment will be described.
The F operation will be described in detail.

First, stationary light removal integration by the second AF area sensor 135 is performed while projecting the AF auxiliary light 131 (step S501). Next, sensor data is read by the second AF area sensor 135 (step S502).

Subsequently, main subject detection is performed based on the sensor data of the third AF area sensor 135 (step S503). Then, the normal integration operation is performed by the AF area sensor 12 (step S504).

Next, sensor data is read from the AF area sensor 12. Here, the second AF area sensor 135
Is stored in an area of the RAM 11c different from the sensor data (step S505). Then, a distance measurement operation is performed based on the sensor data of the AF area sensor 12 (step S).
506).

Subsequently, it is determined whether or not detection is possible based on information such as reliability as a result of the distance measurement calculation (step S507).
Here, when it is determined that detection is possible, it is determined whether or not the subject is in focus (step S508). Here, in the case of out-of-focus, the lens is driven based on the amount of lens drive to be focused (step S509). Then, step S504
The operation from is repeated until focusing is achieved.

If the detection is not possible in step S507, a distance measurement calculation is performed based on the sensor data of the second AF area sensor 135 (step S510). Then, it is determined whether or not the distance measurement result can be detected (step S51).
1).

If the detection is possible, the chromatic aberration generated due to the use of the infrared light component as the distance measuring light beam is corrected (step S512). This chromatic aberration correction amount is stored in the EEPROM 11e in advance. Next, focus determination is performed using the distance measurement data after the chromatic aberration correction (step S513), and the process ends when the focus is achieved, and proceeds to step S515 when the focus is not achieved.

Based on the distance measurement data after the chromatic aberration correction, the lens driving amount for focusing is calculated, the lens is driven (step S515), and the steady state by the second AF area sensor 135 while projecting the AF auxiliary light 131 is performed. Light removal integration is performed (step S516), and sensor data is read from the second AF area sensor 135 (step S51).
7). Thereafter, step S510 and the subsequent steps are repeatedly executed until focusing is achieved.

On the other hand, if the detection is not possible in step S511, the flow advances to step S514. Then, it sets an undetectable flag and returns. At this time, the camera performs an out-of-focus display.

As described above, when the distance cannot be detected even when the distance is measured with the stationary light from which the infrared light has been cut, the stationary light is removed and integrated while projecting the auxiliary light of the infrared light. Since the distance measurement calculation is performed based on the distance, it is possible to detect even a low-contrast or low-luminance subject. Also,
By correcting the chromatic aberration error due to the infrared light component,
The same focusing accuracy as in the case of the stationary light can be satisfied.

Next, FIG. 19 shows a configuration of a modification of the second embodiment and will be described.

Here, the description of the common parts with the first embodiment (FIG. 6) will be omitted, and the description will proceed mainly on the characteristic parts.

As shown in FIG. 19, the distance measuring optical system 36 and the second distance measuring optical system 137 are integrally modularized. A dichroic mirror 140 that reflects only infrared light and passes visible light is disposed behind the field lens 38 of the distance measuring optical system 36. Infrared light is pupil mask 1
38, the second AF sensor 1 passing through the re-imaging lens 136
It is led to 35. On the other hand, the visible light that has passed through the dichroic mirror 140 passes through the infrared cut filter 132 and is reflected by the total reflection mirror 141, and is then guided to the AF area sensor 12. The infrared cut filter 132 is formed by coating a multilayer film of a dielectric coat on glass.

The fields of view of the AF area sensor 12 and the second AF area sensor 135 are made coincident, and their pixel positions are associated with each other. Each AF area sensor 12, 135
The parameters such as the size and pitch of the photodiodes 51 and 61 can be independently set, and need not always be the same.

The distance measuring optical system 36 and the second distance measuring optical system 1
Also for 37, the optical parameters such as the re-imaging magnification can be set independently, and the space and the corresponding A
It may be changed according to the F area sensor. Thus, the distance measuring optical system 36 and the second distance measuring optical system 137 can be integrated in the lower part of the mirror box and can be configured in a small space.

In the embodiment described above, the present invention is applied to the TT
Although this is an example in which the present invention is applied to an L-passive type distance measuring device, it is needless to say that the same effect can be obtained by applying to an external light passive type distance measuring device. Although the infrared light emitting diode is used as the AF auxiliary light, the strobe 20a may be used as the auxiliary light.

Further, the type of illumination is predicted by calculating the light amount ratio between the visible light component (infrared cut sensor data) and the infrared light component (visible light cut sensor data and no steady light removal) to predict the fluorescent lamp and the like. In the case of an incandescent light bulb, a strobe can be emitted at the time of shooting to prevent color cast.

[0134]

According to the present invention, it is possible to provide a TTL type distance measuring apparatus capable of accurately focusing on a main subject.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a distance measuring device according to the present invention.

FIG. 2 is a further conceptual diagram of the distance measuring apparatus of the present invention.

FIG. 3 is a further conceptual diagram of the distance measuring apparatus of the present invention.

FIG. 4 is a configuration diagram of a camera employing the distance measuring device according to the first embodiment.

FIG. 5 is a microcomputer 11 of the camera according to the first embodiment.
5 is a flowchart for explaining a main routine of FIG.

FIG. 6 is an optical path diagram of the camera according to the first embodiment.

7A is a distance measuring optical system (phase difference detecting optical system) 36. FIG.
FIG. 2B is a cross-sectional view showing the configuration of FIG. 1, and FIG. 2B is a perspective view showing the configuration of the distance measuring optical system.

8A is a diagram showing a state of a light receiving unit of the AF area sensor 12, FIG. 8B is a diagram showing an overview of the AF area sensor 12, and FIG. It is a figure showing a situation.

FIG. 9 is a diagram showing a configuration of a pixel 50 in an infrared cut area 101.

FIG. 10 is a flowchart illustrating a flow of an AF operation according to the first embodiment.

FIG. 11 is a timing chart showing a flow of an AF operation according to the first embodiment.

FIG. 12 is a flowchart illustrating processing of a subroutine “main subject detection”.

FIG. 13 is a flowchart illustrating a process of a subroutine “shape determination processing”.

14A is a diagram showing a main subject, and FIG.
FIG. 4 is a diagram illustrating a state where a label area is divided, and FIG. 4C is a diagram illustrating distance measurement areas 403 to 405.

15A is a diagram illustrating a spectral sensitivity characteristic of the visible light cut filter 108, and FIG. 15B is a diagram illustrating a spectral sensitivity characteristic of the infrared cut filter 107.

FIG. 16 shows an infrared cut region 101 and a visible light cut region 1
It is a figure for explaining the modification of a 1st embodiment which provides the 3rd sensor field which does not have an infrared cut filter nor a visible light cut filter other than 02.

FIG. 17 is an optical path diagram of an optical system of a camera according to a second embodiment.

FIG. 18 is a flowchart for explaining in detail an AF operation by the distance measuring device of the camera according to the second embodiment.

FIG. 19 is a diagram illustrating a configuration of a modification of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor part 2 First sensor part 3 Second sensor part 4 Infrared cut part 5 Visible light cut part 6 Focus adjustment part 7 Light projection part 8 Steady light removal part

Continued on the front page F-term (reference) 2F065 AA06 DD00 DD04 FF05 FF09 GG07 GG08 GG23 JJ03 JJ05 JJ26 LL12 LL30 NN12 PP22 QQ03 QQ13 QQ14 QQ23 QQ25 QQ34 QQ36 SS13 UU05 2F112 AA09 AC06 FA06 FA03 FA09 FA45 2H051 BA24 CB13 CC03

Claims (4)

[Claims] A first sensor having infrared cut-off means; a second sensor having visible light cut-off means; and a focus adjusting means for adjusting focus based on outputs of the first sensor means and the second sensor means. And a distance measuring device. 2. The apparatus according to claim 1, further comprising a light projecting means for projecting light of a predetermined wavelength onto the subject, wherein said focus adjusting means comprises: an output of said first sensor means when said light projecting means is not operating; 2. The distance measuring apparatus according to claim 1, wherein the means adjusts a focus based on an output of the second sensor means during operation. 3. The distance measuring apparatus according to claim 1, wherein said second sensor means further comprises a stationary light removing means for removing a stationary light component from a received light amount. 4. The distance measuring apparatus according to claim 1, wherein said first sensor means and said second sensor means are formed on the same IC chip.