JPS60211435A - Control element for quantity of light - Google Patents

Abstract

PURPOSE:To obtain an element excellent in stability and durability by varying partially the temperature of liquid in which fine particles are present and moving the fine particles, making luminous flux incident on the movement path of the fine particles, and controlling the time when the fine particles are present in the incident luminous flux. CONSTITUTION:A heat generating resistor layer 4 which contains heat generating resistors 6a, 6b... and a reflecting layer 3 which has heat conductivity are provided on an insulating base 5, and a liquid layer 2 consisting of ethyl alcohol containing the fine particles 7 formed of, for example, an air bubble is provided between the reflecting layer 3 and a transparent protection plate 1. The temperature of the liquid layer 2 is varied partially by the heat generating resistors 6a, 6b, 6c... to move the fine particles 7. Luminous flux is made incident on the movement path of the fine particles 7 and the luminous flux is transmitted only where the fine particles 7 are present. Electric feeding to the heat generating resistors 6a, 6b... is controlled to control the time when the fine particles 7 are present in the incident luminous flux.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an element that affects an incident light beam by moving minute particles and thereby controls the amount of light.

[Prior art]

In recent years, it has come into practical use to display, record, etc. using light, especially laser light, as a signal transmission means. When using such light, a means for appropriately controlling the luminous flux is required. Various methods have been proposed for this type of light flux control technology9, such as JP-A-56-55
No. 23 discloses a light control method that partially changes the electric field distribution within a crystal that has an electro-optic effect, thereby partially changing the refractive index distribution within the crystal to appropriately diffract an incident light flux. There is. However, the electro-optic crystal used in this method is expensive, and in this method, the light beam incident on the crystal must have predetermined polarization characteristics. Furthermore, in this method, there is a restriction that in order to completely reflect the light beam and improve the diffraction efficiency, the light beam must be incident almost parallel to the electrode for applying an electric field.

On the other hand, Japanese Unexamined Patent Publication No. 58-100817 discloses a system in which the incident light flux is controlled by forming and extinguishing vapor bubbles inside a liquid. However, in this method, it is necessary to frequently repeat the formation and disappearance of vapor bubbles, so the stability of the operation of the element is not satisfactory, and when the vapor bubbles disappear, cavitation destruction occurs, which tends to reduce the durability of the element. There is a problem.

More importantly, in this method, it is extremely difficult to control the amount of light.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a light amount control element that has no particular restrictions on incident light and the manner of incidence of the incident light, and has excellent stability and durability.

[Summary of the invention]

According to the present invention, the above object is to cause particles to exist in a liquid, to move the particles by partially changing the temperature of the liquid, to make a light beam enter the movement path of the particles, This is achieved by controlling the residence time of the particles in the incident light beam.

[Embodiments of the invention]

Embodiments of the light amount control element of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view for explaining the operating mechanism of the light amount control element of the present invention, and FIG. 2 is a schematic perspective view thereof.

In the figure, 1 is a transparent protective plate, 2 is a liquid layer made of ethyl alcohol, and 3 is a thermally conductive reflective layer, for example, made of a Ta film. 4 is a heating resistor (6m, 6b.

..., 6e), and each resistor is isolated by an insulating substance 5IO2, and 5 is an insulating support. 7 is a granule formed of air bubbles, 8 is a conductive wire, and is connected to the drive power source (V1 to Vs) on each side of the machine that can independently drive the heating resistors (6a+6b+..., 6e). - The other ends 9 of the auspicious thermal resistors (6a, 6b, . . . , 6e) are grounded or set to a common voltage. Therefore, by controlling the voltage applied to each heating resistor, the temperature of the liquid layer near the heating resistor can be controlled.

1]1 of the heating resistor embedded in the layer 4 made of 5102
1 is, for example, the distance between 20 μm and 1 heating resistor! ! 2 is 50μ
It is m.

When providing bubbles as particles in a liquid using the element shown in Figure 1, the bubbles can be easily formed in the liquid by applying heat to the heating resistor and forming vapor bubbles in the liquid. . For example, in the element having the configuration shown in FIG. 1, if the liquid is ethyl alcohol, approximately 4.2
When a DC voltage of v was applied, bubbles with a diameter of about 150 μm were formed, and the formed vapor bubbles did not disappear even when the applied voltage was lowered. Even when the voltage applied to the heating resistor was lowered to about 1.5 V, the particles composed of air bubbles remained attracted to the vicinity of the heating resistor (5).

Therefore, this made it possible to maintain the position of the bubbles.

The movement of the grains 7 is carried out as follows.

That is, when a voltage is applied to the heating resistor 6b as shown in FIG. When the voltage is applied to the heating resistor 6c, the particles 7 move to the vicinity of the heating resistor 6c. In this way, the grains 7 move by creating a temperature difference in the liquid, and in the case of an element like the one shown in FIG. 1, the grains move near the resistor that is generating heat. go. Therefore, the position 1 of the particles can be controlled by selecting the heating resistor to which voltage is applied. In this case, 1
．． When a voltage of 5 V was applied and at the same time the voltage to the heating resistor attracting the bubbles was cut off, the bubbles moved to the position of the adjacent heating resistor. Also, when moving directly to the second heating resistor 120 μm apart, apply 2V to the heating resistor.
By applying a voltage of (6), the bubbles moved.

This movement of the particles is based on the formation of a temperature difference within the liquid layer 2, and the particles 7 move from the low temperature side to the high temperature side.

In addition, in the device shown in Fig. 1, in order to hold the particles in the liquid, a bias voltage (holding voltage) is applied to the heating resistor that attracts the particles to an extent that does not cause bubbles in the liquid. It is desirable to keep it applied. Another driving method is to apply the above bias voltage to all the heat generating resistors, and apply a relatively high voltage higher than the bias voltage to the heat generating resistors located at the target position to move the particles. The particles are pulled together and then lowered to the bias voltage.

In this way, the granules can be held in place.

FIG. 3 is a schematic plan view showing a first embodiment of the light amount control element of the present invention having the above-mentioned particle movement mechanism, and FIG. In the figure, numeral 11 is a granule, and the core granule 11 is transparent and does not contain air bubbles. 12 is a light shielding filter, 14 is a transparent glass plate, and 15
is an opaque liquid. 16 is a protective layer made of a transparent dielectric, 17 is a heating layer including heaters 18a and 18b, and 19 is a transparent glass substrate. In the device of this example, the thickness of the liquid layer 15 is smaller than the diameter of the particles (bubbles) 11, so the particles 11 are formed on the transparent glass plate 11.
and has a relatively large contact area with the transparent dielectric protective layer 16.

In the device of this embodiment, the particles 11 are heated to the heater 18 by controlling the heat generation temperature of the heaters 18a and 18b.
When the light shielding filter 12 is placed near point a, that is, in the area where the light shielding filter 12 is covered, the incident light beam from above enters the opaque liquid layer 15 through the transparent glass plate 14 in the area where the light shielding filter 12 is covered. , where it is absorbed and emitted downward. Next, when the particles 11 are positioned in the vicinity of the heater 18b, that is, in the area where the light shielding filter 12 is not covered, by controlling the heat generation temperature of the heaters 18a and 18b (the state shown in FIGS. 1 and 2), The incident light flux from above passes through the grains 11 from the transparent glass plate 14, passes through the transparent glass substrates 1 and 9, and is emitted downward.

The operation of the device of this example will be explained with reference to FIG.

The figure is a graph showing the relationship between the voltage V applied to the heater and the time T. First, in the initial state, the heater 18
A voltage is applied to the heater 18aK, and no voltage is applied to the heater 18aK, and the grain body 11 is located near the heater 18b. Next, the voltage applied to the heater 18b is set to 0, and at the same time, a voltage is applied to the heater 18m. As a result, the particles 11 move from the vicinity of the heater 18b to the vicinity of the heater 181L. Continuing to apply voltage to the heater 18a for a time tl, the grain material 1 is heated to the heater 18.
After maintaining the voltage near m for a time t1, the applied voltage is set to O. At the same time, a voltage is applied to the heater 18b. As a result, the particles 11 are moved from the vicinity of the heater 18a to the heater 18a.
Move to the vicinity of b. After continuing the voltage application to the heater 18b for a time t2 and keeping the particles 11 near the heater 18b for a time t, the applied voltage is set to zero. same(
9) At the same time, apply voltage to the heater 18a. As a result, the particles 11 move from the vicinity of the heater 18b to the vicinity of the heater 18a. Thereafter, the granules 11 are moved and held in the same manner. Time To(-t, +tz
) is proportional to the time t2 during which the particles 11 remain in the area not covered by the light shielding filter 12.

Therefore, for example, by keeping To constant and varying t2, the time average of the amount of transmitted light can be set to an arbitrary value.

FIG. 6 is an explanatory diagram of a driving circuit for realizing the driving method in the device of this embodiment. In the figure, 20 is an element section including heaters 18a and 18b, 21 is a switching circuit, and 22 is a voltage. 23 is a control circuit, and 24 is a signal generation circuit. Based on the signal from the signal generation circuit 24, the control circuit 23 generates a heater energization time control signal as shown in FIG. Sui (10) Let's do some stitching. Since such a circuit can be easily realized, a description of the specific configuration of the circuit will be omitted.

FIG. 7 is a schematic plan view for explaining a second embodiment of the light M' control element of the present invention, and FIG. 8 is a cross-sectional view taken along line 1--2. In the figures, similar members as in FIGS. 1 and 2 are given the same reference numerals. However, in this embodiment, two light-shielding filters 12 and 13 are arranged at an appropriate interval, and the heater tSa is located in the part where the light-shielding filter 12 is covered, while the heater 18b is located in the part where the light-blocking filter 13 is covered. located in the area where

The movement of the particles 11 in the device of this example is carried out in the same manner as in the first example. 9 and 10 are graphs showing the relationship between heater applied voltage V and time T in the device of this example. In Fig. 9, first, heater 1
The granules 11 are held near the heater 18m with the voltage applied to the heater 8a set to vl, and then the voltage applied to the heater 18m is set to 0, and at the same time the voltage applied to the heater 18b is set to 0.
to Vl, the grains 11 become light-shielding filters 12.1
It passes through the part where No. 3 is not applied at a certain speed τl, moves to the vicinity of the heater 18b, and is held there. In FIG. 10, when applying the voltage to the heater 18b, the above V
! A larger voltage ■2 is applied. In this case,
The particles 11 pass through the portion not covered by the light blocking filters 12.13 at a speed τ2 greater than the above ill.

Thus, when a light flux is made to enter from below, the amount of light corresponding to the moving speed of the grains 11 is transmitted upward and emitted. In other words, this is nothing but controlling the amount of transmitted light by the residence time of the particles in the area where the light-shielding filter is not applied.

FIG. 11 is a schematic plan view for explaining a third embodiment of the light amount control element of the present invention. In the figure, the same members as in FIG. 7 are given the same reference numerals. However, in this example, ° is a large number of heaters (18 at 18
b+18or"') is provided.

The movement of the grains 11 in the device of this example is carried out in the same manner as in the second example. FIGS. 12 and 13 are graphs showing the relationship between heater applied voltage V and time T in the device of this example. That is, the heater 18a,
By sequentially applying a predetermined voltage 18b, 18c, - for a certain period of time, the step of moving the microscopic particles is continuously carried out from the part covered by the light-blocking filter 12 to the part covered by the light-blocking filter 13. The particles 11 are moved to In the case of FIG. 12, the voltage applied to each heater is relatively high, the energization time is relatively short, and the particles 11 are moved quickly by quick switching. On the other hand, in the case of Figure 13, the voltage applied to each heater is relatively low and the energization time is relatively long, so that the amount of heat generated by each heater is approximately the same as in the case of Figure 12, and slow switching The particles 11 are moving slowly.

According to the element of this embodiment, compared to the element of the second embodiment, a high moving speed can be obtained even if the amount of heat generated by each heater is smaller.

FIG. 14 is a schematic cross-sectional view for explaining the fourth embodiment (13) of the light amount control element of the present invention. 8th in the figure
Similar members in the figures are given the same reference numerals. However, in the device of this example, there are two liquid layers, and the members related to the upper layer are given the branch code -1, and the members related to the lower layer are given the branch code -2. .

In this example element, heater 1, 8a-1, 18
Of course, electricity can be applied to b-1 and the heaters 18a-2 and 18b-2 independently.

In each of the upper and lower two layers of the device of this example, movement of the grains 11-1 and 11-2 is performed in the same manner as in the second example. FIG. 15 is a graph showing the relationship between heater applied voltage V and time T in the device of this example. Granules in the upper layer 11. -1 movement timing and the movement timing of grain body 11-2 in the lower layer are time 1. Therefore, the light beam incident from below the element is transmitted upward in an amount equal to the area where the particles 11-1 and 11-2 overlap in the vertical direction in the part where the light-shielding filter is not applied. and ejects.

(14) The element of this example has the same effect as a focal plane shutter of a camera. Therefore, the device of this example can be used as a shutter device. In addition, in a two-layer structure like the device of this example, by arranging a relatively large number of heaters in a ring shape in each layer, it is possible to continuously rotate the particles around the circumference, and this operation and motor drive By interlocking the shutter with a mechanism, a shutter capable of continuous shooting can be constructed.

In the first to fourth embodiments described above, transmissive type elements are illustrated, but these elements can be made into reflective type elements by providing a light reflective layer between the liquid layer 15 and the heat generating layer 17. You can also do it.

As the liquid in the device of the present invention, an organic liquid, water, or the like can be used, colored as necessary.

As the particles in the device of the present invention, vapor bubbles generated by heating the liquid can be used, and the particles can also be introduced from the outside. I can give an example. Specific examples of such a liquid include bubbles of air, oxygen, nitrogen, hydrogen, helium, neon, argon, -carbon oxide, -nitrogen oxide, methane, etc. when water is used as the liquid. It is also possible to use a liquid that does not mix with the liquid used as the particles. A specific example of this is oil droplets when water is used as the liquid. Furthermore, solid particles having a relatively low density can also be used as the granules.

Furthermore, in the above embodiments, a liquid colored black was used as the light-absorbing liquid, but in the device of the present invention, light-absorbing property also includes the case where only a certain wavelength portion of the incident light beam is absorbed to some extent; Therefore, as the liquid, a transparent chromatic liquid such as an aqueous solution of red dye or an aqueous solution of green dye can be used. Further, in the above embodiments, a case is shown in which the liquid has light absorbing properties and the particles have light transmitting properties, but the opposite case is also possible.

〔Effect of the invention〕

According to the light amount control element of the present invention as described above, a light source other than a laser beam can be used without any special restrictions such as wavelength or polarization characteristics on the incident light beam, and there are no severe restrictions on the angle of incidence of the uncircumcised incident light beam. do not have. Furthermore, the device of the present invention does not require expensive materials such as crystalline materials, and is easy to manufacture.

Furthermore, in the device of the present invention, only zero movement of particles is required for optical meter control, so the operation of the device is highly stable and no large force is applied to the device, so the device has good durability. It is.

Further, according to the device of the present invention, the amount of transmitted light can be easily controlled stepwise, and it is suitable for recording or displaying halftones, and can also be used as a shutter device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining the operating mechanism of the device of the present invention, and FIG. 2 is a perspective view thereof. FIG. 3 is a flat diagram of the device of the present invention, FIG. 4 is a cross-sectional view along IV-IV thereof, FIG. 5 is an explanatory diagram of its operation, and FIG. 6 is an explanatory diagram of its drive circuit. be. FIG. 7 is a plan view of the device of the present invention, FIG. 8 is a sectional view of No. 7 Ml+-■, and FIGS. 9 and 10 are (17) explanatory diagrams of the operation. FIG. 11 is a plan view of the device of the present invention, and FIGS. 12 and 13 are explanatory diagrams of its operation. FIG. 14 is a sectional view of the device of the present invention, and FIG. 15 is an explanatory diagram of its operation. 11: Particles, 12, 13: Light shielding filter, 14: Transparent glass plate, 15: Liquid, 16: Protective layer, 17: Heat generating layer, 18a, 18b, 18c: Heater, 19: Transparent glass substrate, 2o: Element Part, 21 Niswitching circuit, 22
: voltage generation circuit, 23: control circuit, 24: signal generation circuit. (18) tototototototot-to1-totoriωto ω 0 0 glue m 11 ~ O' ν fence

Claims (6)

[Claims] (1) Particles are made to exist in a liquid, and means is provided that can move the particles by partially changing the temperature of the liquid, and a beam of light is incident on the movement path of the particles. 1. A light quantity control element, characterized in that the element is configured to have a light intensity control element as shown in FIG. (2) The light amount control element according to item 1, wherein at least one of the liquid and the particles has light absorption properties. (3) The light amount control element according to item 1, wherein the residence time control means is means for maintaining a predetermined portion of the liquid at a predetermined temperature for an appropriate time. (4) The light amount control element according to item 1, wherein the residence time control means is a means for controlling the speed at which the particles move in the incident light beam. (5) The plurality of particles can move in the incident light beam while maintaining at least a part of them overlap in the direction of the incident light beam, and means is provided for controlling the area of the overlapping portion.
The light amount control element of the first term. (6) The light amount control element according to item 5, wherein the area of the overlapping portion is controlled by the timing of movement of each particle.