JP5307321B2 - Display device - Google Patents

Description

  The present invention relates to a display device and a portable information terminal including the display device, and more particularly to a display device and a portable information terminal including a half mirror panel.

  Recent display devices for mobile phones and personal digital assistants tend to use half mirror panels because they require new expressions. The half mirror panel has a function of specularly reflecting light from the front surface at a high rate while allowing light from the back side to pass at a high rate.

  FIG. 9 is a diagram showing a display unit of a display device in which a display device and a half mirror panel are combined. As shown in FIG. 9, a 7-segment LED (Light Emitting Diode), a dot matrix LED, an EL, or the like is often used as a display means that has been transmitted through a conventional half mirror panel, so that characters appear on the display screen. ing.

However, devices such as the above-mentioned 7-segment LED, dot matrix LED, and EL often have restrictions on expression in addition to displaying simple numbers and characters. Therefore, it is conceivable to use a liquid crystal panel that allows free expression and has high versatility instead of LEDs and the like. Conventionally, there is Patent Document 1 in which this half mirror panel is mounted on a mobile phone. In the technique described in Patent Document 1, a display liquid crystal layer with backlight, a scattering type liquid crystal shutter layer, and a half mirror layer are stacked. As a result, when the scattering type liquid crystal shutter layer is in the light transmission mode, the operating state and information of the product such as when sending or receiving mail are displayed, and when the scattering type shutter layer is in the light scattering mode, the half mirror panel is mirrored. It is used as
Japanese Patent Laid-Open No. 2003-140149

  However, as shown in FIG. 10, when a half mirror panel is overlaid on a display device using a liquid crystal panel mounted with a backlight, a bright portion 11 due to backlight transmission is formed on the display screen. This is because the liquid crystal panel is not a self-luminous display device, and a liquid crystal display device using the liquid crystal panel needs a light source such as a backlight and a front light. For this reason, the display screen is displayed as if a window was created, and characters that are possible when using the above-described EL, etc. are not expressed, so compared with EL etc. in terms of design There was a problem of being inferior.

  In order to solve the above-described problems, a display device according to the present invention includes a liquid crystal panel that displays an image, a half mirror panel disposed on the liquid crystal panel, a backlight that illuminates the liquid crystal panel, and the liquid crystal A control unit that controls the panel and the backlight is provided, and the control unit causes the liquid crystal panel to display black.

  According to the display device according to the present invention, display is performed in a seamless mirror tone by using a combination of a half mirror and a liquid crystal panel which is highly versatile and capable of rich display while utilizing existing design assets. It is possible to provide a display device and a portable information terminal that can raise a target.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. In this embodiment mode, the present invention is applied to a mobile phone that realizes a display that transmits through a half mirror panel without impairing design while using a highly versatile liquid crystal display device.

Embodiment 1 FIG.
FIG. 1 shows an overall view of a mobile phone 100 according to the present embodiment. As shown in FIG. 1, a half mirror panel 10 is formed on the back side of the mobile phone 100. FIG. 2 shows the structure of the display unit of the mobile phone 100 according to the present embodiment. The liquid crystal panel 1 is disposed under the half mirror panel 10, and the backlight 3 is disposed under the liquid crystal panel 1.

  FIG. 3 is a block diagram showing the mobile phone 100 according to the present embodiment. As shown in FIG. 3, the mobile phone 100 includes a liquid crystal panel 1 for displaying an image below the half mirror panel 10, a liquid crystal display control circuit 2 connected to the liquid crystal panel 1 and controlling the liquid crystal panel 1, and a liquid crystal The backlight 3 provided in the panel 1, the backlight control circuit 4 connected to the backlight 3 and controlling the backlight 3, the liquid crystal display control circuit 2 and the backlight control circuit 4 are connected to each other as a control unit. A CPU (Central Processing Unit) 5 and a memory 7 connected to the CPU 5 are included. Various sensors 8 such as an optical sensor, a pressure sensor, or a fingerprint authentication sensor may be provided.

  The memory 7 stores data such as numbers, characters and graphics to be displayed on the liquid crystal panel 1, for example. Further, data may be acquired by downloading or the like via a communication means. The CPU 5 serving as a control unit creates display data based on the data stored in the memory 7 and sends it to the liquid crystal display control circuit 2 and the backlight control circuit 4.

  The liquid crystal display control circuit 2 controls the display on the liquid crystal panel 1. The liquid crystal panel 1 displays characters, numbers, graphics or the like under the control of the liquid crystal display control circuit 2. The backlight control circuit 4 controls turning on or off of the backlight 3 such as turning off the backlight during a call. Further, as will be described later, the luminance of the backlight 3 may be controlled. The backlight 3 is turned on according to the control of the backlight control circuit 4.

  As described above, when the liquid crystal panel 1 is used for the display screen, the liquid crystal display device requires a light source such as a backlight and a front light. For example, when the backlight is used as the light source, the display screen is caused to transmit the backlight. A bright part is made. For this reason, the display screen has a window-like display and lacks design. Hereinafter, in the present specification, such a display having such a window is referred to as a display window.

  In order to prevent this display window, in the present embodiment, the liquid crystal panel 1 is displayed in a black background as shown in FIG. That is, in the liquid crystal panel 1, the CPU 5 or the liquid crystal display control circuit 2 controls the liquid crystal panel 1 so that the background of data to be displayed is black. For example, target data to be displayed is sent from the memory 7 to the CPU 5, and the CPU 5 sends the data to the liquid crystal display control circuit 2 as display data for displaying a black background. Alternatively, a black background may be displayed on the liquid crystal panel 1 side by operating a polarizing plate or the like. The liquid crystal display control circuit 2 displays a display target on the liquid crystal panel 1 based on the display data. Thereby, the background of the liquid crystal panel 1 is displayed on a black background, and only the display target can be displayed on the black background.

  In the present embodiment, the background of the liquid crystal panel 1 is displayed in a black background, so that only the backlight 3 portion is displayed brightly on the liquid crystal panel 1, and only the display target is displayed on the black background without the above-described display window being formed. Can emerge. That is, by displaying the background of the liquid crystal panel 1 on a black background, it is possible to prevent the above-described display window from being formed through the backlight 3. In this way, only the display object can be displayed on a black background, so that it has a seamless and excellent design. Further, since the liquid crystal panel 1 is used, it is possible to provide a mobile phone with high versatility and simplified control. Such a versatile and seamless display is particularly effective for recent mobile phone products that emphasize design.

Embodiment 2. FIG.
Next, the second embodiment will be described. The mobile phone 100 according to the first embodiment described above prevents the display (display window) from forming a window on the display screen by setting the background of the liquid crystal panel 1 to a black background, and displays only the display target. Is displayed on a black background. FIG. 5 is a diagram illustrating a display unit of the mobile phone 100 when the backlight luminance is increased in a dark place. As shown in FIG. 5, a display window may be formed depending on the illuminance around the mobile phone 100 using the liquid crystal panel 1. Moreover, the visibility in the outdoors where the light conditions are complicated may not be ensured. Therefore, in the present embodiment, an illuminance detection unit 6 that detects ambient illuminance is provided. The illuminance detection unit 6 detects the ambient illuminance of the mobile phone, and adjusts the brightness of the backlight 3 that transmits the liquid crystal panel 1 according to the ambient illuminance based on the detection result. Ensure quality.

  FIG. 6 is a block diagram showing a mobile phone 200 having the illuminance detection unit 6. In the mobile phone 200 according to the present embodiment shown in FIG. 6, the same components as those of the mobile phone 100 according to the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 6, the mobile phone 200 according to the present embodiment further includes an illuminance detection unit 6 in addition to the configuration of the mobile phone 100 according to the first embodiment. The illuminance detection unit 6 is connected to the CPU 5. The illuminance detection unit 6 detects the illuminance around the mobile phone 200.

  A display method of mobile phone 200 according to the present embodiment will be described. The illuminance detection unit 6 detects the illuminance around the mobile phone 200 and sends the detected illuminance data to the CPU 5. The CPU 5 determines an appropriate luminance of the backlight 3 based on the detected illuminance data. Then, the determined optimal brightness value of the backlight 3 is sent to the backlight control circuit 4. The backlight control circuit 4 controls the brightness of the backlight 3 so as to have this brightness value, so that the backlight 3 is turned on with a brightness corresponding to the ambient illuminance. As a result, the brightness of the backlight 3 can be controlled in accordance with each illuminance even under high illuminance such as outdoors or under low illuminance such as indoors, so that visibility can be ensured and a display window can be formed through backlight transmission. Can be prevented. FIG. 7 shows a display unit of a mobile phone 200 using the half mirror panel 10 and the liquid crystal panel 1 having the above-described functions.

  FIG. 8 shows an example of the relationship between the ambient luminance and the backlight luminance that controls the backlight luminance to Cd when the ambient luminance is Lx. The brightness of the backlight can be controlled as shown in FIG. That is, in the peripheral illuminances L1 to L2 and L2 to L3, the luminance Cd is controlled to increase in proportion to the illuminance. Here, when the luminance is equal to or higher than a certain luminance L3, the maximum luminance C3 is set. When the luminance is equal to or lower than the certain luminance L1, the lowest luminance C1 is set. Further, in the present embodiment, in the peripheral illuminances L1 to L2 and L2 to L3, the luminance is increased as the peripheral illuminance is increased, but the degree of increase is different. That is, the peripheral illuminances L1 to L2 are controlled so as to increase more slowly than the peripheral illuminances L2 to L3. For example, the ambient illuminances L1 to L2 correspond to, for example, when the ambient illuminance is different indoors, and the peripheral illuminances L2 to L3 correspond to the ambient illuminance that differs outdoors.

  Generally, the illuminance is higher in the outdoor than in the daytime, but if the illuminance is high, the display brightness will be dark and the visibility will be reduced if the backlight brightness remains the same as in the indoor space. . Therefore, in the present embodiment, the brightness of the backlight 3 is controlled so that the rate of increase is T1 between the ambient illuminances L1 and L2 that can be determined to be indoors, and the ambient illuminances L2 to L3 are outdoors. The brightness of the backlight 3 is controlled so that the increase rate becomes T2.

  In addition, the brightness of the backlight can be varied not only by the difference in illuminance between indoors and outdoors, but also by, for example, the difference in illuminance between daytime and nighttime, or the difference between numerals and characters and graphic display. Illuminance is lower indoors at night than outdoors during the daytime. Therefore, the increase rate of the luminance of the backlight may be changed according to the time zone. Further, since the graphic display has many color schemes compared to the number and character display, the light from the backlight may be difficult to transmit. Therefore, the backlight luminance can be appropriately adjusted according to display data, for example, by increasing the backlight luminance more than when displaying characters. That is, for example, in the case where graphic data is displayed rather than the case where character data is displayed, the visibility of the display screen can be ensured by increasing the luminance increase rate according to the ambient illuminance.

  In the present embodiment, as in the first embodiment, by displaying the liquid crystal panel 1 in a black background, it is possible to make only the display object appear on the black background without displaying the entire liquid crystal panel 1 brightly. Accordingly, since the luminance Cd of the backlight 3 can be controlled according to the ambient illuminance, it is possible to prevent a display window from being transmitted through the backlight 3 from being formed on the display screen through the half mirror panel 10. .

  Further, when the display screen is difficult to see because the surrounding illuminance is bright, such as outdoors, it can be improved by increasing the luminance of the backlight. However, increasing the luminance of the backlight increases the amount of current consumption. In addition, under low illuminance such as indoors, the backlight is too bright if the backlight luminance is outdoors, etc., so that a window is formed over the half mirror panel with light transmitted through the black display portion of the liquid crystal panel 1. Sometimes. For this reason, the ambient illuminance of the mobile phone 200 is detected by the illuminance detector 6, and the brightness of the backlight 3 that passes through the liquid crystal panel 1 is adjusted according to the ambient illuminance based on the detection result.

  That is, since the backlight luminance is changed according to the ambient illuminance, both visibility under high illuminance and appearance under low illuminance can be achieved, and display quality can be kept constant. Furthermore, since the brightness of the backlight 3 is controlled to an optimum value necessary for display, it is possible to reduce current consumption. Therefore, it is possible to obtain a mobile phone that is highly versatile and has good visibility and good appearance, such as using a liquid crystal panel that can display richly while utilizing existing design assets, and that makes the display object appear in a seamless mirror effect. be able to. Furthermore, it becomes possible to improve the merchandise as a new display system.

Other embodiments.
The above-described embodiment has been described with respect to a mobile phone that enables seamless mirror-like display. However, the present invention is not limited to a mobile phone and can be widely applied to products that use a display in which the half mirror panel 10 and the liquid crystal panel 1 are combined. is there. In addition, it is particularly effective for products that make an appeal in terms of design while effectively utilizing design assets for liquid crystal displays. Furthermore, although the half mirror panel 10 is specified in the present embodiment, a seamless display can be obtained even in a product that performs liquid crystal display through a smoke-based panel, as in the above-described embodiment.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

1 is an overall view of a mobile phone using a display device according to an embodiment. It is the figure which showed the structure of the display part of the mobile telephone concerning this Embodiment. It is a block diagram of the mobile telephone concerning this Embodiment. It is a figure which shows the display part which made the liquid crystal panel concerning this Embodiment the black background display. It is a figure which shows the display part in half mirror panel transmission at the time of raising a brightness | luminance in a dark place. It is a block diagram of the mobile telephone which has the illumination intensity detection part concerning this Embodiment. It is a figure which shows the display part in the half mirror panel transmission concerning this Embodiment. It is a figure of an example which showed the relationship between ambient illumination intensity and backlight brightness | luminance concerning this Embodiment. It is a figure which shows the LED display in half mirror panel transmission. It is a figure which shows the display part using the liquid crystal panel in the conventional half mirror panel transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Liquid crystal display control circuit 3 Backlight 4 Backlight control circuit 5 CPU
6 Illuminance detection unit 7 Memory 8 Various sensors 10 Half mirror panel 11 Bright portion 100, 200 by backlight transmission Cellular phone Lx Ambient illumination L1, L2, L3 Ambient illumination Cd Backlight luminance C1, C2, C3 Backlight luminance T1 Ambient illumination Is the slope when the ambient illuminance changes from L2 to L3

Claims (9)

A liquid crystal panel for displaying images;
A light source that illuminates the liquid crystal panel;
A half mirror panel that is disposed on the liquid crystal panel and mirror-reflects light incident from the front side and transmits part of light incident from the back side;
A control unit for controlling the liquid crystal panel,
The half mirror panel extends in a frame shape to the outside of the outermost periphery of the liquid crystal panel,
The display device according to claim 1, wherein the control unit controls the liquid crystal panel so that a background of the image is black.   The display device according to claim 1, wherein the control unit controls the display data displayed on the liquid crystal panel to transmit light in a region indicating the image.   The display device according to claim 1, wherein the light source is a backlight. Wherein the control unit, the display device according to any one of claims 1 to 3, characterized in that the black areas other than the image of the display data to be sent to the liquid crystal panel. An illuminance detection unit for detecting ambient illuminance is further provided, wherein the control unit controls an increase rate of the luminance of the light source according to the illuminance, and the increase rate is made different between a predetermined illuminance level and below. The display device according to any one of claims 1 to 4 . Luminance increase rate of the light source, a display device according to any one of claims 1 to 5, characterized in that to increase when more than the predetermined illuminance than below the predetermined illuminance. The control unit may display as claimed in any one of claims 1 to 6, characterized in that the type of the image to adjust the brightness of the light source in response to the case where the graphic display of the character display apparatus. The display device according to claim 7 , wherein the control unit increases the luminance of the light source in the case of the graphic display rather than the character display. A liquid crystal panel that displays an image, a light source that illuminates the liquid crystal panel, and a half mirror that is disposed on the liquid crystal panel and that specularly reflects light incident from the front side and transmits part of light incident from the back side A panel, and a controller for controlling the liquid crystal panel,
The half mirror panel extends in a frame shape to the outside of the outermost periphery of the liquid crystal panel,
The portable information terminal, wherein the control unit controls the liquid crystal panel so that a background of the image is black.

Images