JP2002357762A - Camera with zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the detection and the control of a zoom position with high resolution regardless of the characteristic change of a zoom encoder caused by temperature change or secular change in spite of simple and compact structure. SOLUTION: By providing an area where reflectance is discontinuously changed at a part of a seal 3 stuck to the lens frame 4 of a zoom lens 2 so that the reflectance may be changed corresponding to the turning amount of the lens frame 4, the detection and the control of the zoom position in an area where the reflectance is continuously changed are performed by setting output from a photoreflector 5 in the area where the reflectance is discontinuously changed as reference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a camera with a zoom lens, and more particularly to a zoom position detection of a camera with a zoom lens.

[0002]

2. Description of the Related Art Conventionally, compact cameras equipped with a zoom lens and capable of freely selecting an angle of view for photographing are increasing.

[0003] In addition, miniaturization of zoom lenses of compact cameras has progressed, and accordingly, simplification of zoom position detection is also required. However, a change in focus position due to zooming tends to be large, and high-precision zoom position detection is required.

In order to meet such a demand, a zoom position detecting technique which is structurally simple but has high accuracy has been proposed in Japanese Patent Application Laid-Open No. 5-45179 and Japanese Patent No. 2997409. That is, in the former, a non-contact type zoom encoder that projects light on a reflector and detects a zoom position based on the reflected light has a high reflectance area (white).
And a light-shielding area (black). The zoom lens includes a reflector that has a continuously changing area ratio between the two areas according to zooming of the zoom lens. There is disclosed a non-contact type zoom encoder having a simple structure for detecting the position of the zoom lens and detecting the zoom position. In the latter, according to zooming of the zoom lens, light is projected on a reflector that continuously changes the reflectance, and the reflected light is detected using a photo reflector,
A non-contact type zoom encoder having high zoom position resolution for performing zoom position detection is disclosed.

[0005]

However, the zoom encoder disclosed in Japanese Patent Application Laid-Open No. 5-45179 has only two regions, a high reflectivity region and a light-shielding region, so that the zoom position cannot be adjusted very finely. And
Since the deviation between the position of the photoreflector and the position of the reflector greatly affects the result of the zoom position detection, there is a possibility that the detection accuracy of the zoom position may be deteriorated even if the zoom is repeated.

Further, the zoom encoder disclosed in Japanese Patent No. 2997409 uses a reflector that continuously changes the reflectance in the entire region from the wide end to the telephoto end. In this case, an adjustment process for performing reference positioning is necessary in advance, which may lead to an increase in cost and a possibility that the detection accuracy of the zoom is deteriorated due to a temperature change or a change over time after the adjustment.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to accurately detect a zoom position and perform zooming even if the characteristics of a zoom encoder change due to a temperature change or a change over time while maintaining a high zoom position resolution. An object of the present invention is to provide a camera with a zoom lens capable of performing position control.

[0008]

In order to achieve the above object, a camera with a zoom lens according to the present invention includes a zoom lens and an area where the reflectance changes continuously in response to zooming of the zoom lens. A reflector having, light projecting means for projecting light toward the reflector, light receiving means for receiving light reflected from the reflector, and zoom position detecting means for detecting a zoom position from an output of the light receiving means. Wherein the reflector has a region in which the reflectance varies discontinuously in a part of the reflector.

That is, a camera with a zoom lens according to the present invention, in a zoom encoder having a reflector for continuously changing the reflectance in response to zooming of the zoom lens, changes the reflectance at a specific position discontinuously. By that
The reflectance of the discontinuous region can be set as a reference reflectance.

Further, in order to achieve the above object, a camera with a zoom lens according to the present invention is characterized in that the continuous reflection is performed based on a zoom position detection result in an area where the reflectance changes discontinuously. A zoom position calculating means for calculating a zoom position in an area where the rate changes is further provided.

Therefore, it is possible to adjust the zoom position in the area where the reflectance changes continuously by using the reference reflectance, so that the characteristics of the zoom encoder change due to a temperature change or a change with time. Even if this occurs, accurate zoom position detection and zoom position control can be performed.

[0012]

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

[First Embodiment] FIG. 1 is a diagram showing an internal configuration of a camera with a zoom lens according to a first embodiment.

That is, the camera with a zoom lens according to the first embodiment comprises a camera body 1 and a zoom lens 2 attached to the camera body 1. A seal 3 having a characteristic whose reflectance varies depending on the position on the seal is attached to a lens frame 4 of the zoom lens 2. Note that the seal 3 corresponds to the above-mentioned reflector.

Here, when the zooming operation is performed, the main body 1
The motor 11 attached to the motor rotates, thereby
The mirror frame 4 rotates, and the seal 3 attached thereto is rotated.
Also rotates in the direction in which the reflectance changes. Therefore, the zoom position can be detected by detecting the reflectance of the seal 3. Specifically, light is projected onto the seal 3 from the photo reflector 5 which is a light emitting and receiving element, and the reflected light from the seal 3 is received by the photo reflector 5, so that the zoom position can be detected from the output. Become.

The zooming operation of the camera will be described with reference to FIG.

FIG. 2 is a diagram showing a zooming operation of the camera with a zoom lens according to the first embodiment.

In general, a small camera is carried with the entire zoom lens 2 collapsed in the camera body 1 as shown in FIG.

At the time of photographing, by operating the power switch 10, the zoom lens 2 is extended from the retracted state to the set-up state, as shown in FIG. 2B.
In this state, the zoom lens is located at a position where it can be optically photographed, and pressing the release button 9 enables photographing at the wide end.

When the telephoto side 7 of the zoom switch is pressed after the setup operation, the lens is extended toward the telephoto side, and a photograph can be taken up to the telephoto end as shown in FIG.

That is, when the operation of the zoom switch is stopped halfway, photographing can be performed at an angle of view between the wide end and the tele end. In the optical design, shooting is guaranteed only at the angle of view between the wide end and the tele end, so that accurate zoom position control for the wide end and the tele end and the zoom position when the zoom is stopped It is important to correct the focus position by detecting.

The above-described zoom position detection and zoom position control will be described in more detail with reference to FIG.

In the camera with zoom according to the first embodiment, a photo reflector (PR) 5 for projecting and receiving light, a photocurrent detecting means 6 for detecting an output of the photo reflector 5, Zoom switch (tele side 7, wide side 8), release button 9, power switch 10,
A motor 11, a motor driving means (MD) 12 for driving the motor 11, an arithmetic and control circuit (CPU) 13 including a one-chip microcomputer, a nonvolatile memory 14 for storing various adjustment values and parameters, and measuring a distance to a subject Distance measuring means (AF) 15, focusing lens (not shown)
Control (LD) control means (LD) 1 for controlling the lens
6. Here, PR5 corresponds to the light projecting means and the light receiving means. Further, the CPU 13 corresponds to the zoom position calculating means.

The CPU 13 controls the sequence of the entire camera, and performs zoom control in accordance with the input state of the telephoto side 7 or the wide side 8 of the zoom switch. At the time of the zooming operation by the zoom control, the light projected by the PR 5, for example, the infrared light, is reflected by the seal 3 with different reflectivity according to the amount of rotation of the lens frame 4. The reflected optical signal is received by PR5 again. P
The output photocurrent of R5 is input to the photocurrent detection means 6, and the output photocurrent is converted into a voltage. The output photocurrent converted to a voltage is input to the CPU 13, and at this time,
The digital data is converted into digital information by an A / D converter (not shown) built in the digital camera 3 and detected as digital information. Then, the CPU 13 determines the reflectance of the seal 3, that is, the amount of rotation of the lens frame 4, that is, the zoom position using the digital information.

When the photographer presses the release button 9, the CPU 13 controls the AF 16 to measure the distance between the photographer and the subject 100, and captures the distance measurement result L. Then, a focusing position is determined from the determined zoom position and the captured distance measurement result, and the focusing lens is controlled to be extended through the LD 16.

The present embodiment is used as compensation when the output of PR5 changes in temperature or with time, or when the positional relationship between PR5 and seal 3 changes due to an impact or the like applied to the camera. Uses a seal 3 as shown in FIG. That is, an area 31 having a minimum reflectance (for example, black) and an area 32 having a maximum reflectance (for example, white or silver) are provided in a section from the retracted position to the setup position,
In the section from the wide end (W) to the tele end (T), the area 33 in which the reflectance changes continuously is constituted by using, for example, printing.

In the seal 3 having the region 33 where the reflectivity changes continuously, the calibration region 30 (the regions 31 and 32) where the reflectivity greatly changes corresponds to the region where the reflectivity changes discontinuously. The calibration is performed in the calibration area 30. That is, at the time of setup as shown in FIG.
_0, it detects the output i ₁ of PR5 in the largest region 32 performs the zoom position control and the zoom position detected based on this. Therefore, FIG.
Thus, even if the output characteristic of the PR5 changes as indicated by the one-dot chain line, correct zoom position control and zoom position detection can be performed.

That is, since there is a large change in the reflectance from low to high (from black to white), PR5
Even if the threshold level i _1/2, which is the output change determination criterion, slightly changes, it is possible to determine whether the output is high (H) or low (L). Is determined, the outputs i ₀ and i ₁ , which are outputs at that time, are detected. Then, when the output of the PR5 is changed to i _2, which will be described later, from i _1, and the position and the wide end, is intended to stop the set-up.

Further, in the region 33, configured such that the reflectance of the seal 3 is continuously changed, so that so as to continuously change the level of i ₃ from the output of the PR5 is i _2, this part Allows continuous zoom position determination.

That is, at the wide end (W), the reflectivity is set such that the output of the photoreflector 5 is at the level of i _{2 which} can be calculated from the equation i ₂ = i ₀ +0.8 (i ₁ −i ₀ ). Keep it. In this way, even if i ₀ and i ₁ change due to a temperature change, a change over time, or the like, zoom position control can be correctly performed by calculation.

On the other hand, at the telephoto end, i ₃ = i ₀ +0.
It is set to 2 _(i 1 -i ₀₎ level to become such reflectance _{i 3} can be calculated by the formula. If the reflectivity is set to such a value and the zoom is stopped when the output i of the photoreflector 5 reaches this value, focus cannot be adjusted or the mechanical load increases, and the mechanism is destroyed. Such a situation can be prevented.

At the time of focusing, after the distance measurement result is detected by the AF 15, i ₁ , i ₀ at the time of the above-mentioned setup is performed.
The focus position is determined in accordance with the zoom position information obtained in accordance with i ₂ , i ₃ calculated at the time of detection and the output i of PR5 at the time of photographing, and the LD 16 controls the extension of the focus lens according to this.

The above-described zoom position detection and zoom position control will be described in more detail with reference to FIGS.

When the power switch 10 is turned on by the photographer (step S1), the CPU 13 starts shifting from the retracted state to the set-up state. At this time, since the seal 3 has a large change in reflectance, the level of the output of the PR5 can be determined based on a threshold level i _{1/2 that} can be set in advance without any particular adjustment. So, first, this threshold level i ₁
The step of reading out / 2 from the nonvolatile memory 14, for example, an EEPROM, is step S2. Incidentally, in the nonvolatile memory 14, the threshold level _i 1/2
In addition, table data for correcting the zoom position and the focusing position are also stored.

Next, since the input i of the CPU 13 in the collapsed state is at the L level, the input at this time, ie, PR
5 detects the output, which is referred to as i ₀ (step S
3).

Thereafter, the motor 11 is normally rotated by the MD 12 (step S4), and the zoom lens is extended. When the input i exceeds the threshold level _i 1/2 read the (step S5), and the input i has an H level, and detects the output of PR5 at this time, which is referred to as _{i 1} (step S6 ).

Next, CPU 13 calculates the _{i 2} and _{i 3} from _{i 0} and _{i 1} described above detected (step S
7). The input i is to determine what happened to the i ₂ calculated above (step S8), and when the input i becomes i _2, as the end of setup, stops the motor 11 (step S9). The zoom position at this time is the position of the wide end (W). That is, by stopping the motor 11 when the output i ₂ of PR5 to be obtained at the wide end is obtained, it is possible to control to accurately wide position.

Thereafter, when the power switch 10 is turned off (step S12), the flow proceeds to a flow for returning the zoom lens 2 to the retracted state.

That is, depending on the photographer, the power switch 1
When 0 is turned off, the motor 11 is reversely rotated by the MD 12 (step S13). Then, after the input i is detected to be the i ₁ or more values, which is the input of the set-up position (step S14), and performs the reverse rotation of the motor 11 to the detection of the minimum value i ₀ of the input (step S1
5). Thereafter, the voltage of the motor 11 is reduced (step S
16) The motor 11 is further rotated in the reverse direction for a predetermined time (step S17), so that the zoom lens 2 is in the collapsed state.

On the other hand, the zoom switch is set to the tele side (T) 7
(Step S10), Wide side (W) 8 (Step S1)
When each operation is performed in the 1) direction, the flow advances to the flow of step S18 for telephoto shooting and step S22 for wide shooting shown in FIG. 6, and the rotation and zooming of the motor 11 in each direction are performed.

That is, when the zoom switch is operated to the tele side 7, the MD 12 rotates the motor 11 forward (step S18). Then, it is determined whether or not the zooming operation has been completed halfway (step S19). If the zooming operation has been completed halfway, the input i at that time is detected (step S20), and the process returns to step S9 and the motor 11 is turned off. Stop.

On the other hand, if the zooming operation is ongoing,
CPU13, the input i performs feeding of the zoom lens until _{i 3} calculated above (step S21). Then, the input i is possible to prevent destruction of the mechanism by stopping the motor 11 when it becomes the above i _3.

If the zoom switch is operated to the wide side 8, the motor 11 is rotated in reverse by the MD 12 (step S22). Then, it is determined whether or not the zooming operation has been completed halfway (step S23). If the zooming operation has been completed halfway, the input i at that time is detected (step S24), and the process returns to step S9 and the motor 11 is turned off. Stop.

On the other hand, if the zooming operation is ongoing,
CPU13, the input i performs renormalization of the zoom lens until the _{i 2} (step S25). Then, the input i is if to stop the motor 11 when it is the i _2, it is possible to prohibit the photography other than the zoom region.

Note that the above steps S20 and S24
After the zooming operation, this is a step of detecting two positions of the zoom lens in order to calculate the exposure, strobe, and focus when released by the photographer.

Next, regarding the above-mentioned focusing operation,
This will be described with reference to FIG.

FIG. 7 is a diagram showing a flowchart of the focusing calculation.

The distance L between the subject 100 and the photographer is measured by the AF 15 (step S26). The distance measurement result L thus measured is input to the CPU 13.

The zoom position Z from i ₂ , i ₃ determined in the above-described zoom position control process, the output i of the PR5 which is the position of the zoom lens 2, the position W at the wide end, and the position T at the tele end is

(Equation 1) (Step S27). Then, the focus position is determined from the distance measurement result L and the zoom position Z (step S28), and the focusing lens is controlled to be extended (LD control) by the LD 17 (step 29).

According to the camera with the zoom lens according to the present embodiment described above, the calibration area of the zoom encoder composed of the seal 3 and the PR5 is provided at the set-up position. It is possible to provide a camera with a zoom lens that can perform correct zoom position detection and zoom position control even if the characteristics of the zoom encoder change due to aging or the like.

[Second Embodiment] The camera with a zoom lens according to the first embodiment is characterized in that it can be used for a camera which always performs a setup operation before photographing. On the other hand, the camera with a zoom lens according to the second embodiment can be applied to a camera with a zoom lens without a setup operation.

FIGS. 8 and 9 show a second embodiment of the present invention.
This will be described with reference to FIG.

FIG. 8 is a diagram showing the seal 3 of the camera with the zoom lens according to the second embodiment, and FIG. 9 shows a change in the output of PR5 corresponding to the reflectance distribution of the seal 3. FIG.

The structure of the camera with a zoom lens according to the second embodiment is the same as that of FIG.

In the camera with the zoom lens according to the second embodiment, the maximum reflectance (white or silver) at the wide end (W) and the minimum reflectance (white or silver) at the telephoto end (T) shown in FIGS. By using the seal 3 having a reflectance distribution of (black), it is possible to correctly control the wide-angle end and the telephoto end where zoom position control is difficult. Due to the optical design, photographing is guaranteed only at the angle of view between the wide end and the telephoto end, so if the zoom position control is incorrect, the photograph may be out of focus. In addition, mechanically beyond the telephoto end, the zoom lens 2 is designed to be unable to move, so if the zoom position control is erroneously performed, the mechanism may be destroyed. Therefore, strict zoom position control is important.

In order to perform strict zoom position control, in the second embodiment, a region 81 having a maximum reflectance is provided near the wide end, and a predetermined threshold level A is set.
Or more outputs i ₁ of PR5 are to be obtained. The wide end of the zoom position of 0.8 × _{i 1} (W),
The zoom position of 0.3 × i ₁ is defined as a telephoto end (T), and the area between them is defined as a region 82 where the reflectance changes continuously. And
An area 83 having the lowest reflectance (black) is provided near the telephoto end. In this way, clear discontinuous points are provided, and correct tele end position control is enabled. Moreover, the output _{i 0} of PR5 when the telephoto end, a predetermined threshold level B (0.1i ₁₎ below, that is _{i 0} ≦ _{0.1i 1}
And Therefore, i due to temperature change, temporal change, etc.
Even if there is a change of ₁ , the amount of change is small,
In the second embodiment, by detecting the output i ₁ in the region 81, to calibrate the zoom position.

For example, if the detected output i of PR5 is i =
If it was 0.55i ₁ ,

(Equation 2) Becomes, the zoom position can be detected correctly regardless of the change that is an intermediate (standard) position of the wide-angle end and the telephoto end is i _1.

As described above, according to the second embodiment, even in a camera without a setup operation,
Normally used, or the power switch 10 based on the output i ₁ of PR5 in a wide position in the off, because the zoom position detection and the zoom position control can be performed correct photography focus and exposure A camera with a zoom lens can be provided. In a position where zoom position control is difficult such as a wide end or a tele end, a step is provided in the reflectance, so that accurate zoom position control can be performed without error.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the present invention. is there. Here, the summary of the present invention includes the following in addition to those described in the claims.

(1) A reflector whose reflectance continuously changes in accordance with the position of the zoom lens, a non-contact detecting means for generating a reflected light current according to the reflectance, and a reflectance of the reflector. A zoom encoder for determining the absolute position of the zoom from the reflectance of the reflector, wherein the reflectance is discontinuous on the reflector; A camera equipped with a zoom lens, wherein a changing specific reflectance area is provided, and the reflectance determining means is calibrated in the area where the reflectance continuously changes from the photocurrent value in the specific reflectance area. .

(2) The zoom lens according to (1), wherein the specific reflectance area is arranged in a collapsed area of the zoom and at least one specific area of another zoom. camera.

(3) The camera with a zoom lens according to (1), wherein the (1) specific reflectance region has a high reflectance.

[0063]

As described in detail above, according to the present invention,
It is possible to provide a camera with a zoom lens that can accurately detect a zoom position and control a zoom position even when characteristics of the zoom encoder change due to a temperature change, a change over time, or the like while using a small zoom encoder with a simple structure.

As a result, highly accurate focusing can be achieved. Also, by correct detection of the zoom position, exposure and strobe light emission control are correctly performed, and a photograph with beautiful exposure can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a camera with a zoom lens according to a first embodiment.

FIG. 2 is a cross-sectional view for explaining a zooming operation of the camera with the zoom lens according to the first embodiment.

FIG. 3 is a diagram illustrating a reflector of the camera with the zoom lens according to the first embodiment;

FIG. 4 is a diagram illustrating a change in output of a photoreflector corresponding to a reflectance distribution of a reflector of the camera with a zoom lens according to the first embodiment;

FIG. 5 is a diagram illustrating a part of a flowchart of a zoom position control of the camera with the zoom lens according to the first embodiment;

FIG. 6 is a diagram showing the remaining part of the flowchart of the zoom position control of the camera with the zoom lens according to the first embodiment.

FIG. 7 is a diagram illustrating a flowchart of a focusing operation of the camera with the zoom lens according to the first embodiment;

FIG. 8 is a diagram illustrating a reflector of a camera with a zoom lens according to a second embodiment.

FIG. 9 is a diagram illustrating a change in output of a photoreflector corresponding to a reflectance distribution of a reflector of the camera with a zoom lens according to the second embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 2 Zoom lens 3 Seal 4 Lens frame 5 Photoreflector (PR) 6 Photocurrent detection means 7 Tele-side zoom switch 8 Wide-side zoom switch 9 Release button 10 Power switch 11 Motor drive means (MD) 12 Motor 13 Arithmetic control Circuit (CPU) 14 Nonvolatile memory 15 Distance measuring means (AF) 16 LD control means (LD)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/232 H04N 5/232 A

Claims (3)

[Claims] 1. A zoom lens, a reflector having a region where the reflectance changes continuously in response to zooming of the zoom lens, a light projecting unit for projecting light toward the reflector, and the reflection In a camera with a zoom lens having light receiving means for receiving reflected light from a body and zoom position detecting means for detecting a zoom position from an output of the light receiving means, a part of the reflector has a discontinuous reflectance. A camera with a zoom lens, characterized by having an area that changes to 2. A zoom position calculating means for calculating a zoom position in the region where the reflectance changes continuously based on a result of detecting a zoom position in the region where the reflectance changes discontinuously. The camera with a zoom lens according to claim 1, wherein 3. The camera with a zoom lens has a lens retracted position and a set-up position, and the area where the reflectance changes discontinuously is provided between the retracted position and the set-up position. The camera with a zoom lens according to claim 1.