JP5112390B2 - Display control device, display device, and electronic device - Google Patents

Description

  The present invention relates to a display control device, a display device, and an electronic apparatus that control a liquid crystal display element to display a display image by spatial luminance modulation.

  Conventionally, a liquid crystal display (LCD) has been widely used as a display for portable information devices such as mobile phones and PDAs (Personal Digital Assistants). LCDs have been considered to have a narrow viewing angle compared to CRTs (Cathode Ray Tubes), plasma displays, and the like, but with the recent advances in LCD technology, viewing angles have been widened.

  However, when the portable information device is used in a crowded situation such as in a train or a bus, the content displayed on the display screen of the portable information device may be peeped by the surrounding people. In particular, when creating and browsing an electronic mail, it is not preferable in terms of privacy that the contents are peeped by people around.

  In response to this problem, LCDs capable of controlling the viewing angle have been proposed (see, for example, Patent Documents 1 to 5). In such an LCD, it is possible to switch from one of a normal wide viewing angle mode (public mode) and a narrow viewing angle mode (private mode) having a narrow viewing angle to the other. The narrow viewing angle mode is a mode in which a normal display image can be visually recognized from directly in front of the display screen where the user is present, and a plain image or another image can be viewed from an oblique direction.

  For example, in the viewing angle variable element described in Patent Document 1, an alignment film is formed on each facing surface side of a pair of translucent substrates facing each other, and at least perpendicular to the substrate between the pair of substrates. In addition, a liquid crystal layer in which liquid crystal molecules are aligned to be in a narrow viewing angle display mode is provided. Moreover, the portable terminal device of patent document 2 changes the viewing angle of the information display means by changing the orientation of the liquid crystal between two glass plates.

  In addition, by dividing the display device into several sections and changing the liquid crystal alignment direction etc. in each section, when the display screen is viewed from a direction other than the front in the narrow viewing angle mode, it is displayed on the display screen. There is also a configuration in which another image different from the image is visible. For example, Patent Document 3 describes a liquid crystal display device in which an alignment film sandwiching a liquid crystal layer is divided into a plurality of regions, and the alignment directions of adjacent regions are different. Patent Document 4 describes a liquid crystal display device in which first liquid crystal cells and second liquid crystal cells having different viewing angle directions are alternately arranged.

  Further, in the display device described in Patent Document 5, the liquid crystal display panel has a linear data value / luminance response in a narrow viewing angle range, and a non-linear data value / luminance response outside the narrow viewing angle range. Utilizing having sex.

  Specifically, adjacent data values in the original image are corrected by adding one divided value and subtracting the divided value for the other. The corrected image is viewed as an image equivalent to the original image because the human eye performs spatial averaging when the display screen is viewed on an axis parallel to the normal line of the display screen. When the display screen is viewed off-axis, the element of the division value is added. When the division value changes at a rate proportional to the masking image in the corrected image, both the original image and the masking image are visible off-axis, that is, in an oblique direction with respect to the display screen. If the masking image has a disturbing pattern such as a plaid pattern or a company logo, the original image is substantially hidden from off-axis observers. Thereby, the private mode is realized, and the observer on the axis can see the original image without being looked into.

Japanese Patent Laid-Open No. 9-105958 (published on April 22, 1997) JP 2004-062094 A (published February 26, 2004) JP 2001-264768 A (released 09/26/2001) JP 2004-038035 A (published on Feb. 05, 2004) JP 2007-017988 A (published on January 25, 2007)

  In Patent Document 5, an image processing unit is provided that acquires an original image and a masking image, and creates and outputs the corrected image based on the acquired original image and the masking image. Patent Document 5 discloses that a moving image is used as the masking image in order to further disturb an unpermitted observer.

  In order to make the masking image a moving image, it is conceivable that the image processing unit periodically receives data of various masking images. In this case, the masking image visually recognized off-axis can be changed in various ways. However, the burden of resources for periodically transmitting the masking image data to the image processing unit increases.

  Alternatively, in order to use the masking image as a moving image, the image processing unit acquires one image, and performs various processing processes such as enlarging / reducing the acquired image or changing the color. It is conceivable that the processed and processed image is used as the masking image. In this case, it is possible to prevent an increase in the burden of resources for transmitting the image data to the image processing unit. However, since only one image is used and the above processing is determined in advance, the change in the masking image is limited.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent an increase in the burden of resources for transmitting image data of a side image (masking image) for disturbing the main image. And it is providing the display control apparatus etc. which can change a side image variously.

  A display control apparatus according to the present invention is a display control apparatus that controls a liquid crystal display element so as to display a display image on a display screen by spatial luminance modulation. The main image acquisition unit for acquiring the image data, the side image acquisition unit for acquiring the image data of the side image from the outside, and the luminance in the axial direction parallel to the normal line of the display screen with respect to the luminance from the liquid crystal display element The image data of the main image is modulated based on the non-linear correspondence relationship between the brightness and the off-axis direction and the image data of the side image, and the modulated image data is used as the image data of the display image. The side image acquisition unit includes a side image storage unit that stores image data of a plurality of side images, and a side image storage unit that stores the side image storage unit. A side image selection unit that selects image data of an image and sends the image data to the image composition unit, and includes a side image selection unit that changes the image data of the selected side image as time passes. .

  According to the above configuration, with respect to the luminance from the liquid crystal display element, the image composition unit performs a non-linear correspondence between the luminance with respect to the axial direction parallel to the normal line of the display screen and the luminance with respect to the off-axis direction, and the image of the side image. Based on the data, the image data of the main image is modulated, and the modulated image data is used as the image data of the display image. When the display image is displayed on the liquid crystal display element, an observer located in a region on the axis from the liquid crystal display element (hereinafter referred to as “on-axis observer”) visually recognizes the main image, and An observer located in an off-axis region from the liquid crystal display element (hereinafter referred to as “off-axis observer”) views an image obtained by combining the main image and the side image. As a result, since the main image is disturbed by the side image and is difficult for the off-axis observer to see, the main image is actually only visible to the on-axis observer.

  Further, the side image acquisition unit acquires image data of a plurality of side images from the outside and stores them in the side image storage unit, and the side image selection unit stores the image data of the side image selected from the side image storage unit as described above. It is sent to the image composition unit. And the side image selection part is changing the image data of the side image to select with progress of time.

  Thereby, the side image which an off-axis observer can visually recognize can be changed with progress of time, and animation of a side image can be implement | achieved. In addition, since a plurality of side images are used in this animation, the side images can be changed in various ways compared to the case where animation is realized using one side image.

  Further, since the image data of the plurality of side images is stored in the side image storage unit, the resource for transmitting the image data of the side image to the display control device needs to continue transmitting the image data of the side image. There is no. As a result, an increase in the resource burden can be prevented.

  Note that the order of changing the image data of the side image selected by the side image selection unit may be fixed or changeable from the outside.

  The display control apparatus according to the present invention is an image processing unit that processes the image data of the side image selected by the side image selection unit and sends the processed image data to the image composition unit. You may further provide the image process part to change. In this case, since one side image that can be visually recognized by the off-axis observer can be changed into a moving image with the passage of time, the side image can be further varied. Examples of the processing include switching of color schemes, image size enlargement / reduction, image rotation, and image inversion.

  By the way, when the display image changes, the luminance change speed varies due to the response speed of the liquid crystal in the liquid crystal display element. For this reason, when the side image changes, the speed at which the luminance changes to the luminance corresponding to the modulated image data varies, and as a result, the on-axis observer observes a flicker based on the side image on the display screen (hereinafter, referred to as “flicker”). (It is called “flicker phenomenon”). That is, when the side image is converted into a moving image, a flickering phenomenon occurs, and there is a possibility that the quality of the image visually recognized by the on-axis observer is deteriorated.

  Therefore, in the display control apparatus according to the present invention, when the side image selection unit changes the side image, the image composition unit gradually reduces the degree of modulation of the image data of the main image before the change, You may provide the fade part which returns the said modulation | alteration degree in steps after a change. In this case, since the value of the modulated image data changes stepwise, the flicker phenomenon can be reduced or eliminated.

  In the above case, the off-axis observer fades out the side image before the change from the image in which the side image before the change is superimposed on the main image, and then fades in the side image after the change. You will see. Further, the degree of modulation is preferably reduced step by step to zero, but the effect of the present invention can be achieved if the flicker phenomenon is reduced stepwise to such an extent that the on-axis observer does not care. . Further, the timing at which the side image selection unit changes the side image may be acquired directly from the state information from the side image selection unit, or indirectly from the instruction information to the side image selection unit. You may get it.

  Alternatively, in the display control device according to the present invention, when the side image selection unit changes the side image, the image composition unit changes the degree of modulation of the image data of the main image to the image of the side image before the change. You may provide the fade part which changes in steps from the said degree by data to the said degree by the image data of the side image after a change. In this case, since the value of the modulated image data changes stepwise, the flicker phenomenon can be reduced or eliminated.

  Furthermore, since the degree before the change is directly changed to the degree after the change, the degree of the degree is temporarily reduced before the change, and the change of the side image is completed as compared with the case of returning the degree after the change. It is possible to shorten the time until the image is switched and to quickly switch the side images. Further, since the side image storage unit stores the image data of the side image before and after the change, the change by the fade unit can be easily performed.

  In the above case, the off-axis observer visually recognizes from the image in which the side image before the change is superimposed on the main image to crossfade to the image in which the side image after the change is superimposed on the main image. Become. Further, the timing at which the side image selection unit changes the side image and the changed side image may be acquired directly from the state information from the side image selection unit, or the side image selection You may acquire indirectly from the instruction information to a part.

  In addition, the said fade part can change the said degree in steps by changing the value of the image data of a side image in steps.

  Further, the image composition unit corresponds to the division parameter storage unit that stores the correspondence between the image data value of the main image and the division parameter based on the nonlinear correspondence, and the image data value of the main image. A modulation unit that modulates the value of the image data of the main image based on the division parameter to be performed and the value of the image data of the side image, and the fade unit is a division used by the modulation unit The degree can be changed in stages by changing the parameters in stages.

  In the display control apparatus according to the present invention, the image composition unit includes a private mode in which the modulated image data is image data of the display image, and the image data of the main image is image data of the display image. It is preferable that the public mode can be switched.

  In the public mode, the off-axis observer can also visually recognize the main image, which is suitable when the main image is viewed by a plurality of people. Therefore, convenience is improved by switching between the private mode and the public mode according to the situation.

  In addition, if it is a display apparatus provided with the display control apparatus of the said structure and the liquid crystal display element which this display control apparatus controls, there can exist an effect similar to the above-mentioned effect.

  An electronic apparatus comprising: a display device configured as described above; and a main control device, wherein the main control device transmits image data of the main image and the side image to the display control device. If present, the same effect as described above can be obtained, and an increase in the burden on the main control device (resource) can be prevented.

  As described above, according to the present invention, image data of a plurality of side images is stored, and the side image selected with the passage of time is changed, so that the side images that can be viewed by the off-axis observer are variously changed. In addition, the resource for transmitting the image data of the side image to the display control device does not need to continue to transmit the image data of the side image, so that an increase in the processing load of the resource can be prevented. Play.

It is a block diagram which shows schematic structure of the LCD controller in the electronic device which is one Embodiment of this invention. It is a block diagram which shows schematic structure of the said electronic device. It is a figure which shows the brightness | luminance of an adjacent pixel. It is a graph which shows the responsiveness of the brightness | luminance with respect to a gradation value. It is a graph which shows the correspondence of the gradation value of the main image in the said electronic device, and the gradation value of the image for a display. It is a figure which shows the image of the front view in the said electronic device, and the image of a side view. It is a figure which shows an example of the image of a front view at the time of generation | occurrence | production of the flicker phenomenon. It is a graph which shows the time change of the brightness | luminance of the light which passes on an axial direction when the said flicker phenomenon generate | occur | produces. It is a graph which shows the time change of the said brightness | luminance in case the countermeasure of this invention which suppresses the said flicker phenomenon is taken. It is a block diagram which shows schematic structure of the LCD controller in the electronic device which is another embodiment of this invention. It is a graph which shows the example of adjustment which the parameter adjustment part in the said LCD controller adjusts. In the said embodiment, it is a figure which shows the time change of the side image visually recognized by an off-axis observer per frame period. It is a block diagram which shows schematic structure of the LCD controller in the electronic device which is another embodiment of this invention. It is a graph which shows the example of adjustment which the gradation control part in the said LCD controller adjusts. It is a block diagram which shows schematic structure of the LCD controller in the electronic device which is another embodiment of this invention. It is a figure which shows an example of the transition information which the cross fade control part in the said LCD controller produces in a table format. In the said embodiment, it is a figure which shows the time change of the side image visually recognized by an off-axis observer per frame period. It is a block diagram which shows schematic structure of the LCD controller in the electronic device which is other embodiment of this invention. It is a figure which shows an example of the transition information which the cross fade control part in the said LCD controller produces in a table format.

[Embodiment 1]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a schematic configuration of the electronic apparatus of the present embodiment. Examples of the electronic device 10 include portable electronic devices such as a mobile phone, an electronic dictionary, and a portable communication terminal. However, the present invention is an arbitrary device having an LCD (Liquid Crystal Display) unit (liquid crystal display device). It can be applied to other electronic devices.

  As shown in FIG. 2, the electronic device 10 includes a CPU (main control device) 11, a bus 12, a memory (main control device) 13, and an LCD unit (display device) 14.

  The CPU 11 performs various operations by executing a program stored in a storage element such as a RAM (Random Access Memory) or a flash memory, for example, and performs comprehensive control of various units in the electronic apparatus 10. 12 is performed. In the present embodiment, the CPU 11 transmits image data of the main image and the side image, various instructions, and the like to the LCD unit 14 via the bus 12.

  Here, the side image refers to an image superimposed on the main image in order to disturb the main image for the purpose of preventing peeping. As a side image, an image in which a plurality of gradation values are mixed is more desirable than an image in which a certain gradation value is unevenly distributed because the degree of disturbance of the main image is higher.

  The bus 12 is a common signal line for transmitting and receiving data between various components in the electronic device 10. The memory 13 stores various data and programs. As an example of the memory 13, a ROM (Read Only Memory) that is a read-only semiconductor memory that stores fixed data such as a program necessary for the operation of the CPU 11, data used for calculation, calculation results, and the like are temporarily stored. RAM as a so-called working memory stored in the memory.

  The LCD unit 14 receives image data from the CPU 11 or the memory 13 via the bus 12 and displays an image based on the received image data. The LCD unit 14 includes an LCD module 22 and an LCD controller (display control device) 21.

  The LCD module 22 is a functional unit that displays an image such as a character, a symbol, or a graphic on a display element based on image data of a display image, and is a matrix type LCD element (liquid crystal display) in which display pixels are arranged in a matrix. Element) and a drive circuit for driving the LCD element. The LCD element displays an image by spatial luminance modulation that spatially modulates the luminance of incident light from a light source. The image includes a still image and a moving image.

  The LCD controller 21 controls the LCD module 22. Specifically, the LCD controller 21 transmits image data of the display image to the LCD module 22 and transmits a plurality of control signals for controlling the display of the LCD module 22. Examples of the control signal include a vertical synchronization signal, a horizontal synchronization signal, and a transfer clock signal for transferring image data of a display image to each display pixel of the LCD element.

In the present embodiment, the _on- axis observation located in a region (hereinafter, referred to as “region on the axis”) A _on existing from the display screen of the LCD element of the LCD module 22 in the normal direction of the display screen. The person V _on visually recognizes the main image. On the other hand, an off-axis observer V _off located in an area where the display screen can be visually recognized and other than the area on the axis (hereinafter, this area is referred to as “ _off- axis area”) A _off . An image obtained by synthesizing the main image and the side image is visually recognized. This principle will be described below.

  In general, as the observer moves away from the display element, it becomes difficult to discriminate between adjacent pixels in the display element, and finally it becomes impossible to discriminate. At this time, the observer perceives the average value (average luminance) of luminance in the adjacent pixels.

From this, it can be said that it is shown in FIG. FIG. 3 shows the luminance of adjacent pixels. First, as shown in FIG. (A), the brightness between pixels _p 1 · _{p 2} of adjacent equal to _{I 0.} Next, as shown in FIG. 4B, one pixel p ₁ is changed to a luminance obtained by subtracting a certain luminance I ₁ from the original luminance I ₀ , and the other pixel p ₂ is changed to the original luminance I _2. The brightness is changed to a brightness obtained by adding a certain brightness I ₁ to I ₀ . In this case, the observer, when between the pixels _p 1 · _{p 2} to the adjacent can not be determined, as shown in FIG. (C), region _{p 12} of the pixel _p 1 · _{p 2} to the adjacent pixel The average luminance of the luminance of p ₁ (I ₀ −I ₁ ) and the luminance of the pixel p ₂ (I ₀ + I ₁ ), that is, the original luminance I ₀ is perceived.

  That is, if the observer moves away from the display element to such an extent that adjacent pixels cannot be distinguished even if the luminance of the adjacent pixels is changed as shown in FIG. The original luminance as in a) will be perceived.

  By the way, a normal display element does not respond proportionally to an input gradation value (for example, 0 to 255 when the image data is 8-bit data), and the output luminance is a constant power of the gradation value ( proportional response). For this reason, in a normal display unit, gamma correction is performed, and the output luminance responds in proportion to the input gradation value.

FIG. 4 is a graph showing the responsiveness of the luminance with respect to the gradation value. The gradation value and the luminance after gamma correction are proportional and have linearity as shown in FIG. In this case, assuming that the luminance corresponding to the gradation value (original value) D ₀ is I ₀ , the gradation value (D ₀ + D ₁ ) and the level obtained by adding and subtracting the divided value D ₁ from the original value D ₀ respectively. The luminance corresponding to the tone value (D ₀ -D ₁ ) is luminance (I ₀ + I ₁ ) and luminance (I ₀ -I ₁ ), respectively. Therefore, the average luminance is I ₀ , which is the same as the luminance I ₀ corresponding to the original value D ₀ .

  However, in the case of the LCD element, the light passing in the on-axis direction and the light passing in the off-axis direction not only have different optical path lengths through the liquid crystal, but also the liquid crystal molecules in the traveling direction of the light. The birefringence due to the difference in inclination is different. For this reason, with respect to the light passing in the on-axis direction, even if the gamma correction is performed so that the responsiveness of the luminance with respect to the gradation value is linear as shown in FIG. For light passing in the direction of, the response is nonlinear.

FIG. 4B shows a case where the response is nonlinear. Referring to (b) of the figure, in this case, the luminance I ₂ corresponding to the gradation value (original value) D ₀ is the gradation value (D ₀ + D _{1) obtained} by adding the divided value D ₁ from the original value D _0. ) And the luminance corresponding to the gradation value (D ₀ -D ₁ ) obtained by subtracting the divided value D ₁ from the original value D ₀ is different from the average luminance I ₃ .

Therefore, the gradation value is modulated so that _{one of} the adjacent pixels adds the divided value D ₁ from the original value D ₀ to the main image and the other subtracts the divided value D ₁ from the original value D _0. Let us consider a case in which the processed image is displayed on the LCD element. In this case, the on-axis observer views an image equivalent to the main image (average luminance I ₃ ), but the off-axis observer is modulated with respect to the main image in accordance with the division value D _1. The image (luminance I ₂ ) is visually recognized. Thus, in this embodiment, the divided value D ₁ of the said adjacent pixels of the main image, is associated with the gradation value of the corresponding pixel of the side image. Thereby, the off-axis observer visually recognizes the image in which the side image is combined with the main image.

By the way, referring to FIG. 4B, it can be understood that the difference between the luminance I ₂ and the average luminance I ₃ increases as the division value D ₁ increases. In the case of the present embodiment, if the difference between the luminance I ₂ and the average luminance I ₃ is large, the off-axis observer sees the side image more clearly, which is desirable from the viewpoint of preventing peeping of the main image. Accordingly, the divided value D ₁ is larger is preferable.

On the other hand, since the gradation value needs to be 0 or more, the gradation value (D ₀ -D ₁ ) obtained by subtracting the division value D ₁ from the original value D ₀ also needs to be 0 or more. For this reason, it is desirable to set the division value D ₁ such that the gradation value (D ₀ -D ₁ ) is 0 or a positive number close to 0. Further, the gradation value (D ₀ + D ₁ ) obtained by adding the division value D ₁ from the original value D ₀ needs to be equal to or less than the maximum value of the gradation values. For this reason, the main image needs to be compressed in the range of usable gradation values.

5, the tone value of the main image in the present embodiment, a graph showing a relationship between a gradation value of the display image is satisfying the above condition relates divided value D _1. FIG. 5 shows an example in which the side image has two gradations (0 or 255). Further, in the example of FIG. 5, the solid line and the broken line are expressed as straight lines, but in reality, they are often curved lines.

The solid line in FIG. 5 indicates the case where the gradation value of the side image is 255. In this case, the gradation value of the display image is the compressed original value D ₀ ′ of the main image. Further, the broken line in FIG. 5 indicates a case where the gradation value of the side image is 0. In this case, one of the gradation values of adjacent pixels in the display image is a gradation value (D ₀ ′ + D ₁ ) obtained by adding the division value D ₁ from the compressed original value D ₀ ′ of the main image. The other is the gradation value (D ₀ ′ −D ₁ ) obtained by subtracting the division value D ₁ from the compressed original value D ₀ ′ of the main image. When the side image has multiple gradations, a graph similar to the two broken lines in FIG. 5 is described between the solid line and the two broken lines in FIG. 5 according to the gradation value of the side image. become.

Thus, LCD controller 21 of the present embodiment, as shown in FIG. 5, the correspondence between the gradation value of the main image and the divided value D ₁ is stored as the partition parameter, the tone value of the main image, Modulation is performed based on the gradation value of the side image and the division parameter, and this is transmitted to the LCD module 22 as the gradation value of the display image. Accordingly, the on-axis observer visually recognizes the same image as the main image, while the off-axis observer visually recognizes an image in which the side image is combined with the main image. As a result, since the main image is disturbed by the side image and is difficult for the off-axis observer to view, the main image can be viewed only by the on-axis observer.

  Next, details of the LCD controller 21 will be described. FIG. 1 shows a schematic configuration related to creating a display image using a main image and a side image in the LCD controller 21. As shown in FIG. 1, the LCD controller 21 includes a main image memory (main image acquisition unit) 30, a side image memory (side image acquisition unit, side image storage unit) 31, an order storage unit 32, an image switching unit ( Side image acquisition unit, side image selection unit) 33, color arrangement pattern storage unit 34, color switching unit (image processing unit) 35, enlargement / reduction rate storage unit 36, image enlargement / reduction unit (image processing unit) 37, division parameter storage unit (image) A composition unit 38, an image composition unit (modulation unit) 39, a rotation / inversion information storage unit 40, and a rotation / inversion unit 41.

  The main image memory 30 is a frame buffer that acquires and stores image data of the main image M from the CPU 11 or the memory 13. The image data of the main image M stored in the main image memory 30 is transmitted to the image composition unit 39 at a predetermined timing.

The side image memory 31 acquires and stores the image data of the side image from the CPU 11 or the memory 13. In this embodiment, the side image memory 31 can store image data of a plurality of side images. In the example of FIG. 1, the image data of the four frames of the side images F _{r1 to} F _r4 is stored in the side image memory 31, but the present invention is not limited to this.

  The order storage unit 32 stores data in the order of reading out image data of a plurality of side images in the side image memory 31. The image switching unit 33 switches the image data of the side image read from the side image memory 31 at a predetermined timing in accordance with the order stored in the order storage unit 32. By switching the side images, the side images can be animated.

  The color arrangement pattern storage unit 34 stores data of a plurality of color arrangement patterns. The color switching unit 35 uses the plurality of color arrangement patterns in the color arrangement pattern storage unit 34 to switch the color arrangement pattern of the side image at a predetermined timing. By changing the color arrangement pattern of the side image, the side image can be animated.

  Specifically, the color switching unit 35 first selects a certain color arrangement pattern from a plurality of color arrangement patterns in the color arrangement pattern storage unit 34. Next, the color switching unit 35 changes the color information of the image data of the side image from the side image memory 31 based on the selected color arrangement pattern data, and rotates the image data of the changed side image. Transmit to the reversing unit 41. Then, at a predetermined timing, the color switching unit 35 selects a color arrangement pattern different from the certain color arrangement pattern from the plurality of color arrangement patterns in the color arrangement pattern storage unit 34, and repeats the above operation.

  The rotation / inversion information storage unit 40 stores information on the rotation angle and information on the inversion direction such as left / right inversion and up / down inversion. Further, the rotation / reversal unit 41 rotates the side image at a predetermined timing based on the rotation angle information in the rotation / reversal information storage unit 40, or based on the reverse direction information in the rotation / reversal information storage unit 40. The side image is inverted at a predetermined timing. The side image can be animated by rotating or inverting the side image.

  Specifically, the rotation / inversion unit 41 rotates the image data of the side image from the color switching unit 35 based on the rotation angle information in the rotation / inversion information storage unit 40, and the image of the rotated side image Data is transmitted to the image enlargement / reduction unit 37 and the above operation is repeated. Alternatively, the rotation / inversion unit 41 inverts the image data of the side image from the color switching unit 35 based on the information of the inversion direction in the rotation / inversion information storage unit 40, and converts the image data of the inverted side image to the image It transmits to the expansion / contraction part 37 and repeats the said operation | movement.

  The enlargement / reduction ratio storage unit 36 stores a plurality of enlargement / reduction ratios which are enlargement ratios or reduction ratios of image sizes. The image enlargement / reduction unit 37 uses the plurality of enlargement / reduction rates in the enlargement / reduction rate storage unit 36 to enlarge or reduce the image size of the side image at a predetermined timing. By increasing or reducing the image size of the side image, the side image can be converted to a moving image.

  Specifically, the image enlargement / reduction unit 37 first selects a certain enlargement / reduction rate from a plurality of enlargement / reduction rates in the enlargement / reduction rate storage unit 36. Next, the image enlargement / reduction unit 37 changes the image data of the side image from the rotation / inversion unit 41 so as to become the image data of the side image enlarged or reduced at the certain enlargement / reduction ratio, and the changed side image The image data of the image is transmitted to the image composition unit 39. Then, at a predetermined timing, the image enlargement / reduction unit 37 selects an enlargement / reduction rate different from the certain enlargement / reduction rate from a plurality of enlargement / reduction rates in the enlargement / reduction rate storage unit 36, and repeats the above operation.

  The division parameter storage unit 38 stores the above-described division parameters. The image composition unit 39 modulates the image data of the main image from the main image memory 30 based on the image data of the side image from the image enlargement / reduction unit 37 and the division parameter in the division parameter storage unit 38. It is. The image composition unit 39 transmits the modulated image data to the LCD module 22 as image data of the display image.

FIG. 6 shows a front view image visually recognized by an on-axis observer on the display screen 50 of the LCD element and a side view image visually recognized by an off-axis observer in the electronic device 10 having the above-described configuration. As shown in the figure, the images of the front view and the side view change in the order of (a), (b), (c), and (d) with the passage of time, and repeat this. Specifically, the front-view image is only the main image M even if time passes. On the other hand, the side view image is a composite image of the main image M and the side image F _r1 of the first frame, a composite image of the main image M and the side image F _r2 of the second frame, and the main image M over time. And a composite image of the side image F _r3 of the third frame and a composite image of the main image M and the side image F _r4 of the fourth frame.

  Therefore, in this embodiment, since a plurality of side images are used to realize animation, the side images are changed in a variety of ways compared to a case where animation is realized using one side image. be able to.

  Also, since the image data of the plurality of side images is stored in the side image memory 31, the CPU 11 or the memory 13 that transmits the image data of the side image to the LCD controller 21 transmits the image data of the side image. There is no need to continue. As a result, it is possible to prevent an increase in processing load on the CPU 11 or the memory 13 and to prevent an increase in the occupied time of the bus 12.

  Note that the color switching unit 35 and the image enlargement / reduction unit 37 can be omitted, but by providing the color switching unit 35 and the image enlargement / reduction unit 37, the side image can be further varied.

[Embodiment 2]
Next, before explaining another embodiment of the present invention, the above-mentioned flicker phenomenon and the countermeasure of the present invention for suppressing the flicker phenomenon will be described with reference to FIGS.

FIG. 7 shows an example of an image viewed from the front when the flicker phenomenon occurs. As shown in the figure, when the side image is switched, the on-axis observer visually recognizes the side image _Fr on the main image M on the display screen 50 for a moment. Therefore, a flicker phenomenon occurs every time the side image is switched, resulting in a deterioration in the quality of the main image M visually recognized by the on-axis observer.

  FIG. 8 is a graph showing a temporal change in luminance of light passing in the axial direction when a flicker phenomenon occurs. In the figure, the solid line indicates the time change of the luminance when the side image is switched and the gradation value of the side image in the adjacent pixels p1 and p2 changes from 0 to 255, and the alternate long and short dash line indicates the time of the average luminance. Each change is shown. When the gradation value of the side image is 0, the luminances at the pixels p1 and p2 are L1 and L2, respectively. On the other hand, when the gradation value of the side image is 255, the luminances of the pixels p1 and p2 are both (L1 + L2) / 2, which is the luminance of the main image.

  As shown in FIG. 8, the luminance of the pixel p1 changes from L1 to (L1 + L2) / 2, and the luminance of the pixel p2 changes from L2 to (L1 + L2) / 2. Since the transition speeds are different, the temporal change in the luminance at the pixel p1 and the temporal change in the luminance at the pixel p2 are asymmetric with respect to the broken line whose luminance is (L1 + L2) / 2. For this reason, the temporal change in the average luminance of the adjacent pixels p1 and p2 once deviates from (L1 + L2) / 2, and this is the flicker that the on-axis observer visually recognizes.

  FIG. 9 is a graph showing the change in luminance over time when the measure of the present invention that suppresses the flicker phenomenon is taken. The meanings of the solid line and the alternate long and short dash line in FIG. 9 are the same as the meanings of the solid line and the alternate long and short dash line in FIG.

  Compared to the graph of FIG. 8, the graph of FIG. 9 causes the above luminance to transition step by step for each frame (for example, 1/30 second), and the average luminance after the transition maintains (L1 + L2) / 2. The other points are the same, and the others are the same. In this case, since the amount of change in luminance between frames is small, the period during which the luminance changes is short. Therefore, even if the average luminance of the pixels p1 and p2 deviates from (L1 + L2) / 2, the period is short and the amount thereof is small. As a result, the on-axis observer cannot see the flicker.

  Note that the case where the gradation value of the side image changes from 255 to 0 is the same as the case where the time direction is reversed in FIG.

  Next, the present embodiment will be described with reference to FIGS. The electronic device 10 of this embodiment is different from the electronic device 10 shown in FIG. 2 only in the configuration of the LCD controller 21, and the other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  FIG. 10 shows a schematic configuration of the LCD controller 21 of the present embodiment. Compared with the LCD controller 21 shown in FIG. 1, the LCD controller 21 of the present embodiment omits the color arrangement pattern storage unit 34, the color switching unit 35, the enlargement / reduction rate storage unit 36, and the image enlargement / reduction unit 37. The difference is that a timing instruction unit 60 and a parameter adjustment unit (fade unit) 61 are added, and the other configurations are the same.

  The timing instruction unit 60 instructs the image switching unit 33 and the parameter adjustment unit 61 to switch the side image. The image switching unit 33 switches the side images after several frames (for example, two frames) have elapsed from the frame period in which the instruction from the timing instruction unit 60 is received.

  In the LCD controller 21 shown in FIG. 1, the image composition unit 39 reads the division value corresponding to the gradation value of the main image from the division parameter storage unit 38. On the other hand, in this embodiment, the parameter adjustment unit 61 adjusts the division value read from the division parameter storage unit 38 and transmits it to the image synthesis unit 39.

Specifically, the parameter adjuster 61, when not receiving the instruction from the timing instructing section 60, and transmits the divided value D ₁ read out from the partition parameter storage unit 38 as it is to the image synthesizing unit 39 Yes. On the other hand, when the instruction is received, the parameter adjustment unit 61 adjusts the division value read from the division parameter storage unit 38 step by step, and transmits the adjusted division value to the image composition unit 39.

  FIG. 11 shows an adjustment example adjusted by the parameter adjustment unit 61 in the present embodiment. In the same figure, the division value in each frame period is shown, and the upper part is the case where the gradation value of the side image is 0, and the lower part is the case where the gradation value of the side image is 255. In the present embodiment, each of R (red), G (green), and B (blue) has two gradations, and the side image can represent eight colors. In this case, the modulation of the image data of the main image M is performed for each of the R component, G component, and B component in each pixel.

In FIG. 11, it is assumed that the instruction is received from the timing instruction unit 60 in the first frame period. At this time, when the gradation value of the side image is 0, the division values are (D ₁ × 2/3) and (D ₁ × 1/3) in the second and third frame periods, respectively, It becomes 0 in the frame period. When the gradation value of the side image is 255, the division value remains 0.

Then, the side image is switched in the fourth frame period. When the gradation value of the switched side image is 0, the divided values are (D ₁ × 1/3) and (D ₁ × 2/3) in the fifth and sixth frame periods, respectively, and the seventh value the _{D 1} in the frame period. When the tone value of the switched side image is 255, the division value remains 0.

In the example of FIG. 11, the parameter adjustment unit 61 adjusts stepwise so that the division value becomes 0 in the fourth frame period, but the division value becomes D ₁ in the fourth frame period. It can also be adjusted step by step. At this time, when the gradation value of the side image is 0, the divided value remains D _1. On the other hand, when the gradation value of the side image is 255, the division values are (D ₁ × 1/3) and (D ₁ × 2/3) in the second and third frame periods, respectively, and the fourth frame. It becomes D _{1 in the} period, and becomes (D ₁ × 2/3) and (D ₁ × 1/3) in the fifth and sixth frame periods, and becomes 0 in the seventh frame period.

FIG. 12 shows the temporal change of the side image viewed by the off-axis observer in this embodiment in units of frame periods. (A) of the figure shows a case where adjustment is made in stages so that the division value becomes D ₁ in the fourth frame period. On the other hand, (b) in the figure corresponds to FIG. 11 and shows a case where the division value is adjusted stepwise so that the division value becomes 0 in the fourth frame period. Referring to the figure, in the present embodiment, it can be understood that the side image fades out and the switched side image fades in.

  In this embodiment, the present invention is applied when switching a plurality of side images in the side image memory 31, but the present invention can also be applied when the color switching unit 35 or the image enlargement / reduction unit 37 changes a side image. The present invention can also be applied to the case where streaming data is received from the CPU 11 or the memory 13 as the image data of the side image.

[Embodiment 3]
Next, still another embodiment of the present invention will be described with reference to FIGS. The electronic device 10 of this embodiment is different from the electronic device 10 shown in FIG. 2 only in the configuration of the LCD controller 21, and the other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  FIG. 13 shows a schematic configuration of the LCD controller 21 of the present embodiment. The LCD controller 21 of the present embodiment is different from the LCD controller 21 shown in FIG. 10 in that a gradation control unit (fade unit) 62 is provided instead of the parameter adjustment unit 61, and the other configurations are the same. It is.

  The gradation control unit 62 controls the gradation value of the image data of the side image from the image switching unit 33 and transmits it to the image composition unit 39. Specifically, when the gradation control unit 62 has not received the instruction from the timing instruction unit 60, the gradation control unit 62 transmits the image data of the side image to the image composition unit 39 as it is. On the other hand, when the instruction is received, the gradation control unit 62 adjusts the gradation value of the image data of the side image stepwise and transmits it to the image composition unit 39.

  FIG. 14 shows an adjustment example adjusted by the gradation control unit 62 in the present embodiment. In the figure, gradation values in each frame period are shown. In the present embodiment, each of the side images has four gradations of R (red), G (green), and B (blue), and can express 64 colors. In this case, the modulation of the image data of the main image M is performed for each of the R component, G component, and B component in each pixel.

  In FIG. 14, it is assumed that the instruction is received from the timing instruction unit 60 in the first frame period. At this time, the gradation value decreases by one for each frame period, and becomes all zero in the fourth frame period. Then, the side image is switched in the fourth frame period, and thereafter, the gradation value increases in the reverse order to the first to third frame periods, and the switched side in the seventh frame period. This is the gradation value of the image.

  In the present embodiment, the time change of the side image visually recognized by the off-axis observer is the same as that in FIG. When the gradation value of the side image before and after switching is 2, the gradation control unit 62 may change the gradation value to 2 · 2 · 1 · 0 · 1 · 2 · 2. When the gradation value of the side image before and after switching is 1, the gradation control unit 62 may change the gradation value to 1 · 1 · 1 · 0 · 1 · 1 · 1. As described above, when the gradation value of the side image is an intermediate gradation value, the timing of decreasing or increasing the gradation value is higher than the gradation value whose original gradation value is higher than the gradation value. As long as it does not become large, it can be arbitrarily adjusted.

  In this embodiment, the present invention is applied when switching a plurality of side images in the side image memory 31, but the present invention can also be applied when the color switching unit 35 or the image enlargement / reduction unit 37 changes a side image. The present invention can also be applied to the case where streaming data is received from the CPU 11 or the memory 13 as the image data of the side image.

[Embodiment 4]
Next, still another embodiment of the present invention will be described with reference to FIGS. The electronic device 10 of this embodiment is different from the electronic device 10 shown in FIG. 2 only in the configuration of the LCD controller 21, and the other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the LCD controller 21 shown in FIG. 10, the off-axis observer visually recognizes that the side image before switching fades out and the side image after switching fades in. On the other hand, in the LCD controller 21 of the present embodiment, the off-axis observer visually recognizes the side images before and after the switching as crossfading.

  FIG. 15 shows a schematic configuration of the LCD controller 21 of the present embodiment. The LCD controller 21 of this embodiment is different from the LCD controller 21 shown in FIG. 10 in that a cross-fade control unit (fade unit) 63 is added, and the other configurations are the same.

The crossfade control unit 63 controls the image switching unit 33 and the parameter adjustment unit 61 so as to perform the above-mentioned crossfade. Specifically, the crossfade control unit 63 instructs the image switching unit 33 to switch the side images in the order stored in the order storage unit 32 when the instruction is not received from the timing instruction unit 60. It instructs the parameter adjuster 61 so as to transmit the divided value D ₁ read out from the partition parameter storage unit 38 as it is to the image synthesizing unit 39.

  On the other hand, when the instruction is received from the timing instruction unit 60, the crossfade control unit 63 executes the following processing. That is, the crossfade control unit 63 receives the image data of the side image before switching and the image data of the side image after switching from the sequence data stored in the sequence storage unit 32, and creates transition information.

FIG. 16 shows an example of the transition information. As shown in the figure, the transition information includes the current division value based on the gradation value of the current side image (before switching) and the next division value based on the gradation value of the next (after switching) side image. Are associated with each other. As described above, when the gradation value of the side image is 0, the divided value is D _1, when the gradation value of the side image is a 255, the divided value is 0.

In the example of FIG. 16, when the current division value is D ₁ and the next division value is 0, the division value changes step by step, and each of the second and third frame periods (D ₁ × 2/3) and (D ₁ × 1/3), which is 0 in the fourth frame period, that is, the next division value. Further, if the current division value is 0, if the next division value is D _1, division value is stepwise varied, respectively in the second and third frame periods (D ₁ × _1/3) And (D ₁ × 2/3), and becomes D ₁ , that is, the next division value in the fourth frame period. When the current division value and the next division value are the same, the division value does not change.

  Next, the crossfade control unit 63 controls the parameter adjustment unit 61 to adjust the division value for each pixel of the side image based on the transition information. Then, the cross-fade control unit 63 instructs the image switching unit 33 to switch the side image during the last frame period of the transition information (the fourth frame period in the example of FIG. 16).

  FIG. 17 shows the temporal change of the side image visually recognized by the off-axis observer in the present embodiment in units of frame periods. Referring to the drawing, in this embodiment, it can be understood that the side image is cross-faded and the display of the next side image is completed in the fourth frame period. On the other hand, in the example of FIG. 12, the display of the next side image is completed in the seventh frame period. Therefore, when the side image is crossfade as in the present embodiment, the side image is switched more quickly than when the current side image is faded out and the next side image is faded in as shown in FIG. be able to.

[Embodiment 5]
Next, still another embodiment of the present invention will be described with reference to FIGS. The electronic device 10 of this embodiment is different from the electronic device 10 shown in FIG. 2 only in the configuration of the LCD controller 21, and the other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  FIG. 18 shows a schematic configuration of the LCD controller 21 of the present embodiment. The LCD controller 21 of the present embodiment is different from the LCD controller 21 shown in FIG. 13 in that a cross fade control unit 63 is added, and the other configurations are the same.

  Compared to the crossfade control unit 63 shown in FIG. 15, the crossfade control unit 63 of the present embodiment controls the gradation control unit 62 instead of controlling the parameter adjustment unit 61, and the transition information to be created The other functions are the same.

  FIG. 19 shows an example of the transition information in the present embodiment. As illustrated, the transition information is associated with the tone value of the current side image (before switching) and the tone value of the next (after switching) side image. For example, when the current gradation value is 3 and the next gradation value is 0, the gradation value changes stepwise and becomes 2 and 1 in the second and third frame periods, respectively. It becomes 0 in the first frame period, that is, the next gradation value. When the current gradation value is 0 and the next gradation value is 3, the gradation value changes stepwise and becomes 1 and 2 in the second and third frame periods, respectively. In the first frame period, it becomes 3, that is, the next gradation value.

  Based on the transition information, the crossfade control unit 63 controls the gradation control unit 62 so as to adjust the gradation value for each pixel of the side image. Then, the cross-fade control unit 63 instructs the image switching unit 33 to switch the side image during the last frame period of the transition information (the fourth frame period in the example of FIG. 19).

  In the present embodiment, the temporal change of the side image visually recognized by the off-axis observer is the same as that in FIG. As described above, when the current gradation value or the next gradation value is an intermediate gradation value, the timing for decreasing or increasing the gradation value can be arbitrarily adjusted.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  For example, in the above embodiment, the LCD controller 21 describes only the function that operates in the private mode. However, the function that operates in the public mode is added, and the private mode and the public mode are switched according to an instruction from the CPU 11. It is desirable to be possible. In the public mode, the image composition unit 39 may transmit the image data of the main image M from the main image memory 30 as it is to the LCD module 22 as image data of the display image.

  In the above embodiment, the case where the gradation value of two adjacent pixels in the main image M is modulated has been described. However, the present invention can be similarly applied to three or more adjacent pixels. Further, when a pixel group composed of a plurality of pixels is set, the same can be applied to adjacent pixel groups. In addition, other data values such as pixel values can be used instead of the gradation values.

  The present invention stores the image data of a plurality of side images, and the side image selected with the passage of time is changed, so that the side images that can be viewed by the off-axis observer can be changed in a wide variety of ways, Since the resource for transmitting the image data of the side image to the display control device does not need to continue to transmit the image data of the side image, it is possible to prevent an increase in the processing load of the resource, so the main image and the side image And can be applied to any electronic device that performs display control.

10 Electronic Equipment 11 CPU (Main Control Device)
12 bus 13 memory (main controller)
14 LCD unit (display device)
21 LCD controller (display control device)
22 LCD module 30 Main image memory (main image acquisition unit)
31 Side image memory (side image acquisition unit, side image storage unit)
32 Order storage unit 33 Image switching unit (side image acquisition unit, side image selection unit)
34 Color arrangement pattern storage unit 35 Color switching unit (image processing unit)
36 Enlargement / reduction ratio storage unit 37 Image enlargement / reduction unit (image processing unit)
38 Division parameter storage unit (image composition unit)
39 Image composition unit (modulation unit)
50 Display screen 60 Timing instruction section 61 Parameter adjustment section (fade section)
62 Gradation control part (fade part)
63 Crossfade control part (fade part)

Claims (9)

A display control device that controls a liquid crystal display element to display a display image on a display screen by spatial luminance modulation,
A main image acquisition unit for acquiring image data of the main image from the outside;
A side image acquisition unit that acquires image data of a side image from outside;
Regarding the luminance from the liquid crystal display element, based on the nonlinear correspondence between the luminance with respect to the axial direction parallel to the normal line of the display screen and the luminance with respect to the off-axis direction, and the image data of the side image, the main image An image composition unit that modulates image data of an image and uses the modulated image data as image data of the display image;
The side image acquisition unit
A side image storage unit that stores image data of a plurality of side images;
A side image selection unit that selects image data of a side image from the side image storage unit and sends the image data to the image composition unit, and a side image selection unit that changes the image data of the side image to be selected as time elapses; A display control apparatus comprising:   An image processing unit that processes the image data of the side image selected by the side image selection unit and sends the processed image data to the image composition unit, and further includes an image processing unit that changes the content of the processing over time. The display control apparatus according to claim 1.   When the side image selection unit changes the side image, the image composition unit gradually reduces the degree of modulation of the image data of the main image before the change, and gradually changes the degree of modulation after the change. The display control apparatus according to claim 1, further comprising a fade unit to be returned.   When the side image selection unit changes the side image, the image composition unit changes the degree of modulation of the image data of the main image from the degree based on the image data of the side image before the change. The display control apparatus according to claim 1, further comprising a fade unit that changes step by step according to the degree of the image data.   The display control device according to claim 3, wherein the fade unit changes the degree in steps by changing the value of the image data of the side image in steps. The image composition unit
A division parameter storage unit that stores the correspondence between the image data value of the main image and the division parameter based on the nonlinear correspondence;
A modulation unit that modulates the value of the image data of the main image based on the division parameter corresponding to the value of the image data of the main image and the value of the image data of the side image;
5. The display control apparatus according to claim 3, wherein the fade unit changes the degree stepwise by changing the division parameter used by the modulation unit stepwise. 6.   The image composition unit can switch between a private mode in which the modulated image data is image data of the display image and a public mode in which the image data of the main image is image data of the display image. The display control device according to claim 1, wherein the display control device is a display device.   A display device comprising: the display control device according to any one of claims 1 to 7; and a liquid crystal display element controlled by the display control device. A display device according to claim 8 and a main control device,
The main control device transmits image data of the main image and the side image to the display control device.

Images