JPS625215A - Optical deflection device - Google Patents

Abstract

PURPOSE:To dispense with the rotating mechanism and the driving device and to miniaturize the device by providing the aspheric convex lens, the light source device, the light shutter means, etc. CONSTITUTION:The device consists of an aspheric convex lens 16 composed of partial convex lens parts 18a-18c, etc., where an optical polarizing element 15 is successively dislocated in one direction orthogonal to the optical axis, and a light shutter 20 to open alternatively the partial convex lens parts 18a-18c. Consequently, concerning the deflection in the optical polarizing element 15, the movable part is not found, a small size is obtained and the very high reliability can be obtained. Namely, compared with the case when a polygon mirror and a hologram scanner are used, the rotating mechanism and the driving device come to be unnecessary, the device is small-sized and simple and the durability can be improved.

Description

TECHNICAL FIELD The present invention relates to improvements in optical deflection devices for deflecting light.

BACKGROUND OF THE INVENTION Devices such as laser beam printers and bar code leagues use optical deflection devices to deflect light to a desired angle. Polygon mirrors, hologram scanners, etc. are known as such optical deflection devices, but all of them are equipped with mechanically movable parts such as a rotation mechanism and its drive device, making the devices complicated and large. ,Also,
Sufficient durability was not always achieved.

Means for Solving the Problems The present invention was made against the background of the above-mentioned circumstances, and its gist is (1) that a plane parallel to a plane containing an optical axis is bounded and two an aspherical convex lens consisting of a plurality of divided partially convex lens parts, the focal points of the partially convex lens parts being sequentially shifted in one direction perpendicular to the optical axis;
(2) a light source device that irradiates the aspherical convex lens with light;
(3) It includes a light shutter means for selectively passing light through the partially convex lens portion of the aspherical convex lens.

In this way, the focus of the partially convex lens portion through which light is selectively passed by the light shutter means is sequentially shifted in one direction parallel to the plane containing the optical axis, The light transmitted through the convex lens portion is focused at different positions corresponding to the partially convex lens portion. This focal point corresponds to the shift dimension of the partially convex lens section, and by selecting the partially convex lens section through which light is transmitted by the optical shutter means, it is as if the convex lens were moved in a direction perpendicular to its optical axis. As the lens moves, the light that passes through one point and is irradiated onto the aspherical convex lens is deflected to a desired angle.

Therefore, mechanical blades and moving parts such as a rotating mechanism for deflecting light and a driving device thereof are not required, so that the device becomes compact and has sufficient durability.

The aspherical convex lens is preferably formed into a plano-convex lens shape with a flat negative surface, and the optical shutter means is provided on one of the planar surfaces of the aspherical convex lens. The optical shutter means may be a liquid crystal cell, or may be a solid state optical shutter element made of a material having an electro-optic effect.

Preferably, the aspherical convex lens is made by polishing the spherical surface of a material prepared by laminating plate glass pieces in advance into a convex lens shape, and then sequentially shifting the plate glass pieces in one direction perpendicular to the optical axis to mutually It is constructed by fixing. Alternatively, the aspherical convex lens can be made by polishing a piece of glass material into a convex lens shape, and then dividing the glass material along a plane parallel to the plane containing the optical axis of the convex lens to create multiple pieces of plate glass corresponding to partially convex lens parts. It can also be constructed by creating a glass plate, sequentially shifting the glass pieces in a direction perpendicular to the optical axis, and fixing them to each other.

Further, the light source device preferably includes a monochromatic light source including a semiconductor laser element that outputs laser light, and condenses the laser light output from the semiconductor laser element to one point, and then sends the laser light to the aspherical convex lens. The one point through which the light emitted from the light source toward the aspherical convex lens passes is preferably separated from the aspherical convex lens by its focal length in the optical axis direction. It is located between the point and a point separated by twice the focal length.

This has the advantage that the distance between the convergence points of the light that has passed through the partially convex lens portions is expanded more than the amount of shift between the partially convex lens portions.

Embodiment FIG. 1 shows an optical deflection device used in a laser printer or the like, in which a movable table 12 is disposed on a base lO so as to be movable in one direction.
For example, an actuator 14 is provided to move the positioning point to about 20 positioning points. Actuator 14
is constructed by laminating a large number of piezoelectric ceramic elements, and its total length changes depending on the voltage applied to its electrodes. Therefore, the actuator 14 and the movable table 12 constitute an optical deflection element driving device that positions the optical deflection element 15. Note that the actuator 14 may be an electromagnetic actuator or the like that drives the movable base 12 according to electromagnetic force.

An optical deflection element 15 consisting of an aspherical convex lens 16 and an optical shutter 20 is fixed on the movable table 12 . Second
As shown in the figure and FIG. 3, the aspherical convex lens 16 is
A plurality of partial convex lens parts 18a, 18b in which a plurality of convex lenses are divided with a plane including the optical axis and parallel to the moving direction of the movable table 12, that is, a horizontal plane in FIG.
18c, etc., and the optical shutter 20 includes shutter segments 22a, 22b, 220 disposed corresponding to the partially convex lens portions 18a, 18b, 18c, etc.
Consists of etc. The aspherical convex lens 16 is, for example, a fourth lens.
As shown in the figure, a plano-convex lens polished from a glass material is divided along a plane parallel to the plane containing its optical axis as shown in Figure 5, and the partially convex lens portion 1 obtained by such division is It is obtained by fixing 8a, 18b, 18c, etc. to each other in a state in which they are sequentially shifted toward one direction that is the plane direction of the dividing plane and perpendicular to the optical axis. The aspherical convex lens 16 is prepared by laminating a large number of plate glass pieces 24 as shown in FIG. 6, and is polished into a plano-convex lens shape to obtain the state shown in FIG. 5. partially convex lens portions 18a, 18b, 18
It can also be obtained by fixing parts such as c to each other as shown in FIG.

Shutter segment 22a% 2 of the optical shutter 20
2b, 22c, etc. are partially convex lens parts 18a118b, 18
They are each fixed to one surface of a flat surface such as c. The shutter segments 22a, 22b, 22c, etc. are each made of an electro-optic material that exhibits different optical anisotropy depending on the electric field, and have a pair of transparent electrodes (not shown) sandwiching the material in a direction parallel to the optical axis. We are prepared. By changing the optical anisotropy of the electro-optic material in accordance with the voltage applied to the pair of transparent electrodes, an optical shutter effect can be obtained. Note that the optical shutter 20 of this embodiment has a large number of shutter segments 22 as 22
BS22C, etc., but a transparent electrode is provided on the entire one side of a single substrate made of a substance having an electro-optic effect, while partially convex lens portions 18a and 18b are provided on the other side.
, 18c, etc., or instead of the optical shutter 20, a liquid crystal is sealed in a predetermined thickness, and the liquid crystal is sealed inside the glass plate sandwiching the liquid crystal. A liquid crystal cell in which similar electrodes are formed may be used as an optical shutter.

Returning to FIG. 1, a fixed monochromatic light source 30 made of a semiconductor laser element or the like emits a laser beam in a direction perpendicular to the moving direction of the movable table 12, and the laser beam is focused by a condenser lens 32. After being converged to a light spot 34, the light is diffused again and is irradiated onto the front surface of the light deflection element 15.

The condensing point 34 is located between a point separated from the aspherical convex lens 16 by the focal point and a point separated by two times the focal point in the optical axis direction.

In this embodiment, the monochromatic light source 30 and the condensing lens 32
The light source device is configured by:

In the optical deflection element 15, one of the partially convex lens parts 18a, 18b, and 18c is selectively opened by the optical shutter 20, and the partially convex lens parts 18a, 18c are selectively opened.
The light that has passed through any one of 18b, 18c, etc. is displayed on the screen 3 consisting of the master drum of a laser printer, etc.
The light can be focused on 6. Although not shown, various optical elements are appropriately used between the monochromatic light source 30 and the light deflection element 15 and between the light deflection element 15 and the screen 36 as necessary.

The effects of this embodiment will be explained below.

As mentioned above, the laser beam emitted from the monochromatic light source 30 is focused on a point on the screen 36 through one partially convex lens portion whose transmission is allowed by the optical shutter 20, but as shown in FIG. In this case, the partially convex lens portion is, for example, 18f, and the focal point on the screen 36 is Sf.

Next, when another partially convex lens portion, for example 18g, is opened by the optical shutter 20, the partially convex lens portion 18g
Assume that the laser beam that has passed through is focused on a point 8g on the screen 36. These two condensing points S and S are located at one point l! of the partially convex lens portion 18f shown by the solid line in FIG. The laser beam is deflected in the same way as if it were moved in a direction perpendicular to the optical axis to the position of the partially convex lens portion 18g shown on the li line.

In particular, the focal point 34 is a point Ft that corresponds to twice the focal length of the aspherical convex lens 16 in the optical axis direction of the aspherical convex lens 16.
Since the distance between the condensing points Sf and S is larger than the amount of deviation between the partially convex lens parts 18f and 18g, the moving distance of the condensing point is greatly amplified.

In the above state, when the voltage supplied to the actuator 14 is changed, for example, in any one of 20 steps, the optical deflection element 15 is moved in a direction perpendicular to the traveling direction of the laser beam, Since the laser beam is positioned at a position corresponding to the applied voltage, the focal point of the laser beam is positioned at a desired position on the screen 36 between the focal points of the partially convex lens parts adjacent to each other. For example, the focal point is determined at any one of the 20 positioning points between the focal points Sf and S in accordance with the voltage supplied to the actuator 14.

By controlling the voltage supplied to the actuator 14 and the voltage applied to the optical shutter 20, the laser beam is focused on a predetermined area indicated by a broken line on the screen 36, while By combining this with the control for moving the 36 in the vertical direction, desired characters, figures, etc. can be drawn.

As described above, according to this embodiment, the optical deflection element 15 is arranged in the partially convex lens section 1 that is sequentially shifted in one direction perpendicular to the optical axis.
Aspherical convex lens 16 consisting of 8a, 18bs, 18c, etc.
and an optical shutter 20 that selectively opens the partially convex lens portions 18a, 18b, 18C, etc., so that the optical deflection element 15 has no moving parts and is compact, and has extremely high reliability. is obtained.

That is, compared to the conventional case using a polygon mirror or a hologram scanner, there is no need for a rotation mechanism, a driving device, etc., and the device becomes smaller and simpler, and its durability is improved.

As shown in FIGS. 8 and 9, the aspherical convex lens 16 may be formed integrally with a glass material by polishing, and as shown in FIG. This aspherical convex lens 40, which may be composed of a spherical convex lens 40, includes partially convex lens portions 42a that are sequentially shifted from each other in one direction perpendicular to the optical axis, as described above.
42b, 42c, etc., partially convex lens portion 42a,
42b, 42a, etc. themselves are made of a substance having an electro-optic effect, and transparent electrodes (not shown) are individually provided on both surfaces of the partially convex lens portions 42a, 42b.
, 42a, etc. themselves also serve as shutter segments.

It should be noted that the above-mentioned example is just one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a light deflection device that is an embodiment of the present invention. FIG. 2 is a front view of an aspherical convex lens forming part of the optical deflection element provided in the apparatus of FIG. 1. 3 is a side view of the optical deflection element of FIG. 1. FIG. Fourth
5 and 6 are diagrams each illustrating the manufacturing process of the aspherical convex lens shown in FIG. 2. FIG. 7 is a diagram illustrating the deflection action of FIG. 1. FIGS. 8 and 9 are views corresponding to FIGS. 2 and 3 showing a light deflection element in another embodiment of the present invention. FIG. 10 is a side view showing a light deflection element in another embodiment of the present invention. 16.40: Aspherical convex lenses 18a, 18b, 18cm = 42a, 42b. 42c...: Partially convex lens portion 20: Optical shutter Applicant Brother Industries, Ltd. Figure 2 Figure 3m Figure 4 Figure 5WJ Figure 6

Claims (4)

[Claims] (1) An aspherical convex lens consisting of a plurality of partially convex lens parts divided along a plane parallel to the plane containing the optical axis, and in which the focal point of the partially convex lens parts is sequentially shifted in one direction perpendicular to the optical axis. A light deflection device comprising: a light source device that irradiates light onto the aspherical convex lens; and a light shutter means that selectively allows light to pass through a partially convex lens portion of the aspherical convex lens. (2) The aspherical convex lens is formed into a plano-convex lens shape with one flat surface, and the optical shutter means is a liquid crystal cell provided on one planar surface of the aspherical convex lens. The optical deflection device described. (3) The aspherical convex lens is made by polishing a material prepared by stacking plate glass pieces parallel to the plane containing the optical axis into a convex lens shape, and then moving the plate glass pieces in one direction perpendicular to the light source. The optical deflection device according to claim 1 or 2, which is configured by sequentially shifting and fixing each other. (4) The aspherical convex lens is produced by polishing a piece of glass into a convex lens shape, and then dividing the glass along a plane parallel to the plane containing the optical axis as a boundary to create plate glass pieces corresponding to the partially convex lens portion. The optical deflection device according to claim 1 or 2, which is constructed by sequentially shifting plate glass pieces in one direction perpendicular to the optical axis and fixing them to each other.