Multicolor display apparatus and method for setting gradation value of multicolor display apparatus

A multicolor display apparatus comprising:

• a light guide body on which a design pattern is formed by arrays of fine shapes;
• and
• light sources from which red, green, blue, and white light beams are incident into the inside of the light guide body,
• wherein the multicolor display apparatus displays the design pattern by reflecting the light beams which are incident into the light guide body and guided by the arrays of fine shapes and emitting the reflected light beams from the light emission surface of the light guide body,
• a first set of gradation values of red, green, blue, and white at a point where a specific color of the design pattern of the light guide body is displayed using red, green, blue, and white light are set as I(r), I(g), I(b), and I(w), respectively,
• a second set of gradation values of red, green, and blue in the case of displaying a color close to the specific color using only red, green, and blue light without white light are set as Ir, Ig, and Ib, respectively,
• the fine shapes for each of red, green, blue, and white colors have a height or a pitch which corresponds to the first set of gradation values,
• the first set of gradation values is converted from the second set of gradation values, and
• in a case where a maximum gradation value is set as 100%, and the gradation difference between the gradation values Ir, Ig, and Ib is equal to or less than 5%, the first set of gradation values is converted from the second set of gradation values and the fine shapes for each of red, green, blue, and white colors have a height or a pitch which corresponds to the first set of gradation values as follows
• I(w)=max(Ir, Ig, Ib)
• I(r)=0
• I(g)=0
• I(b)=0.

A method for setting gradation values of a multicolor display apparatus, comprising:

• providing a light guide body on which a design pattern is formed by arrays of fine shapes;
• providing light sources from which red, green, blue, and white light beams are incident into the inside of the light guide body;
• at the timing of setting the fine shapes for displaying the design pattern with a specific color by reflecting the light beams which are incident into the light guide body and guided by the arrays of fine shapes and emitting the reflected light beams from the light emission surface of the light guide body,
• a first set of gradation values of red, green, and blue in the case of displaying a display color close to the specific color using only red, green, and blue light inside the light guide body are set as Ir, Ig, and Ib, respectively, and
• a second set of gradation values of red, green, blue, and white in the case of displaying the specific color using red, green, blue, and white light inside the light guide body are set as I(r), I(g), I(b), and I(w), respectively,
• converting the first set of gradation values Ir, Ig, and Ib into the second set of gradation values,
• in a case where a maximum gradation value is set as 100%, when all of Ir, Ig, Ib are equal to or greater than a set gradation value around 20%, the first set of gradation values is converted into the second set of gradation values as follows
• I(w)=min(Ir,Ig,Ib)×A/100
• I(r)=Ir−I(w)
• I(g)=Ig−I(w)
• I(b)=Ib−I(w),
• where A is a numerical value less than 100, and A/100 being less than;
• and
• converting the converted gradation values into a height or a pitch of the fine shapes, and forming the design pattern based on the height or the pitch of the fine shapes.

A method for setting gradation values of a multicolor display apparatus, comprising:

• providing a light guide body on which a design pattern is formed by arrays of fine shapes;
• providing light sources from which red, green, blue, and white light beams are incident into the inside of the light guide body;
• at the timing of setting the fine shapes for displaying the design pattern with a specific color by reflecting the light beams which are incident into the light guide body and guided by the arrays of fine shapes and emitting the reflected light beams from the light emission surface of the light guide body,
• a first set of gradation values of red, green, and blue in the case of displaying a display color close to the specific color using only red, green, and blue light inside the light guide body are set as Ir, Ig, and Ib, respectively,
• a second set of gradation values of red, green, blue, and white in the case of displaying the specific color using red, green, blue, and white light inside the light guide body are set as I(r), I(g), I(b), and I(w), respectively,
• converting the first set of gradation values Ir, Ig, and Ib into the second set of gradation values,
• wherein, in the fine shapes for each of red, green, blue, and white colors,
• in a case where gradation difference between Ir, Ig, and Ib is equal to or less than 5%,
• the gradation values Ir, Ig, and Ib are converted into the gradation values I(r), I(g), I(b), and I(w) as follows,
• I(w)=max(Ir, Ig, Ib)
• I(r)=0
• I(g)=0
• I(b)=0
• and the converted gradation values are converted into a height or a pitch of the fine shapes, and the design pattern is formed based on the height or the pitch of the fine shapes.

A method for setting gradation values of a multicolor display apparatus including a RGBW light guide body on which a design pattern is formed by arrays of fine shapes and light sources from which red, green, blue, and white light beams are incident into the inside of the light guide body, the method comprising:

• converting first gradation values associated with red, green, and blue in the case of displaying a display color close to a specific color using only red, green, and blue light inside a RGB light guide body into second gradation values associated with red, green, blue, and white for the RGBW light guide body, the converting further including:
• labeling the first gradation values associated with red, green, and blue as Ir, Ig, and Ib, respectively, and the second gradation values of red, green, blue, and white as I(r), I(g), I(b), and I(w), respectively;
• in a case where a maximum gradation value is set as 100%, when all of Ir, Ig, Ib are equal to or greater than a set gradation value around 20%, converting the first gradation values Ir, Ig, and Ib into the second gradation values as follows,
• I(w)=min(Ir,Ig,Ib)×A/100
• I(r)=Ir−I(w)
• I(g)=Ig−I(w)
• I(b)=Ib−I(w)
• where A is a numerical value less than 100, and A/100 being less than;
• and
• assigning a height or a pitch of the arrays of fine shapes in accordance with the second gradation values to form the design pattern.