JP4590136B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an autofocus camera, and more particularly, to an improvement in auxiliary light for an autofocus camera of a type in which a photographing lens is focused using an image signal of a subject.
[0002]
[Prior art]
The image signal of the subject is unclear and is not sufficient for the focusing operation when the location where the subject exists is dark or the subject does not have contrast.
[0003]
For this reason, the use of strobe light, for example, as a light source for AF (autofocus), which has been known for a long time, has been known as a technique for assisting focusing by projecting light from a camera for a long time. This is known from Japanese Utility Model Laid-Open No. 62-146331. This eliminates the need for having an additional light source for AF.
[0004]
[Problems to be solved by the invention]
However, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Sho 62-146331 has a problem that the movable part is necessary and the reliability is poor.
[0005]
In addition, it is generally necessary to irradiate the strobe light uniformly on the screen, and there is a problem that the contrast for distance measurement cannot be formed even when the so-called low contrast subject is irradiated.
[0006]
Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a camera that does not require an additional light source and can measure a distance even in a dark scene or a low contrast subject.
[0007]
[Means for Solving the Problems]
  That is, the present invention includes a distance measuring optical system, a sensor array that detects a subject image through the distance measuring optical system and outputs a pair of image signals, and a discharge arc tube, and the discharge arc tube emits light. Strobe means for irradiating strobe light by causingIn the camera, comprising: a focusing unit configured to focus the photographing lens based on an output of the sensor array when the subject is irradiated with the strobe light. The strobe unit includes a pattern-like infrared component. And a strobe light having a uniformly irradiated visible light component is irradiated on the subject.
[0010]
In the camera of the present invention, an image of a subject is detected via the distance measuring optical system, and a pair of image signals are output by the sensor array. In addition, the strobe light having the discharge arc tube emits strobe light when the discharge arc tube emits light. In addition, based on the output of the sensor array when the subject is irradiated with the strobe light, the photographing lens is brought into focus by the focusing means. When the strobe means is irradiated on the subject, the infrared component of the strobe light is patterned, and the visible light component of the strobe light is uniformly irradiated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
FIG. 2A shows the configuration of the first embodiment of the camera of the present invention, and is an external perspective view of the compact camera.
[0013]
In addition to the photographing lens 2, a finder objective window 3, a distance measuring lens 4, a strobe window 5a having a function of condensing and projecting a part of light, and the like are provided on the front surface of the camera body 1. A display unit 7 including a release switch 6 and a display LCD is disposed on the upper surface of the camera body 1.
[0014]
FIG. 2B is a diagram showing the relationship between the strobe unit and the distance measuring lens in FIG.
[0015]
The strobe includes a xenon discharge tube (Xe tube) 5b, which is a strobe light emitting unit, and a projection strobe window 5a. Since the photo screen is normally horizontally long, it is preferable that the Xe tube 5b be horizontally oriented with its length direction aligned with the longitudinal direction of the camera.
[0016]
Further, it is assumed that the distance measuring device detects a subject image incident from two light receiving lenses 4a and 4b having parallax and obtains a subject distance L from a relative position difference between the plurality of sensor arrays 10a and 10b. is doing.
[0017]
Here, three pairs of sensor arrays 10a and 10b are prepared. These sensor arrays are prepared for distance measurement at the center and left and right of the screen, and have subject detection areas 14C, 14L, and 14R.
[0018]
Further, the strobe emits uniform visible light 11 and contrast infrared light 12 as auxiliary light.
[0019]
Next, the principle of distance measurement of this camera will be described with reference to FIG.
[0020]
FIG. 1 is a block diagram showing the electrical system of the main part of the compact camera according to the first embodiment of the present invention.
[0021]
In FIG. 1, a CPU 17 is arithmetic control means for performing sequence control of the camera. The CPU 17 is connected to the above-described strobe light emitting unit 5 having the Xe tube 5b, the release switch 6, the display unit 7, the shutter unit 18, the focusing unit 19, the EEPROM 20, and the distance measuring device 21.
[0022]
The CPU 17 detects whether or not the release switch 6 has been operated by the user at the time of shooting or the like, and controls the distance measuring device 21. Then, the photographing lens 2 is operated via the focusing unit 19 based on the obtained information. Further, the shutter unit 18 and the strobe light emitting unit 5 are controlled for exposure control. When a sufficient image signal cannot be obtained during distance measurement, the strobe light emitting unit 5 is controlled, and a steady light removal circuit 23 (to be described later) in the distance measuring device 21 is controlled to perform distance measurement.
[0023]
Further, the display unit 7 is controlled by the CPU 17 in order to indicate the mode set at the time of shooting and the number of shot frames. Variations in camera parts and assembly during distance measurement and focusing are checked at the time of manufacture and stored in the EEPROM 20 as correction coefficients. Therefore, the correction coefficients are referred to during shooting, and the CPU 17 cancels the variations. Control is performed.
[0024]
The distance measuring device 21 includes sensor arrays 10a and 10b, light receiving lenses 4a and 4b, an A / D converter 22 and a steady light removal circuit 23.
[0025]
The optical system of the distance measuring device 21 and the sensor arrays 10 and 10b will be described later. The outputs of the sensor arrays 10a and 10b are converted into digital signals by the A / D converter 22 and input to the CPU 17.
[0026]
In the steady light removal circuit 23, only distance measuring light projected from the camera side is integrated, and the background light incident on the sensor arrays 10a and 10b is removed by irradiating the subject with sunlight or artificial illumination. The This steady light removal function can be used during auxiliary light projection to enhance the effect of auxiliary light contrast even in bright places.
[0027]
The distance between the principal points of the light receiving lenses 4a and 4b is referred to as a base line length B. The distance to the sensor arrays 10a and 10b on which images are formed by being placed behind the light receiving lenses 4a and 4b is represented by f. Then, an image of the subject 25 at a distance L is formed on the two sensor arrays with a relative positional difference of x. This x has a relationship of x = B · f / L between B and f and the distance L. Therefore, the main technique is to detect subject images on both sensor arrays.
[0028]
Here, the reason why three pairs of sensor arrays are provided will be described.
[0029]
As shown in FIG. 3, this is devised so that it can be focused by the sensor visual field 14 regardless of the position of the subject 25 in the screen 27, and is not limited to three points. Although there is not, here, three points will be described as an example in order to simplify the explanation.
[0030]
As described above, by arranging the two light receiving lenses vertically, the baseline length direction becomes the vertical direction, so that the shift direction of the image to be detected is also vertical, and the pixel array direction of the sensor array is also the vertical direction. Accordingly, it is preferable that the contrast of the image signal to be detected is formed in the vertical direction.
[0031]
As shown in FIG. 2B or FIG. 5, in order to form a contrast in the vertical direction in this way and to give the same contrast to a plurality of ranging points side by side in the screen, as shown in FIG. It can be seen that an auxiliary light form (infrared light 12) that projects an image of the Xe tube 5b of the strobe light emitting unit 5 is preferable. Light is projected to each of the previous three horizontal distance measuring points, and light that is narrow in the vertical direction is preferable.
[0032]
In addition, there is a concept of projecting an independent light spot on each of these three points. However, it is necessary to prepare a new light source, and space and cost of a light emitting element serving as the light source and its driver are required. In addition, it is difficult to obtain light as strong as strobe light with an LED or a lamp. For this reason, if another dedicated strobe device is provided, an increase in the size of the camera cannot be avoided.
[0033]
Therefore, by making the direction of the Xe tube 5b generally arranged in the lateral direction orthogonal to the direction of deviation of the image to be detected, it is possible to efficiently form a contrast with many points in the screen. In the image detection type AF, it is impossible to measure the distance of a subject without contrast. However, by using such auxiliary light together, accurate distance measurement can be performed.
[0034]
FIG. 4 is a flowchart of control performed by the CPU 17 during distance measurement of the camera having such a configuration.
[0035]
When ranging is started, first, in step S1, image detection is performed by the sensor arrays 10a and 10b. A voltage-converted value obtained by storing the output photocurrent of each sensor in an integrating capacitor (not shown) is A / D converted by the A / D converter 22 and input to the CPU 17.
[0036]
However, if the brightness is low or the subject has no contrast, accurate distance measurement cannot be performed, and these determinations are made in steps S2 and S3. That is, it is determined in step S2 whether the contrast is low brightness or not in step S3.
[0037]
As a result, if the contrast is neither low nor low, the process proceeds to step S6. If the contrast is low or the brightness is low, the process proceeds to step S4 and the background light is stored. Next, in step S5, auxiliary light is irradiated by the strobe light emission control, and image detection is performed using the reflected signal light.
[0038]
Since the strobe light has a contrast, it forms a contrast image on the subject 25 and enables accurate distance measurement.
[0039]
FIG. 5 is a diagram showing details of the photocurrent integration part of the sensor output for this image detection.
[0040]
One sensor 30 in the sensor array will be described. In other words, the integrating circuit 32 is connected to the sensor 30 via the switch 31. An integrating capacitor 33 and an A / D converter 22 are connected to the integrating circuit 32. The sensor 30 is connected to a steady light removal circuit 35 via a switch 34.
[0041]
The integration circuit 32 amplifies the output photocurrent of the sensor 30 and leads it to the integration capacitor 33. Since the charge of the integrating capacitor 33 during integration is sampled and held by turning off the switch 31, it can be read by the A / D converter 22 described above.
[0042]
Further, during the steady light removal operation, the steady photocurrent flows to the steady light removal circuit 35 when the switch 34 is turned on, and only the photocurrent increased during the auxiliary light emission is guided to the integration circuit 32. Therefore, when the reflected signal light does not return from the subject, no charge is stored in the integrating capacitor 33. When the switch 31 is on, the integrating capacitor 33 is charged according to the reflected signal light amount.
[0043]
When the switch 34 is turned off in synchronization with the strobe light emission, an image signal based on the reflected signal is output as an output of the integrating capacitor 33 as a result of A / D conversion.
[0044]
Returning to the flowchart of FIG. 4, the subject distance is calculated by the CPU 17 in step S <b> 6 based on the image thus obtained. In step S7, the photographing lens 2 is controlled by the focusing unit 19, so that accurate focusing can be performed on any subject.
[0045]
As described above, in a camera capable of measuring three points, the processing operation up to step S6 described above may be performed for three points, and the closest distance may be selected and focused.
[0046]
6A and 6B show an example of the configuration of the strobe light emitting unit 5 in the first embodiment, where FIG. 6A is a cross-sectional view and FIG. 6B is a perspective view.
[0047]
A reflectance 37 is provided in a direction excluding the front surface of the Xe tube 5b so that light from the Xe tube 5b is irradiated in front of the strobe. A slit 38 is formed in a part of the reflector 37 behind the Xe tube 5b. The light beam that has passed through the slit 38 is reflected twice in the prism 39 disposed further rearward, is collected by the lens 40 that is cut off visible light, and is projected onto the subject.
[0048]
Thus, since only infrared light is condensed and projected for auxiliary light, the condensed pattern is not imprinted on the photograph while using the strobe.
[0049]
The distance measuring sensor has a sensitivity distribution from visible to infrared, and the light of the Xe tube 5b contains an infrared component as much as visible light. Therefore, the auxiliary light has uniform visible light 11 and contrast. Some infrared light 12 overlaps and is projected as shown in FIG. However, for the distance measuring sensor 10, the light is incident as shown in FIG. An image is formed by the contrast between the infrared light 12 and the visible light 11, and correct focusing can be performed even for a low-contrast object.
[0050]
Further, since the length direction is ensured along the length of the Xe tube 5b, auxiliary light corresponding to a plurality of distance measuring points arranged as shown in FIG. 3 is obtained.
[0051]
As described above, according to the first embodiment, the visible light component of the strobe is used for exposure, while the infrared component is used particularly for distance measurement, and the intense light of the strobe is used. It is possible to provide a camera capable of focusing and taking a photo without a subject that is not good at it.
[0052]
Next explained is the second embodiment of the invention.
[0053]
FIG. 7 shows a second embodiment of the present invention and is a sectional view of an optical system.
In the embodiment described below, the same parts as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
[0054]
This second embodiment is an example applied to a single-lens reflex camera, and detects the in-focus state of the photographic lens 2.
[0055]
A surface 43 corresponding to the film surface is located behind the photographic lens 2 (on the right side in FIG. 7). The surface 43 represents a plane that is also referred to as a planned image formation plane or a film equivalent plane. The condenser lens 44 provided in the vicinity of the surface 43 has a function of guiding an image formed by the photographing lens 2 to the re-imaging lens 46 through the mask 45.
[0056]
An image formed through the re-imaging lens 46 is formed on the sensor arrays 47a and 47b. Here, in the case where the subject image is formed on the film surface (I), the front pin state (F), and the rear pin state (B), the positions of the images formed on the sensor arrays 47a and 47b change. This is apparent from the optical path indicated by the solid line, broken line, and alternate long and short dash line in the figure.
[0057]
By monitoring the image positions on the sensor arrays 47a and 47b, the photographing lens 2 is controlled to perform focusing.
[0058]
In FIG. 7, the optical axis is shown as a straight line, but in an actual camera, each lens is arranged as shown in FIG.
[0059]
That is, the photographing light beam incident through the photographing lens 2 is reflected by the main mirror 50 and can be observed by the user 57 through the prism 55 and the eyepiece lens 56. This optical path portion forms a finder optical system.
[0060]
When the main mirror 50 is retracted from the optical path, an image is formed on the film 53 and shooting is performed.
[0061]
The main mirror 50 is a half mirror, and the light beam transmitted through the main mirror 50 is reflected downward through the sub mirror 51. The light beam reflected here is further reflected by the second mirror 52, and enters the sensor arrays 47a and 47b via the condenser lens 44, the mask 45, and the re-imaging lens 46 described above.
[0062]
When the image signals on the sensor arrays 47a and 47b are detected by the CPU 17 via the A / D converter 22, the focus position is detected based on the principle described above, and the photographing lens 2 can be focused.
[0063]
Further, depending on the image signal from the sensor array, auxiliary light projection by the strobe light emitting unit 5 which is a feature of the present invention is controlled by the CPU 17.
[0064]
A strobe window 5a is provided in front of the Xe tube 5b, which is a strobe light emitting unit, as an optical system that collects only infrared light.
[0065]
Furthermore, if three rows of sensor arrays are prepared, three points in the screen can be measured as in the sensor array 14 of FIG.
[0066]
As described above, according to the second embodiment, effective auxiliary light with high contrast is projected to a plurality of points in the screen by the light of the strobe light extending in the length direction of the Xe tube. This makes it possible to perform range-finding shooting without a subject that is not good at it.
[0067]
Further, since only infrared light is collected, a beautiful photograph can be obtained without leaving a trace of auxiliary light on the photographed photograph.
[0068]
Next explained is the third embodiment of the invention.
[0069]
FIG. 9A is a diagram showing an example of the configuration of a strobe to which a diffractive optical element (DOE) is applied.
[0070]
This diffractive optical element is introduced in “Optics”, Vol. 22, pages 126-130 (Yuzo Ono). Also, SPIE, 1354 (1990) “Diffractive doublet corrected on-axis at two wavelengths (Michael W, Farn, Joseph W. Goodman)” and “The design of achromatized hybrid diffractive lens systems (Camina Londono, Peter P. Clark) "An example in which a diffractive optical element is used in an imaging optical system has been proposed.
[0071]
In FIG. 9A, a strobe window 63 is disposed on the subject side of the strobe arc tube 60 and the mirror surface 62 having a light condensing function.
[0072]
On the object side surface 64 of the strobe window 63, a Fresnel lens for projecting mainly visible light out of the strobe light from the strobe arc tube 60 and the mirror surface 62 is formed. This Fresnel lens is equivalent to that disposed in a conventional strobe window, and has a lens effect on visible light and infrared light.
[0073]
On the other hand, on the surface 65 of the strobe window 63 on the strobe arc tube 60 side, a diffractive lens configured to mainly act on infrared light is disposed.
[0074]
By combining this analytical lens with the Fresnel lens 102, the infrared light mainly from the strobe light from the strobe arc tube 60 and the mirror surface 62 is shown in FIGS. 12 and 3 shown in FIG. It has the effect | action which projects light like 14 shown.
[0075]
FIGS. 9B and 9C show examples of the arrangement of diffraction gratings when light is projected as shown at 12 in FIG. 2B. FIG. 9B is a front view, and FIG. It is sectional drawing to which the center part of the surface 65 by the side of the strobe light emission tube 60 was expanded.
[0076]
As shown in FIG. 9C, it is desirable that the diffraction grating 65 has a saw-like shape called a kinoform (see Japanese Patent Application Laid-Open No. 7-260677). The height of the saw-shaped mountain is almost constant, and the height is obtained by the following equation.
[0077]
h = mλ / (n−1)
Note that m is a positive integer, and preferably m = 1.
[0078]
λ is the peak wavelength of this diffraction efficiency, preferably 700 nm to 1300 nm, and more preferably 900 nm to 1300 nm. n is the refractive index of the strobe window at the wavelength λ.
[0079]
FIG. 10 is a diagram showing diffraction spectral characteristics when the wavelength λ = 1100 nm and m = 1.
[0080]
FIG. 10 shows how much the lens action is received from the diffraction grating at each wavelength. From this figure, it can be seen that the visible light hardly receives the lens action at the surface 65.
[0081]
FIG. 11 is a diagram showing an example of the arrangement of diffraction gratings when light is projected as indicated by 14 in FIG.
[0082]
As described above, also in the third embodiment, the same effect as in the second embodiment described above can be obtained.
[0083]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
[0084]
FIG. 12A shows the configuration of the camera in the fourth embodiment, and is an external perspective view of the compact camera.
[0085]
On the front surface of the camera body 70, a photographic lens 2, a finder objective window 3, a distance measuring lens 4, a strobe window 5a, and the like are provided. In addition, a barrier 70 a that also serves as a power switch is slidably provided on the front surface of the camera body 70. Further, a lens 71 with a visible light cut filter is provided adjacent to the strobe window 5a disposed in the baseline length direction together with the distance measuring lens 4.
[0086]
A display unit 7 including a release switch 6 and a display LCD is disposed on the upper surface of the camera body 1.
[0087]
12B is a cross-sectional view of the camera of FIG. 12A cut along a horizontal plane including the finder objective window 3, the distance measuring lens 4, the strobe window 5a, and the lens 71 with a visible light cut filter.
[0088]
The lens 71 with a visible light cut filter is composed of a prism-shaped mold component mixed with a dye that transmits infrared light and transmits visible light. The visible light cut filter-equipped lens 71 has a function of condensing light irradiated from the end of the xenon discharge tube 5b in a direction orthogonal to the base line length and a function of changing the direction of the light beam. ing.
[0089]
As a result, the infrared component 72 having a high contrast is superimposed on the uniform light 11 composed of the infrared light for exposure assistance and the visible light projected from the reflector 37 of the strobe. This high-contrast infrared light is not visible to human eyes and is not photographed. However, the sensor arrays 10a and 10b made of silicon photodiodes are sensitive and converted into electrical signals. Therefore, by using this contrast, correct distance measurement can be performed even for a low-contrast subject.
[0090]
When strobe light is projected onto a low-contrast object, the infrared light contrasts 72a and 72b are incident on the sensor arrays 10a and 10b through the pair of light-receiving lenses 4a and 4b as shown in the figure. . Therefore, distance measurement based on the principle of triangulation can be performed by obtaining the position difference of the contrast portion.
[0091]
As described above, according to the fourth embodiment, it is possible to irradiate a subject having low contrast with infrared light contrast to enable correct distance measurement.
[0092]
This contrast does not require a special light emitting element, and is formed by a small prism-like optical system provided adjacent to the strobe light emitting portion, so that it can be configured at a low cost and in a small space.
[0093]
In addition, since infrared light has no influence on exposure or printing, it is possible to take a picture as usual.
[0094]
Furthermore, since the strobe light emitting unit is almost built in recent cameras, it is possible to provide a distance measuring device that is resistant to low contrast without greatly increasing the cost.
[0095]
FIG. 13 shows a fifth embodiment of the present invention. In contrast to the fourth embodiment described above, the fifth embodiment is for obtaining an infrared light contrast using an optical system that does not allow infrared light to pass through.
[0096]
FIG. 13A is a cross-sectional view showing the strobe light emitting part and its peripheral part.
[0097]
In the figure, a multi-coat filter 74 having an infrared cut function and a visible light transmission function is formed in a strobe projection window in the form of a cylindrical lens on the front surface of the strobe window 5a. Thereby, the infrared component 75 of strobe light is irradiated nonuniformly. Then, it is determined that distance measurement is performed based on this contrast, and an effect equivalent to that of the fourth embodiment described above is being obtained.
[0098]
In the fifth embodiment, since the visible light 11 is not cut, it becomes uniform as shown. When the strobe light is projected onto the low-contrast subject, a pattern (infrared + visible light) 11a as shown in FIG. 13B is formed on the sensor array 10a. Thereby, triangulation can be performed.
[0099]
In the embodiment described above, the light receiving side has been described as the so-called external light type passive triangular distance measuring method. However, the present invention is not limited to this, and the present invention can also be applied to contrast AF of a digital camera as shown in FIG.
[0100]
FIG. 14A is a diagram showing the configuration of such a digital camera.
[0101]
Therefore, the imaging lens 78 and the xenon discharge tube 5 b are connected to the CPU 17 that controls the camera via the strobe light emitting unit 5 as well as the imaging lens 78 and the focusing unit 19.
[0102]
The strobe light emitting unit 5 is assumed to be capable of pattern irradiation only with infrared light as in the above-described embodiment.
[0103]
In such a configuration, when the low-contrast subject 79 is photographed, the infrared light pattern 80 projected thereon is formed as an image pattern 80 a on the image sensor 78 via the photographing lens 2. . Therefore, the sharpness of the image formed on the image sensor 78 is detected while the focus of the photographic lens 2 is controlled by the CPU 17 via the focusing unit 19. Then, this type of AF performs focusing at a position where the highest contrast result is obtained.
[0104]
At this time, as shown in FIG. 14B, a sensor IR that detects only infrared light is disposed on the image sensor 78 at a predetermined location. As shown in FIG. 14C, R, G, and B filters having a predetermined sensitivity are generally mounted on the image sensor 78. In this example, an IR filter is additionally mounted. Has been.
[0105]
Needless to say, at the time of image reproduction, the IR pixel is devised not to reproduce an infrared image, such as by interpolating between adjacent pixels.
[0106]
As described above, according to such a configuration, even with a digital camera, even in a low-contrast scene that has conventionally been difficult to measure distances, it is possible to focus correctly with contrast AF. .
[0107]
In addition, according to the said embodiment of this invention, the following structures can be obtained.
[0108]
(1) ranging optical system,
A pair of sensor arrays for detecting a subject image via the distance measuring optical system and outputting a pair of image signals;
Strobe means for emitting strobe light by emitting light from a discharge arc tube;
Projecting means for condensing and projecting part of the strobe light so as to be orthogonal to the longitudinal direction of the sensor array;
Focusing means for focusing the photographic lens based on the output of the pair of sensor arrays when the subject is irradiated with the strobe light;
A camera comprising:
[0109]
(2) The camera according to (1), wherein part of the strobe light collected by the light projecting unit is infrared light.
[0110]
(3) The camera according to (1), wherein the pair of sensor arrays are arranged in a direction substantially coincident with a direction in which the strobe light is collected.
[0111]
(4) A part of the strobe light is irradiated onto the subject by an optical system with a visible light cut filter provided adjacent to a strobe reflector, as described in (2) above camera.
[0112]
(5) The camera according to (1), wherein the sensor array includes a part of an image sensor of an electronic camera.
[0113]
(6) ranging optical system;
A sensor array for detecting an image of a subject via the distance measuring optical system and outputting a pair of image signals;
A strobe means having a discharge arc tube and irradiating the strobe light by causing the discharge arc tube to emit light;
Focusing means for focusing the photographing lens based on the output of the sensor array when the strobe light is irradiated on the subject;
In a camera equipped with
A camera comprising optical means for making the infrared component of the strobe light irradiated on the subject into a pattern and making the visible light component of the strobe light irradiated on the subject a uniform illumination.
[0114]
【The invention's effect】
As described above, according to the present invention, an additional auxiliary light source is not required, and the strobe built into most cameras can be used to focus on a dark place or a low-contrast subject with high accuracy. A camera that can be provided can be provided.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram showing an electrical system of a main part of a compact camera according to a first embodiment of the present invention.
FIGS. 2A and 2B show a configuration of a camera according to a first embodiment of the present invention, in which FIG. 2A is an external perspective view of a compact camera, and FIG. 2B is a view of a strobe unit and a distance measuring lens of FIG. It is the figure which showed the relationship.
FIG. 3 is a diagram for explaining the reason why three pairs of sensor arrays are provided.
FIG. 4 is a flowchart illustrating a control operation performed by a CPU 17 during camera distance measurement.
FIG. 5 is a diagram showing details of a photocurrent integration unit for sensor output for image detection.
FIGS. 6A and 6B show an example of the configuration of the strobe light emitting unit 5 in the first embodiment. FIG. 6A is a sectional view, FIG. 6B is a perspective view, and FIG. It is the figure which showed the example of the incident light.
FIG. 7 is a sectional view of an optical system according to a second embodiment of the present invention.
FIG. 8 is a diagram showing an example of lens arrangement in an actual camera in the second embodiment.
9A is a diagram showing an example of the configuration of a strobe to which a diffractive optical element is applied, and FIGS. 9B and 9C are diagrams showing light projection as shown by 12 in FIG. 2B. FIG. 6B shows an example of the arrangement of diffraction gratings in the case where (b) is a front view, and (c) is an enlarged cross-sectional view of the center portion of the surface 65 on the strobe arc tube 60 side.
FIG. 10 is a formula h = mλ / (n−1) for obtaining the height h of the sawtooth peak of the diffraction grating 65 having a sawtooth shape called the kinoform shown in FIG. FIG. 5 is a diagram showing diffraction spectral characteristics when the diffraction efficiency peak wavelength λ = 1100 nm and m = 1.
11 is a diagram showing an example of the arrangement of diffraction gratings when light is projected as shown at 14 in FIG. 3. FIG.
12A and 12B illustrate a fourth embodiment of the present invention, in which FIG. 12A is an external perspective view of a compact camera according to the fourth embodiment, and FIG. 12B is a viewfinder of the camera of FIG. It is sectional drawing cut | disconnected by the horizontal surface containing the objective window 3, the lens 4 for ranging, the flash window 5a, and the lens 71 with a visible light cut filter.
FIGS. 13A and 13B show a fifth embodiment of the present invention, in which FIG. 13A is a cross-sectional view showing a strobe light emitting portion and its peripheral portion, and FIG. 13B is a diagram of strobe light according to the fifth embodiment; It is the figure which showed the pattern.
14A is a block diagram for explaining a contrast type AF of a digital camera, FIG. 14B is a diagram showing an example of a sensor IR arranged on the image sensor 78 of FIG. 7 is a diagram showing sensitivity characteristics of a filter mounted on an element 78. FIG.
[Explanation of symbols]
1 Camera body,
2 Taking lens,
3 Viewfinder objective window,
4a, 4b light receiving lens,
5 Flash unit,
5a Strobe window,
5b Xenon discharge tube (Xe tube),
6 Release switch,
7 Display section,
10a, 10b sensor array,
11 Visible light,
12 Infrared light,
14C, 14L, 14R Subject detection area,
17 CPU,
18 shutter part,
19 Focusing section,
20 EEPROM,
21 distance measuring device,
22 A / D converter,
23 Stationary light removal circuit,
25 Subject.

Claims (1)

Ranging optics,
A sensor array for detecting an image of a subject via the distance measuring optical system and outputting a pair of image signals;
A strobe means having a discharge arc tube and irradiating the strobe light by causing the discharge arc tube to emit light;
Focusing means for focusing the photographing lens based on the output of the sensor array when the strobe light is irradiated on the subject;
In a camera equipped with
The camera according to claim 1, wherein the strobe means irradiates the subject with strobe light having a pattern-like infrared component and a uniformly irradiated visible light component.

Images