Pattern indication using laser beam

• US 4,550,294 A
• Filed: 10/31/1983
• Issued: 10/29/1985
• Est. Priority Date: 10/31/1983
• Status: Expired due to Fees

• Current Assignee: Director-General of the Agency of Industrial Science and Technology, the Ministry of International Trade and Industry of Japan (Government of Japan)
• Original Assignee: Director-General of the Agency of Industrial Science and Technology, the Ministry of International Trade and Industry of Japan (Government of Japan)
• Inventors: Fukui, Yukio, Ohira, Tomohiro, Hirotani, Toyotoshi, Kishi, Yoshiki
• Primary Examiner(s): Buczinski, S. C.
• Assistant Examiner(s): Carniol, Burton J.
• Application Number:
  US06/547,233
• Time in Patent Office: 729 Days
• Field of Search: 332/7.51, 340/365 P, 340/707, 340/708, 340/702, 358/105, 358/107, 358/285, 358/232, 358/233, 358/234, 358/235
• US Class Current: 359/246
• CPC Class Codes: G06F 3/0386 for light pen
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen

Abstract

A method of visually representing output data on a screen by deflecting a laser beam in both horizontal and vertical directions for scanning, and an indicating device for performing the above method. The laser beam is first divided into two polarized waves which are, after being modulated in accordance with the output data, combined into a first synthesized laser beam. The two polarized waves are alternately extinguished synchronously with a predetermined simple harmonic oscillation. The synthesized laser beam is then horizontally deflected by means of a sinusoidally oscillating mirror so that the angular displacement of the deflection oscillates in synchronism with the predetermined simple harmonic oscillation. The resultant deflected beam is again divided into two polarized waves, one of which is then inverted. The resulting two polarized waves are combined to obtain a second synthesized laser beam whose angular displacement in deflection is unidirectional at any phase. The second synthesized laser beam, after being vertically deflected, is projected on the screen for scanning.

Claims

1. A device for visually representing on a screen output data generated from an output data generator, comprising:

(a) a laser beam modulation circuit supplied with the output data and generating modulation signals in accordance with the output data;

(b) a first beam splitter for separating by polarization a laser beam from a laser source into a first polarized wave and a second polarized wave;

(c) a first modulator connected to the laser beam modulation circuit for modulating said first polarized wave according to said modulation signals so that the intensity of said first polarized wave is varied in accordance with said modulation signals and said first polarized wave is periodically extinguished in synchronism with a predetermined simple harmonic oscillation for a period in the range of between (2n+3/2)π and

(2n+5/2)π

of the phase of said predetermined simple harmonic oscillation;

(d) a second modulator connected to said laser beam modulation circuit for modulating said second polarized wave according to said modulation signals so that the intensity of said second polarized wave is varied in accordance with said modulation signals and said second polarized wave is periodically extinguished in synchronism with said predetermined simple harmonic oscillation for a period in the range of between (2n+1/2)π and

(2n+3/2)π

of the phase of said predetermined simple harmonic oscillation;

(e) a second beam splitter arranged for receiving the polarized waves from said first and second modulators and for forming a synthesized laser beam;

(f) a first deflection means having a flat mirror located for receiving said synthesized laser beam and arranged to perform said predetermined simple harmonic oscillation so that the incident synthesized laser beam is deflected with its deflectional angular displacement oscillating in synchronism with said predetermined simple harmonic oscillation;

(g) a third beam splitter receiving the deflected laser beam from said first deflection means for separating same into third and fourth polarized waves corresponding to said first and second polarized waves, respectively, and a fourth beam splitter for synthesizing said third and fourth polarized waves;

(h) an inversion prism located in a light path between said third and fourth beam splitters for inverting either one of said third and fourth polarized waves;

(i) light path length adjusting means located in a light path between said third and fourth beam splitters for adjusting the length of light path of said third and/or fourth polarized waves such that the deflection angle of the deflected synthetic laser beam from said fourth beam splitter is displaced at a cycle of π

based on said predetermined simple harmonic oscillation; and

(j) a second deflection means receiving the deflected synthetic laser beam from said light path length adjusting means for deflecting and projecting same on said screen;

whereby said first and second deflection means scan the modulated laser beam horizontally and vertically to visually represent the output pattern on said screen.

2. A device as set forth in claim 1, further comprising:

coordinate detection means including a digitizer having its surface constituted by said screen, and a stylus for contact with said screen, said coordinate detection means being capable of detecting the pressure and the position of the point of contact between said screen and said stylus and of generating corresponding detection signals; and

processing means supplied with the detection signals for processing same into the output data, whereby as a pattern is drawn on said screen with said stylus, it is fed to said processing means and converted into the output data which are visually represented on said screen.

3. A device as set forth in claim 1, wherein said first deflection means includes a cylindrical metal rod adapted for angular vibration about its axis and having said flat mirror formed on its outer periphery, and an AC electromagnet having two pairs of opposed magnetic poles located on a plane which is vertical to the axis of said metal rod and surrounding said metal rod, said pairs of magnetic poles being supplied with AC currents with a phase difference of π

/2 so that when the AC currents are supplied to said magnetic poles, said metal rod is angularly vibrated sinusoidally with said flat mirror being angularly oscillated sinusoidally synchronously with the AC currents.

4. A method of visually representing output data on a screen, comprising:

introducing a laser beam into a first splitter to divide the laser beam into first and second polarized waves;

modulating the first and second polarized waves to vary the intensity of the waves in accordance with the output data and to alternately extinguish the first and second polarized waves in synchronism with a predetermined simple harmonic oscillation for a period so that the first polarized wave is periodically extinguished in the range of between (2n+3/2)π and

(2n+5/2)π

of the phase of said predetermined simple harmonic oscillation and the second polarized wave is periodically extinguished in the range of between (2n+1/2)π and

(2n+3/2)π

of the phase of said predetermined simple harmonic oscillation;

combining the modulated laser waves to synthesize a first synthesized laser beam;

deflecting said first synthesized laser beam in one plane such that the angular displacement of the deflection sinusoidally oscillates in synchronism with said predetermined simple harmonic oscillation;

introducing the deflected synthesized laser beam into a second beam splitter to divide same into third and fourth polarized waves;

inverting either one of said third and fourth polarized waves;

combining the third and fourth polarized waves to synthesize a second synthesized laser beam;

adjusting the length of light path of said third and/or fourth polarized waves so that the angular displacement of the deflection of the second synthesized laser beam oscillates with a cycle of π

based on said predetermined simple harmonic oscillation; and

deflecting said second synthesized laser beam in a plane vertical to the plane in which the incident second synthesized laser beam oscillates, so that the screen is horizontally and vertically scanned with the deflected second synthesized laser beam to visually represent the output data on the screen.