JPH02207214A - Micro optical scanner - Google Patents

Abstract

PURPOSE:To obtain the optical scanner which can be manufactured at low cost, miniaturized, and made compact on the whole by forming micro rotary polygon mirrors on the same substrate at the same time. CONSTITUTION:Projection parts 2A as rotor electrodes are formed on the outer periphery of a rotary polygon mirror 2 at intervals of 90 deg. corresponding to stator electrodes 4 and become stablest with an attractive force generated by voltage application to a terminal phiA when facing electrodes 4A1-4A4 in a group A. Then when the voltage to the terminal phiA is ceased and a voltage is applied to a terminal phiB, the projection parts 2A on the outer periphery of the rotary polygon mirror 2 move until they face electrodes 4B1-4B3 in a group B, so that the rotary polygon mirror 2 is considered to rotate. Similarly, the voltage is applied to terminals phiC, phiB, phiA... in order to carry on the rotation. Micro rotary polygon mirrors 2 can be mass-produced on one substrate 1 at the same time, so they can be manufactured at low cost and the device can be made compact on the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to lowering the price and downsizing of an optical scanner that changes the direction of light by rotating, vibrating, etc. a polygon mirror.

[Conventional technology]

FIG. 6 shows a specific application example of an optical scanner that changes the direction of light by rotating or vibrating a polygon mirror.

This is a diagram showing the principle of an optical printer using a laser (usually called a laser printer).

Light emitted from a semiconductor laser 101 (this may be another laser) driven by a scanner controller 111 is focused by a collimating lens 102 and enters a rotating polygon mirror 104 driven by a scanner motor 103. .

The light reflected by the rotating polygon mirror 104 is transmitted to the rotating polygon mirror 1
As 04 rotates, it changes direction and exits.

This reflected light is transmitted to the photosensitive drum 1 by a condensing lens 109.
The light is focused on 07.

This photosensitive drum 107 is charged in advance by a charger 106. This electrical charge is discharged by laser light, and a difference in charge is formed depending on the presence or absence of laser light.

Although not shown, after the density of charge is formed,
Toner is applied to the photoreceptor drum.

However, since the toner is attached by electrostatic force, the presence or absence of toner can be determined depending on the presence or absence of charge. This 1-ner is the printing paper 108
is copied to form characters, images, etc.

The sensor 110 is provided to accurately detect the scanning start timing of the light beam.

[Problem that the invention seeks to solve]

In the conventional example described above, the rotating polygon mirror 104 and the scanner motor 103 are large and expensive, and there has been a demand for compactness and low cost.

[Failure to solve the problem]

In order to solve this problem, the present invention forms a minute rotating polygon mirror by creating a rotating polygon mirror and a scanner motor by applying the manufacturing technology of a half-meter integrated circuit, and this minute rotating polygon mirror Electrostatic force is used as a means of driving.

Examples of the rotating polygon mirror used in the present invention include polycrystalline or amorphous silicon coated with a reflective film such as a metal film. Also, currently RIE is used for processing reflective surfaces.
(Reactive Ion Etching) method is considered to be the best method.

[Effect]

According to the present invention, since a plurality of micro-rotating polygon mirrors can be formed simultaneously on the same substrate, they can be manufactured at low cost, and miniaturization is easy, which can greatly contribute to making the device more compact.

Furthermore, it is possible to integrate it with a semiconductor laser, and by reducing the number of parts, it becomes possible to further reduce the cost, make it more compact, and improve reliability.

〔Example〕

A first embodiment of the invention is shown in FIG.

(a) of the figure is a plan view, and (b) is xx in (a).
' is a cross-sectional view along the line.

A rotating polygon mirror 2, a shaft 3 for supporting it, and an electrode group 4 for applying static electricity are provided on a substrate 1.

Electrode group 4 consists of four electrodes arranged at 90° intervals around the axis, with electrodes A, B arranged at equal intervals,
It consists of three groups: C.

Among these, the electrodes 4A1 to /IA4 of the A group are terminals φ,
Then, electrode 4 of group B. B 1 to 4134 are terminals ψ
8, the electrodes 4C1 to 4C4 of group C are terminals φ. are connected to each.

As shown in FIG. 2B, the rotating polygon mirror 2 is rotatably supported on a shaft 3, and a stop is provided at the second portion of the shaft 3 to prevent the rotating polygon mirror 2 from coming off.

Also, the substrate 1 and all electrodes 4. An insulating film 5 is provided between A1-4CI.

The rotating polygon mirror 2 is formed of a conductive material or a semiconductor material, is grounded via a shaft 3, and applies a voltage to a terminal φ4.

On the outer periphery of the rotating polygon mirror, two convex portions as rotor electrodes are provided at 90° intervals in correspondence with the stator electrode 4 described above, and each convex portion is moved by the attractive force caused by voltage application to the terminal φ4. 2
The state is most stable when the person faces the electrodes 4A1 to 4A4 of group A.

Next, when the voltage at terminal φ4 is cut off and the voltage is applied to terminal φ8, the two outer peripheral protrusions of the rotating polygon mirror are connected to each electrode 4B of group B.
1 to 4B4, and the rotating polygon mirror 2 has rotated.

Thereafter, in the same way, the terminal φ. , ψ8, φ, . . . , the rotation can be continued by sequentially applying voltages. In other words, it works as an electrostatic motor using the polygon mirror 2 itself as a rotor.

Laser light that enters from a semiconductor laser 101 as a light source via a collimator lens 102 is reflected from the mirror surface of the rotating polygon mirror 2 and extracted as a laser beam 105. The size of this rotating polygon mirror is about 100 μm to 1 crane, and as described later, it can be formed simultaneously and in large quantities on one substrate by applying semiconductor manufacturing technology, so it can be manufactured at an extremely low cost, and it also reduces the overall cost of the device. It can be made more compact.

In the above embodiment, a four-sided mirror is used as the rotating polygonal mirror 2, but it is not necessary to use a four-sided mirror at all, and other polygonal mirrors including a plane mirror may be used.

Furthermore, although a three-phase drive electrostatic motor is given as an example, it does not necessarily have to be three-phase.

However, the motor operates more smoothly if the number of drive phases is increased, and the more electrodes there are, the more smoothly the motor rotates.

Next, a preferred method for molding the micro-rotating polygon mirror used in the present invention will be described with reference to FIG.

First, a PSG (phosphosilicate glass) layer 61, a polycrystalline silicon layer 21, a PSG layer 62, a metal film 7 are formed on a silicon substrate 1.
1 is laminated and formed.

The thickness of the PSG layers 61 and 62 and the metal film 71 was 50 nm.

Next, a photoresist 8 having the same planar pattern as the rotating polygon mirror to be obtained is formed by photolithography.

Using this photoresist 8 as a mask, the metal film 71 and P
The SG layer 62 is etched, and then the polycrystalline silicon layer 2 is etched.
RT E (Reactive Jon Etch
ing) law or I B E (Jon Beam E
The etched surface is vertically etched using the tcbing method to make the etched surface almost mirror-like.

Thereafter, the metal film 71 is removed and the entire surface is uniformly covered with the PSG layer 63 (FIG. 2b).

Further, a polycrystalline silicon film is formed thereon and etched to form the shaft portion 5. Next, an insulating film 5 is formed, and an electrode group 4 is formed (FIG. 2C).

Next, the PSG layers 62 and 63 are removed at the same time, and the rotating polygon mirror 2 is separated from the substrate 1 and shaft 5.

Finally, a metal film is formed only on the side surfaces of the rotating polygon mirror 2 to complete the process.

Next, a second embodiment of the present invention is shown in FIG.

This is a micro-rotating polygon mirror provided on a semiconductor laser substrate. A minute rotary polygon mirror 2 and an electrostatic motor are formed on a substrate 1 on which a laser is formed in the same manner as in the first embodiment. 80 is the upper electrode of the semiconductor laser;
84 is a stripe pattern of a semiconductor laser.

A current is passed between the electrode 80 and the substrate 1 to cause laser emission, but the current is formed so as to flow only through the pattern 84. The laser light emitted from here is reflected by the rotating polygon mirror 2 and goes out.

This embodiment has a structure in which a laser and a rotating polygon mirror are integrated, and can be made very small.

The cross-sectional structure is shown in FIG. 3(b). The cross section of the semiconductor laser has a normal structure, with cladding layers 81 and 83 provided above and below an active layer 82, and a current being injected from a two-part electrode 80.

In this embodiment, the structure of the semiconductor laser can be any generally known structure and will operate without problems.

FIG. 4 shows a third embodiment of the present invention.

In the structure in which the semiconductor laser and micro-rotating polygon mirror are integrated as shown in the second embodiment, the light emitted from the semiconductor laser does not become a parallel beam, but spreads out at a certain angle. For this reason, the effect of beam swinging by the rotating polygon mirror is considerably reduced. Therefore, in this embodiment, the mirror surface of the rotating mirror 2 is a concave mirror.

As a result, the laser beam is focused, and the effect of beam waving can be increased.

FIG. 5 shows a fourth embodiment of the present invention.

In this embodiment, a concave mirror 9 converts laser light emitted from a semiconductor laser into a parallel beam, and a rotating polygon mirror 2 swings this beam.

This effect is exactly the same as in the third embodiment, but since the angle of the laser beam incident on the concave mirror 9 is always constant, the advantage is that a parallel beam can always be emitted without being affected by the angle at which the beam swings. have.

This concave mirror 9 can be made in exactly the same manner as the rotating polygon mirror 2.

〔Effect of the invention〕

According to the present invention, since a plurality of micro-rotating polygon mirrors can be simultaneously formed on the same substrate, it can be manufactured at low cost, and miniaturization is easy, which can greatly contribute to the miniaturization of the entire device.

Furthermore, it is possible to integrate it with a semiconductor laser, and by reducing the number of parts, it becomes possible to further reduce the cost, make it more compact, and improve reliability.

Further, the present invention can be applied to contact image sensors, optical printers, displays, etc., and can greatly contribute to improving the performance and lowering the prices of these devices.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a plan view and a sectional view showing a first embodiment of the present invention, and FIGS. 2(a) to (b) show a method for manufacturing a micro-rotating polygon mirror used in the present invention. 3(a) and 3(b) are plan views and sectional views showing a second embodiment of the present invention, and FIG. 4 is a plan view showing a third embodiment of the present invention, FIG. 5 is a plan view showing a fourth embodiment of the present invention, and FIG. 6 is a perspective view showing a conventional example. ■... Substrate 2... Rotating polygon mirror 2A.
... Rotor electrode convex portion 3 ... Shaft 4 ... Stator electrode 5 ... Insulating film 8 ... Resis 1-Bakuun
9... Concave mirror 21... Polycrystalline silicon 61.62.63... Phosphorsilicate glass (PSG) 7
1... Metal film 105... Laser beam diagram procedure amendment (method) Contents of amendment April 28, 1999 □ 1) In the 5th line of page 11 of the specification, "Figure 2 (a) The text has been corrected to ``Figure 2 (a) to (d).'' ~ (b) Representation of the case Relationship with the case of the person who makes the correction for the weak light scanner over the name of the invention in 1999 Patent Application No. 27825 Patent applicant
Yo71 Display change address 3-5-11 Domine-cho, Chuo-ku, Osaka-shi, Osaka Name (400) Nippon Sheet Glass Co., Ltd. Representative Tatsuji Nakajima

Claims (1)

[Scope of Claims] 1) A microscopic polygonal mirror is rotatably attached to a shaft erected on a substrate, an appropriate number of stator electrodes are provided on the substrate surrounding the polygonal mirror, and On the mirror body side, rotor electrode portions facing the stator electrodes are provided at appropriate intervals on the outer periphery, and both constitute an electrostatic motor, and by sequentially switching the voltage application to the stator electrodes, a multi-faceted A microscopic optical scanner characterized by a rotating mirror. 2) The microscopic optical scanner according to claim 1, wherein the mirror surface of the polygon mirror is a concave surface to have a light condensing effect. 3) Claim 1 or 2, wherein a semiconductor laser as a light source for projecting a light beam onto the polygon mirror is integrally formed on the substrate.
Microscopic optical scanner described in . 4) The micro optical scanner according to claim 3, further comprising a concave mirror provided between the semiconductor laser and the rotating polygon mirror.