TWI646524B - Liquid crystal on silicon display and brightness adjustment method thereof - Google Patents

Abstract

The invention provides a liquid crystal overlay display comprising a polarization beam splitter, a light source, a liquid crystal overlay substrate and a gain control circuit. The light source is disposed on the first side of the polarization beam splitter. The gain control circuit receives a plurality of brightness values, each of the brightness values having a coordinate value, the coordinate values being on a coordinate axis from the first side to the second side of the polarization beam splitter, wherein the coordinate value of the first brightness value is less than the second brightness The coordinate value of the value. The gain control circuit determines a plurality of gain values according to the coordinate value, and adjusts the brightness value according to the gain value, wherein the gain value of the first brightness value is smaller than the gain value of the second brightness value.

Description

Liquid crystal overlay display and brightness adjustment method thereof

The present invention relates to a liquid crystal overlay display, and more particularly to a brightness adjustment method for a liquid crystal overlay display.

Liquid Crystal on Silicon (LCOS) is a reflective projection display. The liquid crystal overlay display has the advantages of low cost, high aperture ratio (up to 90%), and high resolution. A general liquid crystal overlay display includes a light source, a Polarization Beam Splitter (PBS), and a liquid crystal overlay substrate. The liquid crystal cover substrate is formed on a single crystal germanium, and has a plurality of transistors, an aluminum film electrode, a liquid crystal, a transparent electrode, and the like arranged in a matrix. The light source will inject the light beam into a Polarization Beam Splitter (PBS), and the polarizing beam splitter reflects the light beam to the liquid crystal cover substrate, and the liquid crystal on the liquid crystal cover substrate is used to apply an electric field on the liquid crystal to change the light beam. The polarization state, and the aluminum film electrode will reflect the beam to the polarizing beam splitter and penetrate the polarizing beam splitter, and finally into the human eye. However, the polarization beam splitter in the above optical path may change the intensity of the beam.

Embodiments of the present invention provide a liquid crystal overlay display including a polarization beam splitter, a light source, a liquid crystal overlay substrate, and a gain control circuit. The polarization beam splitter has opposite first and second sides. The light source is disposed on the first side of the polarization beam splitter. The liquid crystal cover substrate is disposed on the third side of the polarization beam splitter. The gain control circuit is coupled to the liquid crystal cover substrate for receiving a plurality of brightness values. Each of the luminance values has a coordinate value that is on a coordinate axis from the first side to the second side of the polarization beam splitter. The brightness value includes a first brightness value and a second brightness value, wherein the first brightness value and the second brightness value belong to the same color, and the coordinate value of the first brightness value is smaller than the coordinate value of the second brightness value. The gain control circuit determines a plurality of gain values according to the coordinate value, and adjusts the brightness value according to the gain value, wherein the gain value of the first brightness value is smaller than the gain value of the second brightness value. After adjusting the brightness value, the gain control circuit transmits the brightness value to the liquid crystal cover substrate.

In some embodiments, the brightness value described above includes a plurality of red brightness values, a plurality of green brightness values, and a plurality of blue brightness values. The gain value of the red luminance value at the first coordinate value is greater than the gain value of the green luminance value at the first coordinate value. The gain value of the green luminance value at the first coordinate value is greater than the gain value of the blue luminance value at the first coordinate value.

In some embodiments, the gain control circuit is further configured to multiply the red luminance value by the red compensation value, the green luminance value by the green compensation value, and multiply the blue luminance value by the blue compensation value. The red compensation value, the green compensation value, and the blue compensation value are different from each other.

In some embodiments, the red compensation value described above is less than the green compensation value, and the green compensation value is less than the blue compensation value.

In some embodiments, the gain control circuit described above substitutes the coordinate value into a monotonically increasing function to obtain a gain value.

In some embodiments, the operation of adjusting the luminance value by the gain control circuit described above is performed according to the following equations (1), (2), (3): Where x is the coordinate value, R _i ( x ) is the red luminance value with the coordinate value x, G _i ( x ) is the green luminance value with the coordinate value x, and B _i ( x ) is the blue luminance with the coordinate value x value. H is a real number, R _G , G _G , B _G are real numbers between 0 and 1, R _C ( x ) is the adjusted red luminance value, G _C ( x ) is the adjusted green luminance value, B _C ( x ) is the adjusted blue brightness value.

In some embodiments, the gain control circuit described above is further configured to perform the following equations (4), (5), (6): Where R _O ( x ) is the red luminance value transmitted to the liquid crystal cover substrate, G _O ( x ) is the green luminance value transmitted to the liquid crystal cover substrate, and B _O ( x ) is the blue color transmitted to the liquid crystal cover substrate Brightness value.

In another aspect, embodiments of the present invention provide a brightness adjustment method for a liquid crystal overlay display. This liquid crystal overlay display Including polarizing beamsplitter, light source and liquid crystal covering substrate. The polarization beam splitter has opposite first and second sides, and the light source is disposed on the first side of the polarization beam splitter. The brightness adjustment method includes: receiving a plurality of brightness values, wherein each of the brightness values has a coordinate value, the coordinate value is a coordinate axis extending from a first side to a second side of the polarization beam splitter, the first brightness value and the second brightness The values belong to the same color, the coordinate value of the first brightness value is smaller than the coordinate value of the second brightness value; the plurality of gain values are determined according to the coordinate value, and the brightness value is adjusted according to the gain value, wherein the gain value of the first brightness value is smaller than the first value The gain value of the two brightness values; and after adjusting the brightness value, the brightness value is transmitted to the liquid crystal cover substrate.

In some embodiments, the brightness adjustment method further includes: multiplying the red brightness value by the red compensation value, multiplying the green brightness value by the green compensation value, and multiplying the blue brightness value by the blue compensation value, wherein the red compensation is performed. The value, the green compensation value, and the blue compensation value are different from each other.

In some embodiments, the step of determining the gain value based on the coordinate value includes substituting the coordinate value of the luminance value into a monotonically increasing function to obtain a gain value.

In some embodiments, the step of adjusting the brightness value described above is performed in accordance with equations (1), (2), (3) above. In some embodiments, the brightness adjustment method described above further includes performing the above equations (4), (5), (6).

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧LCD overlay display

110‧‧‧Light source

112‧‧‧ Beam

120‧‧‧Polarizing beam splitter

121‧‧‧ first side

122‧‧‧ second side

123‧‧‧ third side

124‧‧‧ fourth side

130‧‧‧LCD overlay substrate

140‧‧‧gain control circuit

X‧‧‧ coordinate axis

210‧‧‧Display area

310, 320‧‧‧ Chart

321, 322‧‧‧ coordinate values

331, 332‧‧‧ gain value

410, 420, 430‧‧‧ charts

R, G, B‧‧‧ brightness values

421‧‧‧ coordinate value

422~424‧‧‧gain value

S501~S503‧‧‧Steps

FIG. 1 is a partial schematic view showing a liquid crystal overlay display according to an embodiment.

FIG. 2 is a component configuration diagram showing a liquid crystal overlay display 100 according to an embodiment.

FIG. 3 is a schematic diagram showing determining a gain value according to a coordinate value according to an embodiment.

FIG. 4 is a schematic diagram showing different gain values for different colors, according to an embodiment.

FIG. 5 is a flow chart showing a brightness adjustment method for a liquid crystal overlay display according to an embodiment.

The terms "first", "second", "etc." used in this document are not intended to mean the order or the order, and are merely to distinguish between elements or operations described in the same technical terms.

1 is a partial schematic view showing a liquid crystal overlay display according to an embodiment. Referring to FIG. 1 , the liquid crystal overlay display 100 includes a light source 110 , a polarization splitter (PBS) 120 , and a liquid crystal cover substrate 130 . It should be noted that FIG. 1 is not shown in true dimensions, and for the sake of simplicity, not all components of the liquid crystal overlay display 100 are shown in FIG.

Light source 110 is used to provide light beam 112. For example, the light source 110 can be a high pressure mercury lamp, a metal halide lamp, a light-emitting diode (LED) or other suitable light. source. In some embodiments, the light beam 112 is white light, and the liquid crystal overlay display 100 further includes a color filter. The liquid crystal overlay display 100 generates red, green, and blue light, respectively, in a time-sharing manner. In other embodiments, the paths of red, green, and blue light are separated from each other, and the liquid crystal overlay display 100 has three sets of liquid crystal overlay substrates 130 to process red, green, and blue light, respectively, and finally red light. The green light and the blue light are combined to emit the liquid crystal overlay display 100. Thus, beam 112 can be white, red, green, or blue, and the present invention does not limit the color of beam 112.

The polarization beam splitter 120 is configured to split the unpolarized beam 112 into a P-polarized beam and an S-polarized beam, and one of the polarized beams is reflected to the liquid crystal cover substrate 130.

The liquid crystal cover substrate 130 is used to change the polarization state of the incident light, and reflects the light beam 112 back to the polarization beam splitter 120 and finally onto a screen (not shown). For example, the liquid crystal cover substrate 130 may include a glass substrate, a germanium substrate, a plurality of transistors, a liquid crystal, a transparent electrode, an aluminum film electrode, etc., but those skilled in the art may adopt any aspect of the liquid crystal cover substrate. The present invention does not limit how to implement the liquid crystal overlay substrate 130.

The polarization beam splitter 120 has a first side 121, a second side 122, a third side 123 and a fourth side 124, wherein the first side 121 and the second side 122 are oppositely disposed, and the third side 123 and the fourth side 124 are opposite Settings. The light source 110 is disposed on the first side 121, and the liquid crystal cover substrate 130 is disposed on the third side 123. The first side 121, the third side 123, and the fourth side 124 are on the path of the beam 112, but the second side 122 is not in the path of the beam 112. Specifically, the beam 112 is incident from the first side 121 and reflected by the polarization beam splitter 120. After being emitted by the third side 123, and reflected by the liquid crystal cover substrate 130, the light beam 112 is incident from the third side 123 and finally emitted by the fourth side 124. In another aspect, the first side 121 is between the light source 110 and the second side 122.

The gain control circuit 140 is coupled to the liquid crystal cover substrate 130 and receives a plurality of brightness values and adjusts the brightness values. The adjusted brightness value is transmitted as a voltage to the source of the transistor in the liquid crystal cover substrate 130, thereby determining the electric field applied to the liquid crystal. Each luminance value has a coordinate value that is on the coordinate axis X, and the coordinate axis X extends from the first side 121 to the second side 122 of the polarization beam splitter 120. That is, the smaller the coordinate value corresponds to the position closer to the first side 121 on the polarization beam splitter 120, or the smaller the coordinate value corresponds to the transistor on the right side of the liquid crystal cover substrate 130. However, the present invention does not limit the origin and unit length of this coordinate system.

In the embodiment of FIG. 1, the gain control circuit 140 is disposed outside of the liquid crystal cover substrate 130, such as in a time controller (not shown). However, the gain control circuit 140 may also be disposed in the liquid crystal cover substrate 130 in some embodiments. The present invention does not limit the position at which the gain control circuit 140 is implemented.

2 is a component configuration diagram of a liquid crystal overlay display 100 according to an embodiment. In the embodiment of Figure 2, the light source 110 is implemented as a stripe LED. The liquid crystal cover substrate 130 has a display area 210 therein. The display area 210 has a plurality of transistors therein, and the light beam emitted by the light source 110 is reflected to the display area 210. The coordinate axis X is a side that extends from a side close to the light source 110 to a distance away from the light source 110. However, Figure 2 is only a van For example, the present invention does not limit the installation position of each component in the liquid crystal overlay display 100.

FIG. 3 is a schematic diagram showing determining a gain value according to a coordinate value according to an embodiment. Referring to FIG. 3, as described above, the light beam from the light source 110 is reflected to the display area 210. However, the further away from the light source 110, the more the brightness of the beam will be attenuated. As shown in the chart 310, on the coordinate axis X, the smaller the coordinate value, the less the luminance value will be attenuated, and the larger the coordinate value of the coordinate value will be attenuated, this phenomenon will cause the brightness of the left and right sides of the image to be asymmetrical. Therefore, in this embodiment, the gain control circuit 140 calculates a gain value based on the coordinate value of each luminance value, and adjusts the luminance values based on the gain values. As shown in graph 320, a luminance value having a small coordinate value will have a smaller gain value, and a luminance value having a large coordinate value will have a larger gain value. For example, if a certain first brightness value has a coordinate value 321 , a certain second brightness value has a coordinate value 322 , the coordinate value 321 is smaller than the coordinate value 322 , and the first brightness value and the second brightness value are the same. colour. The gain control circuit 140 sets the first luminance value to have a gain value 331 and the second luminance value has a gain value 332, wherein the gain value 332 is greater than the gain value 331. In other words, the coordinate value is proportional to the gain value. The gain control circuit 140 can adjust the first brightness value and the second brightness value according to the gain values 331, 332, respectively. For example, the gain values 331, 332 are real numbers between 0 and 1, and the gain control circuit 140 may multiply the first brightness value and the second brightness value by the gain value 331 and the gain value 332, respectively. In this way, it is possible to compensate for the situation in which the brightness of the left and right sides of the image is asymmetrical. It should be noted that the gain value in the graph 320 is only an example. In other embodiments, the gain control circuit 140 can set any single order. A monotonically increasing function is brought into the monotonically increasing function to obtain the gain value.

The luminance values accepted by the gain control circuit 140 may include a red luminance value, a green luminance value, and a blue luminance value. However, since beams of different colors may cause different degrees of attenuation, different gains may also be produced for luminance values of different colors. Please refer to FIG. 4. FIG. 4 is a schematic diagram showing different gain values for different colors according to an embodiment. As shown in the graph 410, the red luminance value R is attenuated by a smaller amplitude than the green luminance value G, and the green luminance value G is attenuated by a smaller amplitude than the blue luminance value B. Thus, as shown in graph 420, for a certain coordinate value 421 (also referred to as a first coordinate value), the gain value 422 of the red luminance value will be greater than the gain value 423 of the green luminance value on the same coordinate value, and the green luminance value The gain value 423 will be greater than the gain value 424 of the blue luminance value at the same coordinate value. The brightness of graph 410 multiplied by the gain value of graph 420 will be the brightness value of graph 430. In the graph 430, although the luminance values of the respective colors are identical in the coordinate values, the different colors are adjusted to different degrees of brightness, which may result in a color shift of the image. Therefore, in some embodiments, after adjusting the brightness value according to the gain value, the gain control circuit 140 may multiply all the red brightness values by a red compensation value, and multiply all the green brightness values by a green compensation value. And multiply the adjusted blue brightness values by a blue compensation value. The red compensation value is less than the green compensation value, and the green compensation value is less than the blue compensation value. After the above multiplication, different colors will have consistent brightness.

For example, the above operations of determining the gain value and adjusting the brightness value are based on the following equations (1), (2), and (3).

Where x is the coordinate value, R _i ( x ) is the red luminance value with the coordinate value x, G _i ( x ) is the green luminance value with the coordinate value x, and B _i ( x ) is the blue luminance with the coordinate value x value. H is a real number representing the width or height of the image. R _G , G _G , B _G are real numbers between 0 and 1, and R _G > G _G > B _G . R _C ( x ) is the adjusted red luminance value, G _C ( x ) is the adjusted green luminance value, and B _C ( x ) is the adjusted blue luminance value. The above equations (1), (2), (3) may correspond to the three curves in the chart 420.

Next, the gain control circuit 140 can perform the following equations (4), (5), (6) again.

Wherein R _O ( x ) is a red luminance value output to the liquid crystal cover substrate 130, G _O ( x ) is a green luminance value output to the liquid crystal cover substrate 130, and B _O ( x ) is output to the liquid crystal cover substrate 130 The blue brightness value. Min( R _G , G _G , B _G )/ R _G is the above red compensation value, min( R _G , G _G , B _G )/ G _G is the above green compensation value, min( R _G , G _G , B _G ) / B _G is the above blue compensation value.

FIG. 5 is a flow chart showing a method for adjusting brightness of a liquid crystal overlay display according to an embodiment. Referring to FIG. 5, in step S501, a plurality of brightness values are received, wherein each of the brightness values has a coordinate value which is on a coordinate axis extending from the first side to the second side of the polarization beam splitter. The coordinate value of the first brightness value is smaller than the coordinate value of the second brightness value. In step S502, a plurality of gain values are determined according to the coordinate values, and the brightness values are adjusted according to the gain values, wherein the gain values of the first brightness values are smaller than the gain values of the second brightness values. In step S503, the adjusted brightness value is transmitted to the liquid crystal cover substrate. However, the steps in FIG. 5 have been described in detail above, and will not be described again here. It should be noted that the steps in FIG. 5 can be implemented as multiple code codes or circuits, and the present invention is not limited thereto. In addition, the method of FIG. 5 can be used in conjunction with the above embodiments, or can be used alone. In other words, other steps can be added between the steps of FIG.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (14)

A liquid crystal overlay display comprising: a polarization beam splitter having opposite first and second sides; a light source disposed on the first side of the polarization beam splitter; and a liquid crystal cover substrate disposed on the polarization a third side of the optical splitter; and a gain control circuit coupled to the liquid crystal cover substrate for receiving a plurality of brightness values, wherein each of the brightness values has a target value, and the coordinate value is from the The brightness value includes a first brightness value and a second brightness value, and the first brightness value and the second brightness value belong to the same color, on the first axis of the polarization beam splitter to the first axis of the second side. The coordinate value of the first brightness value is smaller than the coordinate value of the second brightness value, wherein the gain control circuit determines the plurality of gain values only according to the coordinate values, and adjusts the brightness values according to the gain values. The gain value of the first brightness value is less than the gain value of the second brightness value, wherein the gain control circuit transmits the brightness values to the liquid crystal cover substrate after adjusting the brightness values. The liquid crystal overlay display of claim 1, wherein the brightness values comprise a plurality of red brightness values, a plurality of green brightness values, and a plurality of blue brightness values, wherein the first coordinate value The gain value of the red luminance value is greater than the gain value of the green luminance value on the first coordinate value, and the gain value of the green luminance value on the first coordinate value is greater than The gain value of the blue luminance value at the first coordinate value. The liquid crystal overlay display of claim 2, wherein the gain control circuit is further configured to multiply the red luminance values by a red compensation value, multiply the green luminance values by a green compensation value, and The blue brightness values are multiplied by a blue compensation value, wherein the red compensation value, the green compensation value, and the blue compensation value are different from each other. The liquid crystal overlay display of claim 3, wherein the red compensation value is less than the green compensation value, and the green compensation value is smaller than the blue compensation value. The liquid crystal overlay display of claim 1, wherein the gain control circuit substitutes the coordinate values into a monotonically increasing function to obtain the gain values. The liquid crystal overlay display of claim 5, wherein the gain control circuit adjusts the brightness values according to the following equations (1), (2), (3): Where x is the coordinate value, R _i ( x ) is a red luminance value having the coordinate value x, G _i ( x ) is a green luminance value having the coordinate value x, and B _i ( x ) is the coordinate A blue luminance value of the value x, H is a real number, R _G , G _G , B _G are real numbers between 0 and 1, and R _C ( x ) is the adjusted red luminance value, G _C ( x ) For the adjusted green luminance value, B _C ( x ) is the adjusted blue luminance value. The liquid crystal overlay display of claim 6, wherein the gain control circuit is further configured to perform the following equations (4), (5), (6): Where R _O ( x ) is the red luminance value transmitted to the liquid crystal cover substrate, G _O ( x ) is the green luminance value transmitted to the liquid crystal cover substrate, and B _O ( x ) is transmitted to the liquid crystal cover substrate. The blue brightness value. A brightness adjustment method for a liquid crystal overlay display, wherein the liquid crystal overlay display comprises a polarization beam splitter, a light source and a liquid crystal cover substrate, the polarization beam splitter has opposite first and second sides, and the light source is disposed on the polarization The first side of the optical splitter, the brightness adjustment method includes: receiving a plurality of brightness values, wherein each of the brightness values has a target value, the coordinate value being from the first side to the second side of the polarization beam splitter The brightness value includes a first brightness value and a second brightness value, and the first brightness value and the second brightness value belong to the same color, and the coordinate value of the first brightness value is less than The coordinate value of the second brightness value; determining a plurality of gain values based only on the coordinate values, and according to the increase The benefit value is used to adjust the brightness values, wherein the gain value of the first brightness value is less than the gain value of the second brightness value; and after adjusting the brightness values, the brightness values are transmitted to the liquid crystal cover矽 substrate. The brightness adjustment method of claim 8, wherein the brightness values comprise a plurality of red brightness values, a plurality of green brightness values, and a plurality of blue brightness values, wherein the red color is at a first coordinate value The gain value of the brightness value is greater than the gain value of the green brightness value at the first coordinate value, the gain value of the green brightness value at the first coordinate value being greater than the first coordinate value The gain value of the blue luminance value. The brightness adjustment method of claim 9, wherein the brightness adjustment method further comprises: multiplying the red brightness values by a red compensation value, multiplying the green brightness values by a green compensation value, and The blue brightness values are multiplied by a blue compensation value, wherein the red compensation value, the green compensation value, and the blue compensation value are different from each other. The brightness adjustment method according to claim 10, wherein the red compensation value is smaller than the green compensation value, and the green compensation value is smaller than the blue compensation value. The brightness adjustment method of claim 8, wherein the determining the gain values according to the coordinate values comprises: substituting the coordinate values of the brightness values into a monotonically increasing function to obtain the gain values. . The brightness adjustment method according to claim 12, wherein the step of adjusting the brightness values is performed according to the following equations (1), (2), (3): Where x is the coordinate value, R _i ( x ) is a red luminance value having the coordinate value x, G _i ( x ) is a green luminance value having the coordinate value x, and B _i ( x ) is the coordinate A blue luminance value of the value x, H is a real number, R _G , G _G , B _G are real numbers between 0 and 1, and R _C ( x ) is the adjusted red luminance value, G _C ( x ) For the adjusted green luminance value, B _C ( x ) is the adjusted blue luminance value. The brightness adjustment method described in claim 13 of the patent application further includes: executing the following equations (4), (5), (6): Where R _O ( x ) is the red luminance value transmitted to the liquid crystal cover substrate, G _O ( x ) is the green luminance value transmitted to the liquid crystal cover substrate, and B _O ( x ) is transmitted to the liquid crystal cover substrate. The blue brightness value.