JPS61243432A - Strobe photographing device - Google Patents

Abstract

PURPOSE:To match the angle of irradiation of strobe light with the angle of view of a photographic lens by providing a liquid crystal lens at the opening end of a strobe and varying and controlling the focal length of a liquid crystal lens automatically on the basis of lens focal length information. CONSTITUTION:A strobe flashgun is provided with a strobe discharge tube 21 and a parabolic mirror 22 is provided at its focus position. Further, the liquid crystal lens 24 is provided at the opening part and its focal length is varied and set electrically by an applied voltage varying and setting circuit 25. Further, the liquid crystal lens 24 is provided with a transparent plate 30 made of saw-tooth shaped glass and convex lenses 32a and 32b and liquid crystal is charged in cells A and B between them. Further, electrodes 35a and 35b, and 36a and 36b are provided. Then, information is detected from a lens focal length information output part 52 and voltages to electrodes 35 (35a and 35b) and 36 (36a and 36b) of the liquid crystal lens 24 are controlled 53 on the basis of the detection signal and applied to vary the focal length of the liquid crystal lens 24. Thus, the angle of irradiation of strobe light is matched with the angle of view of the photographic lens to utilize the strobe light efficiently and automatically.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a photographic device using a strobe, and in particular, to the angle of irradiation (spreading angle) of light from a strobe light emitter, and the angle of view of the photographic lens used. 〇 [Prior art] Regarding improvement of means for adapting Strobe light emitters are described in, for example, Camera Review (1984,
As described in No. 33, PP76-79), this is a lighting device for photographing that is generally widely used at present. If this standard strobe light emitter does not have an irradiation angle that matches the angle of view of the photographic lens used, only the center of the photograph will be bright and the periphery will be dark, or conversely the entire photograph will be under-illuminated. It becomes. In order to avoid such problems, conventional methods have been used to match the angle of light emitted from the strobe emitter with the angle of view of the photographic lens used, and to use the illumination light efficiently. They took measures to replace and attach a separate Fresnel lens, etc.

[Problem that the invention seeks to solve]

However, the above method has the drawback that the lens needs to be replaced each time, which makes the operation cumbersome and cannot be dealt with quickly.In addition, there is a problem that the strobe irradiation angle cannot be continuously variably adjusted. In particular, there has been a problem in that it is not possible to deal with zoom lenses, which have been increasingly used recently, in an appropriate and efficient manner.

As a strobe and light emitting device that attempts to solve such problems, there is a strobe light emitting device disclosed in the patent application ``Stroke Device with Liquid Crystal Lens'' (Japanese Patent Application No. 59-226479) filed by the present inventors. A liquid crystal lens is placed in front of the strobe discharge tube, and by controlling the voltage or frequency applied to this liquid crystal lens, the focal length of the lens can be changed to continuously change the irradiation angle to the desired angle. It is something.

However, the above-mentioned "stroll device with liquid crystal lens" K still has the following problems to be solved.

That is, in the above-mentioned apparatus, it is necessary to manually input focal length information of the photographing lens to the light emitting device each time, so there is a problem in that the operability in this respect is poor. In particular, the above problem becomes more noticeable when many interchangeable lenses or zoom lenses are used.

Therefore, the present invention aims to continuously and automatically adjust the irradiation angle of the strogo light to match the angle of view of the photographic lens when the photographing lens is replaced in the same photographic device or when the photographing device itself is replaced. To provide a strobe photographing device which can be set as follows, can efficiently utilize strobe light, and has excellent operability.

[Means for solving problems]

In order to solve the above problems and achieve the objects, the present invention is characterized by taking the following measures. In other words, Stro attaches a liquid crystal lens to the open end of a parabolic mirror with a discharge tube near its focal point, which diffuses the reflected light from the parabolic mirror and illuminates the subject at a predetermined irradiation angle. Applied voltage control means detects information from a lens focal length information output unit provided on the photographing lens side of the device main body by a detection means, and controls the voltage or frequency applied to the liquid crystal lens based on the detected lens focal length information. This feature is characterized in that the irradiation angle of the flash light is variably controlled by changing the focal length of the liquid crystal lens.

[Effect]

By taking such measures, the focal length of the liquid crystal lens is automatically variably adjusted based on the focal length information of the photographing lens.

〔Example〕

Figures 1 and 2 are views showing an embodiment of the present invention. Figure 1 is a front view showing the light emitting device attached to the camera body (hereinafter referred to as the camera), and Figure 2 is the main body of the camera. FIG. 3 is a diagram showing a specific configuration of the main parts of the device.

In FIG. 1, 1o is a camera, and 20 is a strobe light emitter 1c detachably attached to the center of the upper surface of the camera 10 in a sliding manner. t A photographing lens 11 is attached to the center of the front of the camera 10, and a release button 12, a film winding knob 13, etc. are attached to both ends of the top surface. The mirror is □゛.

The strobe light emitter 20 includes an elongated tubular strobe discharge tube 21 as a light source for photographing, a strobe discharge tube 22, a drive circuit 23 for driving the strobe discharge tube 21t to emit light, and the paraboloid. Reflection from mirror 22
□Knee 1, a liquid crystal lens 24 that diffuses the emitted light beam and irradiates the subject at an irradiation angle with a predetermined spread; an applied voltage variable setting circuit 25 that electrically variably sets the focal length of this liquid crystal lens 24; A voltage control circuit 53 is provided.

The strobe light emitter 20 is connected to the X contact of the camera 10, and when a release operation is performed using the release button 12 of the camera JO, the strobe discharge tube 21 discharges in synchronization with this, causing an instantaneous discharge. Emits light to illuminate the subject.

When a photograph is taken under this illumination and the exposure amount reaches the appropriate amount, the exposure amount circuit, etc. that measures the amount of exposure on the film surface by the camera 1oK is activated, and the output signal is used to control the stroke drive circuit 23.
A dirt level of an SCR (not shown) or the like is set to a low level, and at that point, light emission is immediately stopped.

As shown in FIG. 2, the liquid crystal lens 24 in the straw light emitter 20 includes a transparent plate 30 made of a member such as glass having a sawtooth Fresnel structure on both sides, and
Cells A and B are respectively formed between convex lenses 32* and 32b disposed on both sides of the lens via spacers 31* and 31b, and liquid crystals 33m and 33b are sealed in each cell A and B, respectively. It becomes. And this liquid crystal lens 24 is
It is fixed to the open end portion of the parabolic mirror 22 via the frame 34. 35a.

Reference numeral 35b indicates transparent electrodes attached to both surfaces of the transparent plate 30, and 36* and 36b indicate transparent electrodes attached to the inner surfaces of the convex lenses 32h and 32b, respectively, so as to face the electrodes 35h and 35b. . The electrodes 35h and 35b are both grounded, and the other electrodes 36g and 36b are both connected to an AC voltage application terminal 37 via a lead wire. Thus, the liquid crystal 33g in cell A is connected to electrodes 35a, 36h, and K, and the liquid crystal 33b in cell B is connected to electrodes 35b, 3, and 3.
6b, respectively, to obtain an AC voltage when applied.

By the way, as the liquid crystals 33h and 33b sealed in cells A and B on both sides of the transparent plate 30 in the liquid crystal lens 24, nematic liquid crystals having the same characteristics are used, and their optical axes are indicated by arrows 38h and 38b. As shown, alignment processing such as 5-rubbing is performed so that they are perpendicular to each other, and these alignment directions are perpendicular to the optical axis of the liquid crystal lens 24, making it possible to create a variable focal length lens that does not require the use of a polarizing plate. It is configured.

That is, the incident light can be decomposed into two mutually orthogonal polarized components, namely, the orientation direction of the liquid crystal molecules of the liquid crystal 33h in FIG. 2 and the orientation direction of the liquid crystal molecules of the liquid crystal 33b. First, consider the case where a polarized light component parallel to the alignment direction of the liquid crystal 33b, which is a component of the incident light, enters the liquid crystal lens 24. The light beam component in this case becomes an extraordinary light beam with respect to the liquid crystal 33b. Therefore, in this state, the liquid crystal 33b
When a voltage is applied to the electrodes 35b, 36b on both sides of the electrodes 35b, 36b, the liquid crystal molecules gradually change direction in a direction perpendicular to the electrodes 35b, 36b according to the voltage, so that the apparent refraction of the liquid crystal 33b for the extraordinary ray component The rate is the crystal 3 for extraordinary light.
Since the extraordinary light component for 3b becomes an ordinary light component in the liquid crystal JJa, the apparent refractive index does not change and is not affected by the effect of changing the focal length. Therefore, you will continue straight ahead. On the other hand, the liquid crystal 33b which is the other incident light component
The component corresponding to ordinary light does not change the apparent refractive index in this liquid crystal 33b and is not affected by the variable focal length, but
In the liquid crystal 33b, the component corresponds to the extraordinary light, so the apparent refractive index changes according to the applied voltage, similar to when the extraordinary light enters the liquid crystal 33b, resulting in the effect of varying the focal length. become. If the same voltage is applied to the liquid crystals 33b and 33a, they will receive the same focal length variable effect. Therefore, by overlapping the two variable focal length lenses so that their optical axes are perpendicular to each other, the variable focal length lens can operate as a variable focal length lens for polarized light in any direction. In this way, a liquid crystal lens whose focal length can be varied independently of the polarization direction of incident light without using a polarizing plate has been realized.

The AC voltage application terminal 37 is connected to a common terminal of a manual/automatic mode changeover switch 39. This switch 39 is switched to the manual side MA when the photographing lens 11 side is not equipped with a focal length information output function,
If the photographing lens 11 side is equipped with a focal length information output function, the mode is switched to the automatic side AU. In this case, it is desirable to configure the camera so that it is switched to the FiMA side in the normal state and automatically switched to the KAU side when a photographic lens equipped with a focal length information output function is attached.

If a cord with a plug for transmitting lens focal length information is used as a means for this, when the plug of the cord is inserted into the Stroll 2 emitter 20, the switch 39 is set to A U III in conjunction with the plug insertion operation. A means of switching, or a contact provided on the lens mount and a hot switch,
- When transmitting lens focal length information using the contact provided at the switch 35!, the switch 35! '1AUIIllK There is a means for automatically switching.

The applied voltage variable setting circuit 25 is connected to the MA side of the switch 39. This circuit 25 includes a DC power supply 4
0, a DC/AC converter 41 that converts the DC input supplied from this DC power supply 40 into an AC voltage of, for example, about 1 kHz, and voltage dividing resistors 81 to R7 that divide the output voltage of this converter 41. A circuit 42, a selection switch 43 arranged to selectively take out each of the divided voltages v1 to v6 of this voltage dividing circuit 42, and a selection switch 43 that further controls the divided voltages taken out by this selection switch 43 to a predetermined level. It consists of a continuous variable resistor 44 which is variably adjusted and taken out.

In this way, when the photographic lens 1 attached to the camera 91011C is of a standard lens type, the settings are made such that an appropriate irradiation angle can be obtained by selecting, for example, v4 with the selection switch 43. When a narrow-angle lens system is attached as the photographic lens 11, if V51 is selected with the selection switch 43, for example, the applied voltage becomes larger than when a standard lens system is attached, and the liquid crystal 33a.

The refractive index of 33b increases. As a result, the liquid crystal lens 2
The irradiation angle of the light emitted through the lens system 4 is narrowed, so that a range corresponding to the viewing angle of the narrow-angle lens system is efficiently illuminated. Furthermore, when a wide-angle lens is attached as the photographic lens 11, the selection switch 4
For example, when V3t- is selected in 3, the applied voltage becomes smaller than when the standard lens system is attached, and the liquid crystal 33a.

The refractive index of 33b becomes small. As a result, the liquid crystal lens 2
The irradiation angle of the light emitted through the lens system 4 is expanded, and a range matching the viewing angle of the wide-angle lens system can be uniformly illuminated. If a lens system is attached as the photographic lens 11 that cannot be handled by simply switching and setting the selection switch 43, the variable resistor 44 is slid. In other words, it is possible to set an irradiation angle that is suitable for the photographic lens system. In this case, if the resistors R1 to R7'li are semi-fixed resistors, it will be easier to adapt them. Also, shooting lens 1
When a zoom lens system is used as the zoom lens system, a variable resistor 44 is used which has a scale in advance corresponding to the zoom position of the zoom lens system, and this variable resistor 44 is used to make the variable i+iiiu. For example, the illumination angle can be easily adapted to a wide range of viewing angles.

Reference numeral 51 denotes lens focal length information setting means, which has the ability to output focal length information on the photographing lens 11 side; if there is no such function, it artificially sets lens focal length information F and supplies it to the applied voltage variable setting circuit 25. Shows the means.

Reference numeral 52 denotes a lens focal length information detection means, and when the photographing lens 11 side is provided with an output function of lens focal length information, the information F2t is detected and the applied voltage control circuit 5
3.

The detection means 52 can be electrical means or mechanical means depending on the added information output function.

In other words, if the information output function added as an electrical means is one in which each lens has a built-in resistive element (variable resistive element in the case of a zoom lens) that has a unique electrical resistance, the resistance value of that resistive element Means for inputting an electrical signal indicating this as Helen's focal length information F2 to the applied voltage control circuit 53 via a contact provided on the lens mount and a contact on the hokto shoe, which come into contact when the lens is mounted on the camera. Use. In the case of a zoom lens, the resistance value is a change value of a variable resistance element that changes in accordance with the displacement of the zoom operation member, that is, a resistance value commensurate with the focal length. Note that the route for inputting the information F2 to the applied voltage control circuit 53 is not only through the contacts as described above, but also by directly connecting the photographing lens 11 and the flash to the light emitter 20 using a cord with a plug or the like. It may also be done by In this case, it is also possible to remove the stroge light emitter 20 from the camera 10 and use it.

On the other hand, as a mechanical detection means, if the added information output function is a protrusion specific to each lens, that is, the position or amount of protrusion is set to a unique state for each lens, an interlocking mechanism can be used. A means for mechanically operating a switch configured similarly to the selection switch 43 in the applied voltage control circuit 53 is used. In the case of a zoom lens, the position or amount of protrusion of the protrusion changes depending on the displacement of the zoom operation member.

Applied voltage control circuit 53, the applied voltage variable setting circuit 2
5, and can send out a predetermined voltage based on detection information from the detection means 52.

Next, the operation of the apparatus configured as described above will be explained. If the photographing lens 11 side does not have a function to output focal length information, the lighting angle of the flash light is set manually. Based on the lens focal length information F, the selection switch 43 is manually operated to select the resistors R1 to R6'f.
When c is selected, variable resistor 44″ft: Adjust the voltage to be applied to the liquid crystal lens 24 by variable operation as necessary. Then, the predetermined voltage is applied to the liquid crystal lens 24 via the MA side of the mode selector switch 39. As a result, the focal length of the liquid crystal lens 24 changes, and the angle of light irradiation from the flash is set to match the angle of view of the photographing lens 11.

If the photographic lens 11 side has a function to output lens focal length information, the irradiation angle of the strobe light is automatically set. That is, when such a photographing lens 1 is attached to the camera 10, the mode changeover switch 39 is switched to the AU side.

Then, the focal length information F2 of the photographing lens 11 is detected by the lens focal length information detection means 52, and is supplied to the applied voltage control circuit 53. Then, the applied voltage control circuit 53 is activated, and a predetermined voltage is applied to the liquid crystal lens 24 via the AU side of the mode changeover switch 39. As a result, the focal length of the liquid crystal lens 24 changes, and the irradiation angle of the strobe light is automatically set to match the angle of view of the photographic lens 11.

In this way, in this embodiment, a predetermined voltage can be applied from the applied voltage variable setting circuit 25 to the liquid crystal lens 24, which is provided so that its focal length can be varied according to the applied voltage. Therefore, the angle of view of the photographic lens 11 and the irradiation angle of the strobe light can be matched, and efficient illumination can be performed appropriately in accordance with the photographic lens 1 of the camera used. In particular, when a focal length information output function is added to the photographic lens 11 side, the information is detected by the lens focal length information detection means 52, and the applied voltage control circuit 53 operates to automatically set the irradiation angle. The operation is extremely simple, and you can take good pictures under appropriate lighting without losing the opportunity to take a photo. Moreover, even if the photographing lens 11 is a zoom lens whose viewing angle constantly changes, the applied voltage is automatically (variably set) in conjunction with the zoom operation member, so that proper irradiation can be achieved just like other lenses. The angle can be set.In addition, since strobe light can be used most efficiently, it is possible to improve the effective guide number when shooting with a lens with a long focal length.

Note that the present invention is not limited to the embodiments described above. For example, as the liquid crystal lens 24, a liquid crystal lens having a structure in which the radius of curvature is different in the vertical direction and the horizontal direction may be used. The focal length of the liquid crystal lens 24 may be varied by changing the frequency instead of changing the magnitude of the applied voltage, or by changing both the voltage magnitude and frequency at the same time. It may also be a means for variable control. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

The present invention is equipped with a liquid crystal lens that diffuses the reflected light beam from the parabolic mirror and irradiates it onto the subject at a predetermined irradiation angle. The detection means detects information from a lens focal length information output section provided on the photographing lens side of the photographing device main body, and applies a voltage or frequency to the liquid crystal lens based on the detected lens focal length information. It is characterized in that it is variably controlled by voltage control means, and the focal length of the liquid crystal lens is changed to variably adjust the angle of light irradiation from the straw.

According to the present invention, the focal length of the liquid crystal lens is automatically variably adjusted based on the focal length information of the photographing lens. As a result, even when the photographic lens is replaced in the same photographic device, or when the photographic device itself is replaced, the irradiation angle of the strobe light is continuously adjusted to match the angle of view of the photographic lens. Automatically determined,
It is possible to provide a strogo photography device that can efficiently utilize strogo light and has excellent operability.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing one embodiment of the present invention, with Figure 1 being a front view showing Metro with the light emitting device attached to the camera, and Figure 2 showing the specific configuration of the main parts. It is a diagram. 10...Camera 2.11...Photographing lens, 20...
Stroge light emitter, 21... parabolic mirror, 22... Stroge? Discharge tube, 23... Drive circuit, 24... Liquid crystal lens, 25... Applied voltage variable setting circuit, 30... Transparent plate, 31 m, 3 l B-spacer, 32 a
, J J b ... Convex lens, 33*, 33b...
・Liquid crystal, 34...7 rams, 35 m, 35 b
, 36 m, 36 b --- transparent electrode, 39
. . . Manual/automatic mode changeover switch, 5. . . . Lens focal length information setting means, 52 . . . Lens focal length information detection means, 53 . . . Applied voltage control circuit. Applicant's agent Patent attorney Atsushi Tsuboi Figure 1

Claims (1)

[Claims] A strobe discharge tube, a parabolic mirror with the strobe discharge tube placed near the focal point, and a parabolic mirror attached to the open end of the parabolic mirror to diffuse the reflected light flux from the parabolic mirror and achieve a predetermined irradiation angle. A liquid crystal lens that illuminates the subject, a detection means that detects information from a lens focal length information output section provided on the photographing lens side of the photographing device body, and a lens focal length information detected by this detection means. What is claimed is: 1. A strobe photographing device comprising applied voltage control means for automatically and variably adjusting the focal length of the liquid crystal lens by variably controlling the voltage or frequency applied to the liquid crystal lens.