JP2007052238A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device which has simple constitution and is improved in visibility of an image without being made large-sized. <P>SOLUTION: A reflection/transmission switching panel 103 which switches between a reflection mode wherein light A made incident from the side of a liquid crystal display panel 101 is reflected to the liquid crystal display panel 101 and a transmission mode wherein the light from a backlight part 102 comprising a backlight prism 102_1 and a lamp light source 102_2 is transmitted to irradiate the liquid crystal display panel 101 according to whether a voltage VB is applied is arranged between the liquid crystal display panel 101 and the backlight part 102. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device including an image display panel for displaying an image.

  In an electronic device such as a digital camera or a mobile phone, an image display device including an image display panel represented by a liquid crystal display panel is preferably incorporated. In such an image display device, a technique for improving the visibility of an image displayed on the image display panel has been proposed. For example, Patent Document 1 improves the visibility of an image displayed on a liquid crystal display panel by adopting external light from above and irradiating the backlight with a lamp provided below. Technology has been proposed.

Further, in Patent Document 2, the display surface of the liquid crystal display panel is divided into a transmissive display area and a reflective display area, and when the surrounding brightness is less than a predetermined value, an image is displayed in the transmissive area. There has been proposed a technique for displaying an image in a reflective display area when the ambient brightness is a predetermined value or more.
JP 10-142599 A JP 2004-228722 A

  However, the technique proposed in Patent Document 1 requires both a configuration in which external light is introduced from above into the liquid crystal display panel and a configuration in which a lamp for irradiating backlight is provided below. Therefore, there is a problem that the configuration is complicated.

  The technique proposed in Patent Document 2 divides the display surface of the liquid crystal display panel into a transmissive display area and a reflective display area, and selectively selects one of the display areas according to the surrounding brightness. An image is displayed. That is, an image is displayed only on half of the display surface of the liquid crystal display panel. For this reason, in order to improve the visibility, a liquid crystal display panel having a relatively large size is required, so that there is a problem that the apparatus becomes large.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image display device having a simple configuration and an improved image visibility without increasing the size of the device.

The image display device of the present invention that achieves the above object provides:
An image display panel for displaying images;
A backlight unit that illuminates the image display panel from the back;
A reflection mode that is disposed between the image display panel and the backlight unit and reflects light incident from the image display panel side toward the image display panel according to control, and from the backlight unit. A reflection / transmission switching panel that switches to a transmission mode that transmits light and irradiates the image display panel is provided.

  The image display device of the present invention includes a reflection mode for reflecting light incident from the image display panel side toward the image display panel between the image display panel and the backlight unit according to control, and the backlight. A reflection / transmission switching panel that switches to a transmission mode that transmits light from the light unit and irradiates the image display panel is disposed. For this reason, when the surroundings are bright such as outdoors, the image can be clearly displayed on the image display panel by switching the reflection / transmission switching panel to the reflection mode. On the other hand, when the surroundings are dark, such as indoors, the reflection / transmission switching panel is switched to the transmission mode and the light from the backlight unit is irradiated to the image display panel, thereby clearly displaying the image on the image display panel. be able to. Therefore, the technique proposed in Patent Document 1 that incorporates external light from above and irradiates the backlight with a lamp provided below, or the liquid crystal display panel display proposed in Patent Document 2. Compared with the technique of dividing the surface into a transmissive display area and a reflective display area, the visibility of the image can be improved with a simple configuration and without increasing the size of the apparatus.

  Here, the reflection / transmission switching panel preferably uses a liquid crystal material.

  In this way, depending on whether or not a voltage is applied to the reflection / transmission switching panel, the orientation of the molecules of the liquid crystal material of the reflection / transmission switching panel can be changed. You can easily switch between mode and transparent mode.

  It is also a preferred aspect that the image display panel is a liquid crystal display panel.

  In this way, it is possible to provide an image display device that is reduced in power consumption and size.

  Furthermore, the light source constituting the backlight unit may be an LED or an EL element.

In addition, the image display device of the present invention is
An external light detection sensor for detecting the brightness of external light;
The reflection / transmission switching panel includes a switching control unit that switches to the reflection mode when the outside light is bright and switches to the transmission mode when the outside light is dark according to the detection result of the outside light detection sensor. Is also preferable.

  In this way, the reflection / transmission switching panel can be automatically switched between the reflection mode and the transmission mode according to the brightness of external light.

Furthermore, the reflection / transmission switching panel can freely adjust the reflectance when in the reflection mode,
The switching control unit switches the reflection / transmission switching panel between the reflection mode and the transmission mode according to the detection result of the external light detection sensor, and adjusts the reflectance when in the reflection mode. It is also preferable.

  Even if it is the same external light, the brightness of the external light differs between when it is sunny and when it is cloudy. Therefore, the visibility of the image can be further improved by adjusting the reflectance in the reflection mode according to the brightness of the external light.

  It is also preferable that the image display device is incorporated in an electronic device.

  Thus, an electronic device with a simple configuration and an improved image visibility can be provided without increasing the size of the apparatus. Here, the electronic devices include a digital camera, a mobile phone, a personal computer, a car navigation device, and the like.

  According to the present invention, it is possible to provide an image display device having a simple configuration and an improved image visibility without increasing the size of the device.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is an external perspective view of a digital camera in which the first embodiment of the image display device of the present invention is incorporated, as viewed obliquely from the front. FIG. 2 is an external perspective view of the digital camera of FIG. FIG.

  As shown in FIG. 1, a photographing lens 11 is provided at the center of the front surface of the digital camera 1. Further, an optical viewfinder objective window 12 and an auxiliary light emitting unit 13 are provided on the upper front of the digital camera 1. Further, a shutter button 14 and a slide type power switch 15 are provided on the upper surface of the digital camera 1.

  Further, as shown in FIG. 2, an optical viewfinder eyepiece window 16, a menu switch 17, an execution / screen change-over switch 18, and an image display device 100, which will be described in detail later, are provided on the back of the digital camera 1. It has been.

  FIG. 3 is a block diagram showing a circuit configuration of the digital camera shown in FIG.

  The digital camera 1 shown in FIG. 3 includes the photographing lens 11 and the auxiliary light emitting unit 13 described above. Further, the digital camera 1 includes a shutter unit 21, an image sensor (CCD) 22, an analog signal processing unit 23, a CPU 24 that comprehensively controls the operation of the digital camera 1, a drive circuit 25, an A / D (analog / digital) part 26 is provided. The drive circuit 25 includes a motor and a motor driver for driving the photographing lens 11 and the shutter unit 21, a timing light circuit for driving the auxiliary light emitting unit 13 and the image sensor 22, and the like.

  The subject light that has passed through the photographing lens 11 and the shutter unit 21 enters the image sensor 22. The image sensor 22 converts the incident subject light into an analog image signal, which is an electrical signal, and outputs the analog image signal to the analog signal processing unit 23.

  The analog signal processing unit 23 performs noise reduction processing or the like on the analog image signal output from the image sensor 22 and outputs the analog image signal subjected to the processing or the like to the A / D unit 26. The A / D unit 26 performs A / D (analog / digital) conversion processing on the analog image signal and outputs a digital image signal.

  The digital camera 1 also includes a digital signal processing unit 27, a temporary memory 28, a compression / decompression unit 29, and a built-in memory (or memory card) 30. The digital image signal that has been A / D converted by the A / D unit 26 and converted to digital is input to the digital signal processing unit 27. The digital signal processing unit 27 performs predetermined digital signal processing on the input digital image signal to complete image data representing the subject image of the current shooting scene, and temporarily stores it in the temporary memory 28. The data stored in the temporary memory 28 is compressed by the compression / decompression unit 29 and recorded in the built-in memory (or memory card) 30. Depending on the shooting mode, the compression process may be omitted and the recording may be performed directly in the built-in memory 30. In addition, the data stored in the temporary memory 28 is read out to the image display device 100, whereby an image of the subject is displayed on the image display device 100.

  Furthermore, the digital camera 1 is provided with the operation switch unit 31 including the menu switch 17 and the execution / screen changeover switch 18 described above, and the shutter button 14. When photographing, the operation switch unit 31 is operated to set a desired photographing state and the shutter button 14 is pressed. Next, an image display device 100 that is a first embodiment of the image display device of the present invention will be described with reference to FIGS. 3, 4, and 5.

  4 is a perspective view of the appearance of the image display device shown in FIG. 3 as viewed from diagonally above, and FIG. 5 is a cross-sectional view of the image display device shown in FIG.

  The image display device 100 includes a liquid crystal display panel 101 (corresponding to an example of the image display panel according to the present invention) for displaying an image, as shown in FIGS. In addition, the image display apparatus 100 includes a backlight unit 102 that illuminates the liquid crystal display panel 101 from the back. As shown in FIGS. 4 and 5, the backlight unit 102 includes a backlight prism 102_1 and a cylindrical lamp light source 102_2.

  Further, the image display apparatus 100 includes a reflection / transmission switching panel 103 disposed between the liquid crystal display panel 101 and the backlight unit 102. The reflection / transmission switching panel 103 uses a liquid crystal material, and a voltage VB is applied to the reflection / transmission switching panel 103. The reflection / transmission switching panel 103 reflects external light such as sunlight A incident from the liquid crystal display panel 101 side toward the liquid crystal display panel 101 according to whether or not the voltage VB is applied, and The panel is switched to a transmission mode in which the backlight from the backlight unit 102 is transmitted and irradiated on the liquid crystal display panel 101.

  As shown in FIG. 3, the image display device 100 includes an external light detection sensor 104 that detects the brightness of external light and a reflection / transmission switching panel 103 according to the detection result of the external light detection sensor 104. A switching control unit 105 that switches to the reflection mode when the outside light is bright and switches to the transmission mode when the outside light is dark is provided. Further, the image display device 100 is also provided with a connection cable 106 for connecting the image display device 100 to the circuit board of the digital camera 1, as shown in FIG. Here, the reflection mode and the transmission mode in the reflection / transmission switching panel 103 will be described.

  FIG. 6 is a diagram for explaining the reflection mode and the transmission mode in the reflection / transmission switching panel.

  FIG. 6A shows the reflection / transmission switching panel 103 in the state switched to the reflection mode. The reflection / transmission switching panel 103 includes a transparent electrode 103a and a liquid crystal material 103b. Here, the switch 105 a included in the switching control unit 105 is turned on, and the voltage VB is applied to the transparent electrode 103 a of the reflection / transmission switching panel 103. Here, the molecules of the liquid crystal material 103b have an approximately ellipsoidal shape, and the arrangement changes so that the major axis of the ellipsoid is parallel or oblique to the transparent electrode 103a when the voltage VB is applied. . For this reason, sunlight A which is external light reflects.

  On the other hand, FIG. 6B shows the reflection / transmission switching panel 103 in the state switched to the transmission mode. Here, the switch 105 a provided in the switching control unit 105 is turned off, and the voltage VB is not applied to the transparent electrode 103 a of the reflection / transmission switching panel 103. In this state, the arrangement changes so that the major axis of the ellipsoidal molecule of the liquid crystal material 103b is orthogonal to the transparent electrode 103a. For this reason, the backlight light B from the backlight part 102 permeate | transmits the liquid crystal material 103b.

  The image display apparatus 100 according to the first embodiment receives light A incident from the liquid crystal display panel 101 side according to whether or not the voltage VB is applied between the liquid crystal display panel 101 and the backlight unit 102. A reflection / transmission switching panel 103 that switches between a reflection mode that reflects toward the liquid crystal display panel 101 and a transmission mode that transmits light from the backlight unit 102 and irradiates the liquid crystal display panel 101 is arranged. . For this reason, when the surroundings are bright such as outdoors, the image can be clearly displayed on the liquid crystal display panel 101 by switching the reflection / transmission switching panel 103 to the reflection mode. On the other hand, when the surroundings are dark, such as indoors, the reflection / transmission switching panel 103 is switched to the transmission mode, and the liquid crystal display panel 101 is irradiated with light from the backlight unit 102, so that an image is also displayed on the liquid crystal display panel 101. It can be displayed clearly. Therefore, the technique proposed in Patent Document 1 that incorporates external light from above and irradiates the backlight with a lamp provided below, or the liquid crystal display panel display proposed in Patent Document 2. Compared with the technique of dividing the surface into a transmissive display area and a reflective display area, the digital camera 1 having a simple configuration and incorporating the image display device 100 is not enlarged and the image visibility is improved. be able to.

  The image display apparatus 100 includes an external light detection sensor 104 that detects the brightness of external light and a reflection / transmission switching panel 103 when the external light is bright according to the detection result of the external light detection sensor 104. Since the switching control unit 105 that switches to the reflection mode and switches to the transmission mode when the outside light is dark is provided, the reflection / transmission switching panel 103 is automatically switched between the reflection mode and the transmission mode according to the brightness of the outside light. Can be switched.

  Further, the reflection / transmission switching panel 103 can freely adjust the reflectance when in the reflection mode. The switching control unit 104 switches the reflection / transmission switching panel 103 between the reflection mode and the transmission mode according to the detection result of the external light detection sensor 104 and adjusts the reflectance when in the reflection mode. It is. For this reason, for example, the reflectance in the reflection mode can be automatically adjusted according to the brightness of external light that is different between when it is sunny and when it is cloudy. Therefore, the visibility of the image can be further enhanced.

  FIG. 7 is an external perspective view of an image display device different from the image display device shown in FIG.

  The same components as those of the image display apparatus 100 shown in FIG. 4 are denoted by the same reference numerals, and different points will be described.

  The image display device 200 shown in FIG. 7 is different from the image display device 100 shown in FIG. 4 in that the backlight unit 102 is replaced with a backlight unit 202. The backlight unit 202 includes a backlight prism 102_1 and a plurality of LEDs 202_1, ..., 202_n. The liquid crystal display panel 101 may be irradiated with light from the plurality of LEDs 202_1, ..., 202_n via the reflection / transmission switching panel 103.

  FIG. 8 is an external perspective view of an image display device different from the image display device shown in FIGS.

  The same components as those of the image display apparatus 100 shown in FIG. 4 are denoted by the same reference numerals, and different points will be described.

  The image display device 300 shown in FIG. 8 is different from the image display device 100 shown in FIG. 4 in that the backlight unit 102 is replaced with a white EL (electroluminescence) element 302 that emits white light. ing. In the white EL element 302, an organic light emitting layer is formed on a transparent substrate via a transparent electrode, and a reflective electrode is further formed on the organic light emitting layer. Here, when an electric field is applied between the transparent electrode and the reflective electrode, the phosphor in the organic light emitting layer emits light, and the emitted light is emitted toward the reflection / transmission switching panel 103. The liquid crystal display panel 101 may be irradiated with the light from the white EL element 302 through the reflection / transmission switching panel 103.

  9 and 10 are external perspective views showing the front surface and the back surface, respectively, of a mobile phone in which the second embodiment of the image display device of the present invention is incorporated.

  A cellular phone 2 shown in FIGS. 9 and 10 is a folding cellular phone including an upper part 2010 and a lower part 2020.

  As shown in FIG. 9, the upper part 2010 includes an image display device 2100 that is the second embodiment of the image display device of the present invention, a mouthpiece 2012 for emitting sound from a speaker, and an antenna 2013. It has been. Further, as shown in FIG. 10, the upper part 2010 is provided with a photographing lens 2014.

  On the other hand, as shown in FIG. 9, the lower part 2020 is provided with an operation unit 2021 including various operation buttons 2021_1 and 2021_2, and an earpiece 2022 for transmitting the voice of the speaker to the microphone.

  FIG. 11 is a block diagram showing a schematic configuration inside the mobile phone shown in FIG. 9 and FIG.

  The mobile phone 2 is provided with a photographing lens 2014 and a CCD solid-state image sensor 2031.

  The mobile phone 2 receives an image signal obtained by the CCD solid-state imaging device 2031 and performs various image processing such as gain adjustment, A / D conversion, white balance correction, and gamma correction. Is provided.

  Further, the mobile phone 2 is provided with an image display device 2100 shown in FIG. The image display device 2100 is smaller in size as compared with the image display device 100 described above, but the components and functions are the same.

  Further, the mobile phone 2 is provided with a recording unit 2033, and an image memory (not shown) provided in the recording unit 2033 by sending an image signal further compressed in the image processing unit 2032. 2) the image signal is recorded.

  Further, the mobile phone 2 includes an operation unit 2021 in which a large number of operation buttons are arranged and detection of operations of these operation buttons is performed, as shown in FIG. 9, and a control unit 2034. Based on the operation state of the operation button in 2021, the control unit 2034 controls operations of the image processing unit 2032, the recording unit 2033, the image display device 2100, and a communication unit 2035 described later.

  The microphone 2036 shown in FIG. 11 is arranged at a position inside the earpiece 2022 shown in FIG. 9 and picks up the voice of the speaker. The speaker 2037 is inside the mouthpiece 2012 shown in FIG. It is deployed in the system and emits voice sent from the other party.

  The communication unit 2035 is connected to the microphone 2036 and the speaker 2037, and further to the antenna 2013 shown in FIGS. 9 and 10, and is in charge of communication for the telephone under the control of the control unit 2034. The communication unit 2035 is also in charge of sending and receiving so-called e-mails, but since there is no direct relationship with the features of the present invention, further detailed description of the functions of the telephone and e-mail is omitted.

  The mobile phone 2 includes an image display device 2100 having the same components and functions as the image display device 100 of the first embodiment. For this reason, in this mobile phone 2, when the surroundings are bright, such as outdoors, the image can be clearly displayed by switching to the reflection mode. On the other hand, when the surroundings are dark, such as indoors, the image can be clearly displayed by switching to the transmissive mode and irradiating light from the backlight unit.

  FIG. 12 is an external perspective view of a notebook personal computer in which the third embodiment of the image display apparatus of the present invention is incorporated.

  The personal computer 3 includes a main body 3010 and an image display device 3100 that is the third embodiment of the image display device of the present invention. The image display device 3100 is larger in size than the image display device 100 described above, but the components and functions are the same, and thus the description thereof is omitted. The main body 3010 is provided with a keyboard 3030 and a touch pad 3040. The main body 3010 includes a CPU (central processing unit), a main memory (random access memory), a hard disk, a USB communication device, and the like, as will be described in detail later. Further, the main body 3010 has a CD-ROM loading port 3011 into which a CD-ROM or the like is loaded and a flexible disk loading port 3012 into which a flexible disk is loaded. A CD-ROM drive and a flexible disk drive for accessing a CD-ROM and a flexible disk loaded from the loading ports 3011 and 3012 are built in. In addition, the main body 3010 has a USB connection unit 3013 to which a USB connector compliant with the USB (Universal Serial Bus) standard is connected.

  FIG. 13 is a diagram showing a schematic circuit block of the personal computer shown in FIG.

  In the personal computer 3 shown in FIG. 13, the CPU 3001 that executes various programs and the programs stored in the hard disk device 3003 constituting the main body 3010 shown in FIG. 12 are read out and developed for execution by the CPU 3001. A main memory 3002, a hard disk device 3003 storing various programs and data, a flexible disk 3004_1 is loaded, a flexible disk drive 3004 accessing the loaded flexible disk 3004_1, and a CD-ROM drive 3005 accessing the CD-ROM 3005_1. A USB communication device 3006 that is connected to a device such as a digital camera and takes in image data from the device, and the image display device 3100 and keyboard 30 shown in FIG. 0, touch pad 3040 are provided. These are connected to each other via a bus 3015.

  The personal computer 3 includes an image display device 3100 having the same components and functions as the image display device 100 of the first embodiment. For this reason, in the personal computer 3, when the surroundings are bright, such as outdoors, the image can be clearly displayed by switching to the reflection mode. On the other hand, when the surroundings are dark, such as indoors, the image can be clearly displayed by switching to the transmissive mode and irradiating light from the backlight unit.

It is the external appearance perspective view which looked at the digital camera with which the image display apparatus of 1st Embodiment of this invention was integrated from the diagonally upper front. It is the external appearance perspective view which looked at the digital camera of FIG. 1 from back diagonally upward. It is a block diagram which shows the circuit structure of the digital camera shown in FIG. It is the external appearance perspective view which looked at the image display apparatus shown in FIG. 3 from front diagonally upward. It is sectional drawing of the image display apparatus shown in FIG. It is a figure for demonstrating the reflection mode and transmission mode in a reflection / transmission switching panel. It is the external appearance perspective view which looked at the image display apparatus different from the image display apparatus shown in FIG. 4 from front diagonally upward. It is the external appearance perspective view which looked at the image display apparatus different from the image display apparatus shown in FIG. 4, FIG. 7 from front diagonally upward. It is an external appearance perspective view which shows the surface of the mobile telephone with which 2nd Embodiment of the image display apparatus of this invention was integrated. It is an external appearance perspective view which shows the back surface of the mobile telephone with which 2nd Embodiment of the image display apparatus of this invention was integrated. It is a block diagram which shows schematic structure inside the mobile phone shown to FIG. 9, FIG. It is an external appearance perspective view of the notebook-type personal computer in which 3rd Embodiment of the image display apparatus of this invention was integrated. It is a figure which shows the schematic circuit block of the personal computer shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Cellular phone 3 Personal computer 11, 2014 Shooting lens 12 Optical viewfinder objective window 13 Auxiliary light emission part 14 Shutter button 15 Power switch 16 Optical viewfinder eyepiece window 17 Menu switch 18 Execution / screen changeover switch 21 Shutter unit 22 Image sensor (CCD)
23 Analog signal processing unit 24 CPU
25 Drive Circuit 26 A / D (Analog / Digital) Unit 27 Digital Signal Processing Unit 28 Temporary Memory 29 Compression / Expansion Unit 30 Built-in Memory (or Memory Card)
31 Operation switch unit 100, 200, 300, 2100, 3100 Image display device 101 Liquid crystal display panel 102, 202 Backlight unit 102_1 Backlight prism 102_2 Lamp light source 103 Reflection / transmission switching panel 103a Transparent electrode 103b Liquid crystal material 104 External light detection sensor 105 switching control unit 105a switch 106 connection cable 202_1, ..., 202_n LED
302 White EL (electroluminescence) element 2010 Upper part 2012 Speaking mouth 2013 Antenna 2020 Lower part 2021 Operation part 2021_1, 2021_2 Operation button 2022 Earpiece 2031 CCD solid-state image sensor 2032 Image processing part 2033 Recording part 2034 Control part 2035 Communication part 2036 Microphone 2037 Speaker 3001 CPU
3002 Main memory 3003 Hard disk device 3004 Flexible disk drive 3004_1 Flexible disk 3005 CD-ROM drive 3005_1 CD-ROM
3006 USB Communication Device 3010 Main Body 3011 CD-ROM Loading Port 3012 Flexible Disk Loading Port 3013 USB Connection Port 3015 Bus 3030 Keyboard 3040 Touchpad

Claims (8)

An image display panel for displaying images;
A backlight unit for illuminating the image display panel from the back;
A reflection mode that is disposed between the image display panel and the backlight unit and reflects light incident from the image display panel side toward the image display panel according to control, and from the backlight unit. An image display apparatus comprising: a reflection / transmission switching panel that switches to a transmission mode that transmits light and irradiates the image display panel.   The image display device according to claim 1, wherein the reflection / transmission switching panel uses a liquid crystal material.   The image display device according to claim 1, wherein the image display panel is a liquid crystal display panel.   The image display device according to claim 1, wherein the light source constituting the backlight unit is an LED.   The image display device according to claim 1, wherein the light source constituting the backlight unit is an EL element. An external light detection sensor for detecting the brightness of external light;
The reflection / transmission switching panel includes a switching control unit that switches to the reflection mode when the outside light is bright and switches to the transmission mode when the outside light is dark according to the detection result of the outside light detection sensor. The image display device according to claim 1. The reflection / transmission switching panel can freely adjust the reflectance when in the reflection mode,
The switching control unit switches the reflection / transmission switching panel between the reflection mode and the transmission mode according to the detection result of the outside light detection sensor, and adjusts the reflectance when in the reflection mode. The image display device according to claim 6, wherein:   The image display device according to claim 1, wherein the image display device is incorporated in an electronic device.

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