JP2002148694A - Lens focal position adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens focal position adjusting device by which the image of a chart by a photographic lens being what is called an interchangeable lens is simultaneously observed by plural persons in the case of adjusting the attaching position of the photographic lens in a lens barrel in which the photographic lens is housed. SOLUTION: This lens focal position adjusting device 1 is equipped with the chart 30 illuminated by a light source 10 through a diffusing plate 20, a collimating lens 40 changing light transmitted as divergent light through the respective parts of the chart 30 into parallel beams, a mount 60 on which the lens barrel 2b is set, a solid-state image pickup element (CCD) 70 arranged the a reference position with respect to the lens barrel 2b, and a controller 80 processing an image signal generated by the CCD 70, outputting it to a monitor 3 and controlling the quantity of illuminating light emitted by the light source 10. An operator adjusts the attaching position of the photographic lens 2a to the lens barrel 2b by focusing on the image of the chart 30 by the lens 2a while viewing a video on a monitor 3 in which the image signal is inputted from the controller 80.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens focal position adjusting device for adjusting the focal position of a taking lens as a so-called interchangeable lens with respect to a light beam at infinity with respect to a lens barrel containing the taking lens. .

[0002]

2. Description of the Related Art Generally, photographing lenses (so-called interchangeable lenses) which are used by being replaced with cameras such as single-lens reflex cameras are manufactured and sold. This replacement photographing lens is housed in a lens barrel, and when the lens mount is locked to a body mount formed on the camera body, the lens mount surface and the film surface are separated from each other by a predetermined distance. With the positioning, the taking lens is fixed to the camera. In order to ensure that the photographing lens is correctly positioned even when the lens barrel is locked to any camera body, an appropriate lens and photographing lens are manufactured as interchangeable lenses for sale. Adjustments have been made. More specifically, the lens mount of the lens barrel is locked to the body mount formed on the camera body, and the focusing ring provided on the lens barrel is aligned with the infinity index, and the infinity light flux ( Collimated light) is incident on the taking lens,
The focal position of the photographing lens with respect to the lens mount surface of the lens barrel is adjusted so that the image point of the photographing lens is located at a predetermined position on the camera body, that is, on the film surface.

Conventionally, the focus position of such a photographing lens with respect to an infinite luminous flux is adjusted by appropriately moving at least a part of the photographing lens with respect to a lens barrel while confirming the focal position using a lens focal position adjusting device. Let it be done. FIG. 3 shows an example of the lens focal position adjusting device.

As shown in FIG. 3, a conventional lens focal position adjusting device 4 includes a light source 10 such as an incandescent lamp or a halogen lamp.
A diffusion plate 20 for suppressing the light distribution bias due to the filaments in the light source 10; a chart 30 which is a transparent plate in which vertical stripe patterns having different sizes are drawn radially from the center; A collimating lens 40 that converts the illumination light that has passed radially through each of the edges of the pattern 30 into a parallel light beam;
And a mount 60 having the same shape and mechanism as a body mount formed on a normal camera body, and a reference position with respect to a flange surface of the mount 60 (for a normal camera body). And an eyepiece 65 arranged so that the object-side focal point substantially coincides with the position of the film surface with respect to the formed flange surface of the body mount.

In this lens focal position adjusting device 4, when the lens barrel 2b accommodating the photographing lens 2a is set on the mount 60, the photographing lens 2a is arranged so as to be coaxial with the collimating lens 40 and the eyepiece 65. . However,
The optical axis of the collimating lens 40 is coaxial with the collimating lens 40 by being bent by the reflecting mirror 50. In this state, the light source 1
When the illumination light is emitted from 0, the light that has passed through each part of the chart 30 as divergent light is converted into a parallel light flux by the collimating lens 40 and enters the imaging lens 2a.

At this time, the photographing lens 2a is adjusted in advance with a certain degree of accuracy so that a focal point exists at or near a reference position with respect to the lens barrel 2b, and is assembled in the lens barrel 2b. In the state where the focusing ring provided in the image is coincident with the infinity index, the image of the chart 30 illuminated by the light source 10 is formed at or near the reference position as the image of the subject at infinity. Thus, the operator focuses on the mirror by moving the mounting position of the photographing lens 2a with respect to the lens barrel 2b in the optical axis direction while looking into the eyepiece lens 65 and observing the image of the chart 30 in an enlarged manner. The mounting position of the taking lens 2a with respect to the cylinder 2b can be adjusted accurately.

[0007]

However, according to the conventional lens focal position adjusting device 4 as shown in FIG.
During the adjustment, only one eye had to look into the monocular eyepiece for a long time, so that the working efficiency was poor.

In addition, only one worker who looks through the eyepiece lens 65 can observe the image of the chart 30, and the focusing of the image of the chart 30 is performed by the subjectivity of the worker. Is performed continuously over a long period of time or by a plurality of operators, the accuracy of each product may vary.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to adjust the mounting position of a photographic lens with respect to a lens barrel that houses a photographic lens as a so-called interchangeable lens. In doing so, the image of the chart by the taking lens can be observed with both eyes,
An object of the present invention is to provide a lens focal position adjusting device that allows a plurality of persons to objectively detect the image forming position of the chart image.

[0010]

According to the present invention, there is provided a lens focus position adjusting device configured to solve the above-mentioned problems, comprising: a light source; a chart having a pattern illuminated by light from the light source; A collimator optical system that converts the light diverged from each part of the pattern of the chart illuminated by the light source into a parallel light flux, and an adjusted object that accommodates the adjusted lens, A mount for detachably fixing the optical axis of the lens to be adjusted in a state where the optical axis of the lens is coaxial with the optical axis of the collimator optical system; and a reference to the object to be adjusted when the object to be adjusted is fixed to the mount. An image sensor that is arranged at a position and captures an image of the chart formed by the lens to be adjusted; and processes an image signal generated by the image sensor and outputs the processed signal to a monitor. Rutotomoni, said image sensor and a control unit for controlling the output of the light source in accordance with the output of the image signal so as to imageable exposure, characterized.

With the above-described configuration, when the object to be adjusted is mounted on the mounting portion and the illumination light from the light source irradiates the chart, the light diffused in each portion of the chart is emitted by the collimator optical system. A parallel light beam is incident on the lens to be adjusted. At this time, the lens to be adjusted forms an image of the chart illuminated by the light source as a subject at infinity at the reference position or in the vicinity thereof. Then, the image of the chart formed by the lens to be adjusted is photoelectrically converted by the imaging element into an electric signal, and is generated as an image signal. The control unit processes the image signal and outputs the processed image signal to the monitor, and controls the output of the light source according to the output of the image signal so that the image pickup device has an exposure amount that allows imaging.

Thus, the image of the chart at the reference position on the object to be adjusted is displayed on the monitor to which the image signal is input, so that the operator observes the image of the chart displayed on this monitor while watching the image of the chart. By adjusting the focus by moving the position of the adjusted lens with respect to the adjustment body in the optical axis direction, the position of the adjusted lens with respect to the adjusted body can be accurately adjusted. In addition, since the image of the chart is projected on the monitor, observation with binoculars can be performed, so that it is possible to work efficiently. Furthermore, since the focus can be adjusted by multiple people by observing the image on the monitor,
Objective adjustment can be performed without variation in the accuracy of the assembling position of the lens to be adjusted.

In the lens focal position adjusting device according to the present invention, a light source may be arranged on the side of the chart opposite to the side where the collimator optical system is located so that the illumination light passes through each part of the chart. The light source may be arranged on the same side of the chart as the side where the collimator optical system is located, such that the light is reflected by each part of the chart.

Further, in the lens focal position adjusting device according to the present invention, the mount portion may be for fixing a lens barrel for accommodating a so-called interchangeable lens, or the photographic lens may be integrated into the camera body. It may be for fixing a camera. In any case, by disposing the imaging element at a reference position on the optical axis of the taking lens with respect to the object to be adjusted, a deviation of the focus of the taking lens from the reference position is detected.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lens focal position adjusting device according to the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a schematic configuration of a lens focal position adjusting device 1 according to an embodiment of the present invention. In FIG. 1, the same components as those of the conventional lens focal position adjusting device 4 shown in FIG. 3 are denoted by the same reference numerals.

The lens focal position adjusting device 1 includes a light source 1
0, diffusion plate 20, chart 30, collimating lens 4
0, reflector 50, mount 60, solid-state image sensor (CC
D) 70 and a control device 80.

The light source 10 is a halogen lamp that emits white illumination light. The diffusion plate 20 is a translucent plate for diffusing the illumination light so as to have a uniform light amount distribution by suppressing the bias of the light distribution by the filament of the light source 10, and to be irradiated with the illumination light from the light source 10. In front of the light source 10. The chart 30 is a transparent plate in which vertical stripe patterns having different sizes are drawn radially from the center, respectively, and is arranged in parallel with the diffusion plate 20 with the diffusion plate 20 sandwiched by the light source 10. I have.

The collimating lens 30 is arranged such that an extension of the optical axis passes through the center of the light source 10 and the center of the chart 30 and the front focal point coincides with the center of the chart 30. The light that passes as light is converted into a parallel light flux. The reflecting mirror 40 mounts the light collimated by the collimating lens 30 on the mount 6.
Reflects toward zero.

The mount 60 has the same shape and mechanism as a body mount formed on a camera body such as a single-lens reflex so that the lens barrel 2b accommodating the photographing lens 2a can be attached and detached so as to be replaceable. When the lens mount of the lens barrel 2 b is locked to the mount 60, the optical axis of the photographing lens 2 a is coaxial with the optical axis of the collimator lens 30 bent by the reflecting mirror 50. A plurality of types of mount adapters are prepared for the mount 60 so that the shape and mechanism can be changed according to the mount standard of each manufacturer. Therefore, by appropriately selecting a mount adapter according to the lens mount of the lens barrel 2b to be adjusted and attaching the mount adapter to the mount 60, the lens barrel 2b having a different lens mount shape can be set on the mount 60.

The CCD 70 is an image pickup device provided with a complementary color filter for generating a color image on the surface of the image pickup surface.
It is arranged at the reference position for b. Here, the reference position is a position equivalent to the position of the film surface when the lens barrel 2b is set on the camera body. Note that the distance from the flange surface of the body mount formed on the camera body to which the lens barrel 2b is applied to the film surface is set to a uniform length for each manufacturer's standard. Called.

Further, the CCD 70 is connected to a rack-and-pinion type moving mechanism (not shown) for enabling parallel movement along the optical axis of the photographing lens 2a fixed to the mount 60 via the lens barrel 2b. Is being held. The moving mechanism (not shown) includes a rotating shaft having a ring-shaped handle coaxially fixed at a tip thereof, a pinion gear coaxially fixed at a tip of the rotating shaft opposite to a side to which the handle is fixed, and A rack gear having teeth meshed with a pinion gear is provided, and the CCD 70 is attached to the rack gear. When the handle of the moving mechanism (not shown) is rotated, the CCD 70
Is translated along the optical axis direction of the photographing lens 2a (the direction of the arrow in FIG. 1). Therefore, the lens barrel 2 to be adjusted
Even when the mount adapter is attached to the mount 60 in accordance with the lens mount b, the CCD 70 is located at a distance from the flange surface of the mount adapter by a distance corresponding to the flange back of the mount standard.
Can be arranged.

The control device 80 processes the electric signal generated by the photoelectric conversion by the CCD 70 and outputs it to the monitor 3 as an image signal, and controls the amount of illumination light emitted from the light source 10 according to the output of the image signal. . FIG. 2 shows a schematic configuration of an internal circuit of the control device 80.

As shown in FIG. 2, the control device 80 comprises a process circuit 81, a luminance signal / color signal (Y / C) separation circuit 8
2. Complementary color / primary color matrix circuit 83, color difference matrix circuit 84, luminance signal processing circuit 85, analog / digital (A / D) converter 86, memory 87, digital / analog (D / A) converter 88, RGB decoder 89, CCD driver 90, synchronous signal generation (SSG)
Circuit 91, memory control circuit 92, light source circuit 9
3 and a battery 94.

The A / D converter 86 includes an A / D converter 86a for the color difference signal RY and a color difference signal BY.
A / D converter 86b for luminance signal Y and A / D converter 86b for luminance signal Y
A / D converter 86c is provided.

Further, the memory unit 87 stores the color difference signal R-
The D / A converter unit 88 includes a Y, BY memory 87a and a luminance signal Y memory 87b.
D / A converter 88a for -Y, D / A converter 88b for color difference signal BY, and D / A for luminance signal Y
The converter 88c is provided.

The SSG circuit 91 generates a synchronizing pulse signal and transmits the synchronizing pulse signal to the process circuit 81, the Y / C separation circuit 82, the complementary color / primary color matrix circuit 83, the CCD driver 90, and the memory control circuit 92. And synchronize. The CCD driver 90 includes the SSG circuit 9
1 and transmits a CCD drive signal synchronized with the synchronization pulse signal to the CCD 70,
70 is controlled.

The process circuit 81 receives the electric signal generated by the CCD 70 via the cable C, and performs processing such as correlated double sampling, clamping, blanking, and amplification on the electric signal. Y / C separation circuit 8
2 separates the electric signal subjected to various processes in the process circuit 81 into a chrominance signal C and a luminance signal Y by a bandpass filter, and inputs the chrominance signal C to a complementary color / primary color matrix circuit 83; , One of the luminance signals Y is input to the luminance signal processing circuit 85.

The complementary color / primary color matrix circuit 83 has a Y / C
The color signal C input from the separation circuit 82 is converted into an RGB signal and output to a color difference matrix circuit 84. The color difference matrix circuit 84 converts the color difference signal R-
A / D converters 86a and 86b generate Y and BY
Output to The A / D converters 86a and 86b convert the respective color difference signals RY and BY into digital signals and output the digital signals to the memory 87a for color difference signals RY and BY. The -Y memory 87a stores the respective color difference signals RY and BY converted into digital signals.

On the other hand, the Y signal processing circuit 85 performs a process of averaging the high-frequency component of the luminance signal Y input from the Y / C separation circuit 82 by using a low-pass filter, and outputs the result to the A / D converter 86c. The A / D converter 86c converts the luminance signal Y into a digital signal, and the luminance signal Y memory 87b stores the luminance signal Y converted into a digital signal.

The memories 87a and 87b are controlled by the memory control circuit 92 to simultaneously output the color difference signals RY and BY and the luminance signal Y to the D / A converters 88a to 88c. Each of the D / A converters 88a to 88c
The color difference signals RY, BY and the luminance signal Y are converted into analog signals, respectively, and the color difference signals RY, BY and the luminance signal Y are output to the RGB decoder 89. RGB decoder 8
9b indicates the color difference signals RY, BY and the luminance signal Y.
Is converted into an RGB signal and output to the monitor 3.

The light source circuit 93 sets the amount of illumination light in accordance with the luminance signal Y from the D / A converter unit 88 so that the amount of exposure falls within the latitude of the CCD 70, and uses the set amount of illumination light. Is radiated from the light source 10, the power supplied from the battery 94 is adjusted and output to the light source 10.

The procedure for adjusting the position of the taking lens 2b in the lens barrel 2a in the lens focal position adjusting device 1 described above will be described.

In the lens focal position adjusting device 1 of this embodiment, when the lens barrel 2a, which is the object to be adjusted, is set on the mount 60, the photographing lens 2a attached to the lens barrel 2a
Are arranged coaxially with the collimating lens 40 via the reflecting mirror 50. In this state, when the main power supply of the control device 80 is turned on, electric power from the battery 94 is supplied to the light source 10 via the light source circuit 93, and the light source 10
Illumination light is emitted. Illumination light emitted from the light source 10 is diffused in the diffusion plate 20 so as to have a uniform light amount distribution, and then illuminates the chart 30.

The light that has passed through each part of the chart 30 as divergent light is converted into a parallel light beam by the collimating lens 40, and then enters the photographing lens 2a in the lens barrel 2b set on the mount 60. At this time, shooting lens 2
a is adjusted in advance with a certain degree of accuracy so that a focal point exists at or near the reference position with respect to the lens barrel 2b, and is assembled in the lens barrel 2b. Therefore, the focusing ring ( In a state where (not shown) coincides with the infinity index, the image of the chart 30 illuminated by the light source 10 is formed as an image of the subject at infinity at or near the reference position. If the lens barrel 2b is provided with an aperture mechanism, the aperture is set to open.

C arranged at a reference position with respect to the lens barrel 2b
The CD 70 photoelectrically converts the image of the chart 30 (sometimes out of focus at this point) by the photographing lens 2a, converts the image into an electric signal, and outputs the electric signal to the control device 80. The electric signal is subjected to various processes in the control device 80 and then output to the monitor 3 as an RGB image signal.

On the monitor 3, an image of the chart 30 by the photographing lens 2a is displayed. At this time, if the position of the focal point of the photographing lens 2a coincides with the reference position with respect to the lens barrel 2b, an image in which the stripes of the chart 30 can be clearly recognized in detail is displayed on the monitor 3. . On the other hand, when the focus position of the photographing lens 2a is shifted from the reference position with respect to the lens barrel 2b, the screen of the chart 30 in which the focus is shifted and the stripe pattern group is not clear is displayed on the monitor 3.

Accordingly, when the image of the out-of-focus chart 30 is displayed on the monitor 3, the operator observes the image of the chart 30 displayed on the monitor 3 while observing the image of the chart 2a with respect to the lens barrel 2b. By moving the assembling position in the optical axis direction to focus the image, the imaging position of the image of the chart 30 by the photographing lens 2a can be matched with the reference position with respect to the lens barrel 2b.

As described above, according to the lens focal position adjusting device 1 of the present embodiment, the image of the chart 30 at the reference position with respect to the lens barrel 2b is displayed on the monitor 3 to which the image signal is input from the control device 80. Is projected,
By focusing while observing the image of the chart 30 on the monitor 3, the mounting position of the photographing lens 2a with respect to the lens barrel 2b can be adjusted. Also,
Since the image of the chart 30 is projected on the monitor 3, the focusing can be performed by a plurality of persons, so that the objective adjustment without variation in the accuracy of the assembling position of the photographing lens 2a can be performed.

[0040]

As described above, according to the lens focal position adjusting apparatus of the present invention, when the assembling position of the taking lens is adjusted with respect to the lens barrel in which the so-called interchangeable lens is housed. In addition, the image of the chart by the photographing lens can be observed with both eyes, and the image formation position of the image of the chart can be objectively detected by a plurality of persons.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a lens focal position adjusting device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic internal configuration of a control device of the present embodiment.

FIG. 3 is an explanatory diagram showing a schematic configuration of a conventional lens focal position adjusting device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens focal position adjusting device 2 a photographing lens 2 b lens barrel 3 monitor 10 light source 20 diffuser 30 chart 40 collimator lens 60 mount 70 solid-state imaging device (CCD) 80 controller 81 process circuit 82 luminance signal / color signal (Y / C) Separation circuit 83 Complementary color / primary color matrix circuit 84 Color difference matrix circuit 85 Luminance signal processing circuit 86 Analog / digital (A / D) converter section 87 Memory section 88 Digital / analog (D / A) converter section 89 RGB decoder 90 CCD driver 91 Synchronization Signal generation (SSG) circuit 92 Memory control circuit 93 Light source circuit 94 Battery

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Tadashi Takahashi 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. (72) Masahiko Kawamura 2-36-9 Maenocho, Itabashi-ku, Tokyo No. Asahi Gaku Kogyo Co., Ltd. (72) Inventor Takayuki Ito 2-36-9 Maeno-cho, Itabashi-ku, Tokyo F-term inside Asahi Gaku Kogyo Co., Ltd. 2H011 AA01 BA31 BB04 CA00 CA14 DA05 2H051 AA06 BA47 BA70 BA72 CA17 GA03 GA13 GB15 GB19 2H100 BB02 2H101 EE08 EE31

Claims (5)

[Claims] 1. A light source, a chart having a pattern illuminated by light from the light source, and a chart arranged on the chart so that a front focal point coincides with the chart.
A collimator optical system that converts light diverged from each part of the pattern of the chart illuminated by the light source into a parallel light beam; and an adjusted body that accommodates the adjusted lens, wherein the optical axis of the adjusted lens is the collimator optical system. A mount portion that is detachably fixed in a state of being coaxial with the optical axis of the lens, and is arranged at a reference position with respect to the object to be adjusted when the object to be adjusted is fixed to the mount portion, and is formed by the lens to be adjusted. An image pickup device for picking up an image of the chart, processing an image signal generated by the image pickup device, outputting the processed image signal to a monitor, and outputting the image signal so that the image pickup device has an exposure amount that allows image pickup. A control unit for controlling the output of the light source in response to the change. 2. The lens focal position adjusting device according to claim 1, wherein the light source is arranged at a position sandwiching the chart with the collimator optical system. 3. The lens according to claim 1, further comprising a diffusion plate between the light source and the chart for uniforming a light amount distribution of illumination light from the light source. Focus position adjustment device. 4. The apparatus according to claim 1, wherein said imaging element is held movably along said optical axis of said adjustable lens fixed to said mount via said adjustable body. , 2 or 3. 5. The object to be adjusted fixed to the mount portion,
The lens focal position adjusting device according to any one of claims 1 to 4, wherein the lens barrel is a lens barrel that is interchangeably attached to and detached from a body mount of the camera.