JPS61137124A - Image formation optical system with variable image formation characteristic - Google Patents

Abstract

PURPOSE:To control an image formation state by using an optical element which varies the state of the wave front of incident luminous flux by moving a grain body in liquid. CONSTITUTION:When a specific voltage is impressed to the heating resistance body 6b of an optical element, etc., the vapor bubble 7 of the grain body is formed nearby the resistor 6b of a liquid layer 2 of ethyl glycol, etc., between a reflecting layer 3 and a transparent protection plate 1 and never disappears even when the voltage impressed to the resistance body 6b, etc., is lowered. In this state, the hold voltage to the resistance body 6b is cut off and a necessary voltage corresponding to the distance from the resistance body 6b, etc., is impressed to an adjacent resistance body 6c, etc., so that the air bubble 7 moves to the position of the resistance body 6c and is held similarly. Only a light beam which has high incidence height to a pupil as to an incidence light beam is shifted in phase owing to absorption and scattering by variation in the wave front state of the incident luminous flux by the grain body, so when the optical element is inserted into the optical system as a soft-focus filter, only a part with high incidence height of spherical aberration is affected to cause flare aberration, thereby controlling the image formation state such as drawing ability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an imaging optical system with variable imaging characteristics.

[Prior art]

Generally, some photographic lenses have a soft focus function by forming an entrance pupil in a special shape. However, in such a method, when the diameter of the aperture diaphragm is changed, the soft focus functions in response to the change in the diameter of the aperture, which is inconvenient for photographers who require flexibility in the soft focus function.

[Summary of the invention]

An object of the present invention is to provide an imaging optical system that can control the imaging state.

The present invention achieves the above object by using an optical element that changes the state of the wavefront of an incident light beam by moving particles present in a liquid.

Similarly, in the present invention, the particles include three states, i.e., gas, solid, and liquid. Examples of gases include vapor bubbles formed by boiling a liquid, and bubbles made of components that are difficult to dissolve in liquids, such as argon, air, oxygen, nitrogen, hydrogen, helium, and
These are bubbles of neon, -carbon oxide, -nitrogen oxide, methane, etc. The solid is a material with relatively low density, such as a polymeric material, and the liquid is a liquid that does not mix with the original liquid, such as a combination of water and oil.

The F1 invention ζ will be explained in detail below.

[-)! :Example]

Figures 1 and 2 are diagrams for explaining the moving mechanism of the grains used as the optical element of the present invention. 3 is a thermally conductive reflective layer, e.g. T
It consists of a membrane. 4 is a heating resistor (6a, 6b, . . .
6e) and an insulating substance S (O
The heating resistors 1-15 separated by z are insulating supports. 7 is a grain that is not formed by vapor bubbles and converts the wavefront of the incident light beam; 8 is a wire that connects the guide 14;
6b, .-5e) can be driven individually to f, respectively, using individual drive voltages (vI to v5) l, l! ! Thickness 4%s On the other hand, the heating resistor (6a.

61], . . . , 6e), the other end 9 is set to ground or 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. In the layer 4 consisting of Sth) 2,
The width lI of the heat generating resistors is, for example, 20 μm, and the interval 12 between the heat generating resistors is 50 μm.

When a voltage is applied to the heating resistor 6b as shown in FIG. ,
When 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 forming a temperature difference in the liquid, the particles 7
If the element is as shown in FIG. 1, the particles will move near the resistor that is generating heat.

Therefore, by selecting the heating resistor to which voltage is applied,
The position of the particles can be controlled.

By moving the particles in this way, the wavefront of the light incident on the element is changed.

Figure 1 When providing bubbles in the liquid as particles using the element shown in Figure 1, it is easy to form bubbles in the liquid by applying heat to the heating resistor and forming vapor bubbles in the liquid. You can. For example, in the device with the configuration shown in Figure 1, when the liquid is ethyl alcohol, when a DC voltage of about 4.2 V is applied across the heating resistor, bubbles with a diameter of about 150 μm are formed; The vapor bubbles did not disappear even when the applied voltage was lowered. And the particles made of air bubbles are
Even when the voltage applied to the heating resistor was lowered to about 1.5V, it remained attracted to the vicinity of the heating resistor. Therefore, this made it possible to maintain the position of the bubbles. 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.
The bubbles were moved by applying a voltage of .

In this way, in the device shown in Figure 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 a level that does not create bubbles in the liquid. It is desirable to keep the voltage applied in order to maintain the position of the particles. Another driving method is to apply the above bias voltage to all heating resistors, and then apply a relatively high voltage higher than the bias voltage to the heating resistors located at the desired 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 shows an example of an optical element used in the present invention,
It is a figure which shows the example used as a soft focus filter, such as a photographic lens. 18 is a glass substrate on which ring-shaped electrodes 11 and 13 are arranged concentrically. Heat generating resistors 12a, 12b, 12c, . . . and 14al14b114C, .
b.

It is assumed that 14c... is made of a transparent material. As will be described later, reference numeral 15 indicates a light beam effective portion of the photographic lens, and the ring-shaped barb 11 is located outside the effective portion, and the ring-shaped barb 13 is located inside the effective portion. Also, Seikoku 1
One end of the terminals 1 and 13 is kept at a constant potential by a switch 17, and the other end is grounded. In addition, particles such as bubbles become the heating resistor 12a in the first state where the electrode 11 is kept at a constant potential.

12b, 12c..., and in the second state when the switch 17 is switched, the grains on the heating resistor 12a are on the heating resistor 14a, and the grains on the heating resistor 12b are on the heating resistor 14b.
At the top, the particles on the heating resistor 12c are transferred onto the heating resistor 14c toward the center, and as a result, all the particles move onto the inner electrode 13.

FIG. 4 is a diagram showing a state where the soft focus filter explained in FIG. 3 is incorporated into a photographic lens, and 20 is a photographic lens;
1 is the aperture of the lens, and 22 is the soft focus filter explained in FIG. The plate filter is installed near the diaphragm 21, and has the function of moving the particles into the effective light beam area and arranging them at approximately equal intervals near the periphery of the diaphragm by switching the switch as described above. When the particles are outside the effective light beam area, the electrodes, heaters, etc. are transparent, so the photographic lens 2
Is the resolving power of 0 the same as usual?When the grains are moved, only the rays with a high height of incidence on the pupil among the incident light rays undergo a phase change due to absorption, scattering, etc.
Mainly, only the portion where the incident height of the spherical aberration is high is affected, and all flare-like aberrations occur. Therefore, it is possible to produce effects such as controlling depiction quality as a soft focus filter for a photographic lens.

In this example, the ring-shaped transparent heater in the beam effective area is single layered, but if multiple heaters are arranged concentrically and the position and number within the particle area is controlled, control corresponding to the aperture diameter can be achieved. In addition, it can be used as a filter with more complex effects, and it can also function as a filter that controls the MTF value of the lens. In addition, although it does not necessarily have to be a ring-shaped arrangement, by selecting the arrangement and type of particles according to the purpose, it can also be applied as an amplitude filter or a phase filter, and as a filter for improving purification such as apodyses. be.

The present invention has been described in detail above using the drawings. In the present invention, an optical element that converts the wavefront of a transmitted light beam by moving particles in a liquid is used in the coupling optical system, and the imaging characteristics of the imaging optical system can be made variable. There is.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams for explaining the principle of the optical element used in the present invention, and FIGS. 3 and 4 are diagrams showing embodiments of the present invention. DESCRIPTION OF SYMBOLS 1...Transparent protective plate, 2...Liquid thin layer, 3...Reflection layer, 4...Heating resistor layer, 5...Support, 6a,
6b, 6c, 6d, 6e---heating resistor, 7.
... Granular body, 11.13 ... Electrode, 12.14 ... Heat generating resistor, 15 ... Light beam effective part, 16 ... Power supply, 1
7... Switch, 18... Glass substrate, 20...
Photographic lens, 21...Aperture, 22...Soft focus filter.

Claims (1)

[Claims] (1) A liquid layer, granules provided in the liquid layer that are different from the liquid, and a method for creating a part in the liquid layer whose temperature is different from the temperature of the liquid at the position where the granules of the liquid layer exist. An imaging optical system characterized in that the imaging characteristic is made variable by arranging in the imaging optical system an optical element that changes the state of a wavefront of an incident light beam by movement of the particles.