JP4596862B2 - Strobe device and camera equipped with the same - Google Patents

Description

  The present invention relates to a strobe device for a camera.

  In camera photography, a strobe light source such as a lamp has been conventionally used as illumination in a dark place. When a light source such as a lamp is used, a hemispherical reflecting mirror is provided on the back side of the light source, and the light is condensed and illuminated so as to draw a parabola toward the subject. However, in recent years, among the demands for miniaturization, those using light-emitting diodes (hereinafter referred to as LEDs) as strobe light sources have begun to spread. A digital camera, a mobile phone with a camera function, or the like using an LED light source can be seen.

  When an LED is used as a strobe light source, the configuration shown in FIG. 9 is generally used. FIG. 9 shows a conventional block diagram of a strobe device using LEDs. That is, as shown in FIG. 9, a Fresnel lens 2 is disposed in front of the LED 1 to illuminate the subject using the LED light as parallel light. Since the light from the LED 1 has directionality, the light does not reach too far. Therefore, the Fresnel lens 2 is disposed in front of the LED 1 so that the light from the LED 1 is collimated and condensed so that the brightness is uniform and the light can reach as far as possible. . In addition, there is a configuration in which a diffusion plate is disposed between the LED 1 and the Fresnel lens 2 in order to increase the brightness as much as possible.

  However, with the configuration as described above, when photographing a subject at a short distance, the strobe illumination is too bright and the center of the photograph cannot be clearly seen. In particular, when a book or the like is copied, there is a problem that the characters are not clearly visible and the characters cannot be read.

  The present invention has been made in view of the above problems, and provides a strobe device that clearly and clearly captures even at a short distance.

As a means for solving the above problems, the strobe device of the present invention is a strobe device in which a liquid crystal element using a polymer dispersed liquid crystal is arranged in front of an LED that constitutes a point light source , wherein the liquid crystal element is transparent. A pair of substrates made of glass, that is, a lower substrate and an upper substrate are arranged to face each other with a certain gap, and a circle electrode that is a lower transparent electrode is a circular electrode and an annular electrode on the inner surface of the lower substrate An upper transparent electrode is also provided on the inner surface of the upper substrate, the polymer-dispersed liquid crystal is sealed via a sealing material, a power supply electrode is connected to the circle electrode, and one end is the lower electrode It extends to the outer edge of the substrate, and its tip is a connection terminal, and connection electrodes are provided between the circle electrodes and between the circle electrode and the feeding electrode.

The circle electrode is a single circular electrode provided at the center of the lower substrate.

The circle electrode includes a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is formed on the circular electrode. An opening is provided at each position that crosses the line in a straight line, and the opening is connected to provide a single linear feed electrode formation path. The feed electrode formation path is connected to the feed electrode and the feed electrode. Thus, connection electrodes connected to the respective electrodes of the circle electrode, that is, the circular electrode and the annular electrode are provided.

Furthermore, the circle electrode comprises a circular electrode provided in the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and the circular electrode is formed on a part of the annular electrode. An opening is provided at each position that crosses the line linearly, and a single linear feed electrode formation path is provided by connecting the openings, and the first feed electrode and the first feed electrode are formed on the feed electrode formation path. A first connection electrode connected to each of the circle electrodes, ie, the circular electrode and the annular electrode, a second power supply electrode, the second power supply electrode, A second connection electrode that connects the circle electrode to the circular electrode is provided.

The circle electrode includes a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode. An opening is provided at each position that crosses the line in a straight line, and the opening is connected to provide a single linear feed electrode formation path. The feed electrode formation path is connected to the feed electrode and the feed electrode. A connection electrode connected to the circular electrode of the circle electrode, and a connection electrode connecting the circular electrode and the annular electrode, and a connection electrode connecting the annular electrodes to each other.

The circle electrode includes a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is formed on the circular electrode. An opening is provided at a position that crosses the line in a straight line toward each other, and the opening is connected to provide a single linear feed electrode formation path. The first feed electrode and the first feed electrode are formed on the feed electrode formation path. A connection electrode connected to the power supply electrode and connected to the circular electrode of the circle electrode, a connection electrode connecting the circular electrode and the annular electrode, and a connection electrode connecting the annular electrodes to each other; A second power supply electrode is provided, and a connection electrode connected to the second power supply electrode and connected to the outermost annular electrode of the circle electrode is provided.

Furthermore , the circle electrode comprises a circular electrode provided in the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and the circular electrode is formed on a part of the annular electrode. An opening is provided at a position that crosses the line linearly toward each other, and a single linear feed electrode forming path is provided by connecting the openings. The feed electrode forming path includes a plurality of feed electrodes and the plurality of feed electrodes. Connecting electrodes connected to the respective electrodes of the circle electrode, that is, the circular electrode and the annular electrode, are connected to the feeding electrode.

Further, the voltage applied to the circle electrode is different for each electrode. The voltage applied to the circle electrode can be adjusted in 5 to 10 steps for each electrode, and the voltage adjustment in 5 to 10 steps is performed in conjunction with the focal length. The connection electrodes connected to the respective circle electrodes are configured such that the electrode lengths are constant and the electrode widths are different.

The circle electrode and the connection electrode are made of the same material and are made of a metal film having a high sheet resistance. Further, the power supply electrode is formed from a metal film having a low sheet resistance.

  The strobe device of the present invention has a configuration in which a liquid crystal element using a polymer dispersed liquid crystal is disposed in front of a light source, and this liquid crystal element has regions where light transmittance from the light source is different from the first to the fifth floor. Divided into keys. And the area | region divided | segmented into 1-5 gradations here makes circular shape, or the concentric circular shape which surrounds this circular shape.

  Further, in the region divided into 1 to 5 gradations, the transmittance can be adjusted in 5 to 10 stages, and the adjustment is performed in conjunction with the focal length.

  Further, PNLCD liquid crystal is used as the polymer dispersed liquid crystal used in the liquid crystal element of the present invention.

  In addition, a camera equipped with a strobe device includes the strobe device of the present invention described above.

  As an effect of the invention, the liquid crystal element using the polymer dispersed liquid crystal is disposed at the front part of the light source because the light of the light source is extinguished to reduce the amount of light and reduce the light intensity. When a liquid crystal element using a polymer dispersed liquid crystal is used, transmitted light and scattered light from the liquid crystal element are adjusted by adjusting a voltage applied to the liquid crystal element. That is, the light transmittance and the degree of light scattering are adjusted to produce a dimming effect. Due to this dimming action, it is possible to take clear pictures even at short distances.

  Moreover, LED makes a point light source. Accordingly, light is emitted in a state of being circular in the vicinity of the light source. Therefore, if the transparent electrode to which the voltage of the liquid crystal element is applied is composed of a circular electrode or a circle electrode composed of a circular electrode and an annular electrode, the light from the light source can be effectively used in a small area. In addition, it is also required to photograph a subject including a three-dimensional subject and a background beautifully. In such a case, if the gradation of the dimming degree due to transmittance or scattering is performed not only with one gradation but with a plurality of gradations, and the degree of dimming is changed, an overall clear image is obtained. can get. The number of gradations of the dimming degree is determined by the number of gradation divisions of the circle electrode. The larger the number of gradations of the electrode, the better. However, the number of divisions of 1 to 5 gradations is generally sufficient.

  If different voltages are applied to each electrode of the circle electrode, that is, for each electrode of the divided gradation, gradations having different degrees of dimming can be obtained. In the case of short-distance shooting, generally, the subject is often brought to the center of the photo. Therefore, if the central circular portion is made to have a higher dimming degree and the dimming degree is sequentially set lower as it goes to the outer periphery, the overall light hitting condition is made uniform and the whole is made uniform. A clear image can be obtained. Furthermore, each electrode of the divided gradation needs to change the transmittance or the degree of light attenuation due to scattering according to the change in the focal length. If the degree of dimming does not change appropriately depending on the focal length, a clear picture cannot be obtained at all times. Many current cameras are of the autofocus type, and the focal length is automatically adjusted. In the present invention, the applied voltage can be adjusted in 5 to 10 steps for each electrode of the circle electrode based on the signal of the automatic focal length. The degree of light reduction due to transmittance and scattering can be adjusted in 5 to 10 stages. This can be achieved by incorporating a voltage adjustment function on the drive circuit side of the liquid crystal element. As described above, when the voltage is adjusted in conjunction with the automatic focal length, the dimming degree is adjusted according to the distance, and a clear image is always obtained even if the focal length changes.

  In the present invention, as a first configuration in which a different voltage is applied to each electrode of the circle electrode, a single feeding electrode forming path formed of a straight line across the annular electrode of the circle electrode is provided, and the feeding electrode forming path One first power supply electrode and a first connection electrode connected to each electrode of the circle electrode in connection with the first power supply electrode are provided. The first connection electrodes have a certain length, and the electrodes have different widths. In addition, the feeding electrode forming path is formed by providing an opening in the annular electrode of the circle electrode at a position crossing in a straight line toward the circular electrode, and connecting these openings. The circle electrode and the first connection electrode are formed from a metal film having a high sheet resistance. The first power supply electrode is formed from a metal film having a low sheet resistance. In this configuration, a predetermined current / voltage is applied to one power supply electrode from the outside, and a required voltage is applied to each electrode of the circle electrode via each first connection electrode. The voltage is obtained by setting the width of the first connection electrode formed from a metal film having a high sheet resistance. With such a configuration, a desired applied voltage can be obtained with only one external connection terminal. In addition, the size of the liquid crystal element can be reduced. Further, the liquid crystal driving circuit may be a relatively simple circuit. Further, the voltage drop can be suppressed to a low level by forming the first power supply electrode with a metal film having a low sheet resistance.

  Further, a second power supply electrode is provided in the power supply electrode formation path along with the first power supply electrode, and is connected to the second power supply electrode and connected to the circular electrode of the circle electrode. The structure which provides an electrode is taken. As a result, even if voltage fluctuation due to temperature change occurs, voltage adjustment is possible by applying a voltage from the two directions of the first power supply electrode and the second power supply electrode. A stable applied voltage can be obtained. This produces an effect that a stable state can always be obtained in the degree of dimming.

  In the present invention, as a second configuration in which a different voltage is applied to each circle-shaped electrode, a single first feeding electrode made of a straight line across the annular electrode of the circle electrode is provided and connected to the feeding electrode. Thus, a first connection electrode is provided which includes a connection electrode connected to the circular electrode of the circle electrode and a connection electrode connecting adjacent electrodes of the circle electrode. The circle electrode and the first connection electrode are formed from a metal film having the same material and high sheet resistance. The first power supply electrode is formed from a metal film having a low sheet resistance. In this configuration, the width of the first connection electrode provided between adjacent electrodes of the circle electrode is adjusted to obtain a desired applied voltage. By adopting this configuration, a desired applied voltage can be obtained with a single connection terminal to the outside. In addition, the liquid crystal element can be downsized. Further, the liquid crystal driving circuit may be a relatively simple circuit. Further, the voltage drop can be suppressed to a low level by forming the first power supply electrode with a metal film having a low sheet resistance.

  Furthermore, a second power supply electrode and a second connection electrode connected to the second power supply electrode and connected to the outermost annular electrode of the circle electrode are provided. As a result, even if voltage fluctuation due to temperature change occurs, voltage adjustment is possible by applying a voltage from the two directions of the first power supply electrode and the second power supply electrode. A stable applied voltage can be obtained. This produces an effect that a stable state can always be obtained in the degree of dimming.

In the present invention, as a second configuration for applying a different voltage for each circle-shaped electrode,
The power supply electrode connected to each of the circle electrodes is provided. That is, since the power supply electrode is provided for each electrode of the circle electrode, the number of power supply electrodes is increased, but the voltage applied to each electrode of the circle electrode can be freely set, and the error of the applied voltage is reduced. Also, the applied voltage can be easily adjusted against voltage fluctuations due to temperature changes, and a stable voltage distribution can be obtained. This produces an effect that a stable state can always be obtained in the degree of dimming.

  In the present invention, PNLCD liquid crystal is selected as the polymer dispersed liquid crystal used in the liquid crystal element. This PNLCD responds at a low voltage of 1 V to 3 V, and the response speed is as fast as 10 to 30 ms. Further, since it has a remarkable light dispersion action, it can be applied as a liquid crystal material suitable for the present invention.

  If the camera is equipped with the strobe device configured as described above, it is possible to take a beautiful and clear picture even at a close distance.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. First, the illustration will be briefly described. FIG. 1 is a layout view showing the configuration of the strobe device according to the first embodiment of the present invention. 2 is a cross-sectional view of the main part of the liquid crystal element in FIG. 1, and FIG. 3 is a plan view of the lower substrate in FIG. 4 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the second embodiment of the present invention. FIG. 5 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the third embodiment of the present invention. 6 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the fourth embodiment of the present invention. FIG. 7 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the fifth embodiment of the present invention. The figure is shown. FIG. 8 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the sixth embodiment of the present invention.

  First, the configuration of the strobe device according to the first embodiment of the present invention will be described with reference to FIG. Reference numeral 10 denotes a light source. In the present embodiment, an LED is used. However, the LED is not particularly limited to the LED, and a light source having a light source close to a point, for example, a bean lamp may be used. A liquid crystal element 20 is a liquid crystal element using a polymer dispersed liquid crystal. The liquid crystal element 20 has a configuration in which the liquid crystal element 20 is disposed on the front portion of the light source 10, that is, on the light emitting surface side of the light source 10. In FIG. 1, the liquid crystal element 20 is disposed in front of the light source 10, light emitted from the light source 10 enters the liquid crystal element 20, the light is dispersed by the liquid crystal element 20, and the dispersed light is the liquid crystal element 20. The state radiated from is schematically depicted. Although not shown, a subject is present on the radiation surface side of the light dispersed from the liquid crystal element 20.

  The structure of the liquid crystal element 20 for dispersing light will be described with reference to FIGS. As shown in FIG. 2, the liquid crystal element 20 includes a pair of substrates made of transparent glass, that is, a lower substrate 21 and an upper substrate 31 facing each other with a certain gap. A circle electrode 22 as a lower transparent electrode is provided on the inner surface, and an upper transparent electrode 32 is also provided on the inner surface of the upper substrate 31. The polymer-dispersed liquid crystal 35 is sealed with a sealing material 37. Although not shown in the figure, insulating spacers are dispersed in the sealing material 37, and a certain gap is secured with the spacers.

  In addition to the circle electrode 22, the lower substrate 21 is provided with a feeding electrode 25 connected to the circle electrode 22 as shown in FIG. 3. The circle electrode 22 here is a single circular electrode provided substantially at the center. The power supply electrode 25 is provided to apply a predetermined voltage to the circle electrode 22 from the outside. One end of the power supply electrode 25 extends to the outer edge of the lower substrate 21, and the tip thereof serves as a connection terminal.

Here, the lower substrate 21 and the upper substrate 31 are made of transparent glass. As the glass, soda glass, quartz glass, borosilicate glass, normal plate glass, or the like is used, and most glass having a thickness of 0.3 to 1.1 mm is selected. The circle electrode 22 and the upper transparent electrode 32 are formed of a metal film made of an indium oxide ITO (Indium Tin Oxide) film doped with tin. This ITO film is formed by a vacuum deposition method, a sputtering method, a CVD method or the like and then formed into a desired shape by an etching method. In the present embodiment, the circle electrode 22 and the upper transparent electrode 32 are both circular circular electrodes. Moreover, in order to obtain a high voltage, it is formed thinly to a thickness of 100 to 200 mm, and has a high sheet resistance value of about 10 kΩ to 500 Ω / cm ² .

  The polymer-dispersed liquid crystal 35 is obtained by dispersing liquid crystal fine particles of 0.5 to several μm in a polymer material. The polymer dispersed liquid crystal 35 has a light transmission state (transparent) and a light scattering state (white turbidity) depending on the presence or absence of an electric field. Change between. As such liquid crystal, PNLCD, PDLCD, NCAP, PSCT and the like are known. In this embodiment, PNLCD (polymer network liquid crystal) is used. This PNLCD is a mixed material of a polymer material (monomer) and a liquid crystal material (for example, nematic liquid crystal), and is a liquid crystal in which monomers are polymerized by ultraviolet irradiation to form a polymer network. It becomes transparent when a predetermined voltage is applied, and becomes cloudy when no voltage is applied. This PNLCD responds at a low voltage of 1 V to 3 V, and the response speed is as fast as 10 to 30 ms. Further, since it has a remarkable light dispersion action, it can be applied as a liquid crystal material suitable for the present invention.

  An epoxy resin, an acrylic resin, or the like is used as the material of the sealing material 37, and an insulating spacer having a required particle diameter is blended in order to provide a gap (gap) therein. As the spacer material, glass balls or glass fibers are used.

The power supply electrode 25 is provided to apply a required voltage to the circle electrode 22, but is formed of a material having good conductivity because it is necessary to suppress a voltage drop as small as possible. As these materials, copper, gold, aluminum, chrome and the like can be selected. From the viewpoint of corrosion resistance, gold is preferable. For example, when a gold metal film is formed on the power supply electrode 25 to a thickness of 1000 to 3000 mm, a low sheet resistance value in the range of 10Ω to 1Ω / cm ² can be obtained.

  Next, the operation and effect of the liquid crystal element 20 having the above configuration will be described. A liquid crystal element using a PNLCD becomes cloudy when no voltage is applied, and becomes transparent when a required amount of voltage is applied. White turbidity is caused by scattering due to a difference in refractive index between the liquid crystal and the polymer network (PN), and transparency is caused by the disappearance of the refractive index difference between the liquid crystal and the PN. In the transparent state, light is transmitted almost 100% through the liquid crystal material. As the voltage is gradually increased from 0 to a voltage that becomes transparent, the degree of light scattering decreases sequentially, and the transmittance increases sequentially. And finally, the cloudy state turns into a completely transparent state. To take a picture at a short distance, it is necessary to weaken the light of the flash that hits the subject. In order to weaken this light, a liquid crystal element is arranged in the front part of the strobe, and the brightness is adjusted so that the subject can be clearly seen by adjusting the light transmittance and the degree of dimming due to light scattering. Such a good brightness is set at an optimum voltage amount between the applied voltage 0 and the voltage amount that becomes transparent. A moderate brightness can be obtained with the light transmittance and the degree of light reduction due to scattering under this optimum voltage.

  The brightness with which the subject is clearly visible varies depending on the focal length of the subject. Therefore, it is necessary to change the applied voltage depending on the focal length. That is, if the distance of the subject is far, the applied voltage is increased to increase the light transmittance and reduce the degree of scattering. That is, the degree of dimming is reduced. In this way, moderate brightness is obtained because the light reaches far. Many of the recent cameras have an autofocus function, and the lens position is automatically adjusted by a focal length signal obtained. The applied voltage is adjusted using the focal length signal. Adjustment of the applied voltage according to the focal length can be performed by incorporating it in the driving circuit of the liquid crystal element. Here, the voltage adjustment based on the focal length is sufficient if it can be adjusted in a range of 5 to 10 steps for short-distance shooting. Even if it is increased from 10 levels, the clearness of the image does not change much. Also, if there are less than 5 stages, defocusing will appear.

  The light transmittance and the degree of scattering are also affected by the size of the gap amount (the gap amount between the upper and lower substrates). When the gap amount is small, the light scattering is small and the transmittance is high. Further, when the gap amount is large, a high applied voltage is required. In general, the gap amount is preferably set in the range of 3 to 8 μm.

  As described above, by disposing a liquid crystal element using polymer dispersed liquid crystal in the front part of the strobe, it is possible to obtain a clear photographic image with a moderately bright subject. In addition, when the subject is at a long distance, a photograph in the same state as when the liquid crystal element is not provided can be obtained by photographing with the liquid crystal element in a state of 100% light transmittance.

  Next, a liquid crystal element of a strobe device according to a second embodiment of the present invention will be described with reference to FIG. Here, FIG. 4 shows a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the second embodiment of the present invention. The liquid crystal element of the second embodiment is different from the liquid crystal element of the first embodiment described above only in the configuration of a circle electrode provided on the lower substrate, and the other components are the same as the liquid crystal element of the first embodiment. Taking the configuration. That is, the upper substrate is provided with an upper transparent electrode, and the lower substrate is provided with a circle electrode 42 divided into three gradations as a transparent electrode, as shown in FIG. A first connection electrode 46 connected to the first power supply electrode 45 and connected to each gradation electrode of the circle electrode 42 is provided. The upper substrate and the lower substrate provided with these electrodes are arranged to face each other with a certain gap, and a polymer dispersed liquid crystal is sealed through a sealing material. The components such as the upper substrate, the upper transparent electrode, the polymer dispersed liquid crystal, and the sealing material have exactly the same specifications as those of the first embodiment described above, and detailed description thereof is omitted here. To do. Further, the liquid crystal element of the present embodiment is also used by being disposed in the front part of the light source.

  In the liquid crystal element of the present embodiment, as shown in FIG. 4, a circle electrode 42 as a lower transparent electrode is provided on the lower substrate 41. The circle electrode 42 is a round circle electrode 42a provided substantially at the center. And two annular electrodes 42b and 42c provided concentrically on the outer peripheral area of the circular electrode 42a. And each boundary part of this circular electrode 42a and the annular electrodes 42b and 42c is provided with a fixed gap | interval (gap amount of 10-20 micrometers). In addition, openings are provided in portions of the annular electrodes 42b and 42c so as to cross a straight line toward the circular electrode, and a single linear feed electrode forming path 48 is provided by connecting the openings. Then, in this formation path 48, one first feeding electrode 45 made of a straight line, and each electrode of the circle electrode 42 connected to the feeding electrode 45, that is, a circular electrode 42a, an annular electrode 42b, an annular electrode 42c. A first connection electrode 46 is provided for connection to each. The first connection electrode 46 is composed of connection electrodes 46a, 46b, and 46c in FIG. One end of the first power supply electrode 45 extends to the outer edge of the lower substrate 41, and that end serves as a connection terminal with the outside. Voltage supply to each electrode of the circle electrode 42 is configured to be performed via the first power supply electrode 45 and the first connection electrode 46. That is, the voltage application of the circle electrode 42 to the circular electrode 42a is performed through the path of the first supply electrode 45 → the connection electrode 46a → the circular electrode 42a. Similarly, the voltage application to the annular electrode 42b is performed through the path of the first supply electrode 45 → the connection electrode 46b → the annular electrode 42b. The same applies to the annular electrode 42c. The width of the feeding electrode forming path 48 is formed in the range of 50 to 100 μm. If this width is too large, it will affect the light transmittance and the uniformity of the degree of scattering. When it is in the range of 50 to 100 μm, it hardly affects the transmittance and the degree of scattering.

  Here, the connection electrodes 46a, 46b, and 46c are formed of an ITO metal film having a high sheet resistance and made of the same material as the circular electrode 42a and the annular electrodes 42b and 42c. The lengths are set to the same fixed length, and the widths of the electrodes are set to different widths. The resistance value is changed by sequentially changing the width, and the voltage applied to each electrode of the circle electrode 42 is changed. In FIG. 4, the first connection electrode 46a connected to the center circular electrode 42a has the smallest width, the first connection electrode 46c connected to the annular electrode 42c has the largest width, and the annular electrode 42b. The width of the first connection electrode 46b connected to is set to the middle width between the connection electrode 46a and the connection electrode 46c. If the width of the connection electrode 46 is reduced, the electrical resistance increases, causing a voltage drop and lowering the applied voltage. Conversely, when the width is increased, the resistance decreases, the voltage increases, and the applied voltage increases. Also, the first supply electrode 45 is formed of a material having good conductivity such as copper, gold, aluminum, and chromium in order to suppress the voltage drop, similarly to the supply electrode described in the first embodiment. good. In consideration of corrosion resistance and the like, it is preferable to form a gold metal film having a low sheet resistance in the same manner as the power supply electrode of the first embodiment described above.

  In the liquid crystal element having the above configuration, the voltages applied to the circular electrode 42a, the annular electrode 42b, and the annular electrode 42c increase in the order of the circular electrode 42a <the annular electrode 42b <the annular electrode 42c. Therefore, the liquid crystal located at the circular electrode 42a portion has a low applied voltage, and therefore, scattering is increased, the transmittance is low, and the degree of dimming is increased. On the other hand, the liquid crystal at the portion of the annular electrode 42c has a high applied voltage, so that the scattering is reduced, the transmittance is increased, and the degree of dimming is reduced. In the liquid crystal located at the annular electrode 42b portion, the degree of dimming between the circular electrode 42a portion and the annular electrode 42c portion is obtained. This means that three levels of brightness can be obtained within the same distance. This also means that the brightness of the illumination can be adjusted for each subject having a different distance with respect to a plurality of subjects having a slightly different distance. This makes it possible to obtain a picture of a clear image as a whole with uniform brightness for any subject.

  Further, the arrangement structure of each electrode is relatively simple, and only one connection terminal with the outside is required, so that it is easy to reduce the size.

  Also in this embodiment, the applied voltage is adjusted according to the focal length with the subject, and the brightness of the illumination is adjusted. The applied voltage needs to be changed depending on the focal length. In other words, if the subject is far away, it is necessary to increase the applied voltage to increase the light transmittance and reduce the degree of scattering. That is, it is necessary to reduce the degree of dimming. In this way, since the light reaches far, a moderate brightness is given to a subject with a long distance. This adjusts the applied voltage using a focal length signal obtained from the autofocus function. Adjustment of the applied voltage according to the focal length can be performed by incorporating it in the driving circuit of the liquid crystal element. As described above, even if the focal length varies, the applied voltage is adjusted in accordance with the fluctuation of the focal length. Therefore, the brightness of the illumination is adjusted according to the distance, and a clear video picture can be obtained. Here, the voltage adjustment based on the focal length is sufficient if it can be adjusted in a range of 5 to 10 steps for short-distance shooting. Even if it is increased from 10 levels, the clearness of the image does not change much. Also, if there are less than 5 stages, defocusing will appear.

  The circle electrode 42 shown in FIG. 4 is composed of electrodes divided into three gradations. However, as the number of divided gradations increases, the number of regions with different dimming levels increases, and even if there is a difference in distance. Make the brightness uniform. Therefore, a uniform and clear image can be obtained over the entire photograph. However, for short-distance shooting of about several tens of centimeters, a large number of gradation divisions are not necessary, and a sufficiently clear photograph can be obtained with at most five gradation divisions.

  In the present embodiment, the circle electrode 42 is tailored in a circular shape. In the case of using a point light source such as an LED, light is emitted in a state of being circular in the vicinity of the light source. Therefore, the light of the light source can be effectively used in a small area by taking a shape according to it. This also applies to the first embodiment described above.

  Next, a method for forming the circle electrode 42, the first connection electrode 46, and the first power supply electrode 45 provided on the lower substrate 41 will be described. First, a deposited film made of ITO is formed on the entire upper surface of the lower substrate 41 on the lower substrate 41 by a vacuum deposition method with a thickness of 100 to 200 mm. Next, a paste is prepared by mixing organic gold with an oxidizing resin, and using this paste, a gold paste print film is formed to a thickness of 5 to 10 μm using a screen printer at a place where the first feeding electrode 45 is provided. Form with. Use an organic solvent whose boiling point is not so high, and select an organic solvent that does not leave a resin component evaporated at a temperature of about 500 ° C. The printed film of the gold paste is formed on the deposited ITO film. Next, baking is performed at a temperature of about 500 ° C., the resin content of the gold paste printing film is completely evaporated, and gold is baked on the ITO vapor deposition film. As a result, a gold metal film having a thickness of 1000 to 2000 mm can be obtained.

  Next, a positive photoresist film is formed on the ITO vapor deposition film and the gold metal film by a method such as printing. This positive photoresist film is a photosensitive material that has the property of being decomposed by ultraviolet irradiation to become soluble in the developer and removed from the substrate surface during development. Next, the portions corresponding to the respective electrodes of the circle electrode 42 (circular electrode 42a, annular electrodes 42b, 42c), the first feeding electrode 45, and the respective electrodes (46a, 46b, 46c) of the first connection electrode 46 are made opaque. The positive type photomask is placed on the resist film and irradiated with ultraviolet rays. Parts other than each electrode (circle electrode 42a, annular electrodes 42b, 42c), first power supply electrode 45, and first connection electrode 46 (46a, 46b, 46c) of the circle electrode 42 on the photomask are transparent. Therefore, ultraviolet rays are transmitted and irradiate the resist film. As a result, the resist film in portions other than the respective electrodes (circular electrode 42a, annular electrodes 42b, 42c) of the circle electrode 42, the first feeding electrode 45, and the respective electrodes (46a, 46b, 46c) of the first connection electrode 46. Is decomposed and becomes soluble in the developer, so that each electrode of the circle electrode 42 (circular electrode 42a, annular electrodes 42b, 42c), the first power supply electrode 45, and the first connection electrode 46 (with the developer) 46a, 46b and 46c) are removed from the resist film. Next, in order to finish the gold metal film for the first power supply electrode 45 to a required size, the exposed gold metal film is immersed in a gold metal film stripping solution and peeled off. Next, each electrode of the circle electrode 42 (circular electrode 42a, annular electrodes 42b, 42c), the first feeding electrode 45, and the first connection electrode 46 (46a, 46b) is immersed in an etching solution for ITO. , 46c), the exposed ITO film is removed. Finally, the remaining resist film, that is, each electrode of the circle electrode 42 (circular electrode 42a, annular electrodes 42b, 42c), each of the first feeding electrode 45, and each electrode (46a, 46b) of the first connection electrode 46 46c) The upper resist film is removed by immersing in a resist stripping solution. As a result, a pattern of each electrode (circle electrode 42a, annular electrodes 42b, 42c) of the circle electrode 42, the first feeding electrode 45, and each electrode (46a, 46b, 46c) of the first connection electrode 46 is obtained.

  By adopting the above forming method, each electrode of the circle electrode 42 (circular electrode 42a, annular electrodes 42b, 42c) and each electrode (46a, 46b, 46c) of the first connection electrode 46 are formed together. Manufacturing costs can be reduced. Further, since the formation method using the photoresist and the photomask method is adopted, the dimensional accuracy is high, and the widths of the respective electrodes (46a, 46b, 46c) of the first connection electrode 46 can be accurately finished with desired dimensions. . In addition, since the dimensions can be managed with high accuracy, a large number of annular electrodes having a large number of gradation divisions can be provided.

  Next, a liquid crystal element of a strobe device according to a third embodiment of the present invention will be described with reference to FIG. Here, FIG. 5 shows a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the third embodiment of the present invention. As shown in FIG. 5, the liquid crystal element according to the third embodiment is different from the liquid crystal element according to the second embodiment described above in that the second power supply electrode 55 b is provided in the power supply electrode formation path 58 of the lower substrate 51. And a second connection electrode 57 connected to the center circular electrode 52a and newly connected to the power supply electrode 55b.

  As shown in FIG. 5, a circle electrode 52 is provided on the lower substrate 51. The circle electrode 52 is composed of an electrode divided into three gradations of two annular electrodes 52b and 52c provided concentrically with a central circular electrode 52a. Each of the two annular electrodes 52b and 52c is provided with an opening, and a straight feeding electrode forming path 58 is provided by connecting the openings. The power supply electrode forming path 58 is provided with one first power supply electrode 55a and a first connection electrode 56 that is connected to the first power supply electrode 55a and connected to each electrode of the circle electrode 52. ing. The first connection electrode 56 includes a connection electrode 56a connected to the first power supply electrode 55a and connected to the circular electrode 52a, and a connection electrode 56b connected to the first power supply electrode 55a and connected to the annular electrode 52b. The connection electrode 56c is connected to the first electrode 55a and connected to the annular electrode 52c. Furthermore, one second power supply electrode 55b and a second connection electrode 57 connected to the second power supply electrode and connected to the circular electrode 42a are provided.

  Here, the circle electrode 52, the first connection electrode 56, and the first power supply electrode 55a have exactly the same specifications as the circle electrode, the first connection electrode, and the first power supply electrode in the second embodiment described above. Forming. The second connection electrode 57 is formed of a metal film made of ITO having a high sheet resistance, like the first connection electrode 56. Note that the length and width of the second connection electrode 57 are not particularly limited, and may be set as appropriate. The second power supply electrode 55b is preferably formed of a gold metal film, like the first power supply electrode 55a.

  By adopting the above configuration, voltage adjustment can be performed by applying a voltage from the two directions of the first power supply electrode and the second power supply electrode even if voltage fluctuation due to temperature change occurs. Thereby, voltage fluctuation due to temperature change can be suppressed to a small value, and a stable voltage distribution can be obtained for each electrode of the circle electrode 52. This means that a constant brightness can be obtained without changing the brightness of the illumination. Needless to say, the same effects as those described in the second embodiment can be obtained.

  Next, a liquid crystal element of a strobe device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the fourth embodiment of the present invention. The liquid crystal element of the strobe device according to the fourth embodiment of the present invention differs from the liquid crystal element of the first embodiment described above only in the configuration of the lower transparent electrode provided on the lower substrate, and the other components are the same as those described above. The same specification as the component of the liquid crystal element of the first embodiment is used. And it arrange | positions and uses in the front part of a light source.

  As shown in FIG. 6, the lower substrate of the liquid crystal element according to the fourth embodiment is provided with a circle electrode 62 on a lower substrate 61. The circle electrode 62 includes a circular electrode 62a in the center and two annular electrodes 62b and 62c formed concentrically, and is an electrode divided into three gradations. Each of the annular electrodes 62b and 62c is provided with an opening, and a feeding electrode forming path 68 composed of one straight line is provided by connecting the openings. A first power supply electrode 65 is provided in the formation path 68. The first power supply electrode 65 is provided with a connection electrode 66a connected to the circular electrode 62a. Furthermore, a connection electrode 66b that connects the two electrodes to the gap between the circular electrode 62a and the annular electrode 62b, and a connection electrode 66c that connects the two electrodes to the gap between the annular electrode 62b and the annular electrode 62c are provided. The connection electrode 66a, the connection electrode 66b, and the connection electrode 66c constitute the first connection electrode 66. One end of the first power supply electrode 65 extends to the outer edge portion of the lower substrate 61, and the end portion serves as a connection terminal portion to the outside.

Here, the circle electrode 62 composed of the circular electrode 62a and the annular electrodes 62b, 62c, and the first connection electrode 66 composed of the connection electrodes 66a, 66b, 66c are composed of an ITO metal film, and have a thickness of 100 mm to 200 mm. The sheet resistance is about 10 kg / cm ² , indicating a very high sheet resistance. The first power supply electrode 65 is made of a gold metal film, has a thickness of 1000 to 3000 mm, has a sheet resistance value in a range of 10Ω to 1Ω / cm ² , and exhibits a very low sheet resistance. The voltage applied to each of the circular electrode 62a, the annular electrode 62b, and the annular electrode 62c is circular electrode 62a <annular electrode 62b <annular electrode 62c, and the applied voltage is applied to the first feeding electrode from the outside. The voltage can be adjusted to a desired applied voltage by adjusting the resistance value by adjusting the applied voltage or the width of the connection electrodes 66a, 66b, 66c.

  The liquid crystal is the same as that used in the first embodiment, and PNLCD is used. In the liquid crystal element having the above configuration, the liquid crystal located at the circular electrode 62a portion has a low applied voltage, and therefore the scattering increases, the transmittance is low, and the degree of dimming increases. On the other hand, the liquid crystal at the portion of the annular electrode 62c has a high applied voltage, so that the scattering is reduced, the transmittance is increased, and the dimming degree is reduced. In the liquid crystal located at the annular electrode 62b portion, the degree of dimming between the circular electrode 62a portion and the annular electrode 62c portion is obtained. This means that three levels of brightness can be obtained within the same distance. This also makes it possible to adjust the brightness of the illumination for each subject with respect to a plurality of subjects having slightly different distances. This makes it possible to obtain a picture of a clear image as a whole with uniform brightness for any subject.

  Further, the arrangement structure of each electrode is relatively simple, and only one connection terminal with the outside is required, so that it is easy to reduce the size.

  Furthermore, also in this embodiment, the applied voltage is adjusted according to the focal length with the subject, and the brightness of the illumination is adjusted. The circular electrode 62a, the annular electrode 62b, and the annular electrode 62c can adjust the applied voltage in 5 to 10 steps according to the focal length. As a result, even if the focal length varies, the applied voltage is adjusted accordingly, and the brightness of the illumination is adjusted according to the distance, so that a clear picture can be taken. The adjustment of the applied voltage according to the focal length can be obtained by incorporating a voltage adjustment circuit in the liquid crystal drive circuit using the automatic focal length signal.

  Next, a liquid crystal element of a strobe device according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the fifth embodiment of the present invention. The liquid crystal element of the strobe device according to the fifth embodiment of the present invention has a configuration in which the second power supply electrode and the second connection electrode are newly incorporated in the lower substrate of the liquid crystal element of the above-described fourth embodiment. Yes.

  In the lower substrate of the liquid crystal element of the fifth embodiment, a circle electrode 72 is provided on a lower substrate 71 as shown in FIG. The circle electrode 72 includes a circular electrode 72a at the center and two annular electrodes 72b and 72c formed concentrically, and is an electrode divided into three gradations. Each of the annular electrodes 72b and 72c is provided with an opening, and a feeding electrode forming path 78 is provided by connecting the openings. A first power supply electrode 75 a is provided in the formation path 78. The first power supply electrode 75a is provided with a connection electrode 76a connected to the circular electrode 72a. Furthermore, a connection electrode 76b that connects the two electrodes in the gap between the circular electrode 72a and the annular electrode 72b, and a connection electrode 76c that connects the two electrodes in the gap between the annular electrode 72b and the annular electrode 72c are provided. The connection electrode 76a, the connection electrode 76b, and the connection electrode 76c constitute the first connection electrode 76. One end of the first power supply electrode 75 extends to the outer edge portion of the lower substrate 71, and the end portion serves as a connection terminal portion to the outside. The configuration so far is exactly the same as the configuration of the lower substrate of the fourth embodiment described above. In the present embodiment, a second power supply electrode 75 b is further provided, and a second connection electrode 77 connected to the second power supply electrode and connected to the outermost annular electrode 72 c of the circle electrode 72 is provided. .

  Here, like the circle electrode 72 and the first connection electrode 76, the second connection electrode 77 is formed of an ITO metal film. The second power supply electrode 75b is formed of a gold metal film, like the first power supply electrode 75a.

  The voltage applied to each of the circular electrode 72a, the annular electrode 72b, and the annular electrode 72c is circular electrode 72a <annular electrode 72b <annular electrode 72c, and the applied voltage is applied to the first feeding electrode 75b from the outside. The desired applied voltage can be adjusted by adjusting the applied voltage or the resistance value by adjusting the width of the connection electrodes 76a, 76b, and 76c.

  By adopting the above configuration, voltage adjustment can be performed by applying a voltage from the two directions of the first power supply electrode and the second power supply electrode even when a voltage variation due to a temperature change occurs. Thereby, voltage fluctuation due to temperature change can be suppressed to a small value, and a stable voltage distribution can be obtained for each electrode of the circle electrode 72. A constant brightness can be obtained constantly without changing the brightness of the illumination. Furthermore, it goes without saying that the same effects as those described in the fourth embodiment can be obtained.

  Next, a liquid crystal element of a strobe device according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a plan view of the lower substrate of the liquid crystal element used in the strobe device according to the sixth embodiment of the present invention. In the lower substrate of the liquid crystal element of the sixth embodiment, a circle electrode 82 is provided on a lower substrate 81 as shown in FIG. The circle electrode 82 includes a circular electrode 82a at the center and two annular electrodes 82b and 82c formed concentrically, and is an electrode divided into three gradations. A power supply electrode 85 is connected to each electrode of the circle electrode 82. That is, the feeding electrode 85a is connected to the circular electrode 82a at the center, the feeding electrode 85b is connected to the annular electrode 82b, and the feeding electrode 85c is connected to the annular electrode 82c. Here, the power supply electrode 85 is configured by the power supply electrode 85a, the power supply electrode 85b, and the power supply electrode 85c. The feeding electrode 85a and the feeding electrode 85b are formed in openings provided in the annular electrode 82b and the annular electrode 82c. In addition, one end of the power supply electrodes 85a, 85b, and 85c extends to the outer edge portion of the lower substrate 81, and the end portion serves as a connection terminal portion to the outside.

  Here, each of the circle electrodes 82 is formed of an ITO metal film, and each of the power supply electrodes 85 is formed of a gold metal film.

  The voltage applied to each of the circular electrode 82a, the annular electrode 82b, and the annular electrode 82c via the feeding electrode 85a, the feeding electrode 85b, and the feeding electrode 85c is circular electrode 82a <annular electrode 82b <annular electrode 82c. Apply the set voltage.

  By adopting such a configuration, although the number of connection terminals with the outside increases, the set voltage can be applied to each electrode of the electrode circle electrode 82 without error. And desired illumination brightness can be obtained. Moreover, even if voltage fluctuations due to temperature changes occur, the applied voltage can be adjusted via the respective feeding electrodes. Thereby, voltage fluctuation due to temperature change can be suppressed to a small value, and a stable voltage distribution can be obtained for each electrode of the circle electrode 82. And constant brightness can be obtained without changing the brightness of the lighting.

  When a person or book is photographed at a short distance with a camera equipped with a strobe device in which the liquid crystal element having the structure described in detail is disposed in front of the light source, a beautiful and clear photograph can be obtained. The problem that the light that has been generated in the past is too strong to be clearly seen is eliminated. Further, when shooting a long-distance subject, the light transmittance of the liquid crystal element can be made close to 100%, so that a clear picture that is completely different from the conventional one can be taken. The transmittance close to 100% can be automatically adjusted by the liquid crystal driving circuit in conjunction with the focal length.

  In the description of the embodiments so far, the number of connection terminals with the outside (liquid crystal element drive substrate) provided on the lower substrate has been described as the number of power supply electrodes for supplying power to the circle electrodes. However, a connection terminal to the outside of the upper transparent electrode provided on the upper substrate is also required. Generally, a method is adopted in which these connection terminals are gathered on either the upper substrate or the lower substrate and are connected to the outside by a wiring cable such as an FPC. The configuration of the present invention can also greatly reduce the number of connection terminals. This greatly contributes to miniaturization of the liquid crystal element.

1 is a layout view showing a configuration of a strobe device according to a first embodiment of the present invention. It is principal part sectional drawing of the liquid crystal element in FIG. FIG. 3 is a plan view of a lower substrate in FIG. 2. It is a top view of the lower board | substrate of the liquid crystal element used for the strobe device which concerns on 2nd Embodiment of this invention. It is a top view of the lower board | substrate of the liquid crystal element used for the strobe device which concerns on 3rd Embodiment of this invention. It is a top view of the lower board | substrate of the liquid crystal element used for the strobe device which concerns on 4th Embodiment of this invention. It is a top view of the lower board | substrate of the liquid crystal element used for the strobe device which concerns on 5th Embodiment of this invention. It is a top view of the lower board | substrate of the liquid crystal element used for the strobe device which concerns on 6th Embodiment of this invention. It is the conventional block diagram of the strobe device using LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light source 20 Liquid crystal element 21,41,51,61,71,81 Lower board | substrate 22,42,52,62,72,82 Circle electrode 25,85 Feed electrode 31 Upper board | substrate 32 Upper transparent electrode 35 Liquid crystal 37 Sealing material 42a, 52a, 62a, 72a, 82a Circular electrodes 42b, 42c, 52b, 52c, 62b, 62c, 72b, 72c, 82b, 82c Annular electrodes 45, 55a, 65, 75a First feeding electrodes 46, 56, 66, 76 One connection electrode 46a, 46b, 46c, 56a, 56b, 56c, 66a, 66b, 66c, 76a, 76b, 76c Connection electrode 48, 58, 68, 78 Feed electrode formation path 55b, 75b Second feed electrode 57, 77 Second connection electrode

Claims (19)

In a strobe device in which a liquid crystal element using a polymer dispersed liquid crystal is arranged in front of an LED that constitutes a point light source , the liquid crystal element has a pair of substrates made of transparent glass, that is, a lower substrate and an upper substrate are fixed. It is arranged to face each other with a gap, a circle electrode that is a lower transparent electrode is provided as a circular electrode and an annular electrode on the inner surface of the lower substrate, and an upper transparent electrode is also provided on the inner surface of the upper substrate, The polymer-dispersed liquid crystal is sealed through a sealing material, a power supply electrode is provided connected to the circle electrode, one end extends to the outer edge of the lower substrate, and the tip becomes a connection terminal A strobe device comprising a connection electrode between the circle electrodes and between the circle electrode and the power supply electrode . The strobe device according to claim 1, wherein the circle electrode is a single circular electrode provided at a central portion of the lower substrate . The circle electrode is composed of a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is directed toward the circular electrode. An opening is provided at each position crossing the straight line, and the opening is connected to form a single linear feed electrode formation path. The feed electrode formation path is connected to the feed electrode and the feed electrode. each electrode of the circle electrodes, i.e., the flash device according to claim 1, characterized in that is provided with a connection electrode for connecting each of said circular electrodes, the annular electrode. The circle electrode is composed of a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is directed toward the circular electrode. An opening is provided at each position crossing the straight line, and the opening is connected to provide a single linear feed electrode formation path. The first feed electrode and the first feed are provided in the feed electrode formation path. A first connection electrode connected to an electrode and connected to each electrode of the circle electrode, i.e., the circular electrode and the annular electrode, a second power supply electrode, the second power supply electrode, and the circle electrode; The strobe device according to claim 1 , further comprising a second connection electrode that connects the circular electrode . The circle electrode is composed of a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is directed toward the circular electrode. An opening is provided at each position crossing the straight line, and the opening is connected to form a single linear feed electrode formation path. The feed electrode formation path is connected to the feed electrode and the feed electrode. A connection electrode connected to the circular electrode of the circle electrode; and a connection electrode connecting the circular electrode and the annular electrode; and a connection electrode connecting the annular electrodes to each other. The strobe device according to claim 1 . The circle electrode is composed of a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is directed toward the circular electrode. An opening is provided at each position crossing the straight line, and the opening is connected to provide a single linear feed electrode formation path. The first feed electrode and the first feed are provided in the feed electrode formation path. A connection electrode connected to the electrode and connected to the circular electrode of the circle electrode, a connection electrode connecting the circular electrode and the annular electrode, and a connection electrode connecting the annular electrodes to each other; the second feeding electrode provided flash device according to claim 1, characterized in that is provided with a connection electrode connected to the outermost annular electrode circles electrode connected to the second feeding electrodes. The circle electrode is composed of a circular electrode provided at the center and a plurality of annular electrodes provided concentrically on the outer peripheral area of the circular electrode, and a part of the annular electrode is directed toward the circular electrode. An opening is provided at each position crossing the straight line, and the opening is connected to provide a single linear feed electrode formation path. The feed electrode formation path includes a plurality of feed electrodes and a plurality of feed electrodes. each electrode of the circle electrode connected, i.e., the flash device according to claim 1, characterized in that is provided with a connection electrode for connecting each of said circular electrodes, the annular electrode. The strobe device according to any one of claims 1 to 7, wherein a voltage applied to the circle electrode is different for each electrode. The strobe device according to any one of claims 1 to 8 , wherein the voltage applied to the circle electrode can be adjusted in 5 to 10 steps for each electrode. The strobe device according to claim 9 , wherein the voltage adjustment in 5 to 10 steps is performed in conjunction with a focal length. The connection electrode to connect to each of the circles electrodes, the length of each electrode is constant, the strobe apparatus according to any one of claims 1 to 10, characterized the width of the electrode be different from each other . The circle electrodes and before Kise' connection electrodes are made of the same material, the strobe apparatus according to any one of claims 1 to 11, characterized in that it consists of metal film having a high sheet resistance. Before SL feeding Denden poles flash device according to any one of claims 1 to 12, characterized in that it consists of a low sheet resistance metal film. The strobe device according to any one of claims 1 to 13, wherein the liquid crystal element has regions having different light transmittances from a light source divided into 1 to 5 gradations. 15. The strobe device according to claim 14 , wherein the region divided into 1 to 5 gradations has a circular shape or a circular shape and a concentric annular shape surrounding the circular shape. 16. The strobe device according to claim 14 , wherein the transmittance of each of the regions divided into 1 to 5 gradations can be adjusted in 5 to 10 steps. The strobe device according to claim 16 , wherein the 5 to 10-step transmittance adjustment is performed in conjunction with a focal length. The polymer dispersed liquid crystal, a strobe apparatus according to any one of claims 1 to 17, characterized in that a PNLC D-type liquid crystal. A camera comprising a strobe device, comprising the strobe device according to any one of claims 1 to 18 .

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