Liquid crystal display for laser marker

• US 5,726,673 A
• Filed: 05/09/1995
• Issued: 03/10/1998
• Est. Priority Date: 11/11/1992
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Komatsu Seisakusho
• Original Assignee: Kabushiki Kaisha Komatsu Seisakusho
• Inventors: Mori, Akira, Saito, Yoshinori, Tsuda, Yukihiro
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): KIM, JULIANA
• Application Number:
  US08/432,186
• Time in Patent Office: 1,036 Days
• Field of Search: 345/87, 345/103, 345/94
• US Class Current: 345/87
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: G06K 15/1204 involving the fast moving of an optical beam in the main scanning direction G06K15/1233 - G06K15/129 take precedence
• CPC Class Codes: G06K 15/1238 simultaneously exposing more than one point
• CPC Class Codes: G06K 15/1252 using an array of light modulators, e.g. a linear array
• CPC Class Codes: G06K 15/1257 on more than one main scanning line

Abstract

A liquid crystal display for a laser marker for attaining a higher marking speed, characterized in that a liquid crystal display screen (10) is divided into a first zone (10a) where a sub-scanning is first performed and a second zone (10b) where a sub-scanning is performed following the first zone (10a) sub-scanning, that switching of display is performed independently for each of the first and second zones (10a, 10b), and predetermined voltages are applied, respectively, to row and column electrodes after those row and column electrodes are grounded, whereby display switching processing can be performed independently for each of the first and second zones. Completion of the sub-scanning of the first zone (10a) is detected by a position detecting means, and when such a detection is done, switching of display in the first zone (10a) is independently performed. In addition, when the position detecting means detects the completion of sub-scanning of the second zone (10b), switching of display in the second zone (10b) is performed independently.

Claims

1. A liquid crystal display device for a laser marker in which, when changing display of a liquid crystal display screen provided with row and column electrodes for each of pixels, shifting is effected to a display period in which a predetermined effective voltage potential value is applied respectively to the row electrodes and the column electrodes after passage of a non-display period in which voltage potentials of the row and column electrodes are made identical, wherein the liquid crystal display device comprises:

a controller which outputs a voltage potential command value to the liquid crystal in such a manner that, an effective voltage potential value greater than the predetermined effective voltage potential value is applied to the row and column electrodes for a predetermined time of an initial stage of the display period in which a transparent rate of display pixels reaches a predetermined voltage potential value and a transparent rate of non-display pixels does not reach the predetermined voltage potential value, and the predetermined effective voltage potential value is applied to the row and column electrodes from a time point when the predetermined time elapsed until a time point when the display period ends.

2. A liquid crystal display for a laser marker wherein row and column electrodes are provided for each of pixels of a liquid crystal, during a display period a first voltage potential is applied to the row electrodes and a second voltage potential is applied to the column electrodes to thereby create the display and during a non-display period voltage potentials of the row and column electrodes are substantially identical, and predetermined voltage potentials are applied to the row and column electrodes to perform switching of display of a liquid crystal display screen, a laser beam is irradiated on the liquid crystal display screen and scanned on the liquid crystal display screen to mark a predetermined pattern displayed on the liquid crystal display screen onto a target object, the liquid crystal display comprising:

display switching means for dividing the liquid crystal display screen into a first zone to be firstly subjected to a sub-scanning operation and a second zone to be subjected to a sub-scanning operation following the first zone, for performing switching operation of the display over the first and second zones independently of each other, and for grounding the row and column electrodes for the first and second zones respectively and then applying the predetermined voltage potentials to the row and column electrodes;

said display switching means being further constructed and arranged for starting the display of the second zone from a time t₀ prior to a display end time t₁, of the first zone and prior to a time period necessary for activating the display and, for starting the display of the first zone from a time t₂ prior to a display end time t₃ of the second zone and prior to a time period necessary for activating the display;

position detecting means for detecting a position on the liquid crystal display screen at which the sub-scanning is being carried out; and

means for controlling the display switching means to perform switching operation of display of the first zone when the position detecting means detects completion of the sub-scanning of the first zone and to perform switching operation of display of the second zone when the position detecting means detects completion of the sub-scanning of the second zone.

3. The liquid crystal display for a laser marker as set forth in claim 2, wherein the sub-scanning is carried out by irradiating the laser beam and rotating a light reflector for reflection of the laser beam to thereby change a reflection direction of the laser beam, and the position detecting means detects the position of the sub-scanning on the basis of a rotation command signal for the mirror.