JP2010054524A - Focus variable glasses - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focus variable glasses enhancing convenience by reducing size/weight of a circuit controlling a focal length of a liquid crystal lens. <P>SOLUTION: The focus variable glasses 1 includes a first liquid crystal lens 2a interposing a liquid crystal between a first electrode 25a and a second electrode 26a and a second liquid crystal lens 2b interposing a liquid crystal between a third electrode 25b and a fourth electrode 26b. The focus variable glasses 1 includes a voltage increasing circuit 6 and a driving circuit 7 generating driving signals applied to the first to the fourth electrodes by the voltage generated by the voltage increasing circuit 6. The driving circuit 7 has a first level shifter 8a applying a pulse signal to the first electrode 25a, a second level shifter 8b applying a pulse signal to the third electrode 25b, a third level shifter 8c applying a pulse signal to the second and the fourth electrodes 26a and 26b and a microcomputer 9 controlling retardation of pulse signals output from each level shifter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to variable focus glasses using a variable focus liquid crystal lens.

  Conventionally, a liquid crystal lens having a variable focal length by a voltage applied to a liquid crystal layer is known, and variable focus glasses using this liquid crystal lens have been proposed. (For example, refer to Patent Document 1). The variable focus glasses described in Patent Document 1 adjust the voltage applied to the liquid crystal lens by the value of the variable resistance, and control the focal length of the liquid crystal lens.

  In addition to the above, a configuration of variable focus glasses has been proposed in which control circuits for controlling the left and right liquid crystal lenses are separately provided so that the left and right liquid crystal lenses can be controlled independently (see, for example, Patent Document 2). ). By providing the liquid crystal lens drive circuit described in Patent Document 1 separately to the left and right liquid crystal lenses as in the variable focus glasses described in Patent Document 2, the left and right liquid crystal lenses can be controlled independently. It becomes possible.

Japanese Patent Laid-Open No. 61-177432 (2nd page, FIG. 2) Japanese Patent No. 2998233 (2nd page, FIG. 2)

  However, the above-described conventional technique has the following problems. The driving circuit for the liquid crystal lens described in Patent Document 1 adjusts the value of the variable resistor by operating a knob to control the focal length of the liquid crystal lens. For this reason, there has been a problem that the circuit for controlling the focal length of the liquid crystal lens becomes large and the convenience as variable focus glasses decreases.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems and to provide variable focus glasses with improved convenience by reducing the size and weight of a circuit for controlling the focal length of a liquid crystal lens.

  In order to solve the above-described problems and achieve the object, the variable focal-length glasses of the present invention adopt the configuration described below.

  The variable focus glasses of the present invention include a first liquid crystal lens in which a liquid crystal layer is sandwiched between first and second electrodes, a second liquid crystal lens in which a liquid crystal layer is sandwiched between third and fourth electrodes, A voltage circuit that generates a voltage; and a drive circuit that generates a drive signal to be applied to the first to fourth electrodes by the voltage generated by the voltage circuit. The drive circuit outputs a pulse signal to the first electrode. A first driver for applying, a second driver for applying a pulse signal to the third electrode, a third driver for applying a pulse signal to the second and fourth electrodes, and first to second And a control unit that controls the phase difference of each pulse signal output from the three driving units.

The variable focus glasses of the present invention are configured to control the focal length of a liquid crystal lens based on the phase difference between pulse signals applied to each electrode, and control the liquid crystal lens as compared with the prior art using a variable resistor or the like. The circuit can be reduced in size and weight.
The variable focus glasses of the present invention are configured to apply a pulse signal from a common driving unit to the second electrode of the first liquid crystal lens and the fourth electrode of the second liquid crystal lens. The circuit for controlling the lens can be further reduced in size and weight.

  Thus, the variable focus glasses of the present invention can improve the convenience as variable focus glasses by reducing the size and weight of the circuit for controlling the liquid crystal lens.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Description of Configuration: FIGS. 1 to 3]
First, the configuration of the variable focus glasses of the embodiment of the present invention will be described. FIG. 1 is a perspective view showing a configuration of variable focus glasses 1 of the present embodiment. As shown in FIG. 1, the varifocal glasses 1 of this embodiment include a frame 3, and a first liquid crystal lens 2 a and a second liquid crystal lens 2 b held by a lens frame 3 a of the frame 3. The first and second liquid crystal lenses 2a and 2b are lenses whose focal length can be controlled by a voltage applied to the liquid crystal layer, and are used for adjusting the visual acuity of the left and right eyes, respectively.

  Here, the configuration of the liquid crystal lenses 2a and 2b will be described. FIG. 2 is a cross-sectional view showing a configuration example of the liquid crystal lenses 2a and 2b. As shown in FIG. 2, the liquid crystal lenses 2a and 2b have a structure in which the liquid crystal 22 is sandwiched between opposing transparent substrates 20 and 21. As the liquid crystal 22, for example, homogeneous alignment type or vertical alignment type liquid crystal is used. A seal 23 is provided at the periphery between the transparent substrates 20 and 21 to prevent the liquid crystal 22 from leaking and to keep the liquid crystal layer at a predetermined thickness.

  Electrodes 25 and 26 are formed on the opposing surfaces of the transparent substrates 20 and 21, respectively. Further, a Fresnel lens structure 24 is formed on the electrode 26 of the transparent substrate 21. On the electrode 25 formed on the transparent substrate 20 and the Fresnel lens structure 24 formed on the transparent substrate 21, an alignment film for aligning liquid crystals is formed (not shown).

  The focal length of the liquid crystal lenses 2a and 2b can be changed by changing the refractive index of the liquid crystal 22 by the voltage applied to the electrodes 25 and 26 and switching the surface refraction effect at the interface between the Fresnel lens structure 24 and the liquid crystal 22. .

  Returning to the description of the overall configuration of the variable focus glasses 1. As shown in FIG. 1, the varifocal glasses 1 have a circuit housing portion 3b on one vine of a frame 3, and each circuit for driving the liquid crystal lenses 2a and 2b is housed in the circuit housing portion 3b. . Furthermore, the varifocal glasses 1 have a battery housing part 3c on the other vine of the frame 3, and a battery is housed in the battery housing part 3c. The variable focus glasses 1 include operation switches 4 a and 4 b for performing various operations on the vine of the frame 3.

  Next, the internal configuration of the variable focus glasses 1 of the present embodiment will be described. FIG. 3 is a block diagram of the variable focus glasses 1 of the present embodiment. As shown in FIG. 3, the varifocal glasses 1 of this embodiment include a battery 5 and a booster circuit 6 that boosts the output voltage of the battery 5 to a predetermined voltage (for example, 10 [V]). The variable focus glasses 1 of the present embodiment also include a drive circuit 7 that drives the liquid crystal lenses 2a and 2b.

The drive circuit 7 includes first to third level shifters 8a to 8c that perform signal voltage conversion. The first to third level shifters 8a to 8c are examples of first to third driving units, respectively. The drive circuit 7 includes a microcomputer 9 as a control unit that applies control signals to the first to third level shifters 8a to 8c. The microcomputer 9 is connected to the operation switches 4a and 4b.
Here, one electrode of the first liquid crystal lens 2a is referred to as a first electrode 25a, and the other electrode is referred to as a second electrode 26a. Also. One electrode of the second liquid crystal lens 2b is referred to as a third electrode 25b, and the other electrode is referred to as a fourth electrode 26b.

  The first level shifter 8a is connected to the first electrode 25a. The second level shifter 8b is connected to the third electrode 25b. Further, the third level shifter 8c is connected to the second electrode 26a and the fourth electrode 26b. The microcomputer 9 is supplied with a voltage from the battery 5, and the first to third level shifters 8 a to 8 c are supplied with a voltage from the booster circuit 6.

  The microcomputer 9 applies rectangular wave pulse signals 10a to 10c to the level shifters 8a to 8c based on signals from the operation switches 4a and 4b. Each level shifter 8a to 8c converts the pulse signal applied from the microcomputer 9 into the level of the voltage (for example, 10 [V]) applied from the booster circuit 6, and applies it to each electrode of the liquid crystal lenses 2a and 2b as a drive signal. Apply.

  That is, the pulse signal 11a is applied to the first electrode 25a from the first level shifter 8a. The pulse signal 11b is applied to the third electrode 25b from the second level shifter 8b. Further, the pulse signal 11c is applied from the third level shifter 8c to the second electrode 26a and the fourth electrode 26b. A method of driving the liquid crystal lenses 2a and 2b by the drive circuit 7 will be described in detail later.

[Description of Driving Method of Liquid Crystal Lens: FIG. 4]
Next, a method of driving the liquid crystal lenses 2a and 2b by the driving circuit 7 of the variable focus glasses 1 of this embodiment will be described. FIG. 4 is an explanatory diagram showing a pulse signal applied to each electrode of the liquid crystal lenses 2a and 2b and a voltage applied to the liquid crystal by the pulse signal.

  First, consider the first liquid crystal lens 2a. In FIG. 4, reference numeral 30 denotes a pulse signal 11a applied to the first electrode 25a, and reference numeral 31 denotes a pulse signal 11c applied to the second electrode 26a. Reference numeral 32 denotes a voltage applied to the liquid crystal of the first liquid crystal lens 2a by the first electrode 25a and the second electrode 26a.

The microcomputer 9 applies a pulse signal to the first level shifter 8a and the third level shifter 8c so that the pulse signal 11a and the pulse signal 11c have a predetermined phase difference P. As a result, as indicated by reference numeral 32, a voltage difference between the pulse signal 11a and the pulse signal 11c is applied to the liquid crystal.
Here, assuming that the ratio of time during which a predetermined voltage is applied to the liquid crystal (T1 / T2 in FIG. 4) is the duty ratio D and the maximum value of the voltages of the pulse signals 11a and 11c is Vm, the voltage applied to the liquid crystal. The effective value Ve is expressed by the following equation (1).

  When the phase difference P between the pulse signal 11a and the pulse signal 11c is 90 °, the ratio of time during which voltage is applied to the liquid crystal (duty ratio D) is 0.5. Further, when the maximum voltage Vm of the pulse signals 11a and 11c is 10 [V], the effective value Ve of the voltage applied to the liquid crystal is 7.07 [V] according to the equation (1).

The variable focus glasses 1 of the present embodiment change the effective value of the voltage applied to the liquid crystal by controlling the phase difference P between the pulse signal 11a and the pulse signal 11c, and the focal length of the first liquid crystal lens 2a. Can be controlled.
Similarly, the effective value of the voltage applied to the liquid crystal is changed by controlling the phase difference between the pulse signal 11b applied to the third electrode 25b and the pulse signal 11c applied to the fourth electrode 26b. Thus, the focal length of the second liquid crystal lens 2b can be controlled.

  As described above, the varifocal glasses 1 of the present embodiment are configured to control the focal length of the liquid crystal lens based on the phase difference between the pulse signals applied to the respective electrodes, compared with the prior art using variable resistors and the like. Thus, the circuit for controlling the liquid crystal lens can be reduced in size and weight.

  The variable focus glasses 1 of the present embodiment are configured to drive the liquid crystal by the difference between the pulse signals applied to the electrodes. For this reason, the level of the voltage generated by the voltage circuit to drive the liquid crystal lens can be made one, and the circuit for controlling the liquid crystal lens can be further reduced in size and weight.

  Furthermore, the variable focus glasses 1 of the present embodiment are pulsed by the third level shifter 8c common to the second electrode 26a of the first liquid crystal lens 2a and the fourth electrode 26b of the second liquid crystal lens 2b. The configuration is such that the signal 11c is applied, and the circuit for controlling the liquid crystal lens can be further reduced in size and weight.

  Thus, the variable focus glasses of the present invention can improve the convenience as variable focus glasses by reducing the size and weight of the circuit for controlling the liquid crystal lens.

It is a perspective view which shows the structure of the variable focus spectacles of this embodiment. It is sectional drawing which shows the structure of a liquid crystal lens. It is a block diagram which shows the structure of the variable focus spectacles of this embodiment. It is explanatory drawing which shows the pulse signal applied to each electrode of a liquid crystal lens, and the voltage applied to a liquid crystal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Variable focus spectacles 2a 1st liquid crystal lens 2b 2nd liquid crystal lens 3 Frame 3a Lens frame 3b Circuit storage part 3c Battery storage part 4a, 4b Operation switch 5 Battery 6 Booster circuit 7 Drive circuit 8a-8c Level shifter 9 Microcomputer 10a- 10c, 11a to 11c Pulse signal 20, 21 Transparent substrate 22 Liquid crystal 23 Seal 24 Fresnel lens structure 25, 26 Electrode 25a First electrode 26a Second electrode 25b Third electrode 26b Fourth electrode

Claims (1)

A first liquid crystal lens having a liquid crystal layer sandwiched between first and second electrodes;
A second liquid crystal lens having a liquid crystal layer sandwiched between third and fourth electrodes;
A voltage circuit for generating a predetermined voltage;
A drive circuit that generates a drive signal to be applied to the first to fourth electrodes by the voltage generated by the voltage circuit;
The drive circuit is
A first driver for applying a pulse signal to the first electrode;
A second driving unit for applying a pulse signal to the third electrode;
A third driver for applying a pulse signal to the second and fourth electrodes;
And a control unit that controls a phase difference between the pulse signals output from the first to third driving units.

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