JPS60212736A - Optical control element - Google Patents

Abstract

PURPOSE:To form an optical control element which has no special restriction in an incident form, etc. of an incident light, and also is excellent in stability and durability, by moving granules by changing partially the temperature of a liquid, and providing a light shielding body on a part of a moving path. CONSTITUTION:Since light shielding filters 35, 35' are provided, a luminous flux 101 which advances so as to pass through in a liquid layer 33 being in the vicinity of a heating resistor 34a is made incident on the liquid layer 33, but a luminous flux 102 which advances so as to pass through in the liquid layer 33 being in the vicinity of a heating resistor 34b, and a luminous flux which advances in order to pass through other part are shielded by a light shielding body and are not made incident on the element. Accordingly, when a granule 30 is held in the vicinity of the heating resistor 34b, the incident luminous flux 101 transmits the light transmitting liquid layer 33, travels straight as it is and is emitted. On the other hand, in when the granule 30 is held in the vicinity of the heating resistor 34a, the incident luminous flux 101 is effected by the granule and emitted in a wave front state different from the straight traveling. The incident luminous flux 101 can be controlled by controlling the position of the granule 30 in the liquid layer 33.

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, thereby controlling 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 technology, for example,
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, the cavity 7 is destroyed, which reduces the durability of the element. There is a problem that it is easy to decrease.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, an object of the present invention is to provide a light 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 purpose is to cause particles to exist in a liquid, to move the particles by partially changing the temperature of the liquid, and to make a beam of light enter the moving path of the particles. This is achieved by providing a light shield so that the light beam does not enter a part of the moving path.

[Embodiments of the invention]

Embodiments of the light 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 first operating mechanism of the light 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, which is made of, for example, a Ta film. 4 is a heating resistor (6&.

6b, . . . , 6e), and each resistor is isolated by an insulating material 810□, and 5 is an insulating support. 7 is a particle formed of air bubbles, 8 is a conductive wire, and a heating resistor (sa, sb, . . . ).

6e) can be driven independently (V□
~vs), while the heating resistor (6a.

The other ends 9 of the terminals 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. The width t8 of the heating resistor embedded in the layer 4 composed of 5io2 is, for example, 20 μm, and the interval t8 between the heating resistors is 50 μm.

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 once formed, the vapor bubbles did not disappear even if the applied voltage was lowered. Even when the voltage applied to the heating resistor was lowered to about 1.5V, the particles composed of air bubbles remained attracted to the vicinity of the heating resistor.

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 applied voltage is cut off and a voltage is applied to the heating resistor 6c, the particles 7 move to the vicinity of the heating resistor 6C. In this way, by creating a temperature difference within the liquid, the particles 7 move, and in the case of an element like the one shown in Figure 1, the particles move near the resistor that is generating heat. . Therefore, the position of the particles can be controlled by selecting the heating resistor to which voltage is applied. In this case, 1.5
When a voltage of 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. When the bubbles were moved directly to a second heating resistor 120 μm apart, the bubbles were moved by applying a voltage of 2 V to the heating resistor.

This movement of the particles 7 is based on the temperature difference formed 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 Figure 1, in order to hold the particles in the liquid, a bias voltage (holding voltage) that does not create bubbles in the liquid is applied to the heating resistor that attracts the particles. It is desirable to keep it. Another driving method is to apply the above bias voltage to all the heat generating resistors, and then apply a relatively high voltage higher than the bias voltage to the heat generating resistors located at the target position to move the particles. , attracts the particles and then lowers the bias voltage. In this way, the granules can be held in place.

FIG. 3 is a schematic sectional view for explaining the second operating mechanism of the light control element of the present invention. In the figure, 11 is a transparent protection plate, 1
2 is a liquid layer; 3 is a protective layer; 14 is a light energy absorption layer; 15 is a transparent substrate; 16 is a half mirror; 117 is a grain;
18 is a galvano mirror; 11sa is a rotation axis of the galvano mirror; 19 is a light source section such as a semiconductor laser; 20 is an imaging optical system; and 21 is a transparent section (21m, 21b, 21c, 21d).

21.) Slit plates, 22a, 22b.

22 c 122 d r 22 a is the imaging optical system 20
23 is a rod-shaped light source.

The rod-shaped light source 20 illuminates the slit plate 21, and the light beams passing through each light-transmitting part (21a to 21e) of the slit plate 21 are focused by the imaging optical system 20 onto the light energy absorption layer 14, and the light energy absorption layer 14 is It is converted into heat at 14 and warms the liquid layer 12 through the protective layer. Image of the light-transmitting part of the pick-up and top plate formed in this light energy absorption layer 14 (22 breath to 226)
acts to provide the liquid layer with enough heat to hold the particles 17 in the liquid layer 140 at the position corresponding to the position where this image is formed. In other words, it functions in the same way as when a bias voltage is applied to the heating resistor shown in FIG. can be freely selected by selecting the opening pattern. On the other hand, the luminous flux L from the light source section】9
1 enters the optical energy absorption layer 14 via the galvanometer mirror 18 and the half mirror 16. This luminous flux L1 has enough light intensity to move the particles 17, and the luminous flux absorbed by the optical energy absorption layer 14 is converted into heat and transmitted to the liquid layer 2 via the protective layer 13. The particles move to the position where the light beam L□ is incident. The position where this light beam is incident on the light energy absorber 114 can be freely controlled by rotating the galvanometer mirror 8.

FIG. 4 is a schematic sectional view for explaining the third operating mechanism of the light control element of the present invention. In the figure, the same members as in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted. 2
4m, 24b, 24c, 24d.

24e each indicates a heating resistor, which is embedded in the optical energy absorbing layer 14. These heating resistors are for holding the position of the particles as described above, and a voltage sufficient to hold the particles is applied to each heating resistor. On the other hand, the amount of heat for moving the particles is provided by the light flux from the light source 19, similar to the element shown in FIG.

FIG. 5 is a schematic sectional view showing a first embodiment of the light control element of the present invention having the particle movement mechanism as described above. In the figure, 30 is a particle fi, 31& and 31b are support substrates, and 32a and 32b are heat generating resistors 34 & and 34b built therein, respectively. 33 is a liquid layer having translucency. Also 35 and 3
5' is a light shielding body. In the device of this example, the particles 30 are moved within the liquid layer 33 between the vicinity of the heating resistor 34& and the vicinity of the heating resistor 34b by controlling the voltage applied to the heating resistors 34m and 34b. , can be held near these heating resistors.

In the device of this embodiment, since the light transmitting filter 35°35' is provided, the light beam 101 traveling through the liquid layer 33 near the heating resistor 34& is transmitted through the liquid layer 33.
However, the liquid layer 33 near the heating resistor 34b
The light flux 102 that travels through the interior and the light flux that travels through other parts are blocked by the light shield and do not enter the element. Therefore, in the element of this embodiment, when the particles 30 are held near the heating resistor 34b, the incident light beam 101 passes through the translucent liquid layer 33 and exits directly therefrom. On the other hand, when the particles 30 are held near the heating resistor 34&, the incident light beam 101
is affected by the particles (i.e. refracted or totally reflected)
The light beam is emitted in a wavefront state different from that of the straight emitted light beam.

Thus, by controlling the position of the particles 30 in the liquid layer 33, the incident light beam 101 can be controlled by K.

FIG. 6 is a schematic sectional view showing a second embodiment of the light control element of the present invention. The element of this example differs from the first example only in that a light reflecting layer 36 is provided on the side opposite to the light beam incidence side. Therefore, in the element of this embodiment, the emitted light beam travels toward the incident side.

FIG. 7 is a schematic sectional view showing a third embodiment of the light control element of the present invention. In this example element, the heating resistor 34
& and 34b are arranged in parallel in the same member, and the particles 30 are connected to the heating resistor 341 in the liquid layer 33.
It is movable between the vicinity of the heating resistor 34b and the vicinity of the heating resistor 34b. In addition, in the device of this example, the substrates 311L, 31
b. Heat generating resistor 7%l132 and heat generating resistor 341 have translucency. Then, the same control as in the above embodiment #1 is performed on the incident light beams 101 and 102.

FIG. 8 is a schematic sectional view showing a fourth embodiment of the light control element of the present invention. The device of this example differs from the third example only in that a light reflection layer 36 is provided between the substrate 31b and the liquid layer 33. Therefore, in the element of this embodiment, the emitted light beam travels toward the incident side.

FIG. 9 is a schematic plan view showing a fifth embodiment of the light control element of the present invention. In the device of this embodiment, the device of the third embodiment as shown in FIG. 7 is used as one unit, and a plurality of units U1 + Uz + . . . are arranged in a play shape. Each grain 30 is movable within each unit between a portion where the light shield 35 is present and a portion where the light shield 35 is not present.

FIG. 10 is a schematic sectional view showing a sixth embodiment of the light control element of the present invention. In the figure, members similar to those in FIG. 5 are designated by the same reference numerals, and explanations thereof will be omitted. 38 is a transparent support substrate, which is covered with 41 and 41'Fi light shields. In the device of this example, a light reflecting layer 42 is provided obliquely within the support substrate 38 as a light shield. The light reflecting layer 42 is located above the heating resistor 34m, and the light reflecting layer 42 is located above the heating resistor 34m.
There is no light shielding body above the light shielding body 2 (that is, it is located in the gap between the light shielding bodies 41 and 41').

In the device of this embodiment, the incident chia flux 102 traveling toward the heating resistor 341 is reflected by the light reflecting layer 42 within the support substrate 38 and travels to the liquid layer near the heating resistor 34b.

Therefore, according to the device of this embodiment, a much larger amount of light can be used for light control than in the above-mentioned embodiments I to 5, and the light utilization rate is increased.

FIG. 11 is a schematic cross-sectional view showing a seventh embodiment of the light control element of the present invention. In the device of this example, the support substrate 38
The only difference from the sixth embodiment is that a light shield is not provided above and the light reflecting layer 42 within the support substrate 38 is relatively horizontal. In the device of this embodiment, the incident light beam 102 is reflected by the light reflecting layer 42, and then totally reflected by the upper surface of the support substrate 38, and travels into the liquid layer 33 near the heating resistor 34b. Similarly to the sixth embodiment, the element of this embodiment also has a high light utilization rate.

FIG. 12 is a schematic sectional view showing an eighth embodiment of the light control element of the present invention. In the device of this example, a light reflecting layer 43 is provided on the side surface of the support substrate 38, and a light reflection layer 43 is provided on the side surface of the support substrate 38.
The only difference from the seventh embodiment is that the angle of the light reflecting layer 42 in the second embodiment is slightly different.

In this example element, the incident light beam 102 is transmitted to the light reflecting layer 42.
After being reflected by the light, it is totally reflected by the upper surface of the support substrate 38, further reflected by the light reflection layer 43, and proceeds into the liquid layer 33 near the heating resistor 34b.

The element of this example also has a high light utilization rate as in the sixth example.

FIG. 13 is a schematic sectional view showing a ninth embodiment of the light control element of the present invention. In the figure, the same members as in FIG. 5 are given the same reference numerals, and their explanations will be omitted. In this embodiment, the upper support substrate 31b is relatively thin, and a light reflecting layer 44 is provided between the substrate 31b and the liquid layer 33 as a light shield above the heating resistor 34a. ing.

In the device of this embodiment, a light beam 101 is made to enter at a slight angle from the side surface of the substrate 31b, and travels while repeating reflection by the light reflection layer 44 and total reflection by the upper surface of the substrate 31b, resulting in "light reflection" as shown in the figure. The liquid flows obliquely from the substrate-liquid interface where #44 does not exist into the liquid layer 33 near the heating resistor 34b.

In the element of this embodiment, since the light beam is incident from the side, it has the advantage that it can be easily reduced in thickness and size when combined with an illumination optical system.

Incidentally, in the above embodiment, an example was shown in which light control is performed based on the difference in refractive index between the liquid 33 and the particles 30; For example, it includes one in which one side is translucent and the other is light-blocking, and light control is performed by utilizing the difference in absorbance depending on the presence or absence of particles.

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 element of the present invention, vapor bubbles generated by heating a liquid can be used, and the particles can also be introduced from the outside. Examples of particles include air bubbles that are difficult to dissolve in the liquid used. Specific examples of this include bubbles of air, oxygen, nitrogen, hydrogen, -\lium, 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.

〔Effect of the invention〕

According to the light control element of the present invention as described above, there are no special restrictions on the wavelength or polarization characteristics of the incident light beam, and light sources other than laser light can be used, and there are no strict restrictions on the angle of incidence of the incident light beam. . 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, light control is performed based on the difference in refractive index between the particles and the liquid or the difference in light absorption between the particles and the liquid, so that the S/N ratio can be increased. Furthermore, in the device of the present invention, K only needs to move the particles for light 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. .

In addition, in the device of the present invention, a light shield is provided to prevent the light beam from entering areas other than those where light control is to be performed, so there is no influence of noise light from those areas, and the desired light control can be performed accurately. can be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining the operating mechanism of the element of the present invention, and FIG. 2 is a perspective view thereof. FIGS. 3 and 4 are cross-sectional views for explaining the operating mechanism of the device of the present invention. 5-8 and 10-13 are cross-sectional views of the device of the present invention. FIG. 9 is a plan view of the device of the present invention. 30: Granules, 31m, 31b: Support substrate, 32+113
2b: heating resistor layer, 33: liquid layer, 34 &. 34b = heating resistor, 35, 35': light shielding body, 36
two-light reflective layer, 38: support substrate, 41.41': light shielding body,
42.43,44: Light reflecting layer. Figure 1 1N 2 Figure ↓ 1 to 3 Figure 1141 Figure @ 5 Diagram 6 Figure 917 Figure 0 118 Figure 19 rM ul LJ2 U3 L, +4 us us @ 10 Figure 11 Figure 34a 34b

Claims (2)

[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 light beam is directed along the movement path of the particles. 1. A light control element, characterized in that a part of the moving path of the particles is prevented from being incident on a light shielding member. (2) The light control element according to item 1, which includes a light reflective layer as a light shield.