JP2009086676A - Information display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve visibility of an image to be displayed in various illuminance environments. <P>SOLUTION: In this information display device configured to display a predetermined image on a reflection type display body, the illuminance around the reflection type display body is detected by an illuminance sensor 9, and when the illuminance region (illuminance regions A, B, C, D) of the detected illuminance changes, an interrupt signal is output by an interrupt control device 10, and when the interrupt signal is output, the luminance of an image displayed on the reflection type display body is corrected by a surface control device 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an information display device that displays a predetermined image on a reflective display.

Conventionally, as this type of display device, for example, an image of a content such as an electronic book is displayed on a reflective display body such as a cholesteric liquid crystal or an electrophoretic display body, and a display for allowing the user to view the displayed image An apparatus is known (for example, refer to Patent Document 1).
JP-A-11-271799

  However, in the conventional display device, the content image is displayed on a reflective display body, that is, a display body that displays using reflected light of light incident on the display screen. For example, in an environment where the amount of light incident on the display screen is small, the visibility of an image that is a display target may be reduced.

  The present invention has been made for the purpose of solving the above-mentioned unsolved problems of the prior art, and is capable of improving the visibility of an image to be displayed under various illuminance environments. It is an object to provide an apparatus.

  In order to solve the above-described problem, an information display device according to a first aspect of the present invention is an information display device that displays a predetermined image on a reflective display body, and the illuminance for detecting the illuminance around the reflective display body And a luminance correction unit that corrects the luminance of the image displayed on the reflective display based on the illuminance detected by the illuminance detection unit.

  According to the first aspect of the invention, since the luminance of the image displayed on the reflective display body is corrected based on the surrounding illuminance, it is possible to perform correction suitable for each illuminance and The visibility of a certain image can be improved.

  In the information display device according to the second aspect of the invention, the brightness correction unit selects a brightness correction table corresponding to the illuminance detected by the illuminance detection unit from a plurality of prepared brightness correction tables, and the selection is made. The brightness of the image displayed on the reflective display body is corrected based on the brightness correction table.

  According to the second aspect, by selecting an appropriate brightness correction table, correction suitable for each illuminance can be performed, and the visibility of an image to be displayed can be easily improved.

  Furthermore, in the information display device according to the third aspect of the invention, the brightness correction unit is configured to determine a predetermined image displayed on the reflective display body when the illuminance detected by the illuminance detection unit is equal to or greater than a predetermined illuminance. It is characterized in that a brightness correction table is selected for correcting the brightness of the portion above the brightness to be small.

  According to the third aspect of the invention, for example, when the illuminance around the reflective display body is extremely large and the amount of light incident on the display screen is extremely large, the reflection by the high-luminance portion of the image to be displayed is performed. The amount of light can be reduced, and the visibility of an image to be displayed can be improved.

  In the information display device according to the fourth aspect of the present invention, the brightness correction unit is configured to determine a predetermined image displayed on the reflective display when the illuminance detected by the illuminance detection unit is equal to or lower than a predetermined illuminance. It is characterized in that a brightness correction table for correcting the brightness of the portion below the brightness to be small is selected.

  According to the fourth aspect of the invention, for example, when the illuminance around the reflective display body is small and the amount of light incident on the display screen is small, the luminance of the halftone portion of the image to be displayed is reduced. It can be corrected. Then, when the outline of the character included in the image to be displayed is halftone, the brightness of the outline is reduced and a character with a high contrast of the outline is displayed to display the image of the image to be displayed. Visibility can be improved.

  Furthermore, in the information display device according to the fifth aspect of the present invention, a CPU that generates raster data of an image to be displayed on the reflective display body, and raster data generated by the CPU is directly displayed on the reflective display body. A display control device, wherein the luminance correction unit corrects luminance data included in the raster data generated by the raster data generation unit.

  According to the fifth aspect of the invention, for example, the manufacturing cost of the information display apparatus can be reduced as compared with a method of storing raster data in a VRAM and correcting the stored raster data.

In the information display device according to the sixth aspect of the invention, a CPU that generates raster data of an image to be displayed on the reflective display, a VRAM that stores raster data generated by the CPU, and a VRAM that is stored in the VRAM. A display control device that displays the raster data on the reflective display body, and the brightness correction unit corrects brightness data included in the raster data stored in the VRAM. According to the sixth aspect of the invention, for example, the load on the CPU can be reduced compared to a method of generating raster data and correcting the generated raster data directly.

Hereinafter, an embodiment of an information display device of the present invention will be described with reference to the drawings.
<Configuration of portable information terminal>
FIG. 1 is a block diagram showing a schematic configuration of a portable information terminal 1 according to an embodiment of the present invention. As shown in FIG. 1, a portable information terminal 1 includes a CPU (Central Processing Unit) 2, a RAM (Random Access Memory) 3, a storage device 4, an input device 5, a display control device 6, and a VRAM (Video RAM). 7, a display device 8, an illuminance sensor 9, and an interrupt control device 10.

  Among these, the CPU 2 reads various programs and data such as a basic control program stored in the storage device 4, develops and executes these various programs and data in a work area provided in the RAM 3, and the portable information terminal 1. Control of each part with which is included. Further, the CPU 2 reads a designated image from the storage device 4 in accordance with a pressing signal (described later) output from the input device 5, and outputs raster data of the image to the display control device 6.

  Furthermore, when the current illuminance area data (described later) and an interrupt signal (described later) are output from the interrupt control device 10, the CPU 2 outputs the current illuminance area data (described later) and a refresh instruction to the display control device 6. To do.

  The RAM 3 forms a work area for developing the various programs when the CPU 2 executes the processes according to the various programs, and also forms a memory area for storing data related to the various processes executed by the CPU 2. .

  Further, the storage device 4 stores a basic control program executed by the CPU 2, various application programs, data related to these programs, and the like. Then, the storage device 4 outputs these various programs and data to the CPU 2 in accordance with a read request from the CPU 2. Various programs and data in the storage device 4 are stored in a format that can be read and executed by the CPU 2.

  The input device 5 includes a keyboard having character keys, numeric keys, and various function keys. When the keyboard is depressed, a depression signal corresponding to the depressed key is output to the CPU 2.

  Furthermore, the display control device 6 executes display control processing described later every time a predetermined time elapses, and stores raster data output from the CPU 2 in the VRAM 7. Then, the raster data stored in the VRAM 7 is read out, the luminance data included in the read raster data is corrected based on the current illuminance (described later) output from the CPU 2, and the corrected raster data is converted into the corrected raster data. Output to the display device 8. Here, the luminance data indicates the luminance value of each pixel of the display screen of the display device 8 by a numerical value “0” to “255”, and “0” indicates that the luminance of the corresponding pixel is minimized, “255” indicates that the luminance of the corresponding pixel is maximized.

  Further, the VRAM 7 stores raster data in accordance with a write request from the display control device 6. Then, the VRAM 7 outputs raster data to the display control device 6 in accordance with a read request from the display control device 6.

  The display device 8 includes a reflective display body such as an electrophoretic display body or a cholesteric liquid crystal panel, that is, a display body that performs display using reflected light of light incident on the display screen. Then, when raster data is output from the display control device 6, an image corresponding to the output raster data is displayed on the reflective display.

  Further, the illuminance sensor 9 detects the illuminance around the display screen of the display device 8 and outputs information on the detected illuminance to the interrupt control device 10.

Further, the interrupt control device 10 executes an interrupt process described later every time a predetermined time elapses, determines whether or not the illuminance area around the display screen has changed, and when the illuminance area has changed. Outputs the current illuminance range data (described later) and an interrupt signal to the CPU 2.
<Contents of interrupt processing>
FIG. 2 is a flowchart of interrupt processing executed by the interrupt control device 10. This interruption process is executed every time a predetermined time elapses. As shown in FIG. 2, the illuminance information is read from the illuminance sensor 9 in step S101.

  Next, the process proceeds to step S102, and the current illuminance range (hereinafter also referred to as “current illuminance range”) is determined based on the illuminance information read out in step S101. Specifically, as shown in FIG. 3, when the illuminance is smaller than 10 [lx], it is determined that the current illuminance area is the illuminance area A (a considerably dark environment such as under a street lamp at night). If it is 10 [lx] or more and smaller than 100 [lx], it is determined that the illumination area is B (a slightly dark environment such as a corner of a room at night). If the illuminance is 100 [lx] or more and smaller than 10000 [lx], it is determined that the current illuminance area is the illuminance area C (a bright environment such as indoors or outdoors in the daytime), and the illuminance is 10,000 [lx]. If it is above, it is determined that the illumination area is D (very bright environment such as outdoors under a clear sky).

Next, the process proceeds to step S103, where it is determined whether or not the illuminance range determined when this calculation process was executed last time and the current illuminance range determined in step S102 are different. Yes) The process proceeds to step S104, and if not different (No), this calculation process is terminated. When this calculation process is executed for the first time, it is assumed that the illuminance area determined when this calculation process was executed last time is the illuminance area C.

In step S104, the current illuminance area data and interrupt signal are output to the CPU 2, and the calculation process is terminated.
<Contents of display control processing>
FIG. 4 is a flowchart of the display control process executed by the display control device 6. This display control process is executed every time a predetermined time elapses. As shown in FIG. 4, in step S201, the CPU 2 outputs image data, that is, an instruction to update the display contents. It is determined whether or not a display content update instruction is output (Yes), the process proceeds to step S202. If a display content update instruction is not output (No), step S204 is performed. Migrate to

  In step S202, raster data output from the CPU 2 is stored in the VRAM 7.

  Next, the process proceeds to step S203, where data of the current illuminance area (hereinafter also referred to as “previous illuminance area”) read from the CPU 2 when this calculation process was executed last time is read from the RAM 3 and read. After the previous illuminance area data is made the current illuminance area data, the process proceeds to step S206. When this calculation process is executed for the first time, it is assumed that the illuminance area C is stored in the RAM 3 as the previous illuminance area data.

  On the other hand, in the step S204, it is determined whether or not a refresh instruction is output from the CPU 2. If the refresh instruction is output (Yes), the process proceeds to step S205, and the refresh instruction is not output. (No) This calculation process ends.

  In step S205, the current illuminance area data output from the CPU 2 is read, and then the process proceeds to step S206.

  In step S206, raster data stored in the VRAM 7 is read.

Next, the process proceeds to step S207, and as shown in FIG. 5, from the luminance correction LUT (Look Up Table) group, the current illuminance range set in step S203 or the step S207.
The brightness correction LUT corresponding to the current illuminance area (illuminance areas A, B, C, and D) read in 205 is selected. Based on the selected luminance correction LUT, the luminance data included in the raster data read in step S206 is corrected.

  Here, the luminance correction LUT corresponding to the illuminance areas A and B sets the correction result (correction value) to “0” when the luminance value (original luminance value) included in the luminance data is “0”. When the luminance value is “255”, the correction result is “255”, and when the luminance value is “0” to “255”, the correction result gradually increases with increasing luminance value. However, it increases with a downwardly convex curve. The luminance correction LUT corresponding to the illuminance area A is corrected to be larger than the LUT corresponding to the illuminance area B.

  Further, in the luminance correction LUT corresponding to the illuminance area C, when the luminance value included in the luminance data is “0”, the correction value is “0”, and when the luminance value is “255”. When the correction value is “255” and the luminance value is “0” to “255”, the correction value is represented by a straight line in which the correction value increases linearly as the luminance value increases.

  In addition, in the luminance correction LUT corresponding to the illuminance area D, the correction value is “0” when the luminance value included in the luminance data is “0”, and the luminance value is “255”. When the correction value is “200” and the luminance value is “0” to “150”, the luminance value is represented by a straight line in which the correction value increases linearly as the luminance value increases. In the range of “150” to “255”, the luminance value increases while gradually decreasing the increasing slope and is represented by a convex curve.

  As described above, according to the portable information terminal 1 of the present embodiment, by selecting an appropriate luminance correction LUT, correction suitable for each illuminance can be performed, and the visibility of an image to be displayed can be improved. It can be improved easily.

  Further, when the ambient illuminance is 10000 [lx] or more, a luminance correction LUT for correcting the luminance of the portion having the luminance value “150” or more in the image displayed on the reflective display body to be small is selected. Therefore, for example, when the illuminance around the reflective display is extremely large and the amount of light incident on the display screen is extremely large, the amount of light reflected by the high-intensity part of the image to be displayed is reduced and displayed. The visibility of the target image can be improved.

  In step S208, the raster data corrected in step S207 is output to the display device 8.

Next, the process proceeds to step S209, where the current illuminance area set in step S203 or the current illuminance area read in step S205 is stored in the RAM 3 as the previous illuminance area, and then the calculation process is terminated.
<Operation of portable information terminal>
Next, the operation of the portable information terminal 1 of the present embodiment will be described based on a specific situation.

  First, on the display screen of the portable information terminal 1, an image of a character whose outline is made halftone by anti-aliasing is displayed, and the illuminance around the display screen is reduced from 20 [lx] to 5 [lx]. Assume that the display control device 6 executes an interrupt process. Then, as shown in FIG. 2, first, in step S101, information on the illuminance, that is, information that the illuminance is 5 [lx] is read from the illuminance sensor 9. In step S102, the current illuminance area is changed to the illuminance area A. It is determined that Also, the determination in step S103 is “Yes”. In step S104, the current illuminance area data (illuminance area A) and the interrupt signal are output to the CPU 2, and the CPU 2 sends the current illuminance area data to the display control device 6. A refresh instruction is output.

  It is assumed that the display control process is executed by the display control device 6 when the CPU 2 outputs the current illuminance range data and the refresh instruction. Then, as shown in FIG. 4, the determination in step S201 is “No”, the determination in step S204 is “Yes”, and the data of the current illuminance range output from the CPU 2 is read in step S205. In step S206, the raster data stored in the VRAM 7 is read. In step S207, as shown in FIG. 5, the current illuminance area (illuminance area A) read from the luminance correction LUT group is read. A luminance correction LUT corresponding to is selected, and based on the selected luminance correction LUT, the luminance of the halftone portion included in the read raster data is corrected to be small, and the outline portion of the character is corrected to be dark. The In step S208, the corrected raster data is output to the display device 8. In step S209, the current illuminance area is stored in the RAM 3 as the previous illuminance area, and the display apparatus 8 contrasts based on the output raster data. An image of a large character is displayed.

As described above, in the portable information terminal 1 according to the present embodiment, the luminance of the image displayed on the reflective display body is corrected based on the ambient illuminance. It is possible to improve the visibility of an image to be displayed.

  Further, when the ambient illuminance is smaller than 10 [lx], the luminance correction LUT for correcting the luminance of the portion where the luminance value in the image displayed on the reflective display body is less than “255” is selected. Therefore, for example, when the illuminance around the display screen of the display device 8 is small and the amount of light incident on the display screen is small, the brightness of the halftone portion of the image displayed on the display screen is corrected to be small. The Therefore, the brightness of the halftone portion of the outline of the character included in the image to be displayed can be reduced, a character with high contrast can be displayed, and the visibility of the image to be displayed can be improved. .

  Further, since the raster data stored in the VRAM 7 is corrected and a character image is displayed on the display screen of the display device 8 based on the corrected raster data, for example, raster data is generated and generated. The load on the CPU 2 can be reduced as compared with the method of directly correcting the raster data.

  In the above embodiment, the illuminance sensor 9 in FIG. 1 and step S102 in FIG. 2 constitute illuminance detection means. Similarly, the display control device 6 in FIG. 1 and steps S205 to S208 in FIG. 1, the display control device 6 in FIG. 1 and step S202 in FIG. 4 constitute a generation means, and the display control device 6 in FIG. 1 and steps S206 to S208 in FIG. 4 constitute a display means.

  Moreover, the said embodiment shows an example of the information display apparatus based on this invention, and does not limit the structure.

  For example, in the above-described embodiment, an example is shown in which raster data is stored in the VRAM 7 and the stored raster data is corrected. However, the present invention is not limited to this. For example, raster data generated by the CPU 2 is directly stored. It may be corrected. By doing so, the VRAM 7 can be omitted, and the manufacturing cost of the portable information terminal 1 can be suppressed.

It is a block diagram which shows one Embodiment of the information display apparatus of this invention. It is a flowchart of the interruption process performed with an interruption control apparatus. It is explanatory drawing for demonstrating the relationship between illumination intensity and an illumination intensity range. It is a flowchart of the display control process performed with a display control apparatus. It is explanatory drawing for demonstrating the brightness | luminance correction LUT.

Explanation of symbols

1 is a portable information terminal, 2 is a CPU, 3 is a RAM, 4 is a storage device, 5 is an input device, 6 is a display control device, 7 is a VRAM, 8 is a display device, 9 is an illuminance sensor, and 10 is an interrupt control device.

Claims (6)

  An information display device for displaying a predetermined image on a reflective display body, the illuminance detection means for detecting the illuminance around the reflective display body, and the reflective type based on the illuminance detected by the illuminance detection means An information display device comprising a luminance correction means for correcting the luminance of an image displayed on a display body.   The brightness correction means selects a brightness correction table corresponding to the illuminance detected by the illuminance detection means from a plurality of prepared brightness correction tables, and the reflective display based on the selected brightness correction table The information display device according to claim 1, wherein the brightness of an image displayed on the body is corrected.   The brightness correction unit is a brightness correction unit that corrects the brightness of a portion of the image displayed on the reflective display body to be small when the illuminance detected by the illuminance detection unit is greater than or equal to a predetermined illuminance. The information display device according to claim 2, wherein a table is selected.   The brightness correction unit is a brightness correction unit that corrects the brightness of a portion of the image displayed on the reflective display body to be less than or equal to a predetermined brightness when the illuminance detected by the illuminance detection unit is less than or equal to a predetermined illuminance. 4. The information display device according to claim 2, wherein a table is selected.   A CPU for generating raster data of an image to be displayed on the reflective display; and a display control device for directly displaying the raster data generated by the CPU on the reflective display; 5. The information display device according to claim 1, wherein luminance data included in the raster data generated by the raster data generation unit is corrected. 6.   A CPU that generates raster data of an image to be displayed on the reflective display, a VRAM that stores raster data generated by the CPU, and raster data stored in the VRAM is displayed on the reflective display. 5. The information according to claim 1, further comprising: a display control device, wherein the luminance correction unit corrects luminance data included in raster data stored in the VRAM. Display device.

Images