CN85109630A - 光调制系统 - Google Patents

光调制系统 Download PDF

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CN85109630A
CN85109630A CN85109630.1A CN85109630A CN85109630A CN 85109630 A CN85109630 A CN 85109630A CN 85109630 A CN85109630 A CN 85109630A CN 85109630 A CN85109630 A CN 85109630A
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桑原绅一郎
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Abstract

关于用来在录相磁盘及数字录音磁盘记录信息的光学式磁盘刻蚀装置中所用的光学调制系统,是由以调制信号激光的电光式光调制器、把该电光式光调制器的输出光变换为电信号的光电变换元件、可以转换调制信号之极性的控制部、向该控制部供给标准的振荡信号的振荡电路,以及对上述光电变换元件的输出信号进行同步检波的同步检波部构成的。

Description

本发明是有关用来在录象磁盘及录音磁盘上记录信息信号的光学式磁盘刻蚀装置所用的光调制系统。
在录象磁盘及数字录音磁盘记录信号时一般都采用称之为光学式的方法。该方法是以在玻璃等圆盘上均匀地涂上一层薄薄的光致抗蚀剂(光化学反应剂)来作为原盘,通过把由光调制器用记录信号调制的激光作为特小直径光点来给上述光致抗蚀剂感光以记录信号,然后再显影在上述原盘上的方式。
图3是表示采用上述方式而构成的一般光学式磁盘刻蚀装置、图中由激光光源51输出的激光LO是通过反射镜52供给光调制器53,在此经过以需要记录的信号进行调整,再通过光束分离器54、快门55、透镜56、反射镜57及物镜58等透镜系列以特小直径光点送到原盘59的光致抗蚀剂上,把信号记录在由马达60等转动的上述原盘59。
光调制器53,有一种利用把电场加在结晶上使结晶折射率产生变化,即所谓电光效应的电光式光调制器,及一种利用通过声波使媒质的折射率变化,即所谓声光效应的声光式光调制器。
电光式光调制器具有调制带宽大于声光式光调制器的优点,原来就有采用这种电光式光调制器的光学式磁盘刻蚀装置。
在由此类的光学式磁盘刻蚀装置把信息信号记录于原盘等时,结合光致抗蚀剂的感光特性的曝光强度,即光调制器53的输出光强度,必须精确地控制于相应于信息信号所定的强度里。
然而,电光式光调制器由于结晶内产生热的影响,它的特性很容易变动,所以采用电光式光调制器的光学式磁盘刻蚀装置,就有调制过的激光强度对于规定值变得不稳定的缺点。该缺点可以通过导入如专利公报昭57-32411号所公开的反馈控制系统来加以解决。
可是,采用这种反馈控制系统,在上述电光调制器的特性产生了超越可控制范围的变化时,就会使该电光光调制器的输出光失去稳定。
例如,图2所示的是上述电光光调制器的光强度附加电压特性图,在特性曲线a上的该特性曲线a的倾斜为正的领域里,以附加电压V为V1的点作为工作点来进行正常工作的反馈系统里,所进行的工作是;光强度I增加,附加电压V就下降,反之,光强度I减少,附加电压V就提高。这里所述的上述特性变化为特性曲线b时,在上述附加电压V是V1的点,该特性曲线b的斜度就变为负,与上述特性曲线a的情形相同,当光强度I增加而进行降低附加电压V的工作时,就不能控制稳定的光强度。
在上述情形时,就倒转上述附加电压V的极性,以V=-V1作为工作点,就能够通过在光强度增加后降低附加电压下降,以及反之光强度减少后则增加附加电压V,使光强度I变为稳定。
如上所述,在上述电光式光调制器的特性发生较大变化而光强度无法控制时,采用转换该电光式光调制器的附加电压的极性的方法,就能够转变为可控制的状态。原来这种极性的转换都是用手动开关来进行的,所以上述电光式光调制器的操作很麻烦。
鉴于上述问题,本发明以自动进行上述极性转换的方法,使上述电光式光调制器变得易于操作。
本发明系统具有一用调制信号调制激光的电光式光调制器、一把该电光式光调制器的输出光变换为电信号的光电变换元件、一可以转换调制信号的极性的控制部、一把标准的振荡信号供给该控制部的振荡电路、以及一对上述光电变换元件的输出信号进行同步检波的同步检波部。
在上述同步检波部对上述光电变换元件的输出信号进行同步检波,而该输出信号的相位与上述振荡信号的相位是反相时,上述控制部的极性就被转换,上述电光式光调制器就由该控制部根据上述激光的强度设定信号电平和上述光电变换元件的输出信号电平的差作相应的调制。
以下参照附图就本发明的光调制装置进行说明。
图1是表示适用于本发明的光调制系统的一实施例的光学式磁盘刻蚀装置结构的方块图,在这个装置里,该光调制系统可用于激光强度的设定。
图1里由激光源1输出的激光L。在电光式光调制器2接受由控制部16供给的调制信号的调制之后,输往光束分离器3。透过该光束分离器3的激光在光调制器4由从信号处理部5输出的记录信号进行调制,经光束分离器6、反射镜7及透镜9等光学系统,以特小直径光点送到原盘8上面。上述光束分离器6的反射光是由光电变换元件19而被变换为电信号并利用于监控记录信号等。
还有上述光束分离器3的反射光被导入光电变换元件10并变换为电信号。由该光电变换元件10所得的检测信号通过放大器11被供给到上述控制部16和同步检波部20。
上述控制部16是由开关12、加法器13、放大器14、转换开关15、放大器17、18所组成。放大器17、18的输出被供给到上述电光式光调制器2。也就是说上述电光式光调制器2是以上述放大器17及18的差动输出电压进行调制的。还原该差动输出电压是通过控制上述转换开关15来转换极性。
上述同步检波部20是通过放大器22而被供给由振荡电路21输出的振荡信号,并用该振荡信号对由上述放大器11供给的检测信号进行同步检波、把根据该结果产生的极性转换控制信号供给上述控制部16的上述转换开关15的控制端。
另外上述振荡信号通过加法器24被供给到上述控制部16的加法器13。
上述振荡电路21是由系统控制部25控制。该系统控制部25以数字信号把设定激光强度的值输给数字模拟变换器23(以下称为D/A变换器),由该D/A变换器23变换成模拟信号,通过上述加法器24被供给到上述控制部16的加法器13。
以下就其工作进行说明。首先打开上述开关12、上述程序控制部25使上述振荡电路21工作的同时,向上述D/A变换器输出值0。这时上述加法器24的输出只是振荡信号,该振荡信号被供给到上述控制部16的加法器13,由具有正相输出和反相输出的上述放大器14进行放大,经上述转换开关15由上述放大器17、18放大之后被供给到上述电光式光调制器2。经过该振荡信号调制之后的上述电光式光调制器2的输出光L由上述光束分离器3分离之后,透射光被导到上述光调制器4,反射光则被导到上述光电元件10变换为电信号,检测出上述振荡频率的信号。该检测信号通过上述扩大器11被供给到上述同步检波部20,用通过上述扩大器22供给的上述振荡信号进行同步检波。以此来判明上述检测信号的相位与上述振荡信号的相位是同相还是反相。在反相的情形时,由于上述电光式光调制器2的特性会有很大变换,所以就必须转换调制信号的附加电压的极性。于是,在上述相位是反相时,上述同步检波部20送出的极性转换控制信号就被供给上述控制部16的上述转换开关15,以此来转换附加于上述电光式光调制器2的调制信号的极性,以便能够稳定控制该电光式光调制器2的输出光L1
而当关闭上述开关12时,激光强度的设定值就由上述系统控制部25而被供给于上述D/A变换器23,在此被变换为模拟信号,经上述加法器而被供给到上述控制单元16,放大之后再供给上述电光式光调制器2。
因而这时的激光L1就具有与上述设定值相对应的强度。
还有一部分激光L1会由上述光束分离器3被导到上述光电变换元件10,变换为电信号。该检测信号经上述放大器11及上述控制部16的开关12而被供给到上述加法器13。上述放大器11是设定为输出负极性的信号,为此,上述加法器13就输出由上述D/A变换器23通过上述加法器24供给的上述设定值的信号与上述检测信号的差。上述放大器11所设定的放大率为上述检测信号的电平要小于上述设定值的信号电平。
在此,如果上述电光或光调制器2的特性产生若干变化而增加了激光L1的强度的话,由上述光电变换元件10输出的检测信号其振幅就要变大,在上述放大器11作倒转放大之后加到上述加法器13,由该加法器13测出的差信号就变小。因此,由上述控制部16所供给的上述电光式光调制器2的调制信号就会变小,上述激光L1的强度也就减低恢复原来的强度。
反之,如果上述特性的变化导致上述激光L1的强度减少的话,由于从上述光电变换元件10输出的检测信号其振幅会变小,所以由上述加法器13输出的差信号就会变大。因此,从上述控制部16供给上述电光式光调制器2的调制信号就变大,而上述激光的强度就增加恢复原来的强度。这样一来通过上述的系统控制部25就能够使与上述D/A变换器23所设定的值相对应的激光L1之强度为稳定。因而与用于上述原盘8的光致抗蚀剂等感光特性相结合的激光强度就能进行精密地设定。
在上述本发明里,通过采用电光式光调制器以标准的振荡信号调制激光,再用光电变换元件从该调制过的激光得出检测信号,该检测信号的相位与标准的振荡信号相位是反相时,就转换加到上述电光式光调制器上的调制信号的极性,所以就能把上述电光式光调制器经常置于可控制的状态,使该电光式光调制器变得易于操作。
另外如实施例所示,因为从系统控制部通过D/A变换器等可以把任意值的信号加到上述电光式光调制器上,所以与光致抗蚀剂等感度特性结合的激光强度就能变为稳定并可精确地进行控制。
图1是适用于本发明的光学调制系统的一施例的光学式磁盘刻蚀装置的方块图。
图2是上述实施例等所用的电光式光调制器的光强度一附加电压特性图。
图3是一般的光学式磁盘刻蚀装置的方块图。

Claims (4)

1、一光学调制系统包括有:一根据调制信号来调制激光的电光式光调制器,把上述电光式光调制器输出的激光变换为电信号的光电变换元件,其特征是有一振荡电路以发出振荡信号;一个相位同步检波部(20)对供给的上述电信号和振荡信进行检波以检测上述电信号与振荡信号是同相还是反相、及一个具有第1和第2装置(14、15)的控制部(16),其中第1装置14备有上述的振荡信号及供给具有反相的第1、第2调制信号,而上述的第2装置(15)受上述相位同步检波部输出的控制,当电信号与上述振荡信号成反相时,上述第1和第2调制信号就会被转换并被供给到上述调制器。
2、在权利要求第1项所述的系统,其特征是:其中所说的第二装置(15)包括有一个开关。
3、权利要求第1项所述的系统,其特征是:其中上述控制部(16)还包括有一个联接在上述光电变换器(10)的输出面的开关(12)、及一接在上述开关(12)和上述第二装置(14)之间的混合器(13),当上述开关(12)被关上时,从上述光电式变换导出的电信号会与一个参考信号进行比较。
4、权利要求1所述的系统,其特征是:其中的第1装置(14)包括有一供给相反极性的第1、第2信号的放大器。
CN85109630A 1984-12-21 1985-12-21 光调制系统 Expired CN1009314B (zh)

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JP59270488A JPH0627913B2 (ja) 1984-12-21 1984-12-21 光変調装置
JP270488/84 1984-12-21

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CN108008749A (zh) * 2017-12-30 2018-05-08 深圳市杰普特光电股份有限公司 激光转接装置
CN108008749B (zh) * 2017-12-30 2023-05-09 深圳市杰普特光电股份有限公司 激光转接装置

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DE3586714T2 (de) 1993-03-25
CN1009314B (zh) 1990-08-22
EP0185557A2 (en) 1986-06-25
JPS61148639A (ja) 1986-07-07
EP0185557A3 (en) 1988-06-29
EP0185557B1 (en) 1992-09-30
KR930008237B1 (ko) 1993-08-27
CA1237778A (en) 1988-06-07
US4709417A (en) 1987-11-24
JPH0627913B2 (ja) 1994-04-13
KR860005251A (ko) 1986-07-21
DE3586714D1 (en) 1992-11-05
ATE81212T1 (de) 1992-10-15

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