JPH05256644A - Range finder - Google Patents

Abstract

PURPOSE:To provide a range finder that is able to sight a ranging point clearly in a finder by way of preventing any out-of-focus to be produced by the parallax of both ranging and finder optical systems. CONSTITUTION:This range finder is provided with a second projecting lens 1b emitting a macro-range photographing visible ray and a second projecting element 2b in addition to a first projecting lens 1a emitting a usual photographing infrared ray and a first projecting element 2a. A distance between the second projecting lens 1b and a light receiving element is made nearer than that between the first projecting lens 1a and the light receiving element, thereby setting them so as not to produce any parallax, so that in this range finder, a quantity of light in short-range projection is decreased to a subject in the macro-range photographing and, what is more, a ranging point is made well checkable by means of the visible ray of this visible range projecting element 2b.

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 for measuring a distance by using light, and more particularly, an active device for projecting pulsed light toward a subject and detecting the subject distance based on the reflected light from the subject. Type distance measuring device.

[0002]

2. Description of the Related Art Generally, there are roughly two types of autofocus (hereinafter abbreviated as AF) devices used in still cameras and video cameras. One is a passive method that uses the luminance distribution information of the subject, and the other is an active method that projects signal light from the camera toward the subject and measures the distance according to the reflected light from the subject.

The passive system has been developed by being mounted on a single-lens reflex type camera whose photographing lens is also used as a finder optical system. However, the so-called TTL passive AF, which uses the subject light that has passed through the taking lens for distance measurement, has a complicated structure and is expensive, and it is costly to employ it in a small popular machine such as a compact camera. It was difficult. Therefore, the active-type AF, which has a low-cost and simple structure and is composed of a finder optical system and a photographing lens as separate bodies, is often used in so-called compact cameras and the like.

[0004]

However, in the active AF described above, when a general compact camera is viewed from the front, an AF lens is provided in parallel in addition to the taking lens and the finder objective lens. .. Depending on the layout position of these lenses, depending on the subject seen in the viewfinder,
A slight shift (hereinafter referred to as parallax) may occur between the subject to be actually photographed, that is, the subject to be focused. The parallax will be described with reference to FIG.

As shown in FIG. 10 (a), the eyes 1 of the projector
When looking into the viewfinder eyepiece lens 11 at 4, the measurement mask 12 provided between the viewfinder eyepiece lens 11 and the objective lens 13 is projected in the vicinity of the center of the viewfinder field frame 17 and is visually recognized as the distance measuring frame 15a.

On the other hand, the distance measuring light projected by the light projecting element 2 projected through the light projecting lens 1 is projected as shown in the drawing and crosses the distance measuring frame 15a at a predetermined distance dA. Therefore, in general, for a subject at a distance of 2 to 3 m, which is frequently photographed, the spot position 16 of the distance measuring light is used.
Since a is projected in the frame of the distance measuring frame 15a, the photographer can obtain a good focus by putting the subject to be photographed in the distance measuring frame 15a and photographing.

However, in the active AF, when an object present at a distance dB that is considerably shorter than the predetermined distance dA is photographed, the AF is measured due to the difference between the positions of the distance measuring optical system and the finder optical system. Distance light spot position 1
6b largely deviates from the inside of the distance measuring frame 15b. Therefore, no matter how much the photographer puts the subject in the distance measuring frame 15b, the focused position cannot be taken because the spot position actually measured is 16b.

As one of the measures against this parallax, FIG.
As shown in FIG. 0 (b), there is a camera provided with another dotted line distance measuring frame 15c in the finder at a short distance. However, there is no criterion for determining from which area the dotted line distance measuring frame 15c should be used, and it must be based on experience. Moreover, two distance measuring frames were displayed at the same time, making it difficult to see.

Further, as shown in FIG. 10 (c), it may be possible to switch the distance measuring frames and display only one by moving the distance measuring frames by liquid crystal or the like according to the parallax. .. In order to perform such a display, first, the camera itself has a complicated structure in which the distance measured by the camera is currently known, and the display is switched according to the distance, which further increases the cost.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a distance measuring device which prevents out-of-focus caused by parallax of a distance measuring optical system and a finder optical system and enables a distance measuring point to be clearly visible in the finder. And

[0011]

In order to achieve the above object, the present invention receives first light projecting means for projecting a light beam to an object and light reflected from the object by the light beam, A light receiving unit that outputs a photoelectric conversion signal and a distance detecting unit that detects a distance to the subject based on the photoelectric conversion signal are provided, and a line connecting the first light projecting unit and the light receiving unit is close to the line. A second light projecting means for distance detection is provided, and the second light projecting means is provided.
To provide a distance measuring device for projecting visible light.

[0012]

The distance measuring device having the above-described structure has the two light projecting elements, the first light projecting element for the long distance (normal) and the second light projecting element for the short distance, and the second light projecting element. The distance between the element and the light receiving element is
The distance is smaller than the distance between the first light projecting element and the light receiving element, and it becomes possible to measure the distance at a shorter distance.
The point of distance measurement is confirmed by circling the point light in the visible range of the emission wavelength of the light projecting element.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1A is a block diagram showing the configuration of a distance measuring device as a first embodiment according to the present invention. This distance measuring device is composed of two projection systems, one for long distance (normal) and one for short distance, and one light receiving system.

First, the light projecting element 2a projects infrared light through the light projecting lens 1a to the object 20a located at a long distance, and the light receiving lens 9 receives the reflected light from the object 20a.
The light is received by a light receiving element 8 such as a PSD via the, and the distance is calculated by an output processing circuit (AFIC) 7.

Similarly, for a subject 20b located at a short distance, a light projecting element 2b driven by a driver 3b projects visible light for distance measurement through a light projecting lens 1b. Then, the reflected light from the subject 20b is received by the light receiving element 8 via the light receiving lens 9, and the output processing circuit (AFI
C) Calculate the distance in 7.

The light-projecting system for short-distance distance measurement includes light-projecting and light-receiving lenses 1a and 9 forming a known light-projecting triangulation distance measuring device.
It is arranged at a position closer to the light receiving element side than the distance between the light emitting element and the light receiving elements 2a and 8. Further, the CPU 5 controls the sequence of the entire camera and the sequence of the distance measuring device. FIG. 1B shows the result of calculating the two output signals of the PSD by the AFIC, by configuring the light receiving element 8 with a known optical position detecting element PSD.

As shown in this figure, in the range where the reflected signal light is detected on the PSD, the IC output is the reciprocal V of the distance.
proportional to d. However, at a shorter distance, the reflected signal light deviates from the detection range on the PSD 8, loses linearity as shown in the figure, and correct distance measurement cannot be performed.

As shown in FIG. 1C, when the light receiving element is closer to the light projecting element, the distance can be measured up to a closer short distance without loss of linearity. As shown in FIG. 2b
The 1 / d-to-IC output by the light projecting element 1 and the 1 / d-to-IC output by the light projecting element 1 have a linear region to a shorter distance when the light projecting element 2b is used. However, on the contrary, since the inclination of the straight line is small, even if a predetermined accuracy can be obtained in the short-distance macro area where a sufficient S / N is secured, it is more accurate to use the light receiving element 2a in a general photographing area. Is preferable.

With respect to the selection of these light projecting elements, when the distance dN is measured, the distance measured by the light projecting element 2a exceeds the range in which the distance can be measured, and it is distinguished from the distance dF similarly detected. In this case, the light projected by the light projecting element 2b is used for distance measurement. That is, the distance is measured by the light projecting element 2b, and when the IC output at a distance longer than the predetermined distance is obtained, the distance is measured by the light projecting element 2a.

FIG. 2 shows a concrete circuit of the output processing circuit (AFIC) 7 of the distance measuring apparatus of the first embodiment. Here, of the constituent members in FIG. 2, the same constituent members as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 2, the baseline length between the light projecting lens 1b and the light receiving lens 9 is s, and the focal length of the light receiving lens is f, P.
Assuming that the distance from the light-projecting end surface of SD8 to the optical axis of the light receiving lens 9 is a and the distance from the optical axis to the signal light incident position is x, the subject distance (focusing distance) d is x = sf / d ... It is shown by the relationship of (1).

The two current signals that are shunted and output according to the signal light incident position on the detection surface of the PSD 8 are AFI.
It is input to the low-impedance preamplifiers 21 and 22 of C7, amplified, and then flows into the compression diodes 23 and 24. Current I1 flowing into these diodes 24, 23
, I2, where t is the total length of the detection surface of the PSD 8, I1: I2 = (a + x): {t- (a + x)} (2).

[0023]

[Equation 1] And the reciprocal 1 / d of the subject distance d is calculated.

The potentials VA and VB of the compression diodes 24 and 23 are input to the operation calculation circuit composed of the transistors 27 and 28 and the constant current source 29 via the buffers 25 and 26. The following relationships are established between the currents Ia and Ib flowing through the transistors 28 and 27 and the currents I1 and I2 flowing into the diodes 24 and 23.

[0025]

[Equation 2]

Here, Is is the diode 23, 2
4. The reverse saturation current of the transistors 27 and 28, and VT is a thermal voltage. Then, from the difference between the expressions (4) and (5), the relationship of I1 / I2 = Ia / Ib (6) is derived. By the way, since the constant current value I0 supplied by the current source 29 and the currents Ia and Ib flowing through the transistors 28 and 27 satisfy the relationship of Ia + Ib = I0,

[0027]

[Equation 3] Becomes Therefore, from the above equation (3),

[0028]

[Equation 4]

Thus, Ia can be known, and the subject distance d can be calculated by the CPU 5. In this example,
The LED 2 is caused to emit light a plurality of times, and the current source 29 is made conductive each time the LED 2 emits light.
Is integrated to improve the accuracy and the current Ia is converted into a voltage. As a result, the CPU 5 reads the converted voltage with the built-in A / D converter. The reset circuit 31 initializes the integration capacitor 30 at the start of integration. When the capacitance value of the integration capacitor 30 is CINT, the integration time for one time is tINT, and the number of times the LED 2 emits light is n, the integration output Vd is

[0030]

[Equation 5] Becomes In the above equations, except for the subject distance d,
The CPU 5 can obtain the subject distance d from the integrated output Vd. Then, when the light projecting lens 1b and the light projecting element 2b are driven via the driver 3b, if the distance between the principal points between the light projecting lens 1b and the light receiving lens 9 is sb, the formula (9) is

[0031]

[Equation 6] By changing all s to sb in the equation (1) and subsequent equations, it is possible to obtain mathematical expressions relating to distance measurement such as light emission of the light projecting element 2b. For example, in the formula (1), if the limit of x that can be measured by the PSD 8 is xmax, and the closest limit distances that can be measured by each light projecting element are dmin1 and dmin2,

[0032]

[Equation 7] However, since s> sb as described above, the relationship of dmin1 <dmin2 (12) holds, and the relationship of FIG. 1 (b) is proved. Further, since the expressions (9) and (10) are expressions proportional to s · f or sb · f, it is also proved that there is a difference between the slopes of the two straight lines in FIG. 1 (b). Next, the operation of the distance measuring device having the PSD shown in FIG. 2 will be described with reference to the flowchart in FIG.

First, it is detected whether or not the 1st switch that operates when the release button of the camera is half pressed is turned on (step S1). When this switch is turned on, short-distance measurement is performed by the LED 2b capable of measuring a shorter distance (step S2).

It is determined whether or not the object distance db obtained by this distance measurement is within a preset range of, for example, 1 m (step S3). In this determination, the subject distance db is 1
If the distance is longer than m (NO), in order to obtain sufficient accuracy in the distance measurement value, the normal (long distance) distance measurement is performed by the IRED 2a as described above, and the distance measurement value da is obtained (step S4).

At this time, the release button is pushed in two times.
It is detected whether the nd switch is turned on (step S
5) If the detection is detected (YES), the distance measurement value da is set to the focal length d (step S6), and then photographing or exposure is performed (step S7), and the camera photographing sequence ends.

If the 2nd switch is not turned on in step S5 (NO), it is determined whether the 1st switch is turned on (step S8). If the 1st switch is turned on (YES), the process returns to step S5. , If off (NO), the process returns to step S1. This step S8
When the 2nd switch is not turned on and the 1st switch is also turned off, there is no intention of the operator (photographer) to photograph,
Assuming that the finger is released from the release button, the process returns to step S1 in the initial state, waits for a shooting opportunity, keeps the shutter half pressed (1st switch is on), and the photographer waits Assuming that, the current situation will be maintained. The above operation is a normal (long-distance) distance measurement.

However, when the subject is closer, as a feature of the present invention, the subject distance db obtained by the distance measurement in the determination of step S3 is within a preset range of 1 m. If it is determined that the distance is within the range (YES), the LBD 2b of the visible light used for the distance measurement is continuously turned on (step S9), and the photographer visually confirms the portion measured by the camera through the viewfinder. be able to.

That is, as described above, parallax is likely to occur in distance measurement at a closer distance, but the photographer can visually check through the finder to confirm the distance-measured portion. For example, when shooting a small insect or a flower, when the user wants to get close to the object and shoot a large image, the distance measuring point can be visually checked and the object can be focused.

Such continuous lighting is continued until the 2nd switch is pushed (step S10) or the 1st switch is turned off (step S11). If the 2nd switch is turned on (YES), the subject distance db measured last time is set to the in-focus distance d (step S
12, S6), exposure is performed (step S7), and the short-range shooting sequence ends.

As described above, in the distance measuring apparatus of the present invention, when the photographer shoots in the macro range, the release button can be pressed while confirming whether the distance measuring spot correctly hits the subject. When the distance spot does not correctly hit the desired subject, the release button is released again, and the release button is pressed again to measure the distance.

As described above in detail, by using the distance measuring device of the present invention, it is possible to confirm the distance measuring spot for focusing on a desired object which is unknown in the conventional compact camera due to parallax. became.

In particular, in focusing in the macro range, even if the focus is a little off, it will greatly affect the quality of the photograph. In the past, small insects and flowers could not be focused, and the photograph was taken with a mere intuition. However, by using the distance measuring device of the present invention, defocusing can be prevented. Next, FIGS. 4 and 5 show an example of a configuration in which the distance measuring device of the first embodiment is actually built in a camera.

Looking at the camera from the front as shown in FIG.
A taking lens 42 is arranged in the center of the camera body 41, and a finder objective lens 13 is arranged above the taking lens 42. Further, from the right side of the finder objective lens 13, a projection lens 1b for short distance measurement,
A light projecting lens 1a for normal distance measurement is arranged, and a light receiving lens 9 is arranged on the left side of the finder objective lens 13. A release button 40 is provided on the upper surface of the camera body 41.

As another example, as shown in FIG. 5A, a projection lens 1a for normal distance measurement is arranged on the right side of the finder objective lens 13, and the light is received from the left side of the finder objective lens 13. The lens 9 and the light projecting lens 1b for short-distance measurement are sequentially arranged. FIG. 5B shows the arrangement of the light projecting system and the light receiving system.

If the second light projecting system is added to the conventional distance measuring device having only one light projecting system in order to provide such two light projecting systems, the cost increases and the distance measuring device becomes complicated and large. Stylization occurs.

However, in the distance measuring apparatus of the present invention, since the second light projecting system uses visible light, it is also used as the display LED when the self-timer is used, or from the retina of the subject during strobe photography. The reflected light of the red light is also used as an LED for reducing the so-called red-eye phenomenon, which simplifies the distance measuring device and suppresses the cost increase.

Next, the operation of an example in which the above-mentioned red-eye reducing LED is also used as the second light projecting system for short distance measurement of the present invention will be described with reference to the flowchart of FIG. here,
The flowchart of FIG. 6 is to be inserted between step S1 and step S2 of the flowchart shown in FIG. 3, and when performing the same operation below, the same step numbers are given and the subsequent description is omitted. To do.

First, the photographer half-presses the release button to turn on the 1st switch to detect whether or not the photographing operation is started (step S1). When the 1st switch is turned on (YES), photometry of a shooting scene is performed by a photometric circuit (not shown) incorporated in the camera (step S20), and the result obtained here is compared with a preset BV value. It is determined (step S21), and BV is determined by the determination.
If is less than 3 (YES), the red-eye reduction LED is continuously turned on (step S22).

Here, the red-eye phenomenon is a phenomenon in which the pupil of the human eye opens in a dark place, and when strobe light is irradiated, the amount of the light reflected from the leash increases and the eye becomes red. The red-eye reduction LED is
By irradiating strong light, the pupil of the subject is made smaller and the red eye phenomenon is reduced. The operations after step S22 are the same as those of step S2 in FIG. 3, the exposure is performed, and the sequence of the photographing operation is completed. As described above, this is an example in which the LED 2b that emits light in order to reduce the red-eye effect is used for short-distance measurement.

Since short-distance (macro) shooting is easily affected by camera shake during exposure, the self-shooting mode is used, and after a predetermined time has elapsed after pressing the shutter,
A photographing method such as exposure is effective.

FIG. 7 shows an example in which a photographing method generally called focus lock is combined with the above-mentioned self photographing mode photographing. Further, when the photographer is considering photographing with the composition as shown in FIG. 7B, in a camera having a distance measuring frame only in the central portion of the screen, first the image shown in FIG. Hold the camera as shown in a), press the release button halfway in this state, and then make the desired composition in the state of FIG. 7B, and press the release button to expose. At this time, if you start exposure immediately, camera shake will occur,
Exposure may be performed after the shutter button is pressed and a predetermined time has elapsed.

The operation of an example in which the distance measuring apparatus of the present invention is equipped with the self-mode function that enables the above-described photographing method will be described with reference to the flowchart of FIG. Here, in the flowchart of FIG. 8, when the same operation as that of the flowchart of FIG. 3 is performed, the same step numbers are given and the description thereof is omitted.

First, when it is detected that the release button is half-pressed (the 1st switch is turned on) (step S1), it is determined whether the self mode is set by a manual switch or the like (step S30). If the self mode is not set in this determination (NO), step S2 of FIG.
Then, the same operation as that described below is performed, and the photographing is ended. If the self mode is set in step S30 (Y
ES), start timer counting (step S31),
Short-distance measurement is performed by the LED 2b (step S
32), the object distance db1 obtained here is input to the CPU 5.

At that time, by pressing the release button, 2
It is detected whether the nd switch is turned on (step S
33) If the 2nd switch is off (NO), 1s
The state of the t switch is confirmed (step S34), and the 1s
If the t switch is in the ON state (YES), it is maintained at step S33, and if it is OFF (NO), the process returns to step S1 in the initial state.

If the 2nd switch is turned on in step S33, the length of the timer count time T1 is compared with the set time Tx (step S35). here,
For example, assuming that the set time Tx is about 2 seconds, the release button is pressed once in normal self-shooting, so the set time Tx is less than or equal to (NO), and the LED 2b blinks strongly to make a distant subject recognize the self-mode. While doing so, a timer count T2 of about 12 seconds is performed (step S3
6).

After the counting, in normal self-photographing,
In order to photograph a subject that is generally farther than the distance (for example, 1 m) that can be measured by the LED 2b, the distance is measured by the IRED 2 (step S37), and then the process proceeds to step S11 shown in FIG. 3 to perform exposure. ..

However, in step S35, if T1 is 2 seconds or more (YES), it is assumed that the composition changing operation as shown in FIG.
On the other hand, focusing is desired (step S38), the same LED blinking is performed in step S36, and after a predetermined time (step S39), exposure is performed. However, step S39
Is considered to be the macro region shooting shown in FIG.
It is useless to project light, and the light can be a detriment to shooting when shooting insects and animals, so the LED can be weakened.

Next, the block diagram of FIG. 9 shows an example of the structure of the distance measuring device of the AF camera capable of performing the self-mode photographing described above. Here, in the constituent members of FIG. 9, the same members as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. This distance measuring device includes first and second projectors 50 and 6
0, a distance light receiver 51, switches 57, 58 and 59, and a CPU 5 to which the respective members are connected.

The first light projector 50 is composed of the light projecting lens 1a, the light projecting element 2a, the driver 3a, etc. shown in FIG. 2. Similarly, the distance measuring light receiver 51 is an output processing circuit (AFIC). 7, PSD 8, and light-receiving lens 9 and are connected to the CPU 5, respectively.

The switch 57 is closed when the release button is pressed halfway, that is, when the 1st switch is pressed, and the switch 58 is closed when the 2nd switch is pressed. The switch 59 is a self-mode setting switch, and the on / off state of the switch 59 is set by the CPU.
5 is detected. The CPU 5 has a function of determining a distance measurement result and a timer count function, and each switch 57, 5
On / off timing detection of 8, 59 and time counting such as self-shooting are performed.

Similarly, the second light projector 60 is composed of a light projecting lens 1b, a light projecting element 2b, a driver 3b and the like. Here, the optical system is omitted and the driver 3b is shown in detail. That is, the LED 2 that projects visible light for distance measurement
The light amount of b is a driver that switches by photoelectrically converting it into a drive current, and the LED 2b is driven by the collector current of the transistor 52. The value of this collector current is the constant voltage source Vref and the operational amplifier 61.
And a feedback circuit formed by resistors 54 and 55.
Turning on / off of the transistor 56 switches the resistance value connected between the negative (−) side input of the operational amplifier 61 and the ground. When the current IF flowing in the LED 2b and the resistance value are R,

[0062]

[Equation 8] Is decided.

Then, the transistor 53 controls the base potential of the drive transistor 52 to generate an LED.
Control on / off of 2b. Therefore, in FIG.
The CPU 5 may control the operations of the transistors 56 and 53 in order to make b blink strongly or weakly.

In the present embodiment, the two types of light-emitting elements used have the wavelengths emitted by one of the visible light and the other by infrared light, and these elements are assumed to be light emitting diodes. Therefore, a light receiving element including a wavelength common to each other and capable of detecting a wavelength in this region is used. Further, the first light projecting system may emit visible light as long as the light intensity is satisfied.
In general, since the efficiency of the LED is higher in the infrared region, infrared light emission is assumed in this embodiment.

Therefore, in the distance measuring apparatus of the present invention, as shown in FIG. 10, the finder B and the light projecting lens 1 are conventionally separate bodies, so that the parallax is always large at a short distance. , A second distance-measuring projection system for short-distance measurement is prepared separately, or it is also used as a lamp to reduce the red-eye phenomenon that occurs during flash photography, and the user can see the position of the spot with visible light. In particular, the focusing rate is significantly improved especially in the macro range.

Further, by making the distance between the second light projecting element and the light receiving element smaller than the distance between the first light projecting element and the light receiving element in the present invention, the distance can be measured at a closer distance, and the macro It is possible to provide a distance measuring device suitable for distance measuring in the range. As described above, according to the distance measuring device of the present invention,
It is possible to provide an AF camera capable of performing appropriate short-distance shooting of insects, flowers, etc. with a simple configuration without increasing the cost. Further, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and applications can be made without departing from the scope of the invention.

[0067]

As described above, according to the present invention, the out-of-focus caused by the parallax of the distance measuring optical system and the viewfinder optical system is prevented, and the distance measuring point is clearly visible in the viewfinder. A device can be provided.

[Brief description of drawings]

FIG. 1 (a) is a block diagram showing a configuration of a distance measuring device as a first embodiment according to the present invention, and FIG.
FIG. 1 is a diagram showing a relationship of 1 / d to IC output by each light projecting element, and FIG. 1C is a diagram showing an arrangement of each light projecting element and a light receiving element.

FIG. 2 is a diagram showing a specific circuit of an output processing circuit (AFIC) of the distance measuring apparatus according to the first embodiment.

FIG. 3 is a flowchart showing an operation of the distance measuring device shown in FIG.

FIG. 4 is a diagram showing a configuration example of the distance measuring device of the first embodiment built in a camera and seen from the front.

FIG. 5 (a) is a diagram showing a second configuration example of the distance measuring device according to the first embodiment incorporated in a camera as seen from the front, and FIG. 5 (b) is a projection diagram thereof. It is a figure which shows arrangement | positioning of an optical system and a light receiving system.

FIG. 6 is a flowchart for explaining the operation of an example in which the second short-distance-distance light projecting system of the present invention also serves as a red-eye reduction LED.

7A and 7B are diagrams showing the composition in the finder when the focus lock and the self-shooting mode are combined.

FIG. 8 is a flowchart for explaining the operation of the distance measuring device equipped with the self-mode function.

FIG. 9 is a block diagram showing a configuration example of a distance measuring device equipped with a self-mode function.

FIG. 10 is a diagram showing an arrangement of light projecting and light receiving systems for explaining parallax.

[Explanation of symbols]

1, 1a, 1b ... Projection lens, 2, 2a, 2b ... Projection element (IRED, LED), 3, 3a, 3b ... Driver, 4 ... Timing circuit, 5 ... CPU, 7 ... Output processing circuit (AFIC) ), 8 ... Light receiving element (PSD), 9 ... Light receiving lens, 11 ... Viewfinder eyepiece lens, 12 ... Measurement mask, 13 ... Objective lens, 14 ... Projector's eye, 15a, 1
5b, 15c ... Distance measuring frame, 16a, 16b ... Spot position, 17 ... Viewfinder frame, 20a, 20b ... Subject, 21, 22 ... Preamplifier, 23, 24 ... Compression diode, 25, 26 ... Buffer, 27, 28, 52,5
3, 56 ... Transistor, 29 ... Constant current source, 30 ... Integrating capacitor, 31 ... Reset circuit, 40 ... Release button, 41 ... Camera body, 42 ... Taking lens, 5
0 ... 1st light projector, 51 ... Distance light receiver, 57, 58, 5
9 ... Switch, 60 ... Second light projector, 61 ... Operational amplifier.

Claims (1)

[Claims] 1. A first light projecting means for projecting a light flux onto an object, a light receiving means for receiving reflected light of the light flux from the object and outputting a photoelectric conversion signal, and the photoelectric conversion signal A distance measuring device including a distance detecting means for detecting a distance to the subject based on a line connecting the first light emitting means and the light receiving means with a second light emitting means for detecting a short distance. And the second light projecting means is
Distance measuring device characterized by projecting visible light.