JP2007047493A - Optical transmission type display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that since a conventional foldable mobile phone has connections of signals made between a primary body part and a liquid crystal display part by running a flexible printed board through a hinge and so on, EMI from there causes noise to be mixed with a speech or disorders an image. <P>SOLUTION: An optical transmission type display system in which a light emitting element of blue is installed on the side of a primary body part and a back light unit coated with a fluorescent body properly emitting yellow light and a liquid crystal display panel are installed in a liquid crystal display part. A liquid crystal driving signal modulated by a specified system is applied to the light emitting element and introduced in a light transmission member, and the majority is introduced into the back light unit of the liquid crystal display part to emit white light in combination with the yellow light from the fluorescent body. Part of the white light is received in blue as it is by a photodetecting element provided in the liquid crystal display part and demodulated into a liquid crystal driving signal to drive a liquid crystal display unit, and color display is performed in combination with the white back light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device.

  In detail, for example, a liquid crystal display is provided for use in, for example, displaying mail or for an attached camera finder, and the main body provided with a dial button is folded when the mobile phone is carried. It concerns the configuration. Usually, a flexible printed board or the like has been adopted for the hinge part connecting the liquid crystal display part and the main body part. However, when the display hardly moves as in the case of reading conventional mails. In addition, the occurrence of EMI (electromagnetic interference) from the exposed wire portion is virtually negligible, and it does not cause disturbance of the image or mixing of noise into communication. With the widespread use of videophones that allow you to talk while watching the other person's facial expression on a liquid crystal display, it is also required to increase the communication speed on the image side.

As a result, the use of a thin coaxial cable, for example, a method of adopting a semiconductor laser or LED as a drive (display) signal for the liquid crystal display to convert it into an optical signal and preventing the occurrence of EMI has been proposed. Yes. Alternatively, a hinge part connecting the liquid crystal display and the main body part is made of transparent plastic or the like, and a signal from the main body part side to the liquid crystal display side is converted into light so as not to generate EMI. .
JP 2000-275444 A Special table 2004-508599 gazette

  In the above-mentioned conventional ones, in particular, Japanese Patent Application Laid-Open No. 2000-275444, no phosphor is added to the core, and R (red), G (green), and B (blue) phosphors are only added to the cladding. If a plurality of optical fibers to which either one is added are arranged in parallel so that white light can be obtained, a backlight of a liquid crystal display device can be obtained.

  However, the method disclosed in Japanese Patent Application Laid-Open No. 2000-275444 does not describe any part of the method for driving the display of the liquid crystal display with an optical signal. Therefore, when the liquid crystal display is driven, If the signal speed is increased, there is a potential problem that it cannot be avoided when an electric signal is used as usual.

  Japanese Patent Application Publication No. 2004-508599 discloses that optical data is sent from the main body to the liquid crystal display, and is presumed to be a so-called liquid crystal drive signal. Therefore, the backlight is not supplied from the main body side via the optomechanical hinge because the state in which electricity is supplied from the power source provided on the main body side is described in FIG. It is expected that a light source is installed on the liquid crystal display side, which complicates the configuration and increases costs.

  The present invention provides, as specific means for solving the above-described conventional problems, a light-emitting element that emits blue or ultraviolet light, a drive circuit that can output light including a desired signal from the light-emitting circuit, A backlight unit that includes a phosphor that emits yellow light and emits light by the light of the light emitting element to illuminate a display device, and a light receiving element that receives a part of the light from the light emitting element and converts the received light into an electrical signal And an optical transmission type display system provided with the above-mentioned electric signal is provided, and a subject is solved.

  According to the present invention, both the liquid crystal driving signal and the backlight are transmitted in the light state from the main body side through the hinge to the liquid crystal display unit. Passing in the light state, without emitting EMI, both the main unit and the liquid crystal display unit do not affect each other, the excellent effect of reducing noise and disturbance of the image during the call Play.

  Further, according to the present invention, as an optical signal in which the liquid crystal driving signal and the backlight are superimposed, the backlight is colored and the display signal is passed through the hinge part and separated on the liquid crystal display unit side so as to be suitable for each signal. With the configuration that performs the decoding process, all signals can be transmitted from the main unit to the liquid crystal display unit with a single optical fiber, combining the excellent effects of simplifying the configuration and reducing the weight of the operation. To play.

  Below, this invention is demonstrated in detail based on embodiment shown in a figure. What is denoted by reference numeral 1 in FIG. 1 is a mobile phone according to the present invention, and this mobile phone 1 is composed of two housings of a main body 2 and a liquid crystal display 3 and is not used. The hinge 4 that connects the two can be folded, and is further reduced in size and is convenient for carrying.

  1 shows only the main part 2 and the liquid crystal display part 3 related to the present invention in order to simplify the drawing and facilitate understanding, but in reality, a receiver, an oscillator, a transmitter Needless to say, parts required for a telephone, such as a telephone, a handset, or a push button dial, are provided respectively.

  First, on the main body 2 side, for example, when making a videophone call, there is a receiver (not shown) that receives an image of the other party's face transmitted simultaneously with the call. A blue light emitting device such as an LED or a semiconductor laser that modulates a received image into a waveform that can be easily reproduced by a liquid crystal display, which will be described later, by a modulation circuit 21 and emits light having a short wavelength such as blue light through a light emitting device driving circuit 22 23 is driven.

  Light from the light emitting element 23 driven as described above is efficiently taken in by using a lens 24 in an optical fiber 25 that passes through a hinge 4 that connects the main body 2 and the liquid crystal display 3. Then, it is sent to the liquid crystal display unit 3 side.

  For example, a backlight unit 31 formed by combining resin members or the like is installed in the liquid crystal display unit 3, and most of the light emitted from the optical fiber 25 is captured. A part of the light is incident on a light receiving element 32 such as a PD (Photo Diode), and is returned to the same electrical signal as that modulated by the modulation circuit 21 provided in the main body 2.

  The signal electrified by the light receiving element 32 is appropriately amplified by an amplifier 33 and demodulated into an image signal by a demodulating circuit 34 and then inputted from a liquid crystal driving circuit 35 to a liquid crystal display 36. An image is displayed on the liquid crystal display 36 by the image signal received by the liquid crystal display 36.

  2 to 4 show the configuration of the backlight unit 31 according to the present invention. A light distribution plate 25a having a suitable trapezoidal shape is attached to the end of the optical fiber 25 on the emission side. It is attached to the light guide plate 31a by an appropriate means such as sticking so that a part protrudes outward.

  Here, in the present invention, as shown in FIG. 2, the light receiving element 32 is provided on the portion of the light guide plate 31 a that protrudes from the liquid crystal display 36 (the portion that guides the light from the light distribution plate 25 a to the light guide plate 31 a). Is attached to receive a part of the light passing through the optical fiber 25 and convert the light into electricity. Therefore, most of the light from the light emitting element 23 enters the light guide plate 31a.

  In the present invention, as shown in FIG. 2 and FIG. 3 as well, fluorescent light that emits yellow light by receiving blue light, for example, in a matrix shape or a lattice shape, is provided on a necessary portion such as a bottom surface or a side surface of the light guide plate 31a. The body 31b is applied. Therefore, by setting the application amount and the application shape of the phosphor 31b to be appropriate, the light traveling from the light guide plate 31a to the liquid crystal display 36 (see FIG. 4) is a white color that is a mixture of blue and yellow. It becomes light.

  FIG. 4 shows the structure of the backlight unit 31. The upper surface of the light guide plate 31a is further covered with a phosphor sheet 31c that promotes color mixing of yellow and blue, if necessary, and is a diffusion film. The brightness is made uniform by 31d and the light collecting film 31e, and the liquid crystal display element 36 is placed on the upper surface thereof.

  As apparent from the above description, in the present invention, an image to be displayed on the liquid crystal display 36 and the white light source of the backlight unit 31 is obtained by modulating the transmitted image signal. Therefore, it is necessary for the modulation circuit 21 provided in the main body 2 to ensure the brightness as a backlight, and if the transmitted image is a moving image, smooth motion reproduction is also required.

  Considering this point, first of all, it is necessary that the modulation speed is faster than the response speed of the phosphor 31b. If the modulation speed is slow, the phosphor 31b produces light and dark, so-called flicker (flicker). The display becomes unsightly. Therefore, in the present invention, the modulation speed is set to be faster than 1 Mbps. Thus, by setting the modulation speed faster than the response speed of the phosphor 31b, the present invention can prevent problems such as flicker even if the backlight and the communication are combined.

  In addition, as described above, in the present invention, since the image to be transmitted is modulated to be a backlight, for example, the modulation degree is determined in proportion to the brightness of the image. In some cases, the brightness of the backlight also becomes bright and dark in accordance with it, which may be difficult to see. Therefore, it is preferable that the modulation circuit 21 provided in the main body 2 has an average signal intensity (duty ratio) that is always around 50%, for example, regardless of the brightness of the image. For example, a modulation method called 8B10B conversion is preferable.

  FIG. 5 shows a main part of another embodiment of the mobile phone 1 according to the present invention. In the previous embodiment, the signal was only one-way from the main body part 2 side to the liquid crystal display part 3. . However, for example, when a camera (self-portrait camera 5) for photographing his / her face when making a videophone is provided on the liquid crystal display unit 3 side, the liquid crystal display unit 3 moves in the direction of the main body unit 2. Signal flow is required.

  In such a case, the liquid crystal display unit 3 is provided with the self-portrait camera 5, the modulation circuit 37 and the light emitting element driving circuit 38 are also provided in the same manner as described above, and the red light emitting element 39, etc. The blue light emitting element 23 mounted on the main body 2 employs LEDs having different wavelengths and is incident on the optical fiber 25 from the liquid crystal display unit 3 side.

  The light receiving element 32 on the liquid crystal display unit 3 side receives light from the blue light emitting element 23 from the main body unit 1 side. By doing so, light of different colors passes through the optical fiber 25 in both directions. The light receiving element 32 on the liquid crystal display unit 3 side is provided with a red cutoff filter 32a. Further, the light receiving element 26 provided on the main body 2 side is provided with a blue cutoff filter 26a. With this configuration, the two-way communication of the present invention prevents mutual interference.

  In this way, bidirectional communication is possible with a single optical fiber 25, and in recent years, the function of a videophone, which is a function that is often installed, can also be achieved with a single optical fiber 25.

  As described above, according to the present invention, a pulse wave having a duty cycle of about 50% can be obtained at high speed by performing the liquid crystal drive signal by 8B10B conversion of 1 Mbps or more. Then, by using the pulse wave as it is for illumination, a backlight can be obtained, and by decoding a part thereof, an image signal for displaying an image on a liquid crystal display can be obtained, One LED can be used for both backlight and image display.

  Also, the light from the blue LED is transmitted through the optical fiber, and the light guide plate is coated with a phosphor that receives blue light and emits yellow light. And is not affected by a change in signal due to diffusion by the phosphor, so that an accurate image can be reproduced.

It is explanatory drawing which shows schematically the whole structure of the mobile telephone which concerns on this invention. It is a top view which shows the structure of the backlight unit which is the principal part of the mobile telephone which concerns on this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a top view which shows another embodiment of the backlight unit of the mobile telephone which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mobile phone 2 ... Main-body part 21 ... Modulation circuit 22 ... Light emitting element drive circuit 23 ... Blue light emitting element 24 ... Lens 25 ... Optical fiber 25a ... Light distribution plate 26 ... Light receiving element 26a ... Blue cut-off filter 3 ... Liquid crystal display part 31 ... Backlight unit 31a ... Light guide plate 31b ... Phosphor 31c ... Phosphor sheet 31d ... Diffusion film 31e ... Condensing film 32 ... Light receiving element 32a ... Red cut-off filter 33 ... Amplifier 34 ... Demodulation circuit 35 ... Liquid crystal drive circuit 36 ... Liquid crystal display 37 ... Modulation circuit 38 ... Light emitting element drive circuit 39 ... Red light emitting element 4 ... Hinge 5 ... Camera for self-portrait

Claims (6)

A light emitting element emitting blue or ultraviolet light;
A driving circuit capable of outputting light emission including a desired signal from the light emitting circuit;
A backlight unit that includes a phosphor that emits yellow light and emits light by light of the light emitting element to illuminate a display device;
A light receiving element that receives part of the light from the light emitting element and converts the received light into an electrical signal;
An optical transmission display system comprising the electrical signal. In the light output from the light emitting element,
The light transmission display system according to claim 1, comprising a signal for driving the display device. In an electronic device in which the main body and the liquid crystal display with backlight are integrated so as to be foldable with a hinge,
On the main body side, a blue or ultraviolet light emitting element is installed,
In the liquid crystal display unit, a backlight unit coated with a phosphor that emits yellow light at an appropriate portion and a liquid crystal display panel are assembled at predetermined positions.
The light emitting element is supplied with a liquid crystal driving signal modulated in a predetermined modulation method, emits light with a predetermined duty, is introduced into the light guide, and most of the light emitting element is connected to the liquid crystal display unit via the hinge. Introduced into the backlight unit to form a white light backlight with yellow light from the phosphor,
A part of the light receiving element provided in the liquid crystal display unit is also received in a blue or ultraviolet emission color, is appropriately amplified and demodulated into a liquid crystal driving signal,
The liquid crystal display is driven by the demodulated liquid crystal drive signal,
4. The optical transmission display system according to claim 1, wherein display is performed in combination with a white backlight from the backlight unit.   The optical transmission display system according to any one of claims 1 to 3, wherein the modulation signal is modulated by a method having a duty ratio of 50%.   5. The optical transmission display system according to claim 1, wherein the modulation signal is faster than a reaction speed of the phosphor.   The light receiving element provided on the liquid crystal display portion side of the light guide body is provided with a filter that blocks red or infrared light, and the end portion on the liquid crystal display portion side of the same light guide body is provided with red or red. A light emitting element for external light emission is provided, and a filter for blocking blue or ultraviolet light is provided on the main body side of the same light guide, thereby enabling bidirectional communication. Item 6. The optical transmission display system according to any one of Items 5 to 6.

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