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1. 发明授权

US5534889A Circuit for controlling bias voltage used to regulate contrast in a display panel 失效
标题翻译：用于控制用于调节显示面板对比度的偏置电压的电路
公开(公告)号：US5534889A
公开(公告)日：1996-07-09
申请号：US119422
申请日：1993-09-10
申请人： Daniel B. Reents , Patrick R. Cooper , James H. Garrett , Philip J. McKenzie
发明人： Daniel B. Reents , Patrick R. Cooper , James H. Garrett , Philip J. McKenzie
IPC分类号： G09G3/36 , G09G5/00
CPC分类号： G09G3/36
摘要： A liquid crystal display (LCD) panel which has its contrast controlled through the use of a pulse width modulation (PWM) circuit contained in the video controller and a contrast control circuit. In response to a particular video refresh mode, the PWM circuit modulates the pulse width of a signal that is an input to the contrast control circuit. The pulse width is changed by the use of a base contrast register and two offset registers. Depending on the video mode, the base register is used alone or is combined with one of the offset registers to provide a signal to indicate the duty cycle of the signal. The pulse width modulated signal is converted to a DC bias contrast voltage which is provided to the LCD panel.
摘要翻译：通过使用包含在视频控制器中的脉冲宽度调制（PWM）电路和对比度控制电路来控制其对比度的液晶显示器（LCD）面板。响应于特定的视频刷新模式，PWM电路调制作为对比度控制电路的输入的信号的脉冲宽度。通过使用基本对比度寄存器和两个偏移寄存器来改变脉冲宽度。根据视频模式，基本寄存器单独使用或与其中一个偏移寄存器组合，以提供信号以指示信号的占空比。脉冲宽度调制信号被转换为提供给LCD面板的DC偏压对比度电压。

2. 发明授权

US5142247A Multiple frequency phase-locked loop clock generator with stable transitions between frequencies 失效
标题翻译：频率间稳定转换的多频锁相环时钟发生器
公开(公告)号：US5142247A
公开(公告)日：1992-08-25
申请号：US741083
申请日：1991-08-06
申请人： Henry F. Lada, Jr. , Hung Q. Le , James H. Garrett , John M. Gromala
发明人： Henry F. Lada, Jr. , Hung Q. Le , James H. Garrett , John M. Gromala
IPC分类号： H03L7/18
CPC分类号： H03L7/18
摘要： A phase-locked loop (PLL) clock generator circuit which is capable of changing the frequency of its outpt clock signal in a stable fashion. Selection of the frequency of the output clock signal is made by way of a selectable frequency divider coupled between the reference clock signal and an input of the PLL, with another frequency divider in the feedback loop of the PLL; each of these frequency dividers are selectable according to a signal on a select bus, translated by way of a ROM look-up table. The circuit also includes a multiplexer having a first input coupled to the PLL output, and a second input coupled to a stable clock signal, for example to the referenc clock signal or to the output of a fixed frequency PLL. The conrol input of the multiplexer is controlled by a state machine which monitors the select bus. Responsive to detection of a transition of the select bus, indicating a new frequency, the state machine issues a pulse to the control input of the multiplexer to cause it to select the stable clock signal for sufficient time to allow the PLL to acquire and lock onto the new frequency, after which the multiplexer again selects the PLL output as the output clock signal. As a result, the unstable and non-linear behavior at the PLL output does not appear at the output of the circuit, with a stable clock signal at a safe frequency appearing thereat during the PLL transitional cycles.
摘要翻译：锁相环（PLL）时钟发生器电路，其能够以稳定的方式改变其外部时钟信号的频率。输出时钟信号的频率选择通过耦合在参考时钟信号和PLL的输入端之间的可选择的分压器与PLL的反馈环路中的另一个分频器进行; 这些分频器中的每一个可以根据选择总线上的信号进行选择，通过ROM查找表进行转换。电路还包括具有耦合到PLL输出的第一输入和耦合到稳定时钟信号的第二输入的多路复用器，例如耦合到参考时钟信号或固定频率PLL的输出。多路复用器的控制输入由监视选择总线的状态机控制。响应于检测选择总线的转换，指示新的频率，状态机向多路复用器的控制输入端发出脉冲，使其选择稳定的时钟信号足够的时间以允许PLL获取并锁定到新的频率，之后复用器再次选择PLL输出作为输出时钟信号。因此，PLL输出端的不稳定和非线性特性不会出现在电路的输出端，稳定的时钟信号出现在PLL过渡周期内的安全频率。

3. 发明授权

US5245328A Method and apparatus for displaying different shades of gray on a liquid crystal display 失效
标题翻译：用于在液晶显示器上显示不同灰度的方法和装置
公开(公告)号：US5245328A
公开(公告)日：1993-09-14
申请号：US597814
申请日：1990-10-15
申请人： James H. Garrett
发明人： James H. Garrett
IPC分类号： G09G3/20 , G09G3/36 , H04N3/12
CPC分类号： G09G3/3611 , H04N3/127 , G09G2320/0247 , G09G3/2025 , G09G3/2051
摘要： A method and apparatus are disclosed which provide a means for both spatially and temporarily resolving the on/off states of a two-state display device such as a liquid crystal display to provide apparent shades of gray. A particular feature of this method is that the cycling between on and off states is not performed in a single, repetitive pattern. Rather, a pattern is utilized which repeats only after many cycles. Additionally, when the 10 method disclosed herein is utilized, adjacent pixels, when selected to display the same shade of gray, do not cycle on and off in synchronization, but rather utilize out-of-phase cycling patterns. This spatial resolution reduces perceived flicker in the display and provides a more stable image. In one embodiment, sixteen shades of gray are provided. The shades are generated by cycling individual pixels such that when averaged over time, the duty cycles of such cycling are 0, 1/9, 1/7, 1/5, 2/7, 1/3, 2/5, 7/15, 8/15, 3/5, 2/3, 5/7, 4/5, 6/7, 8/9 and 1.
摘要翻译：公开了一种方法和装置，其提供用于空间和临时分辨诸如液晶显示器的两状态显示装置的开/关状态的装置，以提供明显的灰度。该方法的一个特点是，在单独的重复模式中不执行打开和关闭状态之间的循环。相反，使用仅在许多周期后重复的模式。此外，当使用本文公开的10种方法时，相邻像素当被选择以显示相同的灰色阴影时，不会同步地进行循环，而是利用异相循环模式。该空间分辨率降低了显示屏中的感知闪烁，并提供了更稳定的图像。在一个实施例中，提供了十六个灰色阴影。通过循环单个像素来生成阴影，使得当随时间平均时，这种循环的占空比为0，1/9，1/7，1/5，2/7，1/3，2 / 5,7 / 15，8/15，3/5，2/3，5/7，4/5，6/7，8/9和1。

4. 发明授权

US5068649A Method and apparatus for displaying different shades of gray on a liquid crystal display 失效
标题翻译：用于在液晶显示器上显示不同灰度的方法和装置
公开(公告)号：US5068649A
公开(公告)日：1991-11-26
申请号：US258269
申请日：1988-10-14
申请人： James H. Garrett
发明人： James H. Garrett
IPC分类号： G02F1/133 , G09G3/20 , G09G3/36 , H04N3/12
CPC分类号： H04N3/127 , G09G3/3611 , G09G2320/0247 , G09G3/2025 , G09G3/2051
摘要： A method and apparatus are disclosed which provide a means for both spatially and temporally resolving the on/off states of a two-state display device such as a liquid cystal display to provide apparent shades of gray. A particular feature of this method is that the cycling between on and off states is not performed in a discernible pattern. Rather, a pseudo-random pattern is utilized which repeats only after many cycles. Additionally, when the method disclosed herein is utilized, adjacent pixels, when selected to display the same shade of gray, do not cycle on and off in synchronization, but rather utilize out-of-phase cycling patterns. This spatial resolution reduces perceived flicker in the display and provides a more stable image. In one embodiment, eight shades of gray are provided. The shades are generated by cycling individual pixels such that when averaged over time, they are: always off; on 20% of the time; 33% of the time; 40% of the time; 60% of the time; 67% of the time; 80% of the time; or, on at all times.

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